Scientific Sessions List

SS001 ASLO Multicultural Program Student Symposium

Benjamin Cuker, Hampton University ([email protected])
Jeanette Davis, Science is Everywhere, LLC ([email protected])
Deidre Gibson, Hampton University ([email protected])

This session is for undergraduate and beginning graduate students, primarily affiliated with the ASLO Multicultural Program (ASLOMP). Students will present their research findings in a friendly atmosphere that encourages constructive criticism. Appropriate submission from students not affiliated with ASLOMP will also be considered. Students may present in this session only once. They are encouraged to present subsequent work in regular sessions.

Key words: Diversity, DEIJ, Students, Education, Inclusion

SS002 Undergraduate Research in Marine and Aquatic Sciences

David Fields, Bigelow Labs for Ocean Sciences ([email protected])
Lisa Rom, NSF ([email protected])

Research opportunities are increasingly offered to undergraduate students in an effort to help them understand marine and aquatic sciences and to offer them an opportunity to consider this field as a career. Undergraduates who have conducted research are invited to present their results in this general session that will highlight the wide variety of student research and provide opportunity for interested faculty to discuss your project with you. The Research Experience for Undergraduate (REU) program brings large numbers of undergraduate students to marine institutions for summer research programs, and students who have participated in REU programs are particularly invited to submit to this session. Students are not limited to this session, and we encourage any undergraduate student who wishes to submit an abstract to a specialized science session in the subject of their research to consider that option as well.

Key words: Undergraduate Research, REU

SS003 Coastal Aquatic Greenhouse Gas Fluxes Under Global Change

Judith Rosentreter, Center for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, Australia ([email protected])
Bradley Eyre, Center for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, Australia ([email protected])
Bryce Van Dam, Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany ([email protected])
Florian Roth, Baltic Sea Centre, Stockholm University, Stockholm, Sweden; Tvärminne Zoological Station, University of Helsinki, Hanko, Finland ([email protected])

Located between land and oceans, coastal aquatic ecosystems such as estuaries and coastal wetlands are dynamic ecosystems that connect the terrestrial, riverine, marine, and atmospheric biogeochemical cycles. They receive large inputs of terrestrial organic matter, and carbon and nitrogen inputs from upstream rivers, groundwater flows, and the ocean. Along the land-to-ocean aquatic continuum, carbon and nitrogen in coastal ecosystems are biogeochemically processed, sequestered in sediments, exported to the ocean, or exchanged with the atmosphere in form of the greenhouse gases carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Therefore, coastal aquatic ecosystems play an important role in regional and global greenhouse gas budgets. Anthropogenic impacts such as land-use changes and global warming can significantly alter these processes and enhance coastal greenhouse gas fluxes. This session aims to bring together the many different disciplines (e.g., biogeochemists, hydrologists, limnologists, oceanographers) to advance our understanding of greenhouse gas fluxes in coastal aquatic and coastal vegetated ecosystems, and how these fluxes may change in the future. We welcome observational, experimental, and modelling studies, especially those exploring the following themes: 1) spatial and temporal variability of coastal greenhouse gas fluxes, 2) drivers that control coastal sediment-water-air gas exchange, 3) advances in existing, and new techniques to determine coastal greenhouse gas fluxes, and 4) anthropogenic impact on coastal greenhouse gas fluxes and future projections under different climate change scenarios, including the impact of extreme events such as floods and fire.

Key words: estuaries, coastal vegetation, greenhouse gases, gas transfer, climate change

SS006 High Resolution Data for a Better Understanding of Marine Ecosystem Functioning and Ocean-Atmosphere Exchange Processes

Maria Calleja, University of the Balearic Islands (UIB) ([email protected])
Ralf Schiebel, Max Planck Institute for Chemistry- MPIC ([email protected])
Iris Hendriks, Mediterranean Institute of Advanced Studies - IMEDEA (CSIC-UIB) ([email protected])
Sara Ferron, University of Hawaii ([email protected])

The transport and cycling of green-house gases, aerosol particles, microbes, and nutrients between ocean and atmosphere is essential for understanding marine ecosystem functioning and has large impacts on global biogeochemical cycles. However, our ability to understand physical, chemical, and biological interactions in the ocean and how they influence, and are influenced by atmospheric processes has been historically and methodologically constrained. Current development and implementation of high-quality sensors and state-of-the-art technologies for the continuous in situ characterisation of the upper ocean and the lower atmosphere have dramatically increased the spatial and temporal resolution of our measurements. These new technological achievements, in combination with traditional measurements and experiments allow for in-depth integral interdisciplinary studies at different temporal (from diurnal to annual) and spatial (from microhabitats to global) scales. With this session, we address participants that are working with high resolution data and fine scale measurements to shed new light on open questions related to marine ecosystem functioning and ocean-atmosphere interactions. We are particularly interest in data that facilitate understanding of marine microbial communities’ response to ecological gradients and anthropogenic disruption, ocean productivity, and air-sea exchange of biologically active gases, aerosols and microbes, all of which plays a pivotal role in ocean carbon sequestration and Earth’s radiative balance. We hope that the session will inspire novel conceptual frameworks and will help identifying essential tools (or set of tools) to accurately monitor and study climate vulnerable processes.

Key words: high resolution data, ocean-atmosphere-exchange, marine microbes, ocean productivity, green-house-gases

SS007 Defining Drivers and Impact of Climatic Change and Other Anthropogenetic Stressors on Polar Ecosystems: for Long-Term Assessment of Resilience, Functionality and Services

Khuong Dinh, University of Oslo, Norway ([email protected])
Sissel Jentoft, University of Oslo, Norway ([email protected])
Joël Durant, University of Oslo, Norway ([email protected])
Chierici Melissa, Institute of Marine Research, Norway ([email protected])

Despite being among the most remote ecosystems on earth, Arctic and Antarctic are facing severe impacts from climate change and other anthropogenic disturbances. Such perturbations and stressors include ocean warming and acidification, altered nutrient input and oxygen content, sea ice loss and freshening as well as various types of pollution and harvesting, all environmental factors that could impact species distributions (such as poleward range shifts), as well as phenology, and demography which again could impact the overall ecosystem functioning and services. However, little is known about how polar species – and not at least the complex ecosystem dynamics – may respond to these key drivers/stressors. For instance, how will different environmental stressors, e.g. long vs. short term perturbations impact polar ecosystem(s)? Are some species more vulnerable than others? There is a great concern that stressors can interact synergistically to magnify each other effects on polar species, triggering the cascading effects on the entire polar food web. Furthermore, the strength and dynamics of these drivers/stressors across the spatial and temporal scales (e.g. seasonality vs. interannual variation) may result in a huge difference in ecological effects. Defining the current and past magnitude, variability and drivers of these stressors would be essential, and not at least how they impact complex polar ecosystem dynamics (at the species, population and individual level) will provide unique knowledge and understanding of the future polar ecosystems under rapidly changing environments. In this special session, we encourage contributions focusing on determining the key abiotic and biotic drivers/stressors – including ocean warming and acidification, altered nutrient input and oxygen content, sea ice loss and freshening as well as various types of pollution and harvesting – in the polar ecosystems both in terms of seasonality and interannual variability. Furthermore, studies on how these drivers interact and affect the polar species and ecosystem(s), from short-term (e.g. phenotypic plasticity) to long-term (evolutionary) responses such as alterations in population genetic/genomic structure, demography, as well as changes in trophic interactions and food web structure are welcome. Key topics of this special session are: Effects of ocean warming, marine heatwaves, acidification, pollution, and freshening on polar phytoplankton, invertebrates, fish, birds, and mammals across seasons. Effects of sea ice changes on the polar community structure and function. The transfer of the legacy and emerging contaminants in the polar food web and the ecological consequences. Atlantification of Arctic community under multiple stressors: changes in competition, niche partitioning and food web structure and dynamics. Phenotypic plasticity, transgenerational plasticity and genetic adaptations of polar species to key stressors/drivers. Impact of climate change and harvesting on population genetic/genomic structure and demography. The mismatch of different trophic levels caused by changes in the phenology. Advancements in developing new methods to assess changes in polar ecosystems: past, present, and future. Polar night ecology

Key words: Global climate change, Multiple stressors, Ocean acidification, Pollution, Arctic ecosystems resilience and recovery

SS008 Ecology Under Ice

Stephanie Hampton, Carnegie Institution for Science ([email protected])
Ted Ozersky, University of Minnesota - Duluth ([email protected])

Seasonal ice cover is an important structuring force for freshwater and marine ecosystems, affecting many physical, biogeochemical, and biological aspects of ecosystem function. Trends in ice extent and winter weather show large alterations to winter conditions over the past several decades, and forecasts suggest even more dramatic changes in winter conditions in the future. As the speed and magnitude of ice loss with climate change becomes increasingly clear, so does the recognition of the need for improved understanding of the ecological and socioeconomic impacts of this wholesale restructuring of seasonally frozen ecosystems. Today, both freshwater and marine researchers increasingly recognize winter and ice cover as important scientific frontiers - from biology and biogeochemistry, to the physical dynamics that structure the aquatic environment under ice. Expansion of winter research has been facilitated by large-scale collaboration and data synthesis as well as by advances in technology of the past two decades, including the development of in situ sensors and more highly resolved remote sensing. Yet, the pace of progress must further accelerate to anticipate the potential impact of these shifting seasonal cycles on biological communities, ecosystem processes, and biogeochemical budgets. Continued growth and evolution of winter research will generate critical information about aquatic dynamics and support model development that can be used to predict the consequences of an increasingly ice-free world. This session invites talks on all aspects of freshwater or marine ice-covered environments, with the goal of increasing dialogue across and within aquatic science disciplines. We welcome contributions ranging in scope and topic. Subjects for example may include remote sensing and other methodological advances for observing ecological patterns and processes, to in situ ecological studies and data syntheses, through the potential socioeconomic impacts of ice loss for humans whose lives and livelihoods have been associated with winter ice cover.

Key words: global change, ice cover, ecology

SS009 Biogeochemical Cycling Across the Land-Ocean-Continuum

Michael Seidel, University of Oldenburg ([email protected])
Patricia M. Medeiros, University of Georgia, USA ([email protected])
Sasha Wagner, Rensselaer Polytechnic Institute, USA ([email protected])
Nicholas D. Ward, Pacific Northwest National Laboratory, USA ([email protected])

Rivers transport large amounts of organic carbon, trace metals and nutrients from land to coastal oceans. At the interface between land and sea, elemental fluxes and transformations are strongly influenced by processes occurring across the continuum of rivers, wetlands, and estuaries. Increasing anthropogenic pressure (e.g., land use changes) and frequency of extreme events (e.g., hurricane landfalls, fires) are increasingly altering the sources and quality of organic carbon and nutrients exported to coastal ecosystems. Preserving the integrity of coastal aquatic systems is key as these systems provide critical ecosystem services to support societal development. It is therefore crucial to understand the biogeochemical connections of the carbon and nutrient cycles to ecosystem processes and microbial processing and how they are affected by humans. In our session we seek to bring together scientists from all areas of biogeochemistry that cut across boundaries, covering ecosystems from a wide range of latitudinal settings and spatiotemporal scales. Contributions that examine carbon and nutrient fluxes across the land-ocean-continuum, biogeochemical transformations in rivers, coastal wetlands, (subterranean) estuaries, and the fate of terrestrial carbon in the marine environment are particularly welcome. We also encourage submissions that seek to explain mechanisms underlying observed patterns in the distribution or rates of sedimentary, particulate, and dissolved organic matter transformation, their linkage to CO2 outgassing or uptake and microbial community composition across aquatic gradients, as well as approaches to quantify the response of coastal aquatic systems to environmental stressors in order to guide possible conservation and rehabilitation efforts.

Key words: coastal aquatic systems, rivers, organic matter and nutrient transformations, biogeochemistry, microbial community composition

SS010 Fungi in Aquatic Ecosystems: Structure, Function and Health

Michael Cunliffe, Marine Biological Association ([email protected])
Serena Rasconi, Université Savoie Mont Blanc, INRAE, CARRTEL ([email protected])
Federico Baltar, University of Vienna ([email protected])
Eva Breyer, University of Vienna ([email protected])
Hans-Peter Grossart, IGB-Berlin ([email protected])

Fungi thrive in aquatic habitats and have important roles in ecosystem functioning and health. Aquatic fungi participate in nutrient cycles, symbiosis, process organic matter and impact food webs by parasitising other aquatic organisms. Recent technological advances, including the application of stable isotope and omics-based approaches, have revealed a widespread functional and taxonomic diversity of aquatic fungi and fungal-like organisms (e.g. Oomycetes). A better understanding of aquatic fungi supports a more comprehensive view of aquatic ecosystems, including food web dynamics. This session covers all aquatic ecosystems, from freshwater ponds, lakes and rivers to estuaries, coastal marine waters, and the open deep ocean, ranging from tropical to temperate and polar regions including sea ice. The session is open to the full taxonomic diversity of aquatic fungi, including hyphal and yeast forms, aquatic lichens and zoosporic groups, such as chytrids, as well as fungal-like organisms (e.g. Oomycetes). We welcome those working both in the field and with model laboratory systems, across the range of aquatic functional roles (e.g. phytoplankton parasites, saprotrophs, symbionts) and diversity-focused studies (e.g. eDNA-based). Our aim is to stimulate a cross-ecosystem and cross-taxa synthesis of aquatic fungi in all their forms and functions, including showcasing recent technological advances to promote wider update across the aquatic mycology field, aquatic sciences in general, and across fundamental and applied interests.

Key words: Ecology, Biological limnology and oceanography, Fungi, Diversity, Functional ecology

SS011 Aquatic Ecosystems in the Face of Landscape Disturbances: From Biological Communities to Biogeochemical Cycles

Bianca Rodríguez-Cardona, Université du Québec à Montréal ([email protected])
Michaela de Melo, Université du Québec à Montréal ([email protected])
João Henrique Amaral, University of Florida ([email protected])
Ada Pastor, Universitat de Girona ([email protected])
Clara Ruiz González, Institut de Ciències del Mar ([email protected])

Aquatic systems are able to create a nexus of numerous ecosystem services, which are increasingly vulnerable to disturbances taking place in all compartments of the biosphere. Disturbance regimes are leading to fast and profound changes to the landscape with direct and indirect effects to adjacent water bodies. For example, human activities are increasingly altering aquatic ecosystems through direct changes in land use such as mining, urbanization, deforestation, agriculture, and infrastructure projects (eg. hydroelectric dams). Additionally, a variety of natural disturbances including abiotic (erosion, land-slides, wildfires, flooding, drought, hurricanes) and biotic origins (e.g.forest infestation/disease), which their regime and magnitude can also be altered by human/activities are also impacting terrestrial-aquatic linkages. These disturbances in the terrestrial environment are likely to impact the amount and quality of terrestrial materials as well as terrestrial microorganisms transported to nearby waters. Thus, the change in flux of carbon, nutrients, and other elements from land to aquatic ecosystems might, in turn, influence aquatic microbial communities and trophic interactions. However, to what extent all this may have consequences on the biogeochemical cycling, structure and functioning of aquatic ecosystems, is very poorly understood. This session invites any theoretical or empirical studies about the effects of landscape anthropogenic or natural disturbances (alone or in combination with other environmental disturbances) on freshwater and marine ecosystems, with focus on biogeochemical cycles and biological communities (metabolic activity, species composition and interactions). We aim at bridging the disconnect between terrestrial and aquatic processes across variable spatial and temporal scales and provide insight into the environmental, ecological, and social consequences of land effects on aquatic environments.

Key words: Disturbance, Terrestrial-aquatic interface, Freshwater, Coastal, Biogeochemical cycles

SS012 The Next Frontier: Linking Remote Sensing, Data Science, Modeling, Open Science, and the Aquatic Sciences To Understand Emergent Properties of Aquatic Systems

Michael F Meyer, U.S. Geological Survey ([email protected])
Kate C Fickas, U.S. Geological Survey ([email protected])
Robert Ladwig, University of Wisconsin - Madison ([email protected])
Rachel M Pilla, Oak Ridge National Laboratory ([email protected])
Simon N Topp, U.S. Geological Survey ([email protected])

In times of an increasingly uncertain climate and growing demand for water resources, there is a need for assessing how aquatic systems worldwide are responding to co-occurring human and climatic disturbances. Over the past half century, remote sensing technology, high performance and cloud computing infrastructure, machine learning techniques, open data practices, and widened training in computer programming have created extraordinary opportunities to expand aquatic science research across spatial and temporal scales. Remote sensing of chlorophyll concentrations has enabled near-global monitoring of algal blooms. Data science and machine learning methods have empowered the prediction of water temperatures and water quality dynamics, while also informing management actions. Process-based models have improved our understanding of lake and reservoir mixing dynamics, which can be consequential for ecosystem regime shifts. Open data practices have increased the amount of publicly available data that many calibration and validation techniques ultimately demand. The nexus of data science, remote sensing, modeling, and open science in the aquatic sciences is a dynamic, rapidly progressing space, where novel aquatic science questions can be posed at unprecedented scales. Given these developments, there can be a lingering question of “What’s next?” To date, many aquatic remote sensing, modeling, and data science efforts have focused on measuring or predicting individual parameters or variables. While these individual efforts are herculean initiatives, a ripe frontier for this nexus is linking limnological, hydrological, oceanographic, and ecological processes and principles with remote sensing, data science, and modeling techniques to understand fundamental emergent properties of aquatic systems and inform monitoring at local-to-global and daily-to-decadal scales. Additionally, the increase of open science and data democratization brings the potential for a more diverse, inclusive, and accessible scientific community and more holistic research.; To build a conversation around multifaceted developments in remote sensing, data science, modeling, and the aquatic sciences, this session invites contributors to share how they use one or a combination of remote sensing, data science, modeling, or open science practices to expand the fields of limnology, oceanography, hydrology, or ecology. We envision this session will host a range of presentation topics, including but not limited to novel methods for atmospheric corrections, scaling of cloud and other high-volume computing environments, assessing water quantity and quality across spatial and temporal scales, quantifying long-term changes in stratification dynamics, and applying data-intensive techniques for basic and applied research questions. While submissions may stem from methodological and technical hurdles encountered in remote sensing and data science fields, we challenge submissions to focus on how their efforts de-silo the aquatic sciences from the remote sensing and data science arenas. We enthusiastically encourage submissions by early career researchers as well as by researchers from BIPOC, LGBTQIA+, and other marginalized identities. An intentional focus on research that breaks down barriers to entry for underrepresented scientists in the fields of remote sensing and aquatic data science, through open science, will yield insight into the power and potential of the next frontier in emergent properties of aquatic systems.; We welcome full-length oral presentations, 5-minute “lightning” presentations, and posters.

Key words: Remote Sensing, Data Science, Machine Learning, Synthesis, Emergent Properties

SS013 Microbial Life and Elemental Cycling in the Deep Ocean: Progress on Processes and Players

Ronnie N. Glud, University of Southern Denmark ([email protected])
Chie Amano, University of Vienna ([email protected])
John Paul Balmonte, University of Southern Denmark ([email protected])
Gerhard J. Herndl, University of Vienna ([email protected])

Microbial life in the deep ocean thrives despite low temperatures, high pressures, and seemingly scarce sources of organic matter. The identities of microorganisms that comprise deep water and sediment communities, the biogeochemical processes they carry out, and their adaptations have been focal points of deep-sea research, with substantial progress in recent years owing to new technologies and investigations in underexplored deep settings. To synthesize recent progress and gain insight from new inquiries, we broadly invite studies that investigate processes mediated by – and those that sustain – microbial communities in the deep ocean. We will focus on organisms ranging from viruses to microbial eukaryotes and welcome perspectives from any analytical tools, methods, and approaches employed. The topics covered can include (but are not limited to) the following: microbial biogeochemical cycles; community structure, connectivity, and assembly; adaptations to high pressure and low temperature; fluxes of matter to the deep sea; viral infections and influences on microbial ecology and biogeochemistry. We also strongly welcome studies that may focus on processes from other parts of the ocean (e.g. epi- and mesopelagic, coastal environments, etc.), but which are nevertheless crucial to our understanding of microbial processing in the deep sea (e.g. through surface-to-deep transfer of sinking particles, pelagic-benthic coupling, mass wasting events, etc.). Finally, we encourage submissions on developing or newly-developed technologies that facilitate progress in deep sea microbial and biogeochemical research.

Key words: deep sea, microbial communities, biogeochemistry, adaptations, material transport

SS014 Atmospheric Supply of Soluble Trace Elements and Isotopes: Advances and Challenges

Rachel Shelley, University of East Anglia ([email protected])
Susanne Fietz, University of Stellenbosch ([email protected])
Alex Baker, University of East Anglia ([email protected])
Morgane Perron, CNRS - Laboratoire des sciences de l’Environnement MARin (LEMAR) ([email protected])

Approximately 50% of primary production occurs in the oceans. Iron (Fe), and other trace elements (TEs), are essential micronutrients as primary producers require Fe for carbon (C), nitrogen (N) and phosphorus (P) acquisition. However, in vast areas of the ocean, marine production is limited by insufficient Fe availability or by the scarcity of a combination of two or more micronutrient TEs. Therefore, the availability of TEs, particularly Fe, exerts a fundamental control on marine biological activity, from bacterial and primary productivity of phytoplankton through to the fisheries which ultimately depend on them. Micronutrient TEs thereby support marine ecosystem services and CO 2 sequestration in most ocean basins and over various timescales. Atmospheric deposition provides an external source of TEs to the surface ocean. Large deposition events can relieve micronutrient (co-)limitation through the partial dissolution of TEs from aerosols. However, large deposition events are sporadic and currently poorly understood. This presents a challenge for predicting how ocean ecosystems will respond to changes in soluble TE fluxes in the future. Therefore, it is vital that models are able to represent and reproduce current and past TE distributions in the ocean in order to improve predictive capabilities. A further challenge is understanding how the different chemical compositions and atmospheric processing of natural and anthropogenic particles impacts TE solubility following deposition to seawater and, thus, the ability of biota to assimilate the TEs. Although mineral dust is proportionally the largest source of aerosol TEs to the global ocean, anthropogenic and wildfire aerosols have a greater ability to dissolve in seawater. This results in the liberation of a larger fraction of bioaccessible TEs, due to several factors. Following aerosol deposition, new resource competition among primary producers can alter community structure and dynamics, which influences the capacity of the ocean to sequester CO 2 , fix nitrogen and produce biological gases which readily form cloud condensation nuclei. All three features exert crucial climate feedbacks. The degree to which autotrophs or heterotrophs are stimulated or suppressed by atmospheric deposition depends on the physicochemical form in which atmospheric TEs are delivered to seawater and on the initial nutrient status of the water. Again, highlighting the need for a more integrated understanding of biogeochemical cycling including the atmospheric component. In this session, we would like to invite submissions from novel experimental and modelling work on TE biogeochemistry at the air-sea interface. Presentations addressing key research questions including the controls on dissolution and/or uptake of aerosol TEs, as well as modelling estimates of aerosol TE deposition fluxes in the present, past, or future are welcomed. Studies focusing on the Southern Hemisphere and other historically under-studied oceanic regions are particularly encouraged. This session has broad applicability to different research communities, e.g., climate change, human health, fisheries, and paleoclimate. As such, we welcome cross-disciplinary submissions which address questions about the flux of TEs across the air-sea interface and the associated impact on marine ecosystems.

Key words: aerosols, soluble trace elements, air-sea interface, micronutrients, biogeochemistry

SS015 Deoxygenation in the Past, Present and Future Ocean

Caroline P. Slomp, Utrecht University ([email protected])
Marilaure Grégoire, University of Liege ([email protected])
Andreas Oschlies, GEOMAR Helmholtz Centre for Ocean Research Kiel ([email protected])
Peter Croot, University of Galway ([email protected])

The ocean is currently rapidly losing oxygen. In the open ocean, this change is mostly attributed to global warming and associated circulation changes, whereas in coastal waters, anthropogenic eutrophication is typically the key driver. Ocean deoxygenation has major impacts on marine life and on the cycling of bio-active elements such as carbon, nitrogen, phosphorus, sulfur and trace metals, that, in turn, can feed back on ocean deoxygenation. Thus, for example, oxygen loss can reduce the habitat of pelagic and benthic animals and can greatly enhance rates of marine nitrogen removal and amplify phosphorus recycling. Strongest effects have so far been reported for Oxygen Minimum Zones and coastal systems that are naturally sensitive to hypoxia linked to water column stratification, which might be affected by sampling biases in the heavily undersampled ocean. Ocean deoxygenation has frequently occurred in Earth’s past, thereby also impacting the evolution of marine organisms. In this session, we invite presentations related to all aspects of deoxygenation in the past, present and future ocean. Hence, we invite modeling, field and laboratory studies on the drivers and consequences of loss of oxygen in marine waters on all spatial and temporal scales. This includes, for example, observational studies in the modern coastal and open ocean, results of Earth System Modeling and reports on the development and application of redox proxies for all relevant periods of Earth’s history (e.g. Oceanic Anoxic Events).

Key words: oxygen, seawater, eutrophication, ocean circulation, global warming

SS018 Mixoplankton: The New Paradigm Testing the Resilience of Our Science in the UN Ocean Decade

George McManus, University of Connecticut ([email protected])
Luciana Santoferrara, Hofstra University ([email protected])
Beatriz Reguera, Instituto Español de Oceanografia ([email protected])
Aditee Mitra, Cardiff University ([email protected])

The past decade has seen the recognition of diverse plankton functional groups in marine ecology, beyond the classical phyto- and protozoo-plankton. The new mixoplankton paradigm incorporates into the food web those protist plankton that engage in photo-phago-trophy to satisfy their nutritional needs. Mixotrophy, as the coupling of photo-osmo-mixotrophy, has been researched within phytoplankton, and especially associated with Harmful Algal Bloom (HAB) events, for decades. However, there are major differences between the photo-osmo-mixotrophic phytoplankton and the photo-phago-mixotrophic mixoplankton. Mixoplankton actively hunt, kill and eat thus removing competitors from the environment, acquiring nutrients, and directly impacting trophic dynamics. Further, we now know that various exemplar ‘phytoplankton’ and ‘protozooplankton’ species – such as the food web supporting Tripos sp. ( Ceratium ), the ecosystem disruptive bloom forming green Noctiluca scintillans , the HAB forming species within the Alexandrium , Prorocentrum , Dinophysis genera - are all in fact mixoplankton. The base of the marine food web is not as traditional science describes, raising profound questions about how we project climate change and allied anthropogenic events in reshaping the marine ecosystem and thence how we manage resources. Methods (field, laboratory, modelling) developed for phytoplankton and protozooplankton need to be adapted for mixoplankton science - where required, new in vivo as well as in silico methods need to be developed. Thus, environmental monitoring needs new methods to replace current sampling protocols which are known to selectively destroy groups of mixoplankton; ecosystem and management models need to properly reflect mixoplankton ecophysiology. To address such challenges, we recently formed the SCOR Working Group 165 – ‘MixONET’. An overarching aspiration of MixoNET is to extend the mixoplankton paradigm beyond blue-sky research to real-life applications such as environmental monitoring, management, policy making, and education. Changes in marine ecosystems with climate change, which will inevitably see changes in mixoplankton (including HAB) populations, will test the resilience of our science as much as of nature. In this session we invite people from all affected sectors to share their ideas and results on this challenging and timely topic.

Key words: mixoplankton, osmotrophy, harmful algal blooms, climate change, food security

SS019 Benthic Metabolism and Fluxes in Shallow Coastal Ecosystems – Controls and Responses to Environmental Stressors

Carmen Castro, Instituto de Investigaciones Marinas (CSIC) ([email protected])
Mariña Amo-Seco, Instituto de Investigaciones Marinas (CSIC) ([email protected])
Peter Berg, University of Virginia (USA) ([email protected])

Benthic metabolism is critically important to evaluate the trophic status and thus, the environmental health of shallow coastal ecosystems. Global warming and coastal eutrophication are altering the benthic metabolism and carbon cycling, which can lead to disturbances of the ecosystem services in coastal areas. However, there are major uncertainties in the benthic metabolism estimates due to the high heterogeneity of coastal regions, and the large variability of metabolic rates at different time scales. This session invites contributions that present new ecological results on benthic metabolism and fluxes, and their controls and responses to environmental changes and stressors in near-shore aquatic systems. This session also welcomes presentations on methodological advances for in situ metabolic and flux measurements and inverse modeling approaches that advance data interpretation.

Key words: benthic metabolism, coastal ecosystems, fluxes, environmental stressors, ecosystem services

SS020 New Insights on The Methane and Nitrous Oxide Cycles from Freshwater and Marine Ecosystems Under Changing Climate

Elizabeth Leon-Palmero, University of Southern Denmark & Princeton University ([email protected])
Sina Schorn, Max Planck Institute for Marine Microbiology ([email protected])
Bess B. Ward, Princeton University ([email protected])
Jana Milucka, Max Planck Institute for Marine Microbiology ([email protected])
Carsten J. Schubert, Swiss Federal Institute of Aquatic Science and Technology (EAWAG) ([email protected])

Methane (CH4) and nitrous oxide (N2O) are important greenhouse gases with a warming potential 34 and 298 times higher, respectively, than that of CO 2 on a 100-year timescale. Both gases increased rapidly in atmospheric abundance during the last decade, with a significant portion of the CH4 and N2O coming from freshwaters and marine ecosystems. In aquatic environments, the production and consumption of CH 4 and N 2 O is tightly controlled by microbial activity. Microbes performing these reactions inhabit both water column and sediments, attach to particles and live in symbiosis with animals. Their activity occurs under both oxic (e.g., methane oxidation, ammonia oxidation) as well as anoxic conditions (e.g., methanogenesis, anaerobic methane oxidation, denitrification). However, recent findings challenge many traditional ideas about CH 4 and N 2 O cycling. For example, CH 4 is also produced in oxic environments by various bacteria and phytoplankton, while N 2 O is consumed in oxic conditions by oxygen tolerant denitrifying or dinitrogen fixing microbes. At the same time, not only microbes, but abiotic reactions may be also responsible for greenhouse gas production. Aquatic ecosystems are currently under tremendous pressure due to globally increasing temperatures and nutrient loads, with a concomitant decrease in oxygen levels. Therefore, the response to these changing conditions may affect the production and consumption of CH 4 and N 2 O in these ecosystems. In this session, we aim to combine our knowledge of microbial greenhouse gas metabolism, including the production, consumption, and fluxes of methane and nitrous oxide in aquatic environments, as well as the underlying microbial communities and interactions among them, in order to assess the controlling factors for greenhouse gas fluxes in the light of climate change. We therefore encourage contributions that address the biogeochemistry and microbiology to all aspects of ongoing experimental, field and modeling work, including molecular-based or isotope labelling studies, as well as flux quantification.

Key words: Methane, Nitrous oxide, Biogeochemistry, Microbiology, Marine/Freshwater

SS021 Responses of Boreal and Arctic Inland Waters to Changing Climatic and Landscape Conditions

Robert Striegl, US Geological Survey, Water Mission Area, Earth System Processes Divsion, Boulder, Colorado, USA ([email protected])
Suzanne Tank, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada ([email protected])
Jan Karlsson, Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden ([email protected])

Lakes, rivers and streams in northern boreal and arctic regions are subject to ongoing changes in water distribution and availability, organic and inorganic chemical loading and processing, and ecosystem structure and composition in response to changing climatic and landscape conditions. Multiple drivers of change include (but are not limited to) warmer temperatures, permafrost thaw, and extended ice-free seasons; altered precipitation and hydrology; and changing flora, fauna, wildfire, and land use. Circumboreal and panarctic understanding of ongoing and projected change in aquatic systems requires detailed process information collected at representative locations, as well as the ability to scale that information spatially across vast unmeasured areas and forward through time. Hence, there is a need to integrate quantitative process-study results and long-term monitoring data with spatially explicit synoptic and remotely sensed information in order to project future conditions. This session welcomes presentations that integrate current and past measurements of aquatic ecosystems with spatial and temporal drivers of change to improve broad scale understanding of current conditions and future trajectories of change in northern inland waters. Related topics include terrestrial release and aquatic biogeochemical processing of carbon, nutrients, suspended solids, and toxins; change in water and materials exports to receiving waters and coastal areas; burial in sediments and atmospheric gas exchange; change inland water surface area and distribution; and change in aquatic community structure and dynamics.

Key words: arctic, boreal, climate change, hydrologic change, aquatic biogeochemistry

SS022 Tackling Food Web Complexity: Exploring the Role of Omnivory in Linking Disparate Trophic Pathways in Marine and Freshwater Ecosystems

Ryan Woodland, Uni MD Centr for Env Science, Chesapeake Biological Laboratory ([email protected])
Jason Stockwell, The University of Vermont ([email protected])
Nina Santos, Uni MD Centr for Env Science, Chesapeake Biological Laboratory ([email protected])

Omnivory is a central facet of the food webs in marine and freshwater systems, yet identifying and quantifying the extent of omnivory and its impact on ecosystem function are often difficult. From unicellular mixotrophs to large, mobile consumers, difficulties stemming from methodological or logistical constraints have historically posed significant barriers to studying omnivory in natural systems. New genetic, biochemical, and modeling tools and techniques are now available that can help shed light into the importance of natural complexity such as pulsed feeding events, differentially digestible prey, ontogenetic niche shifts, and cryptic life histories. At the same time, approaches that involve classic experimental methods remain an invaluable tool for developing quantitative rate and process information that can be used to test hypotheses, inform prey selection dynamics, and parameterize multispecies models. This session brings together presentations that explore the identity, extent, and role of omnivores in marine and freshwater food webs. We are particularly interested in research that explores how omnivory serves to couple disparate trophic pathways, and what the consequences (if any) are for system dynamics. Researchers exploring the dimensions of omnivory at biological scales ranging from the individual to the (sub)population, or scaling the consequences of omnivory to community dynamics or ecosystem function are encouraged to submit presentations to this session. We welcome studies that use cutting-edge techniques such as genomics/metabarcoding, compound-specific stable isotopes, Bayesian mixing models and others, as well as studies grounded in more traditional experimental and observational approaches.

Key words: predator-prey dynamics, trophic, food web, connectivity, mixotrophy

SS023 From Cells to Satellites: Current and Future Directions of Detecting Environmental Change in Aquatic Ecosystems

David Barrett, University of Calgary ([email protected])
Ana Carolina Sinigali Alves Lima, University of Calgary ([email protected])
Frederick Wrona, University of Calgary ([email protected])

In most watersheds, ecosystem changes are responses to complex multiple pressures, including anthropogenic and natural environmental factors and their joint effects/interactions. Managing and monitoring aquatic systems under this scenario remains a complex task for researchers, managers and policymakers. Despite considerable growth in understanding the consequences of multiple environmental stressors on aquatic ecosystem structure and function in the last decade, significant knowledge gaps and challenges remain in developing approaches to detect, quantify and manage stressor interactions in the real world. As the rate of landscape disturbance and climate change continues to increase globally, it is urgent to develop new integrated methods to diagnose multiple stressors and assess ecological indicators' responses to them. Understanding these effects in terms of changes in the ecosystem’s diversity and function is especially important, as well as developing effective management actions, as water stress is a worrying issue internationally. Aquatic monitoring efforts are used worldwide to gather substantial amounts of data on environmental change at a variety of temporal and spatial scales. These data can have multiple sources (i.e., remote sensing, in-situ sampling, genomic, Traditional Knowledge from local and Indigenous communities, high-frequency monitoring equipment, citizen science, etc.). However, their utilization in a coordinated manner to assess environmental change has been limited. It is now essential to determine how monitoring and evaluation programs incorporate measures to understand multiple stressors' effects. To move forward, it is crucial to identify key physical-chemical drivers (i.e., hydrology, water quality, climate, etc.) which directly and indirectly affect biological/ecological receptors (i.e., from cells to ecosystems), as well as the likelihood of stressor exposure, recovery potential/resilience, or vulnerability of the endpoints. Designing the best path forward for observing aquatic ecosystems requires building robust monitoring programs that allow us to address the connection between all dimensions involved: physical, biological, and social. This session aims to bring together researchers and practitioners from a range of geographic regions and programs to share knowledge and experiences on the effectiveness and challenges associated with implementing monitoring programs addressing multiple stressor impacts, including policy and decision-making hurdles they faced. A focus will be placed on solutions and examples of successful implementation and emerging approaches/technologies for monitoring systems. Discussions around the importance of a variety of experimental and in-situ studies and monitoring, with a specific focus on the critical step of translating results and outcomes to monitoring design, adaptive monitoring and policy, are encouraged. We welcome submissions across all aquatic environments (lakes, oceans, deltas, etc.) and geographical regions. The outcomes of this session will help inform ongoing and future effective implementations of monitoring and environmental change programs and to address contemporary and future aquatic environmental issues at an ecosystem/watershed scale.

Key words: Monitoring, Multiple Stressors, Adaptive Monitoring Frameworks, Technology, Program design

SS024 Down the Drain and Down the River: The Transport, Fate and Impact of Micro- and Nanoplastic on Their Way to the Oceans

Zoraida Quiñones-Rivera, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard - Lyon 1 ([email protected])
Stefan Krause, School of Geography, Earth and Environmental Sciences, University of Birmingham ([email protected])
Bjoern Wissel, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard - Lyon 1 ([email protected])
Laurent Simon, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard - Lyon 1 ([email protected])

Description: With the arrival of the Anthropocene, society faces unprecedented challenges in environmental pollution and risk management. Despite many technological benefits of living in the “plastic age”, there are pervasive environmental and public health impacts resulting from the durability, unsustainable use and inappropriate waste management of plastics. In addition to the environmental impacts of larger plastic objects there is growing concern that microplastics (particles < 5mm) pose an even greater environmental risks as they can be toxic, either directly or indirectly via its additives. Recent evidence of increasing accumulation of micro- and nanoplastics (MnP) in aquatic environments including biofilms, sediments and groundwater, raises severe concerns universally. We now developed an improved understanding of MnP at the land surface, in oceans and in rivers. Yet, regarding the passage of MnP from headwaters to the oceans, our understanding of the sources, transport and transformation mechanisms, and changing impacts on environmental and public health risks is still limited. These knowledge gaps bear the risk of neglecting severe negative consequences for environmental and public wellbeing and risk underestimating the legacy of this environmental pollution problem that has been created, despite the fact that the scientific community, regulators and industry stakeholders recognize the global threat of MnP as a critically understudied emerging pollutant. Pushing the boundaries of the current research on MnP transport mechanisms and ecosystem impacts is of global relevance because MnP exposure in freshwaters is likely to be critically high, given that 1) the majority (70-80%) of all microplastics are reaching the sea via rivers, and 2) residence times may be much longer than previously anticipated (reaching decades to centuries). Accordingly, legacy pollution at aquatic-sediment interfaces and remobilization of pollutants if sediment conditions change is a vital concern with severe consequences for the environment and public health. The quantity and quality of freshwater resources is one of the most pressing concerns globally. Hence, quantifying MnP processing in rivers and other inland waters, including groundwater, and identifying contamination hotspots will inform policy development and lead to better environmental management and mitigation strategies. To generate novel insights on MnP dynamics during riverine transport, we encourage submissions from case studies, laboratory experiments, meta-analyses, and modeling along the headwater to ocean transition.

Key words: microplastics, nanoplastics, contaminants, fate, exposure

SS026 Aquatic Microbiomes Over Space and Time in a Changing Planet

Ramiro Logares, ICM-CSIC ([email protected])
Mireia Mestre, MNCN-CSIC ([email protected])
Georgina Brennan, ICM-CSIC ([email protected])
Carlos Pedrós-Alió, CNB-CSIC ([email protected])

Microbiomes have fundamental roles in the functioning of aquatic ecosystems and changes in their configuration could lead to changes in food webs, ecosystem services, and overall ecosystem function, which is of particular concern for the planet (and human) health. Microbiomes vary spatially and temporally, and patterns of variation can be observed on a wide range of scales: spatially, from micro- to planetary scales, and temporally, from seconds to millennia. During the last decades, we started to understand the patterns of variation of microbiomes at different spatiotemporal scales and the ecological processes that drive them: selection, dispersal, drift, and speciation. Yet, knowledge is still limited regarding the main patterns emerging from these processes as well as their operation at different spatiotemporal scales. Much less is known regarding the effects of global change on these processes. Selection can shape microbiomes through abiotic or biotic drivers, and multiple studies have shown how physicochemical variables affect the structure and biogeography of microbiomes. In turn, little is known about how biotic variables influence the configuration of microbiomes, highlighting the large knowledge gap on microbial interactions. Furthermore, while we have a general understanding of how selection over long time scales can lead to diversification, less is known about the action of selection over short time scales potentially leading to the contemporary evolution of microbial populations (months-years). Several studies have contributed to a better understanding of microbial dispersal. Still, many questions remain about this process at planetary scales and across biomes, as well as over large time frames (millennia). Grasping the dispersal capacity of different microbial groups and how global change could affect the overall dispersal of microbes is also among our current challenges. Among the less known mechanisms affecting the structure of microbiomes are drift and speciation. However, recent studies focusing on population genomics are bringing new insights into the fine-grained genomic changes that may lead to population divergence and eventually, speciation. Global change affects aquatic microbiomes (by altering community composition) and microbiomes affect global change (through changes in microbiome function). Ecosystems are changing rapidly due to global change, and predicting future changes in microbiomes will only be possible if we better understand the processes shaping them. This session aims at attracting works focusing on the spatiotemporal patterns of microbiomes, the processes that shape them, as well as their interactions with global change.

Key words: microbiome, spatiotemporal, interactions, evolution, aquatic

SS027 Environmental Benefits and Risks of the Current and Future Seaweed Aquaculture Industry

Glaucia Fragoso, NTNU ([email protected])
Ana Borrero, Seaweed Solutions ([email protected])
Aurora Ricart, Bigelow Laboratory for Ocean Sciences ([email protected])

Seaweed industry, including farming and sustainable wild harvesting, can offer nature-based solutions for climate and environmental change, thus minimizing threats to biodiversity and human welfare and therefore contributing to the United Nation Sustainable Development Goals. Seaweed farming is a multibillion-dollar industry and the fastest-growing aquaculture sector worldwide with high potential for scalability. However, little is known about the consequences, either positive or negative, of seaweed farming and wild harvesting in the surrounding natural ecosystems, and there is a complete lack of mechanistic understanding on the potential impacts of prospective large-scale seaweed farming. This session aims to bring together the current state-of-the-art research on environmental consequences of seaweed farming and harvesting, as well as discuss possible future trajectories of large-scale seaweed farming. This session welcomes research studies, industry and social initiatives, and policy strategies, from across the globe aiming at the assessment, management, and implementation of seaweed farming and harvesting from artisanal to industrial scales. Particularly, we welcome works on: 1) carbon capture by seaweed farms and overall contribution to carbon cycling including natural export pathways, induced sinking and its impacts 2) seaweed ocean acidification amelioration potential; 3) production of high-value molecules for industry replacing carbon intensive commodities and potential contribution to circular economy, global food security and livelihoods; 4) regenerative ocean farming, including seaweed and its effect in water quality through nutrient remediation and control of harmful algal blooms; 5) biodiversity enhancement by seaweed farms and effects in coastal areas; 6) observations or modeling studies that focus on seaweed cultivation as an ecological restoration tool for environmental and climate change impacts; 7) studies of Life Cycle Assessments to account for total GHG emissions in the seaweed industry and methodologies to verify carbon credits. ;

Key words: Seaweed, environment impacts, biodiversity, nutrient remediation, carbon cycle

SS028 Watershed-Based Nutrient Accounting: Biogeochemical Connections From Catchments to Coastal Waters

Dennis P Swaney, Cornell University ([email protected])
Estela Romero, Universitat Autònoma de Barcelona, CREAF ([email protected])
Josette Garnier, Pierre and Marie Curie University and Sorbonne University ([email protected])

The decade has seen significant development of relatively simple methodological approaches to relate various anthropogenic nutrient sources to their delivery to coastal waters, including watershed- and regional nutrient budgets and accounting. Advancements in our understanding of new sources, legacy sources, and spatio-temporal patterns are being achieved by using increasingly more accessible and more highly resolved data with analytical frameworks that provide a synthesis of the information to explain regional variation. One aim of such work is to improve our understanding of nutrient loading and how climate, hydrology, land use change, and other factors affect the resulting loads to coastal waters. Nutrient accounting methods, including material balances and related modelling approaches, are especially valuable for management and policy making because they relate impacts to various anthropogenic sources, and thereby facilitate development of management priorities. Presentations in this session will report on progress to date on methodologies currently in use or under development, recent applications of such approaches, and implications for environmental management and policy.

Key words: nutrient accounting, watershed, anthropogenic nutrient sources, coastal nutrient loading, biogeochemistry

SS029 Causes and Implications of Changes in Plankton Communities Across Timescales

Kristė Makarevičiūtė, GEOMAR Helmholz Centre for Ocean Research Kiel ([email protected])
Andrew Barton, Scripps Institution of Oceanography, University of California San Diego ([email protected])
B.B. Cael, National Oceanography Centre, UK ([email protected])
Alexandra Z. Worden, GEOMAR Helmholtz Centre for Ocean Research Kiel, Max Planck Institute for Evolutionary Biology ([email protected])

Planktonic organisms are important for the functioning of aquatic ecosystems and biogeochemical cycles. Understanding the changes in plankton communities in the past, present, and future is fundamental to unveiling the response of the Earth system as a whole. It is challenging to document and predict shifts in plankton communities as long-term efforts are required in both observational time-series and experimental studies. Moreover, diverse sampling, identification and quantification methods reveal different aspects of plankton dynamics. In this session, we aim to bring together scientists who study planktonic organisms – phytoplankton, zooplankton and mixoplankton - over different time scales and use different conceptual approaches as well as different methodologies, such as microscopy, cytometry, pigment analysis, amplicon sequencing, meta-omics in experimental, observational or modeling studies. Changes of interest include, but are not limited to anthropogenic increase of temperature and acidification, shifts in nutrient availability and trophic dynamics. The session aims to document changes in plankton communities occurring on a range of timescales and the overall goal is to promote understanding of the mechanisms underlying these changes and their consequences for food webs and biogeochemical cycles.

Key words: plankton, global change, time-series, trophic structure, biological carbon pump

SS030 Novel Stable Isotope Approaches In Aquatic Biogeochemistry and Ecology

Matthew McCarthy, UC Santa Cruz ([email protected])
Carsten Schubert, Eawag, Biogeochemistry ([email protected])
Natasha Vokhshoori, Smithsonian, WA. DC ([email protected])

Isotope tools have been widely used in aquatic science, however, over the last decade multiple new techniques have been introduced or refined, and are now being applied to solving broad questions in biogeochemistry, marine ecology, and paleoceanography. These include compound-specific stable- (2H, 13C, 15N) and radio-isotopes (14C) measured on various types of individual organic molecules (e.g. lipids, amino compounds, and carbohydrates), as well as the use of isotopomers, and isotope ratios of heavy metals (e.g. Sr, Pb, Mg, Fe). This symposium seeks to bring together different perspectives and analytical approaches to help solve emerging questions in biogeochemical cycles, ecology, and environmental sciences. We invite submissions regarding development or application of any novel stable isotope approaches for studying aquatic systems. This could include single compound isotopic measurements, allowing investigation of carbon and nitrogen sources and flux in present or past on a new level of detail and specificity, but could also encompass novel analytical, modeling, or applied approaches using bulk stable isotope measurements.

Key words: Stable Isotopes, Compound Specific Isotopes, Isotope Biogeochemistry, Isotope Ecology, Isotope Methods

SS031 Old Carbon, New Ideas – Recent Advances in Understanding Lentic Carbon Burial

Nicholas Ray, Cornell University ([email protected])
Meredith Holgerson, Cornell University ([email protected])
Adam Heathcote, Science Museum of Minnesota ([email protected])

Inland waters play an important role in global carbon and greenhouse gas cycling. Understanding controls on the rate of carbon burial in lentic systems is necessary for accurate quantification of the global carbon sink and predicting how it will respond to change. Recent work demonstrates that (1) ponds and small agricultural catchments may have an outsized role in lentic carbon burial at the global scale, (2) not all carbon burial pathways have been considered in quantifying the lentic carbon sink, and (3) anthropogenic and climate change pressures can lead to both positive and negative feedbacks in regard to rates of lentic carbon burial. These studies highlight recent advances – and remaining uncertainties – in the inland aquatic carbon sink. The goal of this session is to bring together scientists studying carbon burial across inland waters to present their latest findings. We welcome scientists who work across different systems and use various techniques to measure rates of carbon burial, identify sources of organic matter that is buried, quantify controls on C burial, and predict how the carbon sink of inland waters might change in response to anthropogenic pressures and global change.

Key words: carbon burial, global change, lakes, ponds, wetlands

SS032 River-Delta/Estuary-Coast Continuums Under Multi-Stressor Interactions: Connectivity and Dynamics to Enhance Resilience

Agustin Sanchez-Arcilla, Universitat Politecnica de Catalunya (UPC-BarcelonaTech) ([email protected])
Erica Ombres, NOAA Ocean Acidification Program ([email protected])
Joanna Staneva, Helmholtz-Zentrum Geesthacht Zentrum Fur Material- Und Kustenforschunggmbh (HZG) ([email protected])
Kimberly Puglise, NOAA NCCOS ([email protected])
Mindert de Vries, Deltares ([email protected])
Shiri Zemah, Reichman University, Interdisciplinary Center (IDC) ([email protected])

Coastal and marine environments play a major role in carbon neutrality and as carbon markets. In the last few decades, coastal degradation, due to development pressures and climate change, has led to loss of habitats and ecosystem services, decreasing coastal health and attractiveness. Under increasing anthropogenic pressures, coastal systems are experiencing a decrease in resilience and, in some cases, may reach an ecological tipping point or threshold leading to a doubtful recovery. These pressures are exacerbating environmental stressors through changes to the fundamental drivers of ecosystems. An improved understanding of how multiple stressors such as warming, deoxygenation, and ocean acidification interact and subsequently impact species, habitat assemblages, and ecosystems is, thus, a high priority for coastal restoration and resource management, particularly for marine protected areas and vulnerability hotspots. Unexpected interactions between multiple stressors may affect natural processes, reducing coastal resilience and hampering recovery. The proposed session invites contributions on coastal processes and nature-based solutions that enhance resilience and support restoration based on natural dynamics, connectivity, and knowledge of multi-stressor interactions, which are the key to predicting future ecosystem states and avoiding irreversible impacts. Communications on how to combine observations and modelling across scales to assess rates of impacts/recovery are particularly welcome, including the definition of thresholds to irreversible states (tipping points) and coastal decision making. Within this framework, contributions exploring the potential applications of wetlands, seagrass meadows or vegetated dunes, as components of hybrid coastal protection are sought, including resilience and recovery assessments that address the river-coast continuum. Experimental or fieldwork approaches to understanding multistressor interactions are encouraged. These topics should form a fruitful session for discussing advances to enhance coastal resilience and recovery for delta-estuary-coastal systems.

Key words: coastal, dynamics, connectivity, resilience, restoration

SS034 Biodiversity and Ecological Change in Arctic Freshwaters – Community and Food Web Responses to Warming and Changes in Hydrological Regimes

Willem Goedkoop, Swedish University of Agricultural Sciences ([email protected])
Jennifer Lento, Canadian Rivers Institute, Univ. New Brunswick, Canada ([email protected])
Joseph Culp, Wilfrid Laurier University, Canada ([email protected])
Kirsten Christoffersen, Copenhagen University, Denmark ([email protected])

Warming of Arctic regions by far exceeds the global average and has led to alterations of landscape vegetation, catchment hydrology and biogeochemical cycling, as well as gradual changes in the diversity (structural and functional) and ecological processes of lakes and rivers. These changes include the dispersal of warm-adapted species to the north (including invasives), permafrost-thaw induced changes in hydrology/biogeochemistry, alterations of communities, key ecosystem processes/functions, food webs, and the relative role of autochthony/allochthony. This session brings together field and experimental studies that address warming-induced changes to hydrological and biogeochemical regimes and their impacts on the biological assemblages and ecosystem function of lakes and rivers, while also addressing the effects of the introduction of new species. We would like contributors to also focus on the resistance and resilience to change of the assemblages of these vulnerable ecosystems. We envision contributions that illustrate the long-term, gradual changes in landscape biogeochemistry and biological assemblages, as well as examples of abrupt ecological shifts. Such shifts could, for example, be induced by the arrival of new fish species or a change in basal resources induced by changes in N/P ratios. In addition to historical evidence of change and experimental approaches, we also welcome contributions that address future scenarios of change for Arctic freshwater biodiversity and ecosystem function upon continued warming.

Key words: Arctic, Climate change, Biodiversity, Community change, Food web change

SS035 Physical and Biogeochemical Controls of Primary Production Dynamics in Aquatic Ecosystems

Camille Minaudo, University of Barcelona, Spain ([email protected])
Sebastiano Piccolroaz, Università degli Studi di Trento, Italy ([email protected])
Bieito Fernández-Castro, University of Southampton, United Kingdom ([email protected])
Shubham Krishna, Helmholtz-Zentrum Hereon, Germany ([email protected])
Hannah Chmiel, Limnology Center, EPFL, Switzerland ([email protected])

Carbon fixation by primary producers is the key rate-limiting process that shapes the functioning of aquatic ecosystems and defines their role as source or sink of atmospheric carbon dioxide. Many physical and biogeochemical factors determine the rates of primary production, however, their relative contribution is far from being resolved. Most of these controls have double-edge effects and interact with each other, complicating our understanding of the dynamics of primary production across spatial and temporal scales. This understanding is crucial to better predict and manage the consequences of the wide range of anthropogenic pressures acting on aquatic ecosystems. In order to improve our knowledge in this field, we first need to understand how hydro-thermodynamics set favourable or harmful conditions for the growth of primary producers, by e.g., sustaining the supply of nutrients, affecting mixing and stratification, and regulating horizontal and vertical water fluxes. Second, we must improve our understanding of the biogeochemical cycling of key chemical elements (C, N, P, Si, O 2 , Fe) in the water column and the sediment, including phytoplankton ecophysiology, grazing, organic matter remineralization, and inorganic carbon processes. Third, we need to advance our approaches to reliably quantify air-water gas-exchange to better determine the role of surface waters as a net sink or source of carbon dioxide to the atmosphere. The analysis of long-term public or research data, the growing availability of high-resolution physical/biogeochemical data collected with autonomous vehicles/profilers and high frequency sensors, and innovative modelling approaches have all the potential to increase our mechanistic understanding of primary production. We welcome data-driven, conceptual or model-based research on the interaction between physical and biogeochemical processes in natural or anthropogenically disturbed freshwater and marine ecosystems.

Key words: primary production, hydrodynamic, biogeochemical cycle, high-resolution, numerical modelling

SS036 Advances in Methane Cycle Research in Freshwater and Marine Ecosystems: Biological and Physical Processes

Paula Reis, Institut national de la recherche scientifique ([email protected])
Sofia Baliña, Universidad de Buenos Aires ([email protected])
Sarian Kosten, Radboud University ([email protected])
Hans-Peter Grossart, IGB Leibniz-Institute of Freshwater Ecology and Inland Fisheries and Potsdam University ([email protected])

Recent advances in the understanding of the biological and physical controls on the methane cycle in freshwater and marine ecosystems have made explicit that the cycling of this greenhouse gas is much more complex than originally thought. Such advances include experimental and field evidence of oxic methane production; the detection of methane oxidation by aerobic bacteria under anoxic conditions; the recognition of potentially efficient methane oxidation during lake overturn; experimental, isotopic, and biomarker evidence of methane-linked carbon cycling in aquatic food webs; the acknowledgement of the importance of neglected emission pathways such as plant-mediated, ebullition, degassing, and drawdown areas; the development of coupled physical and biogeochemical modeling; and many others. Despite these advances, there is still much uncertainty regarding mechanistic explanations as well as quantitative estimations, upscaling, and prediction of each component of the intricate methane cycle. In this context, to stimulate an interdisciplinary discussion on the recent breakthroughs and remaining uncertainties related to the methane cycle in aquatic ecosystems, in this session we invite contributions related to any aspect of the methane cycle (production, oxidation, accumulation, emission, food web incorporation) and from every scale (molecular to global) in both freshwaters and marine systems.

Key words: methane, greenhouse gas, freshwater, marine,

SS038 Trace Metal and Macronutrient Behaviour in Large Rivers and Estuaries

Adrienne Hollister, Jacobs University Bremen ([email protected])
Hannah Whitby, University of Liverpool ([email protected])
Rebecca Zitoun, GEOMAR Helmholtz Centre for Oceanographic Research ([email protected])
Juan Santos-Echeandía, Spanish Institute for Oceanography ([email protected])

Rivers are a major source of trace metals, macronutrients and organic matter to the global oceans. Processes such as colloidal flocculation, particle adsorption-desorption and biological activity influence the concentrations and speciation of trace metals and nutrients during estuarine mixing, and therefore their overall behaviour and flux to the ocean. Major rivers such as the Amazon are becoming increasingly vulnerable to anthropogenic impacts, including land use change, hydroelectric dams, metal pollution (e.g. from mining), plastic pollution (relevant as metal vectors), and agricultural runoff. These and other anthropogenic impacts to a river’s catchment area can lead to potentially toxic concentrations of metals (e.g. Cu, Zn, Pt, Hg, Pb, Fe), or of macronutrients leading to eutrophication. In addition, climate change is projected to cause both increased droughts and flooding, resulting in changes in river flow and chemical output. These changes may have a drastic effect on trace metal and nutrient sources, cycling, transport, fluxes, reactivity and sinks at the land-ocean interface. As climate and land use changes amplify, it is essential to establish a baseline for riverine trace metal and nutrient concentrations and fluxes to the ocean and sediments, and to understand how these parameters may change with changing environmental conditions. Generally, this session aims to evaluate the behaviour, fluxes, sources and sinks of trace elements and their isotopes (TEI) as well as macronutrients (N, P, Si) from major rivers to the ocean. Contributions focused on observational, experimental, and modelling approaches regarding metal- and nutrient cycling, their chemical and biological transformation and distribution in rivers and estuaries are welcome.

Key words: estuaries, Amazon River, trace metals, macronutrients,

SS039 Coastal Seafloor Biodiversity and Ecosystem Functioning in a Multi-Stressor World

Rebecca Gladstone-Gallagher, University of Auckland ([email protected])
Alf Norkko, Tvärminne Zoological Station, University of Helsinki, Hanko, Finland ([email protected])
Silvia de Juan Mohan, Mediterranean Institute for Advanced Studies (IMEDEA-CSIC/UIB), Balearic Islands, Spain. ([email protected])
Conrad Pilditch, University of Waikato, Hamilton, New Zealand ([email protected])

Coastal ecosystems are diverse and highly productive systems that provide key ecosystem functions and services, including nutrient cycling and climate change mitigation. In the coastal zone, soft sediment seafloor communities and the processes they regulate can influence the dynamics of the entire system through intense benthic-pelagic coupling. For example, feeding activities by dense aggregations of shellfish can improve water clarity and enhance denitrification providing resilience against eutrophication. Similarly, bioturbation by benthic infauna can oxygenate sediments and enhance nutrient and carbon processing. These functions and processes are underpinned by seafloor biodiversity, which is vulnerable to a multitude of human stressors originating from both land and sea. Coastal ecosystems are at the forefront of climate change impacts where increasing temperatures, sea level rise and changes in land-sea connectivity interact with locally generated stressors. The accumulating effects of multiple stressors are of concern because synergistic interactions can give rise to ecological surprise or tipping points and a loss of ecosystem functions and services. Recent research has emphasised the role that multi-scalar diversity (in all its forms) plays in enhancing ecosystem function and providing resilience in the Anthropocene. For example, seafloor functional trait diversity is linked to ecosystem processes and resilience. Functionally diverse communities are more able to withstand and resist stressors if they have a level of redundancy and response diversity that gives more ‘options’ for responding to stress. Importantly, spatial variations in functional and response diversity and ecological connectivity in the seascape may build resilience and aid recovery potential. Ultimately, multiple scales of processes are important for conferring resilience of the seafloor ecosystem function (individual species, populations, communities, in patches and across seascapes). In this session we invite contributions, particularly field based, that explore the role of seafloor biodiversity, in all its forms, in providing resilience to disturbance and stress, including cumulative effects of multiple stressors. For example, we would welcome contributions on the roles that individual behaviours contribute to resilience through influences on processes and functions, novel ways of assessing biodiversity, ecosystem functioning, and how these relationships are modified by human impacts (including climate change), through to the role of seascape habitat diversity in resilience and recovery.

Key words: cumulative effects, benthic ecology, disturbance-recovery, seascape, traits

SS040 Ecological Stoichiometry in a Dynamic World: Exploring the Ecology of Changing Environments Through Theory, Patterns, Processes and Experiments.

Cecilia Laspoumaderes, Univ. Nac. del Comahue - INIBIOMA- CONICET ([email protected])
Cedric Meunier, Biologische Anstalt Helgoland, Alfred Wegener Institut, Germany ([email protected])
Maarten Boersma, Biologische Anstalt Helgoland, Alfred Wegener Institut, Germany ([email protected])
Erik Sperfeld, Universität Greifswald, Germany ([email protected])

Aquatic ecosystems are varied and complex, and cannot be described in a single unified manner. However, each system, whether it is a pelagic, coastal marine or riverine, still follows certain patterns of energy and nutrient transfer. The field of Ecological Stoichiometry aims at understanding the balance of energy and chemical elements in ecological interactions. It examines the trophic relationships linking the elemental physiology of organisms with their food web interactions and ecosystem function. In particular, it explores nutrient dynamics with concepts such as stoichiometric food quality imposed by elemental co-limitation, consumer-driven nutrient recycling or the growth rate hypothesis. Ecological Stoichiometry has been applied on different levels of biological organization, from organelle biochemistry to ecosystems and across diverse organisms from bacteria to plants and animals. In this session, we welcome contributions from the broad community to show how Ecological Stoichiometry can improve our understanding in diverse fields, including studies on individuals, populations, communities, ecosystems, and even human alteration to the Earth system. This session also calls for contributions from across the range of approaches (theoretical, experimental, observational, and modelling) that can be used to investigate the effects of changing environments with the help of Ecological Stoichiometry on all aspects of aquatic ecosystems.

Key words: Carbon, Phosphorus, Nitrogen, Nutrient dynamics, Food web

SS041 Transport, Transformation and Trends of Pyrogenic Carbon in the Aquatic Environment

Rainer Lohmann, University of Rhode Island ([email protected])
Sasha Wagner, Rensselaer Polytechnic Institute ([email protected])
Alysha Coppola, ETH Zurich ([email protected])

Wildfires and fossil fuel combustion produce large amounts of charred pyrogenic organic materials, including black carbon (BC). Pyrogenic carbon is chemically heterogenous and is described as a continuum from charcoal to soot. Black carbon is an incomplete combustion byproduct that could be a sink for fixed carbon, especially when deposited to pelagic sediments or long-term cycling in the oceans. In the atmosphere, BC is a key driver of global climate change; yet it’s feedbacks are not included in Earth System Models. Omitting BC production from assessments of fire impacts leads to an overestimation of the strength of positive feedbacks caused by wildfires. There is a general assumption that rivers deliver most or all BC to the ocean. Yet the sources, transport and transformation of BC are not well constrained in intermediate reservoirs or in atmospheric and ocean circulation models. For example, few BC flux measurements are available in remote ocean sediments to understand this transfer of BC. Once deposited to the ocean, some BC is buried in sediments, and can account for significant fractions of the organic matter preserved in sediments. Dissolved BC, in contrast, cycles in the oceans on millennial timescales. A better understanding of the carbon cycle thus depends on working at the interface of numerous disciplines, including oceanography, paleography, atmospheric science, biogeochemistry, and analytical chemistry. The proposed ASLO session is thus relevant and timely to further expand our understanding of the cycling of pyrogenic carbon, as well as BC components, which is key to understanding carbon mitigation and negative feedback strategies with continued climate change.

Key words: Dissolved Black carbon, black carbon, sedimentation, river, fluxes

SS042 Fishing4Data: Fishing Gear as an Oceanographic Data Collection Platform

A. Miguel Santos, IPMA-Portuguese Institute for the Ocean and Atmosphere ([email protected])
Cooper Van Vranken, Ocean Data Network, USA ([email protected])
Michela Martinelli, CNR, Italy ([email protected])
Hassan Moustahfid, NOAA/US IOOS, USA ([email protected])

Despite the well documented importance of understanding the physical processes occurring in the ocean, there is a lack of in situ subsurface data to calibrate and constrain ocean models and forecasts in coastal and shelf seas. Cost-effective and sustainable ocean and coastal data are needed to help in the understanding of the role of the oceans in earth’s climate and so be able to make improved estimates of how it will change in the future. While the observation of the open ocean is well achieved by automated ocean measurement instruments, coastal and shelf seas suffer from the lack of sub-surface collection platforms. To meet this challenge, there is an emerging community collaborating with fishers using their fishing gears as platforms for sensors to collect oceanographic data in data scarce regions which complement today's ocean observing networks. These data are also important to understand the physical-biological interactions in the marine ecosystems through an end-to-end approach, including fisheries for the stakeholders who collect these data. This theme session provides an opportunity to be aware of the latest developments in technologies and methodologies for acquiring oceanographic data from fishing vessels. Four main topics will be addressed during the theme session: (a) State of the art in ocean observing systems from fishing vessels; (b) Sensors and other devices to be used in fishing gears and vessels; (c) The use and application of these data, e.g. in operational oceanography, models’ validation and forecasting, fisheries research, and commercial fishing activities; (d) Data management to facilitate interoperability and industry data usage.

Key words: Ocean Observing Systems, Emerging techniques and technologies, Fishing vessels, Fishing Gear, Data

SS043 Linking Phenotype and Genotype: Adaptation of Plankton in the Past, Present, and Future

Karin Rengefors, Lund University ([email protected])
Sinead Collins, University of Edinburgh ([email protected])
Raphael Gollnisch, University of Oxford ([email protected])
Dedmer Van de Waal, Netherlands Institute of Ecology & University of Amsterdam ([email protected])

In recent years it has become increasingly clear that ecological and evolutionary processes are tightly coupled and need to be considered over the same time scale in plankton. This is especially evident and important in relation to seasonal environmental dynamics and climatic changes, where the ability of phyto- and zooplankton species to phenotypically adapt will be critical to their future abundance and function. To study eco-evolutionary processes, and their response to multiple environmental change factors, both genetic and phenotypic diversity in populations need to be determined and linked. Furthermore, there is a growing appreciation that the ecological and biogeochemical function of phyto- and zooplankton (as well as their fitness) depends on many correlated traits that change in concert. Thus, understanding how plankton traits will change in the future requires us to understand how complex phenotypes respond to complex environmental change over multiple time scales – no small task. In phytoplankton, this is challenging because few methods are available to study individual cells, most methods depend on being able to culture the cells, and few traits can be easily assessed. In zooplankton, individuals can sometimes be studied directly, but still size can limit certain analyses. The challenges of understanding complex multitrait phenotypes are partially practical, in that high-throughput methods for screening phenotypic traits are largely lacking. There are also conceptual challenges in dealing with multitrait phenotypes, in that trait-based models tend to rely on master-trait approaches and simplified trait correlations and tradeoffs. While such models can be useful, it is not clear what their limits are, or what alternative models that complement them might look like. To this session we welcome studies of marine, brackish, and freshwater phytoplankton (eukaryotic algae as well as cyanobacteria) and zooplankton. We invite experimental studies linking genotype-phenotype, addressing adaptation, selection, response to (multiple) environmental change factors, and artificial experimental evolution. We would also like to see field studies of population differentiation, both genetically and phenotypically, connected to environmental variation. Lastly, we are inviting contributions presenting novel methods that allow high-throughput phenotyping or targeting single-cells of phytoplankton /small individual zooplankton for phenotype and genotype characterization.

Key words: phytoplankton, functional traits, genotype, phenotype, multi-stressors

SS046 Mesocosm Based Experimental Studies to Address Challenges Emerging From Global Change on Stability of Aquatic Ecosystems

Stella Berger, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) ([email protected])
Jens Nejstgaard, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) ([email protected])
Tatiana M Tsagaraki, University of Bergen, Department of Biological Sciences ([email protected])
Meryem Beklioğlu, Middle East Technical University ([email protected])
Behzad Mostajir, Marine Biodiversity, Exploitation and Conservation (MARBEC), University of Montpellier-CNRS-Ifremer-IRD ([email protected])

Global climate change and other anthropogenic pressures have major impacts on the structure, biodiversity and functioning in aquatic ecosystems. Climate change pressures include transitional environmental change, increased variability and extreme events and long-term disturbance. It is still unclear how these pressures affect ecosystem responses, including their resilience and recovery. Large-scale mesocosm or enclosure experiments provide realistic settings by including higher system complexity in terms of species interactions at various trophic levels. Thus, mesocosm experiments are a powerful tool to obtain a mechanistic understanding of how various global change and other anthropogenic pressures affect ecosystem responses. Moreover, mesocosms offer the unique ability to test possible measures to mitigate or counteract anthropogenic pressures through environmental engineering and nature-based solutions. We welcome presentations on empirical studies where scientific questions about various aspects of aquatic ecosystem functioning have been tested using mesocosms or similar ecosystem level experimentations. We particularly invite scientists that study effects of increasing variability and extreme events on resilience and recovery of biodiversity and ecosystem structure and functioning or regime shifts that change ecosystem structure and functions in response to global climate and environmental change. We strongly encourage early career scientists who have participated in the AQUACOSM or AQUACOSM-plus (www.aquacosm.eu) Transnational Access (TA) programs to present their results from the mesocosm experiments. This session also aims to serve as a meeting point for all persons interested in ecosystems scale experimentation on a global scale (see mesocosm.org).

Key words: mesocosm experiments, biodiversity, extreme events, ecosystem stability, nature based solutions

SS047 Multidisciplinary Approaches to Understanding Plastic Pollution in Marine Ecosystems and Its Effects on Marine Species

Montserrat Compa, Centro Nacional Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Consejo Superior de Investigaciones Científicas (IEO-CSIC) ([email protected])
Carme Alomar, Centro Nacional Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Consejo Superior de Investigaciones Científicas (IEO-CSIC) ([email protected])
Salud Deudero, Centro Nacional Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Consejo Superior de Investigaciones Científicas (IEO-CSIC) ([email protected])
Joaquín Tintoré, Balearic Islands Coastal Observing and Forecasting System (SOCIB) ([email protected])

Reporting of the harmful effects that plastic pollution has on marine ecosystems has grown in the past two decades, with almost 700 marine species recorded to ingest plastic. In an effort to identify hotspot areas for plastic accumulation, harmonized protocols have been introduced across regions to quantify how much plastic is in the marine environment; floating on the sea surface, suspended in the water column, and settling on the seafloor with size fractions ranging from nanoparticles to mega-debris. Advanced modelling techniques using regional and global hydrodynamic models coupled with empirical data for ground truthing have provided spatially explicit maps of plastic pollution for studied and remote areas in order to identify sinks and sources. Alarmingly high plastic densities in many regions worldwide have identified their effects on the trophic web, with studies ranging from zooplankton to ichthyofauna to cetaceans. Moreover, these studies have reported ingestion/entanglement of plastic debris to cause not only ecotoxicological effects triggering biomarker responses from plastic exposure but also the potential lethality due to physical harm. Considering the link between plastic pollution in the marine environment and its impacts on marine diversity, this session aims to highlight multidisciplinary approaches to understanding connectivity and transferability of plastic pollution and within marine ecosystems and its effects on species. We invite researchers who employ multifaceted methods investigating plastic pollution to submit their research to this session.

Key words: plastic pollution, trophic web, ecotoxicology, modelling, marine diversity

SS048 Algal Industry for the Greener Future: Algal Cultivation, Biotechnology, Algal Compounds, and Biomass

Brittany Sprecher, University of California San Diego ([email protected])
Soo Hyun Im, University of Konstanz ([email protected])
Tomáš Grivalský, Laboratory of Algal Biotechnology, Institute of Microbiology - Centre Algatech ([email protected])

Aquatic environments have changed considerably during recent decades due to many influences, including: climate change, altered nutrient inputs, land-use modification, and invasive species. Algae are fundamental members in aquatic ecosystems, composed of microscopic photosynthetic organisms and macroscopic seaweeds. As one of the oldest organisms on the planet, their high adaptability has allowed them to thrive in a variety of aquatic habitats, such as lakes, rivers, oceans, or anthropogenic niches. The success and resilience of algae significantly impacts the environment as they are responsible for converting atmospheric CO 2 into oxygen and high carbon compounds. Moreover, as the foundation of both freshwater and marine food chains, algae and their natural products have a huge range of current and potential applications for humans. This session focuses on algal cultivation and algal biotechnology, including valuable compounds as well as biomass produced by microalgae and macroalgae. Algal Biotechnology is a rapidly expanding discipline that seeks to understand and harness the resources from some of the most diverse groups of organisms on the planet. For example, developing applications include pharmaceuticals, pigments and fluorescent molecules, nutraceuticals, feed for aquaculture, feed supplement for cattle to improve weight gain while reducing enteric methane emissions, biofuels, food variations and food supplement, enzymes, wastewater treatment, fertilizers and plant biostimulant applications, bioremediation materials on earth, and even for outer space applications. The session will also focus on macroalgal farming which is contributing to energy security by reducing greenhouse gas emissions via biofuel production as well as production of various products such as textiles, bioplastics, and fertilizers. As macroalgae farming is expanding rapidly worldwide, we aim to discuss how to develop a sustainable aquaculture industry that keeps healthy and diverse aquatic environments. The session will cover (i) algal cultivation methods, including designing of photobioreactors to optimize the growth regimes for specific purposes, (ii) production of algal biomass, (iii) production of valuable compounds by algae, and (iv) genetic engineering of algae for microalgal industry. We hope the topic will attract the attention of top scientists who will be able to present their latest studies focused on algal biotechnology.

Key words: algal cultivation, algal biotechnolog, algal compounds, algal biomass, algal for the future

SS049 Resilience on Ice: Freshwater Ecosystems and the Changing Cryosphere in Mountain and Polar Regions

James Elser, University of Montana ([email protected])
Joseph Vanderwall, University of Montana ([email protected])
Janice Brahney, Utah State University ([email protected])

The cryosphere is changing rapidly and especially so in mountain and polar regions. These changes are having a myriad of effects on associated freshwater ecosystems and the services they provide to society. A better understanding of these changes, and the mechanisms driving them, will help to protect these ecosystems and to support societal adaptation as climate change unfolds. This session invites submissions from those working from diverse perspectives (biogeochemistry, trophic interactions, water quality, evolutionary adaptation, biodiversity, geomorphology, etc) to better understand ongoing changes in lakes, ponds, streams, and wetlands that are on, adjacent to, or strongly influenced by glaciers, snowpack, and permafrost in mountain regions and at high latitudes. We also invite contributions from researchers studying the ecosystem services (e.g. drinking water, hydropower, fisheries, irrigation) that are impacted in cryosphere-supported freshwater ecosystems. With this session we seek to continue to build a diverse global network of cryosphere limnologists working across disciplinary boundaries.

Key words: cryosphere, limnology, biogeochemistry, climate change, glacier

SS050 Disentangling Complex Long-Term pH and O2 Trends in Coastal and Estuarine Systems From Global and Regional Drivers

Ming Li, University of Maryland Center for Environmental Science ([email protected])
Wei-Jun Cai, University of Delaware ([email protected])
Jacob Carstensen, Aarhus University ([email protected])
Hans Paerl, University of North Carolina at Chapel Hill ([email protected])
Jeremy Testa, University of Maryland Center for Environmental Science ([email protected])

Unlike the open ocean which exhibits a clear monotonic trend in acidification and deoxygenation, long-term pH and O2 changes in estuaries and coastal systems are complicated due to a multitude of global and regional drivers. Despite a clear link between nutrient enrichment and hypoxia, the response of coastal eutrophication to a variety of diverse drivers requires improved understanding. In large stratified systems with strong benthic-pelagic coupling and where physical processes regulate oxygen supply to bottom waters, the response of hypoxia to nutrient load is often complex and nonlinear. In addition, climate change, such as warming and changing river flows, may alter key baselines impacting the functioning of coastal systems and their responses to eutrophication. Similarly, coastal pH has shown diverse long-term trends and large spatial variability, featuring acidification in some regions but basification in others. While rising atmospheric p CO2 and respiration of organic material decrease pH and weaken the buffer capacity, a number of other processes act to increase pH, including phytoplankton photosynthesis, human-accelerated chemical weathering and alkalinization in rivers, and export of alkalinity and calcium carbonate from seagrass, salt marsh and other ecosystem components. Discerning how these global and regional drivers affect the dissolved oxygen dynamics and carbonate chemistry is critical for understanding the complex long-term pH and O2 trends in estuarine and coastal systems and developing appropriate management and adaptation strategies. In this session we solicit contributions that address the long-term pH and O2 changes in estuaries and coastal oceans. We welcome theoretical studies that advance our conceptual understanding of the global and regional drivers of the dissolved oxygen dynamics and carbonate chemistry in coastal waters. We also welcome retrospective analysis of long-term monitoring data to distill the effects of climate change, eutrophication and land-use changes in driving the long-term trends in pH and O2 . Finally, we encourage submission of modeling studies that investigate how warming, changing precipitation and draught patterns, storms, rising atmospheric CO2 , river alkalinization, and export of alkalinity and organic matters from seagrass, marsh and other ecosystem components affect the dissolved oxygen and carbonate chemistry in different estuarine and coastal systems.

Key words: hypoxia, acidification and basification, climate change, eutrophication, land-use changes

SS051 Untangling Food Web and Ecosystem Effects of Reciprocal Subsidies

Amanda Subalusky, University of Florida ([email protected])
Cornelia Twining, EAWAG - Swiss Federal Institute of Aquatic Science and Technology ([email protected])
Therese Frauendorf, Colgate University ([email protected])
Tarn Preet Parmar, University of Konstanz ([email protected])
Carmen Kowarik, EAWAG - Swiss Federal Institute of Aquatic Science and Technology ([email protected])

Terrestrial and aquatic food webs are often linked by the movement of energy, materials, and organisms across ecosystem boundaries. Lakes and rivers receive substantial inputs from their surrounding catchments, with cross-ecosystem carbon flows similar to the magnitude of internal fluxes. However, differences in the quantity and quality of subsidies, as well as the location and timing of their input, can significantly impact how terrestrial subsidies drive benthic production. Aquatic ecosystem dynamics in turn drive the production of aquatic macroinvertebrates that can emerge into terrestrial ecosystems as winged adults. Aquatic subsidies to terrestrial systems are generally much smaller than internal fluxes. However, aquatic subsidies can provide potentially limiting resources to terrestrial ecosystems due to their high concentrations of long-chain polyunsaturated fatty acids and trace elements, which can have outsized effects on riparian consumer behavior and fitness. Aquatic subsidies also can have a “dark side,” as they are capable of transporting trace metals and contaminants that can become concentrated in aquatic ecosystems to riparian consumers. The quantity and quality of aquatic subsidies is likely influenced by interactions between aquatic ecosystem dynamics and food web structure. Research on terrestrial and aquatic resource subsidies is often decoupled from one another, which has precluded development of a comprehensive understanding of material fluxes across aquatic-terrestrial boundaries. Furthermore, much of this work has been done in temperate regions, in which seasonal drivers play an important role; however, much less work has been done in tropical river systems, which may function in ways distinct from temperate systems due to differences in seasonality, or in ways that have been lost from many anthropogenically impacted temperate systems. In this session, we will bring together scientists studying aquatic and terrestrial subsidies in both temperate and tropical ecosystems to discuss how quantity and quality of resource subsidies influence ecosystem function and the occurrence of reciprocal subsidies, and how the magnitude and composition of resource subsidies varies across landscapes.

Key words: resource subsidy, aquatic-terrestrial linkage, emergent insect, fatty acid, trace element

SS052 Microbial and Abiotic Factors Influencing the Turnover and Fate of Organic Matter in Aquatic Systems

Andrew Steen, University of Tennessee - Knoxville ([email protected])
Maria Montserrat Sala, Institut de Ciències del Mar (CSIC) ([email protected])
Jesus M. Arrieta, Spanish Institute of Oceanography ([email protected])
Jutta Niggemann, ICBM, University of Oldenburg ([email protected])

Organic matter is a dynamic entity turning over in aquatic systems at highly variable time scales. In the search for controls on organic matter degradation, a multitude of interacting environmental factors have been proposed, including biotic and abiotic conditions, the molecular composition of DOM itself and the low concentrations of the different DOM components. Recent advances in analytical chemistry and biotechnology have provided researchers with an unprecedented ability to characterize the specific organic compounds that participate in biotic and abiotic transformations as well as the enzymes involved in metabolic processes and the genes encoding them. Furthermore, abiotic factors including photolytic degradation and adsorption processes interact with biotic factors in complicated fashion. In this session, we encourage presentations based on studies examining controls and mechanisms of OM turnover, as well as comparative studies and modelling efforts describing a framework for predicting OM turnover. In this session, we will explore how measuring the activities of extracellular and cytoplasmic enzymes in aquatic ecosystems, the concentrations and fluxes of metabolites, the microbes, genes, transcripts, and proteins present in those ecosystems, and the compounds present in dissolved and particulate organic matter all influence each other and the broader ecosystem. Consistent with this year's meeting theme, we are particularly interested in how microbial metabolic processes and microbe-organic matter interactions influence the resilience and recovery of aquatic ecosystems.

Key words: dissolved organic matter, particulate organic matter, metabolites, extracellular enzymes, microbes

SS053 Modelling the Ecology, Evolution & Resilience of Aquatic Ecosystems

Sergio Manuel Vallina, Gijon Oceanography Centre (IEO -- CSIC) ([email protected])
Pedro Cermeno, ICM -- CSIC ([email protected])
Carmen Comas, ICM -- CSIC ([email protected])
Guillaume Le Gland, ICM -- CSIC ([email protected])

The relationship between the ecology, evolution and resilience of ecosystem functions in aquatic ecosystems in the face of environmental changes is one of the central questions in ecosystem ecology. Ecosystem functioning refers to several key ecosystem-level processes such as: productivity; stability (resilience, resistance, persistence, robustness); biogeochemical cycling of essential elements (phosphorus, nitrogen, carbon, silica); the efficiency of mass-and-energy transfer through the food web to upper trophic levels (fish); or the adaptive capacity of the whole ecosystem when environmental conditions change beyond critical thresholds. Essential tools to study and gain a deeper understanding of the mechanisms behind the relationship between biodiversity and ecosystem functioning are: ecological system theory, adaptive dynamics frameworks, mechanistic models, empirical dynamic modeling, statistical models (such as species distribution models or Bayesian Inference models), and machine learning methods. This session calls for works that use any kind of ecosystem modelling approach to address eco-evolutionary questions that can be linked to biodiversity and ecosystem functioning or that seek to quantify the feedbacks between ecosystems and the environment, with an emphasis on stability indicators such as resilience. The works can range from developments in ecological theory to computer simulations. Data analysis of long-term observations (time-series) of aquatic ecosystem variables that allow extracting information on functional stability properties, are also welcome. The session aims to be inter-disciplinary at the interface between aquatic ecology, systems physics, applied mathematics, and computer science.

Key words: Ecosystem functioning, Ecology & evolution, Biodiversity, Stability & Resilience, Aquatic modelling

SS054 Trait Development and Resilience of Aquatic Microbial Communities Under Anthropogenic Stressors in Coastal Ecosystems: A Focus on Coastal Oceans of Global South

Anwesha Ghosh, Indian Institute of Science Education and Research Kolkata, India ([email protected])
Punyasloke Bhadury, Centre for Excellence in Blue Economy, Indian Institute of Science Education and Research Kolkata, India ([email protected])
Krishna Ray, West Bengal State University, India ([email protected])
Amit Kumar, Sathyabama Institute of Science and Technology, India ([email protected])

Coastal oceans are key to maintaining of global scale ecosystem processes including biogeochemical cycling and contribute to blue economy. In Global South, coastal oceans are crucial for offering direct livelihood to millions of coastal communities and contributing to pan regional GDPs. Resident aquatic microbial communities are crucial in maintaining health and functioning of coastal oceans. Multiple combinations of interactions and associations between microbes, known as microbial network, aid in the transfer of energy through the marine food web. The importance of development of traits and resulting microbial guilds can vary in coastal oceans across continents including in Asia and Africa. In particular, increasing anthropogenic stressors in a changing climate have led to ‘urbanization’ of coastal oceans. Coastal oceans are also becoming ‘hotspots’ of antibiotic-resistant genes (ARGs) and can become significant from the viewpoint of public health in parts of Asia and Africa. The aquatic microbial communities are exhibiting signatures of resilience including plasticity in coastal ocean as a result of metabolic interactions with different types of anthropogenic pollutants. There is an urgent need to understand trait development and resilience of aquatic microbial communities in coastal oceans of South to truly achieve nexus towards understanding of health of global oceans. In this session, contributions are welcome from that focuses on coastal ocean microbiome, functional traits in aquatic microbial communities, resilience of microbial communities and linking with broader ecological processes encompassing Global South. In particular, contributions are most welcome from early career researchers who are using multifaceted approaches ranging from ecophysiology, deep- sequencing to ecological modelling towards understanding of aquatic microbial communities in coastal oceans. Submissions are also welcome from authors who are working on aquatic microbial communities of coastal biotopes including mangroves, lagoons, estuaries, coral reefs, seagrass habitat and salt marsh.

Key words: Blue economy, Coastal Oceans, Microbiome, Carbon cycling, Global South

SS055 Remote Sensing of Freshwaters Health from Local to Global Scales Under Climate Change

Monica Pinardi, National Research Council of Italy ([email protected])
Evangelos Spyrakos, University of Stirling ([email protected])
Claude Duguay, H2O Geomatics (spin-off from the University of Waterloo, Canada) ([email protected])

The influence of climate change on freshwater ecosystems is becoming an increasing concern worldwide. At global level, lakes are facing rising temperatures, shifts in stratification phenology and precipitation patterns and an increased frequency of extreme weather events. Understanding the long-term effects and the complex responses of lakes and inland waters in a changing environment is essential to manage water resources effectively and to mitigate the effects of climate change. The preservation of freshwaters in a good health status is a key issue for water potability, food and industry production, nature conservation and recreation. Remote sensing can enable long-term monitoring of freshwaters, supporting water managers decisions providing data and filling knowledge gaps to a better understanding of the regional and local areas most affected and threatened by health status degradation. In this context, in recent decades, space agencies and the remote sensing community have been producing satellite-derived water quality data and products. An example is the Lakes Climate Change Initiative (CCI) Project (https://climate.esa.int/en/projects/lakes/) that provides a long-term global record of five lake essential climate variables: lake water level, extent, temperature, surface-leaving reflectance (from which are derived chlorophyll-a and turbidity), and ice cover. In this special session, we welcome contributions that have developed and/or employed remote sensing methods to investigate the effects of climatic and anthropogenic drivers on inland waters with a particular focus on their ecosystem health. These could deal with a particular aquatic ecosystem or study effects at a global scale.

Key words: earth observation data, climate change, aquatic ecosystems, long-term monitoring, water quality

SS056 Jellyfish in the Changing Ocean

Tinkara Tinta, National Institute of Biology ([email protected])
Martin Vodopivec, National Institute of Biology ([email protected])
Laura Prieto, Instituto de Ciencias Marinas de Andalucia ([email protected])
Mohamed Najib Daly Yahia, Qatar University ([email protected])

Jellyfish (cnidarian subphylum Medusozoa and phylum Ctenophora) exist since the Cambrian period. Since then, these members of gelatinous zooplankton have developed various life forms and lifestyles, which enables them to dwell in nearly all habitats of the global ocean. Recent reports on the local and regional increase of jellyfish blooms, triggered debate over the actual cause and consequences of observed fluctuations and dragged the attention of broader scientific community, resulting in mount of evidence on the role, importance and impacts of jellyfish in global ocean ecosystem. At the same time, studies exposed numerous knowledge gaps, which we need to address to accurately integrate jellyfish and jellyfish-derived organic matter into marine food webs, biogeochemical budgets and models. We propose a very broad jellyfish session that brings together researchers from different disciplines to examine jellyfish and related topics from different perspectives filling recognized knowledge gaps. This session welcomes studies that examine jellyfish diversity, distribution, physiology, behaviour, and ecology, their interactions with other members of the marine food web, especially with microbes and jellyfish potential predators, with particular emphasis on studies that use e-DNA, omics approaches and microscale analyses. We seek applied research on advances in jellyfish observation techniques (from remote sensing to systematic transects, drone observations, underwater cameras, ROVs and Citizen Science) and efforts to establish common monitoring standards and criteria. Studies employing all types of modelling, including fluid dynamics, ecosystem models, individual-based models, Lagrangian models, probabilistic models, coupled physical-biogeochemical models, providing insights into jellyfish dynamics and dispersion on local, regional and global scales, are welcomed. Research investigating the causes and consequences of jellyfish blooms for ecosystem functioning, food web structure, biogeochemical state of marine ecosystems, and the role of jellyfish in marine ecosystem services are seeked. We are interested in studies understanding jellyfish in the past (including fossils) and in the context of future changes in oceanic habitats related to increases in seawater temperature, changes in salinity, nutrient regimes, ocean dynamics, ocean sprawl (offshore platforms, aquaculture facilities, wind farms), and the introduction of non-indigenous species. Last, but not least, we want to welcome research tackling jellyfish and human interaction, from the valorisation of jellyfish, as food or fertilisers and in cosmetics and pharmacology as potential producers of bioactive molecules, to the effects of jellyfish on human health and well-being and jellyfish in history, art, and popular culture.

Key words: jellyfish-ecology, jellyfish-microbes, jellyfish in situ observations, jellyfish-modelling, jellyfish-valorisation

SS057 Drivers and Impacts of Changing Microbial Ecology in Vulnerable Coastal Systems

Arianna Krinos, MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering ([email protected])
Natalie Cohen, University of Georgia ([email protected])
Margaret Mars Brisbin, Woods Hole Oceanographic Institution ([email protected])

Coastal aquatic ecosystems at the interface of land and sea are experiencing a unique suite of challenges–including increasing temperature, acidification, storm events, and anthropogenic nutrient loading. While some climate-related changes happen slowly over time, others cause rapid shifts in ecology through acute disturbance events. How microbial communities respond to a changing environment has the potential to mitigate or exacerbate both long-term and short-term ecosystem impacts. In particular, interactions between microbes may either enhance ecosystem stability or break down in response to environmental change. However, our ability to detect or predict the impacts of long-term and disturbance-driven changes relies on the establishment of baselines and innovative improvements in our chemical and molecular detection capacities. This session invites submissions that explore interactions between different microbes and their role in ecologically-important phenomena, such as eutrophication, harmful algal blooms, salinization, and extreme weather events. These interactions may involve associations between organisms (e.g., co-abundance networks), or explorations of metabolic cooperation (e.g., metabolite exchange or synchronization). We especially invite speakers applying interdisciplinary approaches or developing complementary methodologies for characterizing changes in microbial community structure and function, for example using multi-omic methodology. In addition, time-series data enables statistical inquiry into environmental change, for example by clarifying seasonal succession or identifying ecological niches, and we encourage submissions with a temporal component. We also welcome complementary laboratory and field studies, which help to quantify and characterize coastal microbial response to, and recovery from, environmental impacts.

Key words: omics, ecological interactions, coastal, microbial, time-series

SS058 Citizen Science in Aquatic Ecology: Bridging the Gap Between Science and Society While Assuring Sound Data for Science and Conservation

Fiona Tomas Nash, IMEDEA ([email protected])
Iris Hendriks, IMEDEA ([email protected])
Hilmar Hinz, IMEDEA ([email protected])

The engagement of citizens in marine sciences is a crucial element in the effort to increase societal awareness of environmental issues and science in general. Through its potential for large observer numbers it also has been advocated as a monitoring tool to collect large amounts of scientific data, providing opportunities for large scale and sustained observations over a long term. Citizen science is however also riddled with challenges that sometimes can hamper its potential and balances have to be struck between its function as a communication and/or a monitoring tool providing sound data. The challenges may largely vary between projects and their objectives, and measures can be taken to confront these. This session aims to explore different strategies that projects have developed to master these challenges and provide examples of success. We hope to showcase pathways that might guide others to master these challenges.

Key words: citizen science, conservation, aquatic ecology, human impacts, macroecology

SS059 Ecosystem Tipping Points in the Open Ocean Ecosystem in Polar Seas

Sigrun Jonasdottir, Technical University of Denmark ([email protected])
Marja Koski, Technical University of Denmark ([email protected])

The Polar seas are changing more rapidly than any other ocean area due to global warming. The melting of the Greenland and West Antarctic ice sheets are expected to already have reached a tipping point and the consequences of the freshwater inflow and ice-free fjords, coastal and open ocean areas are still to be seen. Increased freshwater is predicted to increase stratification of the water column, with potential major consequences for the community composition of plankton and therefore for the polar food webs and carbon flux – an ecosystem tipping point equal to the ones observed in coastal and terrestrial ecosystems. In this session, we welcome presentations on climate-induced changes of biodiversity and biological processes from all polar and sub-polar marine pelagic ecosystems. We are equally interested in observations related to climate-induced regime shifts, process studies on ecosystem functions and modelling studies investigating the changes in marine systems and the ecosystem services that they provide.

Key words: Polar, Tipping point, Marine food-web, Biodiversity, Carbon flux

SS060 Omics Ocean Observations to Reveal Microbial Ecosystem Dynamics and Resilience

Matthew Harke, Gloucester Marine Genomics Institute ([email protected])
Kevin Becker, GEOMAR Helmholtz Centre for Ocean Research Kiel ([email protected])
Angela Boysen, Pacific Lutheran University ([email protected])
Benjamin Pontiller, GEOMAR Helmholtz Centre for Ocean Research Kiel ([email protected])

Marine microbes have an outsized effect on global ocean ecosystem function and health. Advances in ‘omics’ have revolutionized our knowledge of the distribution, metabolic capacities, and activity of microbes within the biosphere. While the power of individual ‘omic tools is great, there is immense promise if we can successfully integrate across tools to learn more about connections between the diversity of genes, proteins, and molecules. This promise comes with the challenge of matching different data types that have unique taxonomic specificity, biological regulation, and numerical meaning. This session invites contributions that utilize multi-omic approaches which inform on microbial resiliency in the oceans. We encourage submissions that explicitly tackle the challenges of merging multiple ‘omics’ datasets in new ways, those which explore spatial and temporal dynamics, and/or reveal new insights into plasticity and redundancy within microbial communities.

Key words: Microbes, Oceans, Multi-omics, Resiliency, Redundancy

SS061 Novel Molecular Tools To Assess Biodiversity and Resilience of Aquatic Environments

Xavier Benito-Granell, Institute of Agrifood Research and Technology (IRTA), Spain ([email protected])
Sandra Garcés-Pastor, ICM-CSIC, Spain ([email protected])
Owen S. Wangensteen, University of Barcelona, Spain ([email protected])

We are witnessing an explosion of environmental DNA (eDNA) techniques that has already revolutionized aquatic biodiversity monitoring. eDNA offers the opportunity to complement conventional methods, delivering fast, comprehensive, and traceable biodiversity assessments. This is critical in a moment where human activities constitute a direct threat to freshwater and marine ecosystems around the world. Accurate, fast, and cost-efficient molecular tools are now available for detecting the genetic material isolated from environmental samples and inferring the presence of particular species in the sampled locations, allowing us to capture and understand changes in aquatic biodiversity with unprecedented efficiency. The explosion of large volumes of molecular data has occurred in parallel with the advancement of resilience science, providing an opportunity to approach these complex phenomena from an interdisciplinary point of view (e.g., limnology, community ecology, paleolimnology, food web ecology, coastal fisheries, disturbance ecology) and combining classical and novel bioassesment methods. The time has come now to develop robust methods to infer valuable ecological information from molecular biodiversity data. Robust molecular bioindicators would allow to develop reliable and repeatable molecular biomonitoring protocols, to accurately diagnose ecosystem health status and to evaluate the performance of management policies and recovery plans. This session aims to showcase applications and methods of eDNA research focused on the development of novel ecological quality indicators from molecular biodiversity inventories, which are expected to become key tools to robustly assess resilience and recovery of aquatic ecosystems. We aim to bring contributors from different ecological backgrounds together who synthesize disparate sources of data, including any taxonomical group (or even taxonomy-free indicators), and transcending aquatic ecosystem boundaries. This also explicitly includes the assessment of long-term ecological changes inferred from sedimentary ancient DNA studies. We will favor eDNA studies profiling novel approaches to understand ecological patterns in aquatic systems, discussing how functional biodiversity traits or sequencing data can be used to infer ecological status, introducing new molecular analysis workflows to assess ecosystem health, presenting new methods to improve efficient sampling of aquatic ecosystems, as well as better harnessing the opportunities that high throughput sequencing technologies and automatization can provide. This session will welcome delegates interested in aquatic biomonitoring and molecular bioindicators and will encourage proposals for short (10-12 mins) presentations.

Key words: bioassessment, Environmental DNA, molecular resilience

SS062 Ecosystem Consequences of the Energy Transition

Luca van Duren, DELTARES ([email protected])
Lauriane Vilmin, Deltares ([email protected])
Jan Vanaverbeke, Royal Belgian Institute of Natural Sciences ([email protected])
Josep Lloret, Universitat de Girona ([email protected])

Climate change is one of the major threats to life on earth and a rapid transition from fossil fuels to more sustainable, renewable energy sources is universally
recognized by the global scientific community as an unavoidable priority. Offshore wind is developing at a very high speed and is seen as a major contributor to the solution of the demand for clean energy. This is particularly true for the North Sea, but also elsewhere in the world. However, any large-scale implementation of infrastructure will have some impact on the ecosystem. Potentially harmful effects of wind farms, such as interference with migration routes, as well as loss of feeding habitat for seabirds, collisions with bats and damaging effects of noise from pile driving on fish and marine mammals are receiving a great deal of attention. On the other hand, offshore wind farms generally constitute exclusion areas for intensive fishing and can also seen as opportunities for restoring lost keystone species and ecosystem functions. New marine habitats created by turbine foundations and the surrounding scour protection are rapidly colonized by hard-substrate organisms. These organisms constitute an additional food source for higher trophic levels and influence the surrounding sediments. However, larger-scale consequences of such artificial reef effects on higher trophic levels are not yet clear. Recently, it has emerged that the introduction of turbines may also influence local hydrodynamics, SPM-dynamics and therefore also fundamental ecological processes, such as primary production – the basis of the marine food web. At present, certain effects (e.g. impacts on stratification) have been measured within and in the immediate vicinity of some existing offshore wind farms. However, the first results of (hypothetical) future wind farm scenarios using numerical models, indicate that impacting such physical processes may in the future have far reaching effects throughout the marine food web. While some processes are well understood and can be modelled with a certain amount of confidence, the knock-on effects of shifts at the base of the food web on fish and other higher trophic levels are largely unknown. Guidelines and policy objectives generally target these higher trophic levels. Hence, there are significant gaps between ecological assessment frameworks for offshore wind regarding these ecosystem effects that act through the marine food web. Lagging behind the offshore wind industry, but rapidly catching up, are the developments around offshore solar energy, tidal energy, wave energy and other forms of marine energy generation. These technologies, when implemented at a large scale, will also interact with the system in cumulation with the effects of offshore wind. This session invites contributions focusing on understanding and assessing the magnitude of ecosystem effects, negative as well as positive, due to marine energy infrastructure.

Key words: Energy transition, Ecosystem effects, Nature Inclusive Design, Offshore wind,

SS063 Linking Ocean Microbiomes and Ecosystem Functions

Adam Martiny, University of California, Irvine ([email protected])
Luke Thompson, NOAA Atlantic Oceanographic and Meteorological Laboratory ([email protected])

A range of new techniques have allowed for unprecedented insight into the biodiversity and functioning of marine microbiomes. These approaches are revealing the complex linkages between genotype evolution, gene expression, microbiome interactions, and large-scale biogeochemical cycles. In this session, we encourage submissions focused on lab and/or field measurements of how microbiomes interact with their environment, new approaches for understanding microbiome diversity-functioning relationships, and novel applications of models and theory for how microbial physiology and biodiversity control key ecosystem functions or biogeochemical cycles. We hope to bring together a wide range of researchers interested in ocean microbial diversity and functioning.

Key words: Microbial ecology, Genomics, Biogeochemistry, Marine microbiology, eDNA

SS064 Resilience of Aquatic Ecological Systems to Heatwaves

Daniel Gómez-Gras, Universitat de Barcelona/Hawaii Institute of Marine Biology (University of Hawaii at Manoa) ([email protected])
Pol Capdevila, Universitat de Barcelona ([email protected])
Cristina Linares, Universitat de Barcelona ([email protected])
Núria Marbà, Mediterranean Institute for Advanced Studies (IMEDEA/CSIC) ([email protected])

In the current context of global warming, aquatic systems are experiencing an increase in both the frequency and intensity of extreme climatic events. As such, aquatic heatwaves, discrete periods of extreme warm water temperatures, are emerging as one of the most pervasive threats to both marine and freshwater biodiversity. From lakes to oceans, through estuaries, rivers, and seas worldwide, heatwaves are re-shaping aquatic life across all levels of ecological organization, compromising their resilience and their provision of ecosystem services to human societies. These extreme events are predicted to increase in the coming decades, even if emission reduction policies are effectively applied. Consequently, improving our understanding of the responses of ecological systems at different levels (from individuals to communities) to aquatic heatwaves is essential to anticipate irreversible changes to their structure, functioning and services. This session will therefore welcome contributions that explore the immediate and/or long-term impacts of aquatic heatwaves across disciplines (e.g., oceanography, limnology, population and community ecology, behavioral and functional ecology), levels of organization (e.g., individuals, populations, communities and ecosystems) and taxonomic groups (e.g., fish, plants, macroalgae, invertebrates, plankton). The session will also welcome studies taking place at different spatial and temporal scales, such as contributions related to the exploration of the past, current and future aquatic heatwave trends. Contributions using novel approaches (e.g., to better predict the occurrence of heatwaves) or exploring conservation, adaptation and/or management strategies will also be encouraged. Overall, the session aims to provide an interdisciplinary and cross-taxonomic view of one of the most pressing topics in aquatic sciences. The session will render a general overview of the vulnerability of aquatic systems to current and future heatwave conditions, with the opportunity to promote discussions about the future research challenges.

Key words: heatwaves, global warming, resilience, ecological impacts, extreme climatic events

SS065 Genomics as a Biomonitoring Tool for Marine Ecosystems and Fisheries Management

Eric Raes, Minderoo Foundation, Flourishing Ocean, Australia ([email protected])
Madi Green, The Commonwealth Scientific and Industrial Research Organisation, Australia ([email protected])
Giulia Maiello, University of Rome Tor Vergata, Italy ([email protected])
Tommaso Russo, University of Rome Tor Vergata, Italy ([email protected])

Marine genomics is rapidly enhancing how we study, model, and ultimately protect marine ecosystems. In recent times, a growing number of scientific marine fields are incorporating genomic surveys into their biomonitoring toolkits as genomic methods can deliver significant ecological information including broad and accurate species identification. By harnessing the power of data, new technologies, and information we can better understand the world around us, build knowledge, and make more informed conservation decisions. In particular, given the rapid advancement and reduction in costs associated with implementing environmental DNA (eDNA) methods, it is anticipated that eDNA workflows will become part of the toolkit for conservation planning, adaptive management of Marine Protected Areas and monitoring of global fisheries. Identifying reliable and inexpensive methods to enhance research outcomes and execute effective policies and management strategies is key for protecting marine ecosystems. This session will showcase studies that highlight the advancement and application of high-throughput eDNA technologies as a long-term, ocean-scale biomonitoring tool to characterize marine wildlife, monitor fishing activity and assess ecosystem health. A specific focus of this session is to bring researchers and practitioners together to communicate how eDNA and genomics observations can become standard tools for Marine Protected Area (MPA) management and fisheries monitoring. In conclusion, eDNA has enormous potential to be used as a non-invasive, archivable, and high-throughput biomonitoring tool. The ultimate objective of this session is to share knowledge and insights towards accelerating the application of genomics tools in the day-to-day operations of conservation and fisheries managers – with the ultimate goal to protect life in the oceans.

Key words: eDNA, Marine Protected Areas, Fisheries, Genomics, Policy

SS066 Ocean Acidification 2.0 – From Chemistry to Society

Sam Dupont, University of Gothenburg ([email protected])
Iris Hendriks, IMEDEA (CSIC-UIB) ([email protected])
Jan Newton, University of Washington ([email protected])

Ocean acidification has gained increasing recognition across national and international policy frameworks, such as national ocean action plans, the 2030 Agenda and the UNFCCC. To fully address and minimize its effects, scientists, governments, and end-users will benefit from co-designing science, monitoring, research, and syntheses that support informed choices about national mitigation, adaptation, and preparedness strategies. An overwhelming body of evidence documents ocean acidification, with potential significant impacts on marine species and ecosystems. The increase of atmospheric CO 2 due to fossil fuel burning is the main driver of ocean acidification in the open ocean. In the coastal zone, the variability in p CO 2 and pH is also driven by biological, near-shore and land-based processes, such as river run-off, stratification, and tides. The complexity of bridging chemical and biological changes associated with ocean acidification is often under-estimated. Today, projections rely mainly on proxy variables like pH, carbonate saturation states, dissolved oxygen, temperature, and salinity, and simplistic thresholds to speculate about the status and trends of biodiversity and ecosystem services. Ecosystem response to ocean acidification can be only assessed when considering factors such as adaptation to local chemical variability, evolutionary processes, ecological interactions, and the modulating role of other environmental drivers or stressors. Therefore, global, regional, and local impacts on biology and ecology, whether gradual or stepwise, are not fully resolved. Experimental work often over-simplifies these processes, for instance by focusing on single species and stressors, short-term responses, and static conditions that do not incorporate natural variability. Ocean observing and data are often focused on one or a handful of physical and biogeochemical parameters, but generally do not include biology and ecosystem. On the other hand, results from experimental work and from in situ observing efforts are not always well integrated into synthesis and modeling efforts. As a consequence, although data are being generated about ocean acidification changes and separately about some ecological changes, we are not able to evaluate whether a local resource or ecosystem service is changing due to ocean acidification. The UN Decade program “Ocean Acidification Research for Sustainability” (OARS) aims to provide a road map to fill these gaps. In line with the vision of OARS, this session aims at providing a platform for the ocean acidification community together with those who have a shared interest of protecting and conserving biodiversity in the face of global changes. It will promote actions to address the need for broader, more diverse, inclusive, and interdisciplinary collaboration and co-design of science and action. There is a need for purposeful efforts to facilitate inclusion of all interested researchers in monitoring and ocean acidification research networks. We will encourage submission of poster and presentation focusing on, for instance, co-design approach, new experimental designs encompassing the chemical and biological complexity (e.g. natural variability, ecology, evolution, multiple stressors), syntheses and meta-analyses, and unification of chemical and biological observations.

Key words: Ocean acidification, Observation, Biological impacts, Synthesis, Co-design

SS067 Emissions of CO2 From Fluvial Networks Across Climatic Regions and Land Uses: Patterns, Sources, and Drivers

Susana Bernal, Centre for Advanced Studies, CEAB-CSIC ([email protected])
Flavia Tromboni, University of Nevada ([email protected])
Gerard Rocher-Ros, Swedish University of Agricultural Sciences ([email protected])
Anna Lupon, Centre of Advanced Studies of Blanes (CEAB-CSIC) ([email protected])
Núria Catalan, CNRS-France ([email protected])

Streams and rivers emit large amounts of carbon dioxide (CO 2 ) to the atmosphere, which is sourced both by groundwater inputs of terrestrially produced CO 2 as well as from in-stream metabolic processes. The contribution of these two sources can vary largely across time and space depending on physical factors (i.e. topography, hydrological connectivity, land uses) as well as on biological factors (i.e. ecosystem production, soils and in-stream carbon mineralization, benthonic and microbial communities). Yet, we still lack a general understanding of how these sources, relative contributions and controlling factors vary over spatial and temporal scales with changing climate, hydrological conditions, or land uses. This knowledge gap limits our capacity to assess the role of streams in the carbon cycle, and to predict how CO 2 sources will vary under future climate and human impacts. This special session welcomes empirical and modelling studies focused on understanding the drivers of spatiotemporal variability of stream CO 2 emissions and its contributing sources. We seek contributions that together encompass a wide range of climatic conditions and biomes, including the dry phase of those ecosystems. Studies analyzing patterns of CO 2 emissions at different spatio-temporal scales are welcome as well as more mechanistic studies exploring how environmental factors influence in-stream metabolic activity and associated CO 2 emissions by impacting on stream community structure and functioning.

Key words: CO2 emission, stream metabolism, groundwater CO2 inputs, spatiotemporal variability, patterns across climatic and land use gradients

SS068 Extreme Climatic Events: A Challenge for Shallow Coastal Ecosystems

Sokratis Papaspyrou, University of Cadiz ([email protected])
Alfonso Corzo, University of Cádiz ([email protected])

Global warming due to greenhouse gasses emissions already has significant impacts on Earth’s climate system. In addition to changes in the mean air and sea temperature leading to sea ice melting and sea level rise, it will affect atmospheric and oceanic circulation and, consequently, precipitation patterns, including the frequency and duration of extreme climatic events (ECE) like heatwaves, strong winds, storms and hurricanes. ECE are considered any climatic events with a magnitude that deviates significantly from the local recorded average. Winter storm intensity, increased strength and number of days of winds and increased frequency of heatwaves leading to severe droughts and dessication stress are expected to increase. Coastal environments, where a large fraction of world population is concentrated, will be increasingly exposed to natural hazards, making urgent the need to understand how these changes affect the ecosystem structure and functioning to gain a better scientific understanding of long term impacts. This session will explore the effects of ECE on the shallow coastal communities from the micro to the macroorganisms and from the micro to the macroscale in a multidisciplinary approach.

Key words: Extreme events, Heatwaves, Storms, Droughts, Climate change

SS069 Promoting Resilience Through Climate-Smart Fisheries and Conservation Management

Marina Sanz-Martín, Oceanography Center of The Balearic Islands, Spanish Institute Of Oceanography (COB, IEO-CSIC) ([email protected])
Marta Albo-Puigserver, OCEANOGRAPHY CENTER OF THE BALEARIC ISLANDS, SPANISH INSTITUTE OF OCEANOGRAPHY (COB, IEO-CSIC) ([email protected])
Lucía López-López, OCEANOGRAPHY CENTER OF SANTANDER, SPANISH INSTITUTE OF OCEANOGRAPHY (COST, IEO-CSIC) ([email protected])
Francisco José Ramírez, Institut de Ciències del Mar (ICM-CSIC) ([email protected])
Nur Arafeh-Dalmau, University of Queensland, Centre for Biodiversity and Conservation Science ([email protected])

Climate change is impacting marine ecosystems worldwide with direct and indirect consequences for marine socio-ecological-systems (SES). As these impacts continue to increase in magnitude and frequency, the implementation of climate-adaptation strategies for marine ecosystems is becoming more urgent. Yet, while many scientific tools are being used to evaluate the exposure, sensitivity, risk, vulnerability, and resilience of marine SES, there is a lack of a common framework and coordination between researchers and managers. Thus, climate-adaptation for fisheries and marine conservation requires the use of a common framework, such as the climate-smart process that addresses the vulnerability of ecosystems to climate change impacts.

This proposed session provides a framework to identify the responses of SES to climate impacts and a portfolio of climate-adaptation strategies. Give that the methodological and research advances are increasing the range of available tools to address climate change impacts, it is timely to promote the use of climate-smart framework. These improvements in management and research approaches are key to the successful implementation of climate-smart strategies required to mitigate changes and ensure the future sustainability of marine SES.

Contributions that focus on impacts of climate change on commercial, threatened, or ecologically important marine species and ecosystems and climate-smart management are encouraged. We will discuss the influence of climate change on ecosystem, community and species levels, their socio-economic impacts and how to implement climate-smart adaptation strategies in both conservation and fisheries to support resilience. The main objective of this session is to connect cutting edge climate change science with fisheries and conservation management to advance human-based solutions to the ongoing effects of the climate emergency on marine SES.

We welcome contributions related, but not limited to the following topics:

• Responses of marine resources (i.e. fish stocks) to the impacts of climate change.
• Methods and metrics used to assess fisheries resilience to climate change.
• Advantages and limitations of methods used to evaluate risk, vulnerability and
• resilience of marine SES.
• Ecological and socio-economic impacts of climate change on the fisheries and
• conservation sectors.
• Implementations of climate-smart conservation and fisheries management and
• future directions.

Key words: climate change, resilience, adaptation, fisheries, marine conservation

SS070 Benthic-Pelagic Coupling in Coastal and Continental Shelves: Impact of Recurrent Perturbations, System Resilience, and Recovery

Arthur Capet, Royal Belgian Institute of Natural Sciences (RBINS) - (Operational Directorate Natural Environment (ODNature)) ([email protected])
Ulrike Braeckman, Marine Biology Research Group, Ghent University, Gent, Belgium ([email protected])
Christophe Rabouille, Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL,CEA-CNRS-UVSQ-Université Paris Saclay, 91198 Gif sur Yvette, France ([email protected])
Sebastiaan van de Velde, Department of Geoscience, Environment and Society, Université Libre de Bruxelles, Brussels, Belgium ([email protected])

Coastal continental shelf areas play an important role in modulating the exchange of carbon and nutrients between terrestrial and oceanic realms. These marine ecosystems additionally provide essential ecosystem services, such as food provisioning, biodiversity maintenance, nutrient cycling, and carbon sequestration. At the same time, ongoing global change and the expansion of blue economy activities increase the pressure on these vulnerable systems in the form of recurrent perturbations and extreme events, such as (but not limited to) seasonal hypoxia, marine heat waves, storms, bottom trawling, oil spills, and flood deposits. Benthic-pelagic coupling refers to the exchange of energy, mass, or nutrients between benthic and pelagic habitats. The impact of global change - or anthropogenically induced pressures can affect either or both of the ecosystem compartments, but our understanding of the ensemble of processes in this continuum is limited. This session aims at increasing our understanding of the resilience of these valuable ecosystems towards external and recurrent disturbances of varying intensities and frequencies. This session welcomes research from different disciplines and is open to observational, modeling, and theoretical studies. We particularly encourage abstracts addressing benthic-pelagic coupling and specifically the functions of the seafloor, and welcome abstracts addressing both changes in the frequency and intensity of external pressures, as well as research characterizing the functional and structural responses of ecosystems.

Key words: Coastal zones, Continent-ocean transition, Marine biogeochemistry, Benthic-pelagic coupling,

SS071 Untangling the Role of Environmental Variability in the Resilience and Recovery of Marine Biota to Climate Change

Andrea Anton, Mediterranean Institute for Advanced Studies (IMEDEA), CSIC-UIB, Spain ([email protected])
Maren Ziegler, Justus Liebig University Giessen, Germany ([email protected])

Accurately predicting organismal responses to climate change is essential for the conservation of global biodiversity. The variability of environmental conditions on spatial (from organism to ecosystem scale) and temporal (hours and days to months and years) is a central factor determining the resilience and recovery of marine organisms and populations under climate change. However, the majority of research quantifying and predicting the response of marine organisms to climate change is performed under static (or average) environmental conditions and therefore does not account for environmental variability. This special session welcomes empirical research that incorporates environmental variability (e.g., of temperature, dissolved oxygen, pH, currents, waves, nutrients, etc.) to assess the susceptibility of marine biota to current and future climate change in experimental approaches or quantifies its spatio-temporal scales in marine habitats. We invite researchers who bring together methods or data from various disciplines to answer questions that address short- and long-term fluctuations in the marine physical environment and its intersection with the phenotype of organisms inhabiting a wide range of marine habitats. Studies that describe historical, current, and projected ocean environmental variability under different scenarios of greenhouse gas emissions are also welcome.

Key words: Climate Change, Environmental variability, Marine organisms, Temperature,

SS072 Host-Microbiomes To Protect and Restore Marine Communities of Animals, Plants and Algae

G Muyzer, University of Amsterdam ([email protected])
Aschwin Engelen, CCMAR, Faro, Portugal ([email protected])

Marine organisms, such as seaweeds, seagrasses, and sponges, harbour a rich diversity of associated microorganisms that play a role in host health and defence. Bacteria can provide essential nutrients to their host or protect them from environmental perturbations, such as increasing temperatures or detrimental colonization by microscopic and macroscopic epibiota. This session will bring together leading scientists who study the interactions of marine organisms with their associated microbiomes using novel state-of-the-art techniques with the possibility of monitoring and improving their restoration success.

Key words: holobiont, corals, seagrasses, macroalgae, omics

SS073 From Single Cells to Ecosystems Scales – Connectivity Between Microorganisms and Their Environment

Soeren Ahmerkamp, Max Planck Institute for Marine Microbiology, Bremen ([email protected])
Klaus Koren, Aarhus University ([email protected])
Lars Behrendt, Science of Life Institute, Uppsala University ([email protected])

In aquatic ecosystems, physical transport processes connect organisms to their environment. At the level of a single cell in the range of a few micrometers, transport via diffusion dominates. At millimeter to centimeter scales, transport via laminar flow becomes prevalent until turbulent mixing dominates. In heterogeneous aquatic environments, organisms often face substrate limitation resulting from high metabolic activity that cannot be sustained through passive transport. To overcome these limitations organisms have therefore evolved a variety of mechanisms to optimize mass transfer and navigate within heterogeneous aquatic environments. These allow them to make substrates more readily available and deal with external stressors. A prime example are cilia and flagella, which enable organisms to either seek out food or propel substrates towards themselves. Other examples include collective mixing by bacterial swarming, chemo/phototaxis, or osmotic pressure controls in plants. In recent years, a variety of methods have been developed to better understand the interaction of organisms with flow and the external environment. These methods cover chemical imaging, high-speed imaging, particle velocimetery, NMR-spectroscopy, microfluidics, schlieren, mathematical modelling and many others. We invite submission across disciplines that investigate mass transfer around organisms and within their environment. Typical organisms include corals, sponges, tunicates, ciliates, crustaceans and flagellated prokaryotes but also marine snow particles and others. The particular aim of the session is to highlight new and existing approaches and methods in which physical and biological science is combined. In discussion rounds we aim to share technologies across disciplines and inspire new lines of research.

Key words: Connectivity, Biogeochemistry, Physical Transport, Flow-organism interaction, Mass transfer

SS074 Aquatic Biofilms Under Stress: Barriers or Drivers of Environmental Changes

Giulia Gionchetta, Eawag ([email protected])
Nuria Perujo, UFZ Helmholtz Center for Environmental Research ([email protected])
Anna Freixa, ICRA Catalan Institute for Water Research ([email protected])

Aquatic biofilms are subjected by multiple stressors and their responses to such perturbations are a growing concern for aquatic scientists. Here, we understand stress or perturbation as a measurable change in ecosystems that is caused by chemical, physical or biological anthropogenic pressures. In freshwater and brackish ecosystems, microbial biofilms are key players at the base of trophic networks and, due to their small size and fast generation time, they respond very quickly to environmental changes, performing as indicators of the ecosystem status. In turn, depending on the type and intensity of the stressor microbial biofilms could harbour or be conduit of mixtures of contaminants and/or microorganisms released in the receiving media, becoming barriers or drivers of environmental changes. The main goal of the session is to understand how aquatic microbial biofilms respond to stressors (or multiple stressors) and their potential to act as early warning indicators of ecosystem health. This session welcomes presentations that contribute to elucidating the effects of pollution (e.g., pharmaceutical residues, heavy metals, nutrient loadings, organic contaminants, microplastics, pesticides…) climate change (e.g., warming waters, increase in salinity, changes in precipitation patterns, land uses, droughts, extreme events) or biological stressors (e.g., invasive species) on microbial aquatic biofilms. This includes evidence from field, laboratory and theoretical or modelling based studies. Talks will encompass research conducted over broad spatial and temporal scales to create a comprehensive picture of the current knowledge base. It is worth mentioning that in an increasingly changing future, knowing how microbial communities – and their functions – respond to it will help us to predict the impacts of stressors in aquatic ecosystems.

Key words: multiple stressors, aquatic biofilms, aquatic pollution, climate change, ecosystem health

SS080 Critical Conditioning: Consequences, Controls and Limits on Southern Ocean productivity

William Balch, Bigelow Laboratory for Ocean Sciences ([email protected])
Dennis McGillicuddy, Woods Hole Oceanographic Instituation ([email protected])
Nicolas Bates, Bermuda Institute of Ocean Sciences ([email protected])

The Southern Ocean has physical, chemical, biological and biogeochemical impacts on the waters of all the major ocean basins on Earth. In the top kilometer of the world ocean, this connectivity can be traced through northward flows of Subantarctic Mode Water and Antarctic Intermediate Water, which begin their equatorward journey from various frontal boundaries of the Antarctic Circumpolar system. Mesoscale eddies also spin-off from these frontal boundaries, carrying thousand-meter-deep, semi-contained, water parcels northwards. Common to both of these transport phenomena is the pre-conditioning of these waters by resident microbial communities (e.g. diatom communities at the Polar Front or coccolithophore communities at the Subantarctic Front), prior to and during their northward journey. Indeed, the extent of conditioning that occurs in the Southern Ocean prior to subduction can affect processes like global nutrient budgets and subsequent global ocean productivity a hemisphere away over time scales of decades. It is not an exaggeration that the resilience and renewal of these Southern Ocean waters are related to the resilience and renewal of the global marine ecosystem. The purpose of this session is to highlight the controls on Southern Ocean productivity, how Southern Ocean waters are regionally conditioned biologically, chemically and physically as well as the consequences over decades as these waters leave the circumpolar system towards the northern hemisphere.

Key words: Southern Ocean, Primary production, Trace metals, phytoplankton, Coccolithophores

SS081 JPI Oceans Joint Action: Ecological Aspects of Microplastics – From Scientific Findings to Political Action

Jella Kandziora, JPI Oceans ([email protected])
Aaron Beck, GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel ([email protected])
Tonia Capuano, Universidade Federal de Pernambuco, Brazil ([email protected])
Richard Sempere, Université d'Aix-Marseille ([email protected])
Patrizia Ziveri, Universitat Autònoma de Barcelona ([email protected])

Based on the output of a first call on ecological aspects of microplastics in the marine environment, JPI Oceans (Joint Programming Initiative Healthy and Productive Seas and Oceans) launched a second call in 2018 on the topic ”Sources, distribution & impact of microplastics in the marine environment”. Scientists from 15 countries (JPI Oceans members plus Latvia and Brazil) are working in 6 projects to fill knowledge gaps and deliver societally relevant results on this emerging issue. The projects seek to identify sources of microplastics, to advance analytical methods for identifying smaller micro-and nanoplastics, to monitor their distribution and abundance in marine ecosystems, and understand their effects thereon. The expected results will bring forth information on marine microplastic degradation and help developing concepts to reduce inputs of plastics into the marine environment. The ongoing projects have already provided valuable input to the European Commission’s Technical Group on Marine Litter, which supports and guides the implementation process of the Marine Strategy Framework Directive in close collaboration with EU member states. During this session, the project partners in collaboration with the JPI Oceans Secretariat, will present the recent findings of the funded projects. The aim of our session is to present project outcomes thus far and to discuss with the audience how these scientific results can help policy makers and other user groups take action. Growing scientific evidence on the ubiquity, irreversibility, and long-term persistence of nano- and microplastic pollution in aquatic environments underscores how science-to-policy dialogue should guide corresponding management. In this context, communication and dissemination plays a crucial role to support science-based policy advice. Hence, the JPI Oceans microplastics projects also put special emphasis on public outreach via social media, workshops, stakeholder meetings, popularized publications and awareness raising campaigns. We strive for jointly discussed and agreed solutions to restore and enhance our Ocean, Seas and Waters by contributing to the achievement of goals defined inter alia in the EU Marine Strategy Framework Directive (MSFD – 2008/56/EC), the European Green Deal, the EU Mission Restore our Ocean and Waters, as well as the UN 2030 Agenda for Sustainable Development Goals.

Key words: nano- and microplastics, abundance and distribution of microplastics, impact of marine science, science-to-policy, harmonization of analytical methods

SS082 Mechanisms and Costs of Adaptation to Global Change in Aquatic Systems

Jimmy deMayo, University of Colorado Denver ([email protected])
Hans Dam, University of Connecticut ([email protected])
Melissa Pespeni, University of Vermont ([email protected])
Reid Brennan, GEOMAR Helmholtz Centre for Ocean Research ([email protected])
Cornelia Jaspers, Technical University of Denmark ([email protected])

Global change drivers (e.g., warming, acidification, deoxygenation, harmful algal blooms, etc.) pose individual and combined challenges to the persistence of aquatic populations. There is growing recognition that evolutionary adaptation on contemporary time scales may rescue populations from these challenges. However, cases documenting costs of adaptation and maladaptation that constrain evolutionary rescue remain limited. This session invites contributions documenting processes of adaptation, evolutionary rescue, costs of adaptation, and maladaptation in aquatic populations. We welcome studies at the phenotypic level or genetic level, and particularly their combination using such approaches as experimental evolution, space-for-time substitution, time-series, and the fossil record. Studies that involve multi-stressor experiments and identify the types of interactions (additive, synergistic or antagonistic), or provide new conceptual and methodological perspective on the effects of global change drivers on adaptation are particularly welcome. Across all studies, we seek research that highlights if adaptation is constrained/limited or if populations experience trade-offs/costs (i.e. fitness penalties or decreases) after adapting to novel environments. We seek a diverse group of presentations from students, early career scientists, and well-established researchers working on a variety of organisms from microbial to top predator populations in marine and freshwater habitats.

Key words: Adaptation, Limits, Trade-offs, Global change, Evolutionary rescue

SS083 How Data-Intensive Research Has Increased Understanding of Freshwater Ecosystems Across Broad Geographies and Through Time

Patricia Soranno, Michigan State University ([email protected])
Kendra Spence Cheruvelil, Michigan State University ([email protected])
Katherine E. Webster, Michigan State University ([email protected])

Human-induced global stressors, such as climate change, land use intensification, and the spread of invasive species, are amongst the greatest challenges of the 21st century, with significant consequences for aquatic resources, ecosystem and human health, and the economy. Empirical studies across broad scales of space and time and that include tens to thousands of freshwater ecosystems are critical to further understand the potentially diverse responses of aquatic ecosystems to global changes. This session invites presentations that consider such issues in all types of freshwater ecosystems and for all types of response variables (biology, chemistry, physics). We also invite a broad representation of different analytical approaches for studying freshwater ecosystems at broad scales including, but not restricted to machine learning, artificial intelligence, statistical, process-based, and descriptive approaches. We invite presenters to consider emerging challenges and opportunities for addressing such challenges to conduct research at these broad scales of space and time, to understand freshwaters within diverse ecological contexts, and to look forward to future research directions.

Key words: Landscape Limnology, Climate change, Freshwater ecosystems, Global change, Macrosystems ecology

SS087 Biological Pump Dynamics and Trophic Transfer in Pelagic Ecosystems of the Atlantic

Rubens Lopes, University of Sao Paulo ([email protected])
Rainer Kiko, GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel ([email protected])
Helena Hauss, NORCE Norwegian Research Centre, Norway ([email protected])
Lars Stemmann, Institut de la Mer de Villefranche (IMEV) ([email protected])

The biological pump is a major driver of carbon export from the atmosphere into the upper mixed layer and down to the deep ocean, where carbon is sequestered for several centuries. Plankton- and nekton-mediated processes affect the magnitude of gravitational and active carbon fluxes, controlling a plethora of key mechanisms such as ocean acidification, trophic transfer, and bentho-pelagic coupling. Carbon export efficiency varies significantly depending on the magnitude of photoautotrophic production, the influence of species composition and food web structure at different depths and trophic levels. Both primary and secondary producers are thus major drivers of biogeochemical feedbacks to global change. In recent years, a significant effort was put in motion to promote integrative ocean science connecting countries along and across the Atlantic Ocean, building from the initial impulses given by the Galway and Belém Statements signed by the European Union and Atlantic partners. Important research efforts within this framework investigate Atlantic ecosystems, their microbiome and metazoan communities, the different components of the biological pump and related biogeochemical cycles, and strategies to manage the Atlantic ecosystems in the context of expected global change. The application of novel molecular and imaging tools, in concert with seascape and connectivity studies and modelling approaches, drive recent progress in understanding the pelagic ecosystems of the Atlantic. Questions that now can be addressed also include the resilience and recovery potential of the biological pump and trophic transfer towards global change and human perturbations. This session invites contributions that represent new advances in understanding overall ecosystem functioning and carbon fluxes from the surface to the deep ocean. These could range from process studies over contributions from observational efforts to modelling approaches demonstrating how novel data and analytical tools can improve our understanding of plankton- and nekton-mediated carbon fluxes in the Atlantic during times of global change.

Key words: Biological Carbon Pump, Trophic Transfer, All-Atlantic Research Alliance, Global change, Sustained observations

SS088 Advances in Understanding, Prediction, and Monitoring of Toxic Karenia (Dinoflagellate) Blooms Around the Globe

Anne Booker, Bigelow Laboratory for Ocean Sciences ([email protected])
Tristyn Bercel, Mote Marine Laboratory & Aquarium ([email protected])
Carly Moreno, New York University Abu Dhabi ([email protected])
Cong Fei, New York University Abu Dhabi ([email protected])
Cynthia Heil, Mote Marine Laboratory & Aquarium ([email protected])

The genus Karenia includes 12 species of bloom-forming mixotrophic dinoflagellates that can be found in oceanic and coastal waters worldwide. When they bloom, many Karenia species produce toxins that negatively affect marine ecosystems. These negative effects cascade into local coastal communities by requiring resources to remove dead sea life, harming human health, and decreasing business revenue. Significant advancements have been made in Karenia research focused on bloom monitoring and forecasting, species identification and differentiation, culturing and ecophysiology, microbial interactions and toxin production, impacts on human health and local economies, and climate change-induced range expansion and enhanced detection. Despite these advances, major gaps in knowledge hamper our ability to predict bloom dynamics, such as incomplete genome sequencing and how or why toxins are synthesized. To gain new perspectives and synthesize recent progress, we broadly encourage the submission of abstracts focusing on all aspects of Karenia research. Which Karenia species are affecting our neighborhoods? How do physical oceanographic processes influence bloom formation? What are we learning about this genus in the laboratory and how can this knowledge be applied to understand better and predict Karenia blooms? How do our marine communities respond to blooms and what techniques are we using to build resiliency? Ultimately, we aim to foster a discussion around global Karenia research in order to enhance our understanding of this important genus while identifying commonalities and unique features across species and environments. With this aim in mind, we strongly encourage abstract submissions on topics covering (but not limited) to physical and chemical oceanographic processes influencing Karenia , modeling and monitoring of blooms, ecophysiology and toxin production, molecular and genetic studies, and newly-developed technologies that facilitate research progress of Karenia .

Key words: HAB, Global, Karenia, Phytoplankton, Toxic

SS089 The Biogeochemistry of Dissolved Organic Matter

Sinikka Lennartz, University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment ([email protected])
Sarah Bercovici, University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Germany ([email protected])
Jessika Fuessel, University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Germany ([email protected])
Brett Walker, University of Ottawa, Department of Earth and Environmental Sciences, Canada ([email protected])
Taichi Yokokawa, Agency for Marine-Earth Science and Technology, Japan ([email protected])

Dissolved organic matter (DOM) contains as much carbon as all living biomass on the continents and oceans combined and plays a major role in global biogeochemical cycles. As bacteria can assimilate and respire only dissolved molecules, DOM represents the main mediator of energy flux in marine and freshwater ecosystems. While most of the molecules released by phytoplankton at the surface are respired in seconds to decades, a fraction of DOM escapes remineralization and can persist in the ocean for millennia. As these molecules carry the signatures of their source and subsequent journey through the marine environment, they parallel the sedimentary record as an information-rich set of tracers. Moreover, the molecular diversity of the marine DOM pool poses a metabolic challenge to microbial communities that rely on its utilization. Using interdisciplinary approaches to couple global scale analyses of DOM with microbial and molecular level research is important to fully understand this important pool of carbon. For this session, we invite contributions from all areas of research on DOM biogeochemistry, including both empirical and modeling studies. We encourage contributions that apply innovative analytical approaches, or identify novel concepts, fundamental challenges and the future directions of this fast growing field of research.

Key words: Dissolved organic matter, microbial interactions, biogeochemical cycles, ocean biogeochemistry, freshwater biogeochemistry

SS090 Plastic Pollution in Aquatic Systems: The Role of Biogenic Habitats in the Dynamics and Accumulation of Plastics

Gema Hernán, Mediterranean Institute for Advanced Studies ([email protected])
Julia Máñez-Crespo, Mediterranean Institute for Advanced Studies ([email protected])
Carmen B. de los Santos, CCMAR-Centre of Marine Sciences ([email protected])

Plastic pollution is an emerging environmental problem, as it can negatively affect ecosystems and biodiversity and cause socio-economic damage. The plastic global mass production, disposal and mismanagement have resulted in the accumulation of immense amounts of plastic litter in aquatic environments, with sizes ranging from macro- to nano-plastics. Once plastics enter the aquatic systems, they can be degraded into smaller fragments, be entangled in living organisms, aggregated with natural colloids, settled into the sediment, or become resuspended and transported back out of the system. The increasing concentration of plastics into aquatic systems demands investigating the transport, fate, and impacts of plastic pollution, in particular in ecosystems that are key for biodiversity support. Aquatic ecosystems are vulnerable to the accumulation of plastic waste due to the location of dense human populations, especially along the coasts, with inputs of plastics from rivers and debris washed ashore from the open ocean. In particular, coastal habitats such as seagrass meadows, salt marshes, mangrove forests or oyster and coral reefs are known to enhance trapping, deposition or burial of suspended particles through attenuation of the current and wave energy, through stabilisation of the sediment from resuspension or though their filtering capacity. In the last few years there has been a growing interest about the role of these canopy-forming and biogenic habitats in plastic trapping, leading to research works on the abundance and characterisation of plastics in them, as well as in the biophysical factors underlying their plastic retention capacity. In fact, recent studies evidenced that these habitats trap plastic particles within their biogenic structures, making them microplastic sinks or hotspots of plastic accumulation. This session aims to gather ecological research studies on the assessment and quantification of plastic pollution, from macro- to nano-plastics, in different aquatic biogenic habitats, as well as strategies to reduce and manage plastic litter in these areas. We welcome both observational, experimental, and modelling works elucidating the role of aquatic systems on the dynamic and accumulation of plastics.

Key words: Coastal vegetated habitats, Aquatic vegetation, Biogenic habitats, Microplastics, Plastic pollution

SS091 Environmental Variability in a Multi-Factorial World: Connecting Experiments With Theory in Aquatic Systems

Miriam Gerhard, Universidad de la República, Uruguay ([email protected])
Apostolos-Manuel Koussoroplis, Université Clermont Auvergne, CNRS, Laboratoire Microorganismes Génome et Environnement, F-63000 Clermont–Ferrand, France; ([email protected])
Maren Striebel, Universität Oldenburg, ICBM ([email protected])
Alexander Wacker, Universität Greifswald ([email protected])

Natural systems are variable, and consequences of environmental variability have been increasing in relevance under climate change scenarios where not only changes in mean but also in variability patterns (magnitude, frequency, rate of change, interactions of multiple factors, etc) are expected. Motivated by such observed and predicted changes, investigations including or focusing on variability are accumulating. However, no common framework exists for approaching environmental variability research and the mismatches between theory and empirical data challenge our current understanding. In this session, we will contribute to a more integrated variability research by including studies that deal with relevant aspects of variability and propose how to approach variability from an experimental point of view while fostering integration with modelling approaches and experimental design aspects. Theoretical and experimental studies addressing the following aspects are highly welcome: (i) considering relevant terms of variability research including the components (characteristics) of variability and relevant types of multi-factorial interactions, (ii) applying relevant conceptual frameworks used for understanding the consequences of environmental variability in single and multifactorial scenarios, (iii) highlighting challenges for bridging theoretical and experimental studies involving simple to complex, closer-to-nature scenarios. With this session we aim to provide examples and a guide for future experimental efforts including how environmental variability experiments across different scales, degrees of control, and complexities can be combined according to their strengths and limitations.

Key words: Environmental variability, Climate change, multi-factorial interactions, theory, empirical data

SS092 The Relevance of Small Systems: Pond Ecology in a Changing World

Zsofia Horvath, Institute of Aquatic Ecology, Centre for Ecological Research ([email protected])
Dunja Lukić, Research Department for Limnology, University of Innsbruck, Mondsee, Austria ([email protected])
David Cunillera-Montcusí, GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain & FEHM-Lab (Freshwater Ecology, Hydrology and Management) Section of Ecology, Department of Evolutionary Biology, Ecology and Environmental Sciences University of Barcelona & Departa ([email protected])
Dani Boix, GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain ([email protected])

Ponds are aquatic systems with small surface area (< 5 ha) and shallow depth (< 5 m). Even though these systems are numerous in almost any landscape worldwide, they have received less attention than larger lakes and rivers. Despite their small size, these systems have enormous global importance as they promote biodiversity, play key ecosystem functions, and connect the waterscape acting as stepping-stones in the dispersal of local species. However, their small size also makes them fragile and susceptible to impacts due to global change and other anthropogenic stressors (i.e. agriculture or urbanization) that can alter their water balance and eventually lead to their disappearance. For this session, we welcome both empirical (including a wide variety of ponds and pools) and experimental work (in the form of micro- or mesocosms), in addition to simulations and theory, focusing on population, community, or ecosystem scales in these understudied systems.

Key words: ponds, metacommunities, biodiversity, metaecosystems, ecosystem services

SS093 Coastal Blue Carbon Ecosystems: Advances and Challenges

Miguel-Ángel Mateo, Consejo Superior de Investigaciones Científicas ([email protected])
William Austin, University of St. Andrews ([email protected])
Grace Cott, University College Dublin ([email protected])
Paul Steven Lavery, Edith Cowan University ([email protected])

A catchy name and an apparently easy translation into economical terms has made Blue Carbon (BC) research an unstoppable phenomenon. The capacity of coastal BC ecosystems (CBCE) to capture and store organic carbon in sediments over hundreds or thousands of years is granting these habitats a purportedly relevant place in the context of biospheric sinks and, whether good, bad or both, in carbon trading schemes. Even though mangrove forests, tidal marshes, and seagrass meadows are already recognized in the major climate conventions and frameworks as potentially valuable contributors to climate change mitigation and adaptation, we are still a long way from having the necessary evidence to rigorously assess that potential. Major knowledge gaps are as fundamental as knowing the past and present size of these CBCEs (mapping) and their associated carbon stocks (plant biomass and soil), associated carbon fluxes (through accretion rates), conservation status, restoration potential, and vulnerability (and risk) from ongoing climate and anthropogenic pressures (e.g., global warming, eutrophication, or habitat mechanical destruction). Other key knowledge gaps challenge the very heart of the BC concept, such as whether or not to include algal forests into the BC family, quantifying and adding or not the BC-derived “off-site” stocks, resolving the controversy of a possible double accounting, or the long-standing critical debate on the role of carbonates, and the quantification of non-CO 2 GHG emissions from CBCEs. Technical challenges remain, including the lack of consensus on the application of standardized methodologies. Together with the complexity of the certification procedures and the lack of clear policies at regional, national, and international scales, these knowledge gaps pose significant barriers for BC projects to readily access the voluntary and, additionally, the regulated carbon markets. The challenges above have been identified during the first scoping meeting of the Blue Carbon group of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans), a pan-European intergovernmental platform that increases the efficiency and impact of research and innovation for sustainably healthy and productive seas and oceans. The session welcomes contributions reporting advances which will help to close these knowledge gaps; we equally welcome contributions which challenge the actual soundness of CBCEs as relevant global carbon sinks. Contributions presenting successful or unsuccessful examples of carbon offset projects based on BC ecosystems, as well as initiatives to incorporate other ecosystem services alongside BC would be welcome. New perspectives from modern economics, marketing, or social science approaches are also welcomed. Those contributions with a special emphasis on the leitmotiv of this year’s ASLO ASM, i.e., resilience and recovery, will be prioritized.

Key words: Blue Carbon, Coastal vegetated ecosystems, Carbon cycle, carbon offset projects, biospheric carbon sinks

SS094 Autonomous Instrumentation and Big Data: New Windows, Knowledge, and Breakthroughs in the Aquatic Sciences

Steeve Comeau, Sorbonne Université - CNRS ([email protected])
David Hambright, The University of Oklahoma ([email protected])
Julia Mullarney, University of Waikato ([email protected])
Elisa Schaum, University of Hamburg ([email protected])

The development and deployment of autonomous instrumentation in the aquatic sciences, which has rapidly expanded during the last decade, has led to fantastic new insights into unexplored waters, increased understanding of temporal and spatial dynamics, and amazing discoveries across the aquatic sciences. These tools have allowed us to acquire more data, at higher frequency in time and space, and at a lower cost. Sensors deployed on gliders, autonomous underwater vehicles, and buoyed and float-based profilers have permitted near-real time, high-temporal and -spatial resolution observation of water physics (e.g., temperature, turbulence, currents, optics), chemistry (e.g., dissolved oxygen, pH, major and trace nutrients), and biology (e.g., plankton, environmental DNA, algal toxins). These technologies have led to unprecedented opportunities and understanding of numerous and complex properties of aquatic systems, including oceanic circulation patterns and interactions with the atmosphere, temporal, vertical and horizontal dynamics of plankton and associated biogeochemistry, and physical-chemical-biological interactions in both pelagic and benthic environments. In this special session, we welcome the submission of studies from all fields of oceanography and limnology, from physics to biology, which rely on the use of autonomous instrumentation and/or Big Data to make significant advancement in the understanding of key aquatic processes. Contributions may include studies at global to local scales with broad implications across the aquatic sciences and beyond. A special issue on this topic is expected for Fall 2024 in Limnology and Oceanography .

Key words: Big Data, Machien Learning, Autonomous, Profilers, Gliders

SS095 Lagrangian Transport and Connectivity in Oceanic Flows: Applications to Ocean Dynamics and Marine Ecosystems.

Alejandro Orfila, Spanish National research Council - CSIC ([email protected])
Ismael Hernández-Carrasco, IMEDEA-UIB ([email protected])
Cristobal López, IFISC-UIB ([email protected])
Annalissa Bracco, Georgia Institute of Technology, School of Earth and Atmospheric Sciences ([email protected])

Understanding transport and mixing properties in turbulent flows is a challenging problem not only from the theoretical point of view but also for more applied issues, such as oil spill management, SAR operations, plankton distribution and ecological connectivity. Owing to its inherent turbulent nature, ocean dynamics is highly complex, which makes the assessment of water pathways and the study of oceanic transport phenomena an extraordinarily complicated task. This problem can be approached from a Lagrangian perspective that studies transport and mixing by following trajectories of fluid particles. While the Eulerian perspective describes the basic characteristics of a velocity field, the Lagrangian one addresses its effects on transported substances, which clearly is of utmost relevance for coastal management including marine safety and marine ecosystems protection and management. Lagrangian analysis of the ocean flow based on dynamical systems and complex network theory has been used to develop new approaches to characterize the oceanic flow. They have led to the identification of coherent transport flow structures (i.e. filaments, eddies, fronts, flow avenues, etc) and connectivity patterns, with large proven impacts on biogeochemical cycling and population dynamics. Lagrangian approaches allow indeed to effectively track coupled bio- physical processes occurring along the history of moving fluid parcels. This session invites contributions dealing with Lagrangian approaches aiming at assessment of ocean dynamics and studying the interplay between physical and biological processes (i.e. from biogeochemical tracers to higher trophic levels). Priority will be given to studies that encompass the theoretical point of view, multi-platform ocean observations (drifters, HF radar, satellite data, etc…), numerical modeling and laboratory experiments. The objective of this session is to discuss and stress the importance of properly characterizing Lagrangian transport and connectivity at different scales to best appraise their highly nonlinear impacts on marine organisms, in the context of global changes. The interdisciplinary character of biological, biogeochemical and physical interactions of this session encourages an exchange of ideas and contributions across different fields, such as physical and biological oceanography, complex systems, marine ecology, geophysical fluid dynamics and applied mathematics.

Key words: Lagrangian transport, connectivity, dispersion, biophysical interactions, coherent structures

SS096 Exploring the Ocean Particle Microbiome

Marta Sebastian, Institut de Ciencies del Mar ([email protected])
Laura Alonso-Sáez, AZTI ([email protected])
Otto X. Cordero, Massachusetts Institute of Technology ([email protected])
Viena Puigcorbe, Institut de Ciencies del Mar ([email protected])

Sinking biogenic particles mediate the large-scale export of photosynthetically fixed C from the surface to the deep ocean, in what is known as the marine biological carbon pump. These particles constitute resource-rich microenvironments that get heavily colonized by microbes, which play a key role in particle degradation, ultimately affecting the efficiency of carbon sequestration. Moreover, particles have been found to be hotspots for other biogeochemical processes, e.g., related to the sulfur and nitrogen cycles. Thus, the colonizing microbiome not only modifies the architecture and fate of marine particles but may also play a major role in ocean biogeochemistry. A broad-scale picture of the particle microbiome has emerged in recent years, showing that particle-associated communities are taxonomically and functionally divergent from the free-living ones, but many unknowns still remain. This session welcomes presentations on all aspects concerning the particle microbiome, including their role in the formation and fate of ocean particles, their taxonomic and functional diversity, the cellular and molecular microbial mechanisms involved in particle colonization (e.g. chemotaxis, biofilm formation, cell-to-cell signaling), patterns of particle community assembly and microbial interactions within particles, among others. The session will also provide a platform to share new insights into the biogeography, ecology, and biogeochemistry of particle-associated communities, and their potential interactions with the free-living realm.

Key words: particles, microbiome, biogeochemistry, biological carbon pump, interactions

SS097 What Mechanisms Drive Toxic Algal Blooms?

francesco pomati, Eawag, swiss federal institue of water science and technology ([email protected])
Elisabeth Janssen, Eawag ([email protected])
David Johnson, Eawag ([email protected])
Phuong Nguyen, University of Fribourg ([email protected])

Phytoplankton blooms are a common and recurrent natural phenomenon, which is triggered by various biotic and abiotic factors such as nutrient supply, temperature, light intensity, turbulence, trophic cascades and species interactions. Harmful algal blooms are increasingly prevalent worldwide, yet we do not fully understand the specific mechanisms that result in toxic outbreaks. In this session, we welcome contributions that address questions regarding mechanisms triggering algal blooms, with a specific focus on the processes leading to blooms that are characterised by the production of bioactive metabolites. Why are certain bloom events toxic and others are not? What environmental conditions, abiotic or biotic, favour taxa or lineages that produce bioactive metabolites relative to non-producers? Both marine and freshwater case studies are welcome, and presentations may address the issue either experimentally, using observational data or theoretical modelling. The session will be open to studies focusing on all potential mechanisms leading to the emergence of blooms and bioactive metabolite production in plankton communities, from physiological responses to ecological and evolutionary processes. We are particularly interested in studies that cross disciplinary boundaries.

Key words: traits, secondary metabolites, cyanobacteria, dinoflagellates, diatoms

SS102 Inland and Coastal Aquatic Ecosystems Monitoring from In Situ and Satellite Radiometric Measurements

Héloïse Lavigne, Royal Belgium Intistute of Natural Sciences ([email protected])
Clémence Goyens, Royal Belgium Institute of Natural Sciences ([email protected])
Pierre Gernez, Nantes Université ([email protected])
David Doxaran, Laboratoire D'Oceanographie de Villfrenche, CNRS ([email protected])
Evangelos Spyrakos, University of Stirling ([email protected])

Coastal and inland waters ecosystems are ecologically, culturally, and economically important. Monitoring these environments is therefore essential to understand ecosystem functioning, how to ensure sustainable practices and assess the impact of human activities. Among the large diversity of measurement techniques, optical remote sensing presents some clear advantages. Indeed, earth observation satellites nowadays allow to monitor the spatial variability of water quality parameters over large areas and with relatively short revisiting times. In water and above water radiometers, have a great potential for ecosystem monitoring, especially if they are integrated into autonomous measurement systems providing high temporal resolution data, or if they have a high spectral resolution opening the door to new environmental products based on fine spectral features. However, retrieving relevant information on water constituents from radiometric data in optically complex waters is still challenging. Indeed, although in clear, case-1, waters most of the bio-optic parameters are dependent of the chlorophyll-a concentration, in coastal and inland waters (i.e. case-2 waters) light absorption and scattering is affected by terrestrial inputs of sediments and/or dissolved organic carbon which can make the retrieval of simple parameters such as the chlorophyll-a concentration very complicated. In addition, atmospheric correction algorithms are more challenging because of potentially extreme optical water properties and the proximity with the coast or surrounding land. This session is open to all contributions presenting novel applications of inland and coastal aquatic monitoring based on visible and NIR radiometric remote sensing data either from satellite or in situ sensors.

Key words: optically complex waters, remote sensing, radiometry, water quality, autonomous systems

SS103 Dynamical Niches – Their Formation, Impact and Resilience in the Aquatic Environment

Maximilian Berthold, Mount-Allison University ([email protected])
Rahel Vortmeyer-Kley, ICBM, Uni Oldenburg ([email protected])

Environmental changes occur either statically or dynamically, and they can have large impact on the survival of aquatic species and their community composition as well as the shape and number of available niches. Dynamical niches define regional ecological niches that exist temporally (hours to months). Such niches are governed by geology, climate and hydrodynamics and their spatio-temporal boundaries. Short term events like e.g. eddies, upwelling or inflow events, heatwaves or storms can create such dynamical niches, but also seasonal and decade-long trends within water bodies. For example, temperature, salinity, or nutrients can all create temporally different environmental conditions, which affect the niche size for planktic and benthic organisms. Depending on the created environmental conditions, these dynamical niches may not be filled, or they are filled by species that usually occur at different timepoints and locations within the ecosystem. Thus, the temporally existence of these niches brings up the question of the resilience of the species that fill these dynamical niches. Will they persist when the dynamical niche collapses or will it allow colonization of new habitats for such species? Such colonization events caused by short-term dynamical niches could also change the composition of the species community in the long term. The session welcomes experimental, observational as well as modeling studies that try to characterize the formation of a dynamical niche ranging from a physical point of view to an ecological one. Furthermore, this session will focus on the description of resilience of such dynamical niches from various perspectives in modeling and measurement, like temporal stability or thresholds. Thereby, we invite studies that represent the entirety of organisms and aquatic systems, with a particular emphasis on interdisciplinary work.

Key words: plankton, benthos, species community composition, modeling, population dynamics

SS105 The Role of Human-Nature Relations in the Recovery of Marine Systems

Ana Ruiz, Consejo Superior de Investigaciones Cientificas ([email protected])
Irene Olivé, Stazione Zoologica Anton Dohrn ([email protected])
Maraja Riechers, Leuphana University ([email protected])
Natali Lazzari, Universidad de Santiago de Compostela ([email protected])
Antonio Castro, Universidad de Almeria ([email protected])

Anthropogenic climate change and human pressures are major threats to marine and coastal systems. The combination of both not only compromises the ecological functioning of the systems but also the services from which humans benefit. The current climate crisis and the biodiversity loss associated to these increasing human pressures show that the relationship between humans and the rest of the natural world is failing. Sustainability science has pinpointed fading relations between humans and nature as one of the potential causes for the degradation of ecosystems. Leading from this, it is argued that fostering the re-connection of humans with nature could contribute towards the development of sustainable pathways. The connection between humans and their surrounding nature has been highlighted in their significance over the past decade, as strengthening this connection may simultaneously increase human well-being and the ecological sustainability. The understanding of human-nature interactions and how relations are built can be seen as one realm of fostering transformative change. Within this session, we refer to these interactions as ‘human-nature relations’ to enable various concepts that are used in research today to be integrated under this broad umbrella term. Hence, in this session we welcome contributions from studies illustrating the role of human-nature relations in the conservation and recovery of coastal and marine ecosystems. The session also welcomes contributions related to new methodologies used in the exploration of these relations and of pathways of effectively integrating human-nature connections into marine and coastal sustainable management.

Key words: human-nature connections, leverage points, sustainability, relational values,

SS106 Looking Ahead in Living Shorelines Science and Applications: Ensuring Healthy, Sustainable and Resilient Coastlands

Just Cebrian, Mississippi State University ([email protected])
Eric Sparks, Mississippi State University ([email protected])
Kelly Kibler, University of Central Florida ([email protected])

The degradation of coastlands due to human impacts has many negative consequences, including the loss of important resources, such as fisheries and waterfowl, and the reduction of protection against storm surge, nutrient pollution filtration, and carbon sequestration. The conservation of pristine coastlands can only palliate these problems to a limited extent, since the occupation of coastlands by humans is certain to increase. Thus, we are left with resorting to sound, cost-effective techniques of coastland restoration. One wide umbrella of such techniques, coined living shorelines, has been employed for decades and continues to feature high popularity. Indeed, throughout the world the term living shorelines has become a staple of research, restoration, and management of coastlands. At any rate, living shoreline projects have generated disparate outcomes, with tremendous success in some instances but also glaring failure in others. There are still major gaps in the understanding of living shorelines approaches, particularly regarding synergistic interactions where multiple living shoreline components are restored in unison. Based on such synergistic interactions, how do we best design and combine living shoreline elements for holistic coastland improvement, including enhanced living resources, storm protection, pollution filtration, and carbon sequestration under current future climate conditions? Within these targets of holistic improvement, how do we ensure the process is economically feasible and sustainable over the long run? These gaps in our understanding of living shorelines limit their applicability and impact, and surely are at the base of many of the failures observed with these approaches. Advancement of the science and application of living shorelines requires a thorough overview of the state-of-the-art to date, scrutinizing what has worked and what has not, and elaborating hypotheses targeting the mechanisms that cause success or failure. Testing such hypotheses is essential to unequivocally understand and demonstrate why living shoreline approaches work or fail. With this improved understanding, we can delineate approaches with a high probability of success and, working with a coalition of managers, practitioners and citizen scientists, transfer them to real-world operations with cost-effective, affordable budgets. In this session we will present talks that contribute to these goals. First, we will have summary talks that review living shoreline practices and lessons learned to date. These talks will cover a wide range of aspects, from small- to large-scale projects and from efforts focused on one concrete goal to efforts more holistic in their objectives. Second, we will have talks that show science approaches to test unknown factors of living shoreline performance based on past lessons, and that demonstrate enhanced impact through new or amended designs, mechanistic processes, and simultaneous inclusion of synergistic components. Finally, we will also have talks that illustrate how enhanced living shorelines designs based on scientific analysis can be transferred to real field operations successfully, ensuring their economic feasibility, long term resilience, and outreach with the involvement of citizen scientists and other contingents. This session will contribute significantly to the field of living shorelines, and we will plan to organize a special section for Limnology and Oceanography Letters from it.

Key words: living shorelines, coastal restoration, environmental resilience, synergistic approaches, project sustainability

SS107 Oxic-Anoxic Interfaces: Pathways, Dynamics and Exchanges

Emilio Garcia-Robledo, University of Cadiz ([email protected])
Laura Bristow, University of Gothenburg ([email protected])
Bastien Queste, University of Gothenburg ([email protected])

The decline in oxygen content of aquatic systems is one of the most alarming consequences of anthropogenic global change. Recent decades have seen tremendous shifts in the location and strength of oxyclines globally, impacting biogeochemical pathways and shifting ecosystems. Increasing observational efforts have shown discrepancies with global modelling efforts. These discrepancies demonstrate the need to better understand the physical processes governing these interfaces, the biogeochemical processes and microbes living across them, to improve associated models, which would allow improved predictions in a changing hydrosphere. The transition from oxic to anoxic conditions induces a physiological change; the shift from aerobic to anaerobic metabolisms. These transitions are naturally present in all aquatic environments, whether in the water column or within sediments of marine and freshwater environments and determine the cycling and fate of relevant elements such as C, N, P and S, as well as trace metals. In marine and freshwater environments, recent discoveries of anaerobic processes being active in oxic environments and aerobic processes found in anoxic ones are redefining these transitions. Thus, modifying our understanding of the fate of relevant elements in aquatic environments, and to re-evaluate the consumption and production of inorganic nutrients, potent greenhouse gases (N 2 O and CH 4 ) and toxic gases (H 2 S). The importance of recently discovered metabolisms is also coming to light, largely as a result of technological advances in sequencing, novel single cell techniques and geochemical approaches. This session seeks to bring together researchers from marine and freshwater to reveal and understand the complex interplay between chemical, biological and physical processes at the oxic-anoxic transition in water columns and sediments.

Key words: Biogeochemical cycles, processes, and modelling, Anoxic environments, Hypoxic environments, Microbial ecology, Oceanography

SS108 Impacts of Aquatic Photochemistry and Photobiology in a Changing World

Joanna Kinsey, Quinnipiac University ([email protected])
David Kieber, State University of New York, College of Environmental Science and Forestry ([email protected])
William Miller, University of Georgia ([email protected])
Heather Reader, Memorial University of Newfoundland ([email protected])

Sunlight drives countless photochemical and photobiological transformations that have far-reaching and significant consequences in freshwater, estuarine, and oceanic waters. They affect the surface microlayer and gas exchange, aquatic ecology, particulate, colloidal and dissolved organic matter, primary freshwater and marine aerosols, optics, remote sensing, trace element cycles, xenobiotics (e.g., plastics), and the atmosphere through the production of volatile gases in sunlit surface waters. Recent advances have led to a better understanding of freshwater and marine photochemical and photobiological processes, spanning molecular to global scales; and yet the full impact of climate change and anthropogenic inputs on mechanisms, linkages, and feedbacks that involve aquatic photo-processes are largely unexplored. We welcome submissions in all areas of aquatic photochemistry and photobiology, especially those exploring the potential role of climate change on these processes, their use in remediation and degradation of anthropogenic compounds, and their potential role in observed biogeochemical changes in lakes, rivers, coastal waters, and the ocean.

Key words: Photo-processes, Climate change, Biogeochemistry, Irradiance,

SS109 Urban Coastal Ocean Resiliency: Challenges & Solutions

Jennifer Cherrier, Brooklyn College-CUNY ([email protected])
Jaye Cable, University of North Carolina-Chapel Hill ([email protected])
William Cooper, University of California-Irvine ([email protected])

Over the past century coastal population growth, development, and land use changes have undermined the reliability of urban water systems around the globe and have significantly impacted coastal ecosystem health. Additionally, the global population is projected to reach 9.725 billion by 2050 and by this time, approximately 66% of the world's population will reside in urban areas with most of these cities located along coastlines, thus, urbanization impacts to coastal areas are likely to get worse unless adequately addressed. In particular, aging water infrastructure in many of these urban areas coupled with extreme rainfall events exacerbate stormwater-related pollutant loading and water quality degradation. Specific stormwater-related pollutants can include nutrients, fecal material, heavy metals, and pharmaceuticals and other chemicals of emerging concern, which contribute to bloom events, localized hypoxia, and loss of aquatic life. Depending on geographic location and local practices, the hydrologic routes of pollutant delivery into coastal systems range from non-point to point source and surficial to groundwater. Integrated water management practices and nature-based solutions such as blue-green infrastructure can mitigate pollutant loading into coastal systems, while in situ processes such as photochemical and microbial degradation can ameliorate pollutant effects once introduced. This session will explore urban coastal resiliency with a specific focus on a) challenges caused by urban water systems and associated impacts to coastal ecosystem health, and b) practices, solutions and in situ mechanisms for offsetting these impacts.

Key words: stormwater, water quality, integrated water management, photooxidation, microbial degradation

SS110 Contaminant Fate and Transport in Aquatic Systems and Their Interactive Effects on Ecosystem Functioning

Christopher Filstrup, University of Minnesota Duluth ([email protected])
Kathryn Schreiner, University of Minnesota Duluth ([email protected])
Euan Reavie, University of Minnesota Duluth ([email protected])
Bridget Ulrich, University of Minnesota Duluth ([email protected])
Chan Lan Chun, University of Minnesota Duluth ([email protected])
Brian Lenell, U.S. Environmental Protection Agency, Great Lakes National Program Office ([email protected])

Anthropogenic pollutants are ubiquitous across environmental media, including air, water, sediment, and biota. While the role of legacy pollutants in aquatic systems has been well-documented, much of their fate and interactions with diverse ecosystem components and functions are still poorly understood. Emerging pollutants (e.g., pesticides, flame retardants) challenge our understanding of the full effects of contaminants in the environment. Emerging methodologies, including targeted and non-targeted laboratory analyses, and modeling approaches continue to better define the fate of these pollutants. This session welcomes abstracts focusing on any combination of field, laboratory, and modeling studies focusing on source, fate, and transport of emerging and legacy pollutants through aquatic systems. We welcome studies using transdisciplinary approaches and integrating across the freshwater-to-marine continuum to improve mechanistic understanding of pollutants in aquatic ecosystems.

Key words: contaminants, pesticides, mercury, PFAS, fate and transport

SS111 Novel Analytical Approaches to Understanding Dissolved Organic Matter Reactivity, Fate, and Flux Along the Land Ocean Aquatic Continuum – Combining Qualitative and Quantitative Information

Jeffrey Hawkes, Uppsala University ([email protected])
Stacey Felgate, Uppsala University ([email protected])
Michael Gonsior, UMCES ([email protected])
S. Leigh McCallister, VCU ([email protected])
Leanne Powers, SUNY-ESF ([email protected])

Dissolved organic matter (DOM) is an ultra-complex mixture of chemical constituents, the reactivity, fate, and flux of which are controlled by a combination of intrinsic (i.e. quantity and quality) and extrinsic (i.e. environmental conditions and microbial processing) factors. This makes studying DOM a daunting task, particularly when working across the diverse environments of the land-ocean aquatic continuum, between deep ocean basins, or to link biotic and / or abiotic processes with shifts in DOM composition. Studying aquatic DOM often involves deconvolving a mixed signal across multiple spatial, temporal, and analytical windows. This can require diverse analytical techniques, often in combination with modelling and / or digital approaches, and we are often limited in our ability to integrate quantitative and qualitative data. For example, DOM is typically quantified relative to its DOC concentration, despite C accounting for a variable % of the DOM pool, and characterized using analytical techniques which become qualitative when applied to environmental samples (e.g. absorbance and fluorescence spectrophotometery, mass spectrometry, nuclear magnetic resonance). Most of these techniques operate over a very specific analytical window (e.g. extractable, ionizable, or chromophoric DOM), meaning that the DOM fraction identified by one method can be absent from another, and difficult to relate to bulk DOC. Absorbance, for example, is a commonly used proxy for terrigenous DOM and can be used semi-quantitatively, but the few compound classes which have been structurally defined in both freshwater and marine systems (e.g. CRAMs and terpenoid-derived structures) tend to be non-chromophic. Novel, integrative approaches and the discovery of new tracers and proxies for DOM source, reactivity, and transformation pathways are therefore pivotal in order to trace and understand DOM production via primary producers (photo- and chemoautotrophs), subsequent microbial transformation, and end-fate, whether in the atmosphere, sediments, or the deep ocean. This session therefore aims to highlight the power of combining quantitative and qualitative understanding within and between any aquatic environments, from headwater streams to deep ocean basins. We encourage submissions that integrate processes (e.g. bio- and photo-degradation and transformations) and / or work across multiple disciplines (e.g. hydrology, ecology, chemistry, and biology), and welcome studies that combine high resolution and information rich qualitative analytical methods (e.g. -omics approaches, high resolution mass spectrometery, nuclear magnetic resonance, absorbance and fluorescence spectrophotometery) with quantitative and /or modelling approaches. We also welcome submissions which develop novel approaches, tracers, or proxies for DOM source, form, and reactivity, and those which aim to better understand the methodological biases and constraints of existing techniques.

Key words: Dissolved Organic Matter, Analytical Techniques, Land-Ocean continuum, Mass Spectrometry, Spectroscopy

SS112 Integrating Mixotrophy Into 21st Century Aquatic Microbial Ecology

Susanne Wilken, University of Amsterdam ([email protected])
Sarah Princiotta, Penn State Schuylkill ([email protected])
Suzana Goncalvez Leles, University of Southern California ([email protected])
Sebastiaan Koppelle, University of Amsterdam ([email protected])

The traditional distinction into ‘plant-like’ phytoplankton and ‘animal-like’ zooplankton is increasingly challenged by the widely recognized importance, and seasonal dominance, of mixotrophic protists that are capable of carbon fixation, but can also feed heterotrophically on other planktonic prey. Mixotrophy has the potential to alter energy and nutrient flow through food-webs, for instance by utilization of nutrients bound in prey to fuel primary production performed by mixotrophic predators, which has been hypothesized to increase trophic transfer efficiency and lead to increased biomass at higher trophic levels. Further, grazing by mixotrophs can have significant top-down impacts on the prey population and community structure. The trophic position of mixotrophs themselves can shift when they alter their physiology from more photosynthetic to more heterotrophic depending on environmental conditions and resource availability. However, metabolic responses to environmental triggers, such as light and temperature, are difficult to predict, because the mechanisms that drive mixoplankton trade-offs are not well understood. Methodological challenges have also hampered the quantification of mixotrophy in situ, challenging our ability to understand the global biogeography of mixotrophs relative to their specialized competitors. Nevertheless, identification of mixotrophs and in particular quantification of their metabolic activities remains methodologically challenging. Yet, novel approaches from trait-based ecology and experimental evolution to in-situ single-cell techniques and omic’s datasets open up exciting avenues to explore. The integration of data from such approaches and development of new models might provide a better mechanistic understanding of mixotroph metabolism, their global distribution and their impact on ecosystem functions. Such information is crucial, especially under global change scenarios, where shifts in mixotroph dominance and metabolism are expected to affect marine carbon cycling. Here we aim at improving our understanding of mixotrophs in the microbial food web by discussing work on mixotrophic protists from freshwater and marine environments, using theoretical or empirical approaches, and considering levels of organization from molecular to ecosystem level processes. We particularly welcome contributions that combine several approaches, bridge the gap between different levels of organizations, or compare across ecosystems.

Key words: mixotrophy, protists, microbial food web, plankton,

SS113 Resilience and Recovery in Aquatic Systems: The Impacts of Rapid Acclimation and Adaptation

Steven Declerck, NIOO-KNAW ([email protected])
Jana Isanta-Navarro, Lund University, Department of Biology ([email protected])
Lynn Govaert, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) ([email protected])
Matthew Sasaki, University of Connecticut, Department of Marine Sciences ([email protected])
Luc De Meester, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) ([email protected])

The Anthropocene is characterized by rapidly changing environmental conditions. These stressors put increasing pressure on aquatic systems from glacial lakes to the deep ocean and jeopardize the ecosystem services they provide. Stressors also represent altered selective pressures on populations, leading to a range of responses mediated by physiological plasticity, changes in the microbiome, and evolutionary adaptation. These responses can in turn have feedbacks at the population and community level, with potential to both stabilize and destabilize ecosystem dynamics. Along with gradual environmental change, systems can also exhibit abrupt transitions between alternative stable states. Here too, both plastic and evolutionary trait change might have important consequences, although whether they prevent or promote such transitions is still ambiguous. The relative limits of plastic change, and the interactions between phenotypic plasticity and adaptation are also sources of significant uncertainty. In order to predict, plan for, and manage the societal effects of climate change, we need to examine the interplay between acclimation, adaptation, and ecosystem functioning. This session will highlight the diversity of ways in which aquatic organisms respond to environmental change and the resulting consequences for ecosystem resilience and recovery. We will consider responses over a range of timescales and levels of biological organization, from acclimation of cellular processes and individual physiology to rapid microevolutionary adaptation at the level of populations, as well as processes like species sorting at the community level. By bringing together experts from different fields, our session will provide novel insights into how the capacity for rapid responses affects the resilience and recovery of aquatic systems, and the continuity of ecosystem functioning. We explicitly encourage contributions from all aquatic systems, as we look forward to engaging presentations across the salinity gradient from marine to freshwater habitats.

Key words: eco-evolutionary dynamics, persistence, resistance, local adaptation, hysteresis

SS115 Resilience in Coral Reef Ecosystems

Star Dressler, University of Guam ([email protected])
Atsushi Fujimura, University of Guam ([email protected])

Coral reefs are among the richest ecosystems on earth in terms of biodiversity and productivity, yet are at high risk of habitat degradation and species extinction from climate change and other anthropogenic influences. Resilience refers to the maintenance of key physiological and ecological functions following disturbances, which can be studied from the scale of individual organisms, populations, to entire ecosystems. Ecological factors that can negatively impact coral reefs include increased water temperatures, increased water acidification, overfishing, nutrient pollution, sedimentation, and impacts of climate variability such as the El Niño-Southern Oscillation. On the individual organism and population scale, resilience occurs through eco-physiological plasticity and/or gene expression and regulation during stress, and the capacity for resilience varies greatly across species and populations. Mechanisms related to resilience at this scale include response traits to environmental changes, population growth rates, and genetic diversity that can measured at both short-term and long-term responses to environmental shifts. Other ecosystem attributes that contribute to resilience includes connectivity, temporal and spatial variability, and functional redundancy. Oceanographic parameters, including water currents at small, meso-, and large scales, tidal force, upwelling, and seasonal rainfall patterns influence marine habitats that may impact the resilience of local organisms. These abiotic parameters can alter nutrient availability, stratification, irradiance levels, the degree of larval retention or dispersal, productivity, and numerous other ecological factors. The high temporal and spatial variability of oceanographic patterns often means that locations must be studied over several years before assumptions can be made regarding resilience of coral reef ecosystems. Our ability to understand resilience is enhanced with modern technology, including oceanographic sensing instrumentation and molecular genetics. Many reef-building corals and other reef organisms host endosymbiotic algae, a particular topic of interest among coral reef researchers. This host-symbiont relationship creates a complex of nutrient cycling and is recognized to impact resilience on the individual organism and population scale. Advances in molecular genetics and instrumentation such as flow cytometers have helped researchers understand these relationships in recent years. With documentation of worldwide coral reef habitat degradation spanning decades, competitive research grants continue to fund studies across both tropical and temperate reef ecosystems, and the number of coral reef-related research projects increases. Thus, we expect that the research presented in this session will highlight advancements in our understanding of resilience in coral reef ecosystems across many scales. This includes the species, population, and community levels, as well as across spatial and temporal variation.

Key words: Coral Reefs, Resilience, Coral Reef Ecosystems, Climate Change, Increased Sea Surface Temperature

SS116 Metabolites in the Chemical-Microbe Network

Elizabeth Kujawinski, WHOI ([email protected])
Mary Ann Moran, University of Georgia ([email protected])
Sonya Dyhrman, Columbia University ([email protected])

The chemical – microbe network underpins ecosystem structure function relationships and biogeochemical cycling in aquatic systems. The metabolites of this network are organic molecules produced during biochemical reactions within organisms that cross all taxonomic levels in aquatic systems. They are analytically challenging to quantify due to their heterogeneous chemical nature and their dilute concentrations in aquatic systems relative to background organic matter. Nevertheless, metabolites play critical roles in determining the functions of aquatic microbiomes, serving as growth substrates, co-factors and/or infochemical signals within microbial consortia. Despite the central role of the chemical-microbe network in the aquatic carbon cycle, our knowledge of metabolites and their dynamics in various aquatic systems remains poor. This session invites presentations on all aspects of metabolite cycling in aquatic systems in laboratory, field and/or modelling investigations. We seek studies that explore the mechanisms behind production of metabolites by autotrophic and heterotrophic organisms, as well as empirical observations of metabolite consumption and numerical modelling investigations of predicted metabolite production and consumption. We are particularly interested in studies that consider shifts in metabolite dynamics and the resiliency of the chemical-microbe network under changing planetary conditions. Analytical method developments that expand the lexicon of metabolites in aquatic studies are also welcome.

Key words: metabolomics, microbial interactions, analytical chemistry, metabolic modeling,

SS118 Ecology, Distribution, and Dynamics of Holopelagic Sargassum spp.

Amy Siuda, Eckerd College ([email protected])
Jeffrey Schell, Sea Education Association ([email protected])
Thierry Thibaut, Mediterranean Institute of Oceanography ([email protected])
Charlotte Dromard, Université des Antilles, Campus de Fouillole, UFR Sciences Exactes et Naturelles ([email protected])

Surface-floating, holopelagic Sargassum in the Atlantic Ocean presents scientists and society with a conundrum. On one hand, within its historic Sargasso Sea range, holopelagic Sargassum is recognized as a unique high seas ecosystem valued for the critical habitat it provides for iconic species from endemic invertebrates to sea turtles to economically-important fishes. Conversely since 2011, recurring blooms in the equatorial Atlantic have driven holopelagic Sargassum inundation events with significant, persistent ecological and economic impacts from west Africa to South America, the wider Caribbean, and the southern United States. Given this regime shift, the path forward must balance the competing goals of international conservation, management, and mitigation of this enigmatic drifting ecosystem. A better understanding of annual bloom dynamics, driving factors, and temporal variability will improve beaching forecasts and mitigation of coastal impacts. Furthermore, foundational research on holopelagic Sargassum physiology, ecology, shifting distribution patterns, and transport mechanisms in both offshore and coastal environments are necessary to inform remote sensing and modeling efforts. This session seeks to coalesce work occurring across the Atlantic basin to advance our knowledge of holopelagic Sargassum ecology and distribution and to build a holistic view of the Great Atlantic Sargassum Belt. Submissions reporting on field studies, experimental and taxonomic work, in situ observations, remote sensing, and modeling are all welcome.

Key words: Sargassum, Macroalgae, Atlantic, Caribbean, Ecology

SS120 What Drives Harmful Algal Blooms in Freshwater Ecosystems and How Can We Prevent, Control, and Mitigate their Impacts?

Dail Laughinghouse, University of Florida ([email protected])
Heather Raymond, The Ohio State University ([email protected])
Petra Visser, University of Amsterdam ([email protected])

This session will delve into the drivers for freshwater cyanobacterial harmful algal blooms (cyanoHABs) and effective strategies for their prevention, control, and mitigation. CyanoHABs have resulted in negative impacts to human health (e.g., liver disease, seizures, paralysis, diarrhea, headaches, neurodegeneration, death), food production (yield loss and cyanotoxin accumulation in crops), recreation, and ecosystem function worldwide and have had substantial associated economic impacts. However, we still lack knowledge on which toxic species and toxins will be favored, how these HABs will impact aquatic ecosystems, and how to best manage them. Reports of CyanoHABs and associated impacts are increasing and have been linked to changing climatic conditions, eutrophication related to nutrient enrichment, and increases in awareness and monitoring. The occurrence of intense and widespread cyanoHABs worldwide has revealed important gaps in our understanding of these organisms, specific drivers leading to their occurrence and toxin production, and our ability to forecast, manage, mitigate, and control these catastrophic events. Specifically, there is currently no substantive plan that can provide effective short-term or long-term solutions for controlling blooms. However, as awareness of the threats with cyanoHABs rises, “no action” is not acceptable. There is a need for both short term mitigation and control strategies and, ultimately, long-term prevention strategies that address the core drivers for cyanoHABs. To date, HAB control and mitigation are the most challenging and controversial aspects of HAB science and arguably the least developed.

Key words: Cyanobacteria, Cyanotoxin, Harmful Algal Bloom, Control, Mitigation

SS121 Combining Machine Learning and Process-Based Models in Ecological Prediction

Neil Banas, University of Strathclyde ([email protected])
Bingzhang Chen, University of Strathclyde ([email protected])
Johnathan Evanilla, Bigelow Laboratory for Ocean Sciences ([email protected] )
Clarissa Anderson, Scripps Institution of Oceanography / SCCOOS ([email protected])
Rafael Marcé, Catalan Institute for Water Research (ICRA) ([email protected])

With ocean and freshwater ecosystems facing stresses like climate change, species declines, introduced species, pollution, and expanding resource extraction, there is a pressing need for ecological forecasting. Fields like harmful algal bloom (HAB) forecasting and real-time endangered marine mammal prediction are increasingly moving toward machine learning methods, which extract the quantitative relationships between predictors and response variables in a training dataset and use these relationships to provide predictions. Alternatively, process-based or simulation-based modelling uses differential-equation systems to describe physical transport, environment-dependent growth and mortality, and so on, sometimes generating predictions of many ecosystem components at once, intended to be built from first principles. Ecological predictions need to be 1) accurate and feasible in the short term given the constraints of usually incomplete data, 2) robust in the face of emerging, novel combinations of environmental conditions under climate change, and 3) accountable to the stakeholders influenced by the predictions. Unfortunately, these requirements often pull in opposite directions, and tradeoffs are reflected in the choice of algorithm. Machine learning techniques are usually easier to implement than process models and often generate predictions that are much more accurate, but may fail in a shifting environment given their reliance on a constrained set of relationships. The problem of future-proofing — basing predictions on fundamental and enduring relationships, not circumstantial and ephemeral ones — encourages us to continue to explore and refine process-based models, although in practice the robustness and accuracy of these models is limited by missing processes and the difficulties of parameter tuning. There are also often tradeoffs between model interpretability and predictive skill. In this session, we invite studies that are exploring novel approaches to combining machine learning and process-based methods in ecosystem and event prediction in ocean and freshwater systems, or finding ways to make machine learning approaches more biologically and oceanographically interpretable. Topics may include HAB risk, species range shifts, hypoxia events, heatwaves and extreme phenomena, or biogeochemical interactions.

Key words: forecasting, modeling, machine learning, harmful algal blooms, extreme events

SS122 Vulnerability and Adaptation of Meroplankton Larvae in a Changing Climate

David Fields, Bigelow Labs for Ocean Sciences ([email protected])
Richard Wahle, University of Maine ([email protected])
Alexander (Alex) Ascher, University of Maine ([email protected])
Rachel Lasley-Rasher, University of Southern Maine ([email protected])

The larval stages of marine benthic organisms is an inherently vulnerable period in the life cycle due to the high risk of predation, food limitation, and the vagaries of ocean currents and chemistry, all processes that are critical determinants of recruitment to the adult population. Changes in recruitment year-to-year have implications for the structure of benthic communities, and in some cases, the fisheries that rely on them. Rapidly changing climate and pelagic food webs are shifting the timing and transport of planktonic larvae, altering interactions with prey, predators and competitors with implications for poleward range shifts. The aim of this session is to bring together researchers investigating the impact of climate change on larval dispersal, development, and trophic interactions. We hope to attract presentations based on laboratory studies, field work or models from a range of benthic taxa.

Key words: meroplankton, zooplankton, climate change, pelagic food webs, trophodynamics