Special Sessions

SS01 Instability of Aquatic Ecosystems in a Changing World

Steve Carpenter, University of Wisconsin-Madison, [email protected]
Mike Pace, University of Virginia, [email protected]
Emily Stanley, University of Wisconsin-Madison, [email protected]
Kevin McCann, University of Guelph, [email protected]
Jim Heffernan, Duke University, [email protected]

Sustained changes in climate, land use, and demand for water resources are destabilizing aquatic ecosystems and driving transitions to new ecosystem states. The stability of these emerging states and their capacity to meet human needs are unknown. What is the evidence for changes in aquatic ecosystem stability? Are regime shifts becoming more common? Will the novel ecosystem configurations be stable, or should we expect ongoing instability and change? Papers in the session will address these and related questions using studies of regime shifts, early warnings, loss of stability, abrupt changes, and other topics for benthic, pelagic, freshwater, or marine ecosystems. Talks will be given by each of the 5 organizers and a few other invitees who will be selected to increase the diversity of topics. We will leave the majority of slots open to encourage contributed talks, including talks by postdocs and students.

SS02 Aquatic Ecosystem Management

Steve Carpenter, University of Wisconsin-Madison, [email protected]
Jake Vander Zanden, Center for Limnology, University of Wisconsin-Madison, [email protected]
Catherine Hein, Wisconsin Department of Natural Resources, [email protected]
Michael Shupryt, Wisconsin Department of Natural Resources, [email protected]

Surface water management, both research and practice, are crucial for the future of rivers, lakes, wetlands, and groundwater, and a core interest of ASLO and SFS members. This poster session will provide a setting for presentation and discussion of ongoing projects and recent findings. This session is open to all attendees interested in freshwater resource management. Co-organizers represent University of Wisconsin Extension (Tricia Gorby), Center for Limnology (Steve Carpenter, Jake Vander Zanden), Sea Grant Institute (Jen Hauxwell), and Water Resource Management graduate program (Anita Thompson); Wisconsin Department of Natural Resources (Tim Asplund, Catherine Hein, Michael Shupryt); and Wisconsin Lakes (Eric Olson).

SS03 Opening Up Aquatic Science

Mark Scheuerell, University of Washington, [email protected]
Hilary Dugan, University of Wisconsin, [email protected]
Jordan Read, USGS, [email protected]

Science is about the discovery and sharing of information, but much of the process is often shrouded in mystery. The seemingly endless competition for limited research funding has led to the notions that "knowledge is power" and that data must be protected. These situations tend to slow scientific discovery by hindering larger synthesis efforts and the exploration of new ideas or methodologies. In addition, we are witnessing increasing examples where scientists are unable to successfully reproduce previous findings, bringing into question the integrity of the results. Fortunately, however, we also find ourselves in the midst of an expanding community of developers and practioners of the tools and skills necessary for easier and more transparent design, analysis, and reporting of scientific studies. These advancements have also supported better documentation, management, and access to data, which has facilitated new and often remote collaborations. This session will highlight so-called "open science" tools and best practices being developed and used in the aquatic sciences and beyond. In particular, we welcome talks from projects that 1) use shared software development platforms, such as GitHub, to promote collaborations, manage tasks, and track changes to code; 2) use software like R Markdown to combine text, equations, and code into detailed and reproducible descriptions of the research; or 3) use interactive visualizations (eg, Shiny apps), blogs, and social media for accessible scientific communications.

SS04 Environmental consequences of carbon fluxes and cycling: integrating organic matter quantity and quality

Juliana D'Andrilli, Louisiana Universities Marine Consortium, [email protected]
Erin Hotchkiss, Virginia Polytechnic Institute and State University, [email protected]
Megan Fork, Cary Institute of Ecosystem Studies, [email protected]
Jeffrey Hawkes, Uppsala University, [email protected]

The function and fate of organic matter (OM) in aquatic ecosystems depends on its quantity and quality. Yet, our understanding of ecosystem subsidies and fluxes rarely includes simultaneous measurements of OM flux, form, and manner of cycling (biotic, abiotic). OM is a super-mixture of chemical constituents and the fundamental currency for energy exchange within and among ecosystems. Consequently, determining the amount, composition, reactivity, movement, and fate of OM can indicate processes governing carbon (C) transformation and impact. We aim to highlight the advantages of combining knowing, “How much C is present?” with “What type of C is present?” and “What are the rates of C fixation and loss?”, essentially creating a microscience to macrosystem approach to understanding one or many ecosystems. We welcome studies from aerosol, freshwater, and coastal environments that combine quantitative and qualitative biogeochemical approaches to better understand C fluxes and cycling. We stress that integrating C cycling and flux research is an essential component of informing aquatic sustainability, understanding ecosystem health, projecting greenhouse gas emissions, and predicting consequences of human restoration or degradation of ecosystems. We encourage submissions that integrate processes (e.g., stream metabolism, microbial production and transformations of C, photooxidation, etc.) across multiple disciplines (e.g., hydrology, ecology, chemistry, and biology) and submissions that aim to better understand the methodological biases and constraints of our techniques. Collaboration among researchers using an array of methods to measure and model C fluxes, cycling, and fate will broaden our understanding of ecosystem fluxes under current and future global change.

SS05 Limnological Processes Beneath Ice Cover

Trista Vick-Majors, Michigan Technological University, [email protected]
Alexander Michaud, Bigelow Laboratory for Ocean Sciences, [email protected]
John Priscu, Montana State University, [email protected]

Ice cover is fundamental to the seasonal cycles of inland waters and is a permanent feature of many high-latitude aquatic environments. The presence of ice limits light penetration, influences water column mixing and diminishes atmospheric ventilation. These factors produce a cascade of effects on water column and sediment physiological and biogeochemical processes. For example, long term datasets collected from ice covered lakes in the polar regions have revealed unique physiological adaptations to permanent ice cover, and investigations of temperate systems during the ice covered season have highlighted the importance of under ice processes in the regeneration of nutrients. Experimental data show that autotrophic and heterotrophic organisms respond at the individual and community level to the formation of ice-cover. Rising global temperatures are decreasing ice cover duration and altering ice thickness, which clearly have implications for freshwater biogeochemistry. This session aims to further our understanding of limnological processes under lake ice and highlight the consequences of changing ice covers for limnological processes across local, regional and global scales. We welcome submissions focused on any aspect of limnology including physical, biological, and chemical processes under ice cover and during open water – ice cover transitions, especially those that aim to link biogeophysical processes.

SS06 Biotransport in flux: Animal-mediated nutrient and contaminant fate in altered aquatic environments

Jessica Brandt, University of Connecticut, [email protected]
David Walters, U.S. Geological Survey, [email protected]
Collin Eagles-Smith, U.S. Geological Survey, [email protected]
Matt Chumchal, Texas Christian University, [email protected]
Celia Chen, Dartmouth College, [email protected]

Aquatic animals are important actors in the horizontal, vertical, and trans-boundary distribution of ecosystem-derived materials via waste recycling, migration, emergence, predation, and decomposition. In the last two decades, nutrient-focused biotransport research has expanded to consider co-occurring persistent contaminants - the so-called bright and dark sides of subsidies - which act in concert to influence productivity, animal behavior, and overall health status in recipient ecosystems. However, the extent and magnitude of animal- mediated subsidy effects are ecosystem context dependent and are therefore expected to change as aquatic habitats are continuously altered. Research at this interface of animal subsidies and environmental change represents an important ecosystem science frontier and arena for collaboration between ecotoxicologists and aquatic ecologists.This session will highlight recent work on nutrient and contaminant transfer within and among aquatic ecosystems in the broader context of global change. We plan to convene researchers studying animal- mediated subsidy biotransport through lenses of changing temperatures, food web composition, population sizes, land uses, and habitat extents. Presenters are invited to share results from empirical, theoretical, and simulation- based studies that will contribute to an overarching discussion on subsidy trade-offs under various ecosystem change scenarios.

SS07 From meta-system theory to the sustainable, adaptive management of freshwaters in the Anthropocene

Thibault Datry, IRSTEA, [email protected]
Nuria Cid, Irstea, [email protected]
Jonathan Tonkin, University of Canterbury, [email protected]

Freshwaters are hot spots of biodiversity among the most threatened on Earth. Most if not all practices for their management are based on local scale processes, as a legacy of the persuasive niche paradigm that prevailed in ecology for decades. However, the meta-system paradigm acknowledges that both local (i.e. environmental filtering and biotic interactions) and regional (i.e. dispersal, patch context and spatial flows of material and energy) filters interact to determine the spatial and temporal organization of populations, communities, and ecosystem processes and services in a given landscape. This recently emerged paradigm highlights the need to update policy and management of freshwaters worldwide. The relevance of the meta-system framework as a sustainable and adaptive management approach for freshwaters will be even greater in the near future as climate change and increased water needs for human activities are exacerbating the occurrence and magnitude of extreme events (floods, droughts), altering their connectivity, and producing an unprecedented dynamic environmental and fragmentation setting. This session welcomes contributions aiming at translating the meta-system paradigm into management recommendations for freshwaters and specific suggestions for improving environmental policies, including climate change adaptation. We aim to highlight new research and policy-oriented findings that consider ecological processes at the regional scale to halt and/or reverse the ongoing loss of biodiversity in freshwaters and the growing deficits in ecosystem services they provide.

SS08 Forecasting is the Future: Advancing Methods and Applications of Near-term, Iterative Ecological Forecasting in Aquatic Ecosystems

Cavelan Carey, Virginia Tech, [email protected]
Mary Lofton, Virginia Tech, [email protected]
Tadhg Moore, Dundalk Institute of Technology, [email protected]
Rafael Marce, Catalan Institute for Water Research, [email protected]
Paul Hanson, University of Wisconsin-Madison, [email protected]

How are our aquatic ecosystems going to change in the future? How do human activities affect this trajectory? Can we anticipate how aquatic ecosystems will respond to extreme climatic events? The application of near-term, iterative ecological forecasting – i.e., making predictions about the future state of ecosystems and the services they provide, with fully explicit uncertainties in those predictions, that are updated continuously with new data when they are available – provides much promise for answering these questions. Due to recent advances in data availability and models, the aquatic research community is poised to increasingly use forecasting techniques to predict hypoxic zones, algal blooms, the availability of drinking water, ecosystem functioning, and other metrics of water quality and quantity, which will greatly improve management and society as a whole. However, there are many challenges to improving our ability to make forecasts, such as the need for improvements in ecosystem models, model-data fusion, and the quantification and analysis of uncertainties. This proposed session builds on a highly successful earlier session at the 2019 ASLO meeting in San Juan to highlight new advances in ecological forecasting in the aquatic sciences. We solicit diverse presentations of both methodological and application-based research on forecasting hydrodynamics, biogeochemistry, and ecology in aquatic ecosystems on any time scale, from days to centuries, and especially welcome submissions that examine the role of uncertainty in forecast development, operationalization, and decision support. Our confirmed speakers include a suite of diverse, early career presenters coming from a range of different universities and countries that represent every stage of the iterative forecasting cycle, from cyberinfrastructure to decision support.

SS09 Managing environmental flows to address water scarcity and natural resource conflicts

Eric Stein, Southern California Coastal Water Research Project, [email protected]
Sarah Yarnell, UC Davis, [email protected]
Ted Grantham, UC Berkeley, [email protected]
Julie Zimmerman, The Nature Conservancy, [email protected]

Integrating environmental flows in water management decision-making is critical to sustaining at-risk freshwater ecosystems. Competition for freshwater resources is increasing due to agricultural and municipal demands, desire to expand recycled water use, and climate change and extended droughts. These competing demands can lead to degradation of aquatic ecosystems and conflicts between resource and regulatory agencies entrusted with managing water quality, water supply, and sensitive species and habitats. This session will present alternative multi-objective analytical frameworks for assessing environmental flows needs and balancing demands among sectors. Approaches include statistical and mechanistic models, scenario analysis, and multi-objective decision support tools. Talks will give particular attention to modeling and technical approaches that advance scientific understanding of ecosystem functioning and to the development, implementation, and transferability of decision-support tools to guide management of rivers, lakes, and estuaries. The session will present models for interdisciplinary collaboration and stakeholder engagement during the implementation process, strategies for achieving long-term beneficial outcomes, and approaches for monitoring program effectiveness. Implementation case studies will be used to illustrate development and application of decision making tools to inform environmental flow management.

SS10 Physical, chemical and biological connections in large lake ecosystems

Ted Ozersky, University of Minnesota Duluth, [email protected]
Matthew Church, Flathead Lake Biological Station, University of Montana, [email protected]
Jennifer Hauxwell, UW Sea Grant, University of Wisconsin Madison, [email protected]
Amy Marcarelli, Michigan Technological University, [email protected]
Ashley Moerke, Lake Superior State University, [email protected]

Large lakes (>500 km 2 area and/or >100 m deep) hold the majority of the world’s surface freshwater, are hotspots of biological diversity, and provide vital ecosystem services to millions of people. The size of large lake ecosystems makes them distinct in many respects from smaller lakes. Among these differences are higher spatial heterogeneity of ecological and biogeochemical patterns and processes, greater diversity of habitats, and increased importance of large-scale physical forcing. Like many ecosystems, the large lakes of the world are undergoing unprecedented change, with important consequences for their ecological functioning and their ability to provide ecosystem services in a sustainable manner. This session is focused on highlighting physical, biological and chemical processes that occur in large lakes, as well as the connections between these processes. We welcome contributions on any of the world’s large lakes and especially encourage submissions that examine connections between processes or habitats across diverse temporal and spatial scales in the context of ongoing global environmental change.

SS11 Exploring watersheds under a changing climate via storm-driven solute and sediment retention, transport, and export dynamics

Shannon Speir, University of Notre Dame, [email protected]
Magdalena Bieroza, Swedish University of Agricultural Sciences, [email protected]
Jennifer Tank, University of Notre Dame, [email protected]

Streams and rivers have been identified as critical hotspots for nutrient and sediment retention and transport. Widespread anthropogenic alterations to the landscape, including excess nutrient inputs, changing land cover, and modified hydrology, may influence both retention and transport processes. Additionally, the impacts of climate change on hydrology may add complexity to our current understanding of these processes in aquatic ecosystems. Previous research has shown that, in many watersheds, storm-driven export makes up a large proportion of annual nutrient and sediment export. Looking to the future, storms are expected to increase in both frequency and intensity across the US. For example, in the Midwest and Great Lakes region, more frequent, intense precipitation and changing snow patterns are predicted. As such, recent analyses suggest the impact of storm timing and intensity on retention and transport may be more pronounced as patterns shift under a changing climate; thus, an improved understanding of the patterns and controls on nutrient and sediment export under high-flow conditions will be necessary in order to mitigate anthropogenic impacts on freshwater resources. In the past, exploring storm export presented challenges due to the rapid changes in solute concentrations with increasing discharge and safety concerns associated with high-flow sampling. Recently, explorations of source and transport dynamics have become more accessible with the advent of high-frequency sensing. Researchers are now able to capture high- resolution data during storms, allowing them to examine concentration-discharge (C-Q) relationships and calculate various indices, such as hysteresis and flushing indices, for individual storm events. Such indices are indicative of the magnitude, timing, and source behavior of nutrient loss from the surrounding watershed. Such metrics can then be tied to watershed land cover and land management, season, storm timing, and other variables of interest. The relative importance of storms in controlling nutrient and sediment retention and export is likely to increase with predicted shifts in hydrology, highlighting a need for an increased understanding of controls on storm-driven export, transport, and retention dynamics under a changing climate.

SS12 Feeling the burn: current research and emerging issues in fire, water quality, and aquatic ecosystems

Michael Paul, Tetra Tech Inc., [email protected]
Angela De Palma-Dow, Water Resources Department, County of Lake, CA,, [email protected]
Ryan Hill, United States Environmental Protection Agency, Office of Research and Development, [email protected]
Stephen LeDuc, United States Environmental Protection Agency, Office of Research and Development, [email protected]
Ian McCullough, Michigan State University, [email protected]

Although wildfire is a natural disturbance in many ecosystems, wildfire extent and frequency are increasing across much of North America, particularly in the western United States. There is an urgent need for researchers, managers and the general public to understand and anticipate the full range of effects of increasing fire activity on water quality and ecosystem properties across different aquatic ecosystem types (lakes, reservoirs, streams and rivers). Previous work has demonstrated that fires affect riparian vegetation and shading, water temperatures, geomorphometry, sedimentation and nutrient loading. These changes cascade into impacts on aquatic communities, including algae, invertebrates and fishes. Additionally, there are other less well-studied but potential emerging issues, including differences across aquatic ecosystem types, the mobilization of heavy metals or organic pollutants from natural or anthropogenic sources, chemical residuals from fire retardants and a possible linkage between fire, nutrients and harmful algal blooms. This special session brings together researchers and managers to 1) showcase leading-edge research on the physical, chemical and biological effects of fire on diverse aquatic ecosystems, 2) synthesize known effects, while identifying emerging issues and critical information gaps for future research; and 3) facilitate discussion among researchers and managers coordinating water quality monitoring, managing post-fire impacts and/or implementing mitigation measures.

SS13 Getting to the Bottom of Freshwater Food Webs: A Global Perspective on the Role of Terrestrial Resource Subsidies

Jia Huan Liew, University of Hong Kong, [email protected]
David Dudgeon, The University of Hong Kong, [email protected]
James Thorp, The University of Kansas, [email protected]
Darren CJ Yeo, National University of Singapore, [email protected]
Simon Mitrovic, University of Technology Sydney, [email protected]

Effective conservation and management of freshwater ecosystems often requires careful consideration of adjoining terrestrial ecosystems. This is because the flow of organic matter between freshwater and aquatic ecosystems are central in many ecological processes. However, there is some uncertainty about the role and importance of terrestrial resource subsidies (allochthonous material) in freshwater food webs which may be attributable to a range of factors including methodological limitations and spatial confounders. With the development and availability of new scientific approaches (e.g., compound specific isotopes), researchers now have access to new data and are starting to revise and update our understanding of allochthony. The proposed session aims to bring together some of the world’s most active contributors to this area of study. This will facilitate the sharing of current data collected from both temperate and tropical fresh waters, as well as information gathered with a wide range of research methods. The breadth of coverage will help participants of the session obtain a more holistic understanding of the state of allochthony research globally in order to collectively formulate testable hypotheses which can be tested in future (collaborative) studies. Overall, the potential international collaborations and research output from the proposed session will contribute to informing efforts to protect freshwater ecosystems, especially those occurring in rapidly developing drainage basins.

SS14 Controls and limits on freshwater productivity

Isabella Olesky, Cary Institute of Ecosystem Studies, [email protected]
Chris Solomon, Cary Institute of Ecosystem Studies, [email protected]
Stuart Jones, University of Notre Dame, [email protected]

In an age of unprecedented global change, it is more important than ever for limnologists to refine our understanding of ecological processes in order to make predictions of freshwater systems will function into the future. Aquatic ecosystems are subjected to multiple concurrent stressors (e.g., warming, changing precipitation regimes, and associated nutrient and organic matter loads), which may have implications on production with cascading effects through the aquatic food web. Heterogeneity in hydrologic setting (e.g., morphometry and residence time in lakes, hydrological connectivity and watershed area in rivers) across and within regions complicate our efforts to understand these changes. However, in recent years, there has been a revolution in our understanding of limits and controls on primary production that account for both variation in light environment and load stoichiometry. Large, spatial studies and the advent of relatively affordable sensor technologies have also deepened our understanding of drivers of variability in metabolic regimes. Ultimately, improved understanding of the underlying mechanisms driving aquatic ecosystem productivity will allow for better predictions that can aid managers and decision-makers into the future. In this session, we encourage field scale, laboratory, modeling, and predictive studies which investigate both basic (e.g., biogeochemical cycling) and applied (e.g., fisheries production) questions relating to lentic and lotic productivity dynamics. Studies can include explicit tests of mechanisms relating to benthic and pelagic production, respiration, or feedbacks to other trophic links. We especially seek investigators who are considering how coupled elemental cycles or multiple concurrent stressors may interact or synergistically control various aspects of lake biogeochemistry, physics, and ultimately productivity.

SS15 The ecology of sewage: wastewater-associated bacteria, pharmaceuticals, and nutrients in aquatic ecosystems

Elizabeth Ottosen, University of Georgia, [email protected]
Erin Lipp, University of Georgia Environmental Health Science, [email protected]
Krista Capps, University of Georgia Odum School of Ecology, [email protected]

A critical driver of water resource quality and sustainability is the management of human and livestock wastes. Fecal contamination of lentic and lotic ecosystems has long been recognized as a source of labile nutrients and waterborne pathogens. However, mismanaged waste, including treated and untreated wastewater, can also serve as a source antimicrobial resistance genes, antimicrobial resistant pathogens, and chemical contaminants including antibiotics, pharmaceuticals, and bioactive compounds. Fecal- or sewage-associated bacteria introduced to streams are not simply passively transported, but can become integrated in the aquatic ecosystem where they can undergo selection and exchange genes. In this session, we seek to bring together experts in freshwater ecology, microbial ecology, public health, and water resource management to highlight how treated and untreated wastewater influences the structure and function of aquatic ecosystems, and how passage through aquatic ecosystems impacts the biology of pathogens and the evolution and dissemination of antimicrobial resistance elements.

SS16 Potential impacts of future climate variability on Everglades restoration in Florida, USA

Nicholas Aumen, U.S. Geological Survey, [email protected]
Lynn Wingard, US Geological Survey, [email protected]

One of the largest restoration projects in the world is underway in the Florida Everglades. The goal is to “get the water right”, with billions of dollars committed to restore water flow, timing, distribution, and quality. Restoration goals are not intended to restore the Everglades to a pre-human impact condition. Instead, goals are structured to account for the irreversible loss of wetland area and other human impacts that have occurred already. However, the prospect of global-scale changes in climate have led to reconsideration of our restoration activities and goals in the face of potential changes in temperature, long-term precipitation patterns, tropical storm activity, and sea level. Recent studies documenting coastal peat collapse due to insufficient freshwater flows and rising sea levels show the importance of restoring freshwater flows to slow the inland migration of Everglades coastal habitats. Paleoecology studies in Florida Bay have shown the sensitivity of mangrove ecosystems to past climate variability during times of much slower sea level rise. Analyses using regional hydrological management models have shown the sensitivity of the Everglades ecosystem to relatively small changes in long-term temperature and precipitation patterns. This session will investigate a range of climate topics relevant to Everglades restoration, and will showcase the need for a strong connection between science and restoration policy-making.

SS17 Are ponds just little lakes? Pond carbon cycle, nutrient biogeochemistry, and mixing dynamics

Meredith Holgerson, St. Olaf College, [email protected]
David Richardson, SUNY New Paltz, [email protected]
Kelly Hondula, SESYNC, [email protected]

On a global scale, ponds (roughly < 0.1 km 2 ) comprise over 95% of all lakes and ponds by number, and about 10% by surface area. While ponds go by many names (e.g., shallow lakes, vernal pools, kettle ponds, and sometimes even wetlands), they are hotspots for biodiversity and biogeochemical cycling, and are sensitive to global environmental change. Yet, ponds are understudied relative to larger aquatic systems, which may bias our understanding of freshwater systems. This session will bring together pond scientists to examine ecosystem processes in small water bodies and clarify what (if anything) makes them different than larger lakes. We envision topics covering ecosystem metabolism, greenhouse gas emissions, mixing and stratification dynamics, food webs, organic matter, and eutrophication in both natural and human-constructed ponds. We particularly encourage studies that compare ponds across environmental gradients, or compare ponds with larger lake dynamics. This session will facilitate continued discussion regarding the importance of integrating ponds into our broader understanding of limnology and freshwater science.

SS18 Chemical communication among aquatic organisms – challenged by global environmental changes?

Patrick Fink, Helmholtz Centre for Environmental Research, [email protected]
Mahasweta Saha, Plymouth Marine Laboratory, Plymouth, UK, [email protected]
Christina C. Roggatz, Energy and Environment Institute, University of Hull, UK, [email protected]

Chemical communication is the most widespread and fundamental means of information exchange in both marine and freshwater ecosystems. It mediates organisms’ behaviour with respect to e.g. foraging, habitat selection, reproduction, and evasion of predators. Disruption of chemical communication mechanisms fine-tuned by evolution thus may have severe effects on species interactions and potentially jeopardise ecosystem stability and services. Such disruption may occur through a variety of factors, including pollution and water acidification through elevated atmospheric CO 2 concentrations. In this session, we aim to bring together and summarize recent advances in research on chemical communication processes across marine and freshwater pelagic and benthic habitats and discuss how environmental changes may affect chemical communication processes in the aquatic realm.

SS19 Biogeochemical and ecological change in Arctic lakes and rivers

Willem Geodkoop, Swedish University of Agricultural Sciences, [email protected]
Joseph Culp, Wilfrid Laurier University, [email protected]
Jennifer Lento, University of New Brunswick, [email protected]
Kirsten Christoffersen, University of Copenhagen, [email protected]

Warming of Arctic regions is twice as high as the global average, and has led to unprecedented changes to the landscape, including accelerated melting of glaciers and permafrost thaw, changes in hydrology and biogeochemical cycling, and alterations of landscape vegetation, including increased prevalence of wildfires. These changes will affect the abiotic template of Arctic freshwater ecosystems and induce changes in the flora and fauna and the ecological processes they perform, potentially causing wide-ranging ecological shifts. These changes include, among others, the dispersal of warm-adapted species to the north (including invasives), permafrost-thaw induced changes in hydrology/biogeochemistry, food web changes, and alterations of the relative role of autochthony/allochtony. Such changes will consequences for the biodiversity of Arctic freshwaters, as well as the Indigenous peoples who rely on the ecosystem services that Arctic freshwater systems provide. This session brings together studies that address the changes in biogeochemical pathways and their effects on the biological assemblages and ecosystem function of lakes and rivers. We envision contributions that illustrate the long-term, gradual changes in landscape biogeochemistry and biological assemblages, as well as examples of abrupt ecological shifts and predictions of future changes with continued warming.

SS20 From Phosphorus to Fish: Celebrating the Free-ranging Career of Steve Carpenter

Elena Bennett, McGill University, [email protected]
Jake Vander Zanden, U Wisconsin, [email protected]
Michael Pace, University of Virginia, [email protected]

Sustaining aquatic ecosystems under global change requires scientific knowledge working in collaboration with ecosystem management and society. This session will focus on key areas of scientific knowledge and management collaboration driven forward by the career of noted aquatic ecologist Steve Carpenter. Each talk will focus on one research topic, and discuss how Carpenter’s work contributed to our current knowledge and explore key future directions for research in this area. Research areas will include: trophic cascades, aquatic food webs, freshwater fisheries management, ecosystem manipulations, eutrophication and phosphorus as a slow variable, scenario development, working with decision-makers, and resilience.

SS21 Extreme events across the freshwater-marine continuum: implications for carbon transport and biogeochemical cycling

Alexandria Hounshell, Virginia Tech, [email protected]
Jacob Hosen, Purdue University, [email protected]
Erin Hotchkiss, Virginia Tech, [email protected]

There is growing evidence that extreme events, including droughts, floods and winds from severe storms, and permafrost melting are increasing worldwide due to climate change. These extreme events have a direct impact on carbon transport and biogeochemical cycling from headwater streams to coastal ecosystems, with largely unquantified consequences for the global carbon cycle. For example, extreme events can change water residence time and alter the quantity and chemical composition of carbon flushed into freshwater and marine ecosystems from the terrestrial landscape. How far carbon inputs travel downstream before metabolism, storage, or emission will alter biogeochemical cycling within and among ecosystems. By looking across the aquatic continuum, our session will provide insight on how an increase in the incidence and magnitude of extreme events affects not only the transformation and transport of carbon in each individual ecosystem, but also alters cross-ecosystem carbon subsidies and transformations. We seek presentations that assess how carbon quantity and composition, photochemistry, biological degradation and production, and/or greenhouse gas dynamics (CO 2 , CH 4 ) change in response to extreme events using a suite of different methodological approaches in any aquatic ecosystem type. We particularly welcome submissions that have assessed carbon dynamics across the continuum.

SS22 A Report Card on the Sensor Revolution: contribution of high Frequency Sensors to fulfil knowledge gaps in Aquatic Ecosystem Science

Susana Bernal, CEAB-CSIC, [email protected]
Matthew Cohen, University of Florida, [email protected]
Anna Lupon, CEAB-CSIC, [email protected]
José Ledesma, CEAB-CSIC, [email protected]
Eugènia Martí, CEAB-CSIC, [email protected]

The transport and cycling of carbon and nutrients along fluvial networks is essential for understanding aquatic ecosystem function and has large impacts on global biogeochemical cycles. Historically, our ability to understand hydrological, chemical, and biological interactions in streams and how they influence solute export and gas evasion at different spatiotemporal scales has been methodologically constrained. Current development and implementation of in situ water quality sensors have dramatically increased the temporal resolution of our measurements. However, to which extend has this large availability of data shed new light on open questions in freshwater ecosystem science, inspired novel conceptual frameworks, or provided essential early-warning tools are still open questions. After nearly 20 years into the high frequency water quality sensor revolution, we seek to collate and synthesize how sensors (i) have promoted advances in freshwater ecosystem science and modelling, (ii) can help diagnosing environmental problems and trace patterns of recovery, and (iii) can be combined with low- cost, low-frequency sampling to disentangle hydrological and ecological processes occurring at different time and spatial scales along fluvial networks. This special session welcomes studies showing the value of fine scale measurements for understanding the mechanisms underlying in-stream solute dynamics and the impact of climate change and human activities on solute transport and cycling at different temporal (from diel to annual) and spatial (from microhabitats to landscapes) scales.

SS23 Linking hydrologic regimes to temporal dynamics of aquatic ecosystems

Ethan Baruch, Arizona State University, [email protected]
Tamara Harms, University of Alaska Fairbanks, [email protected]
Albert Ruhi, University of California Berkeley, [email protected]

The seasonality and predictability of hydrologic regimes shapes dynamics of aquatic ecosystems. In streams and rivers, the characteristic patterns of discharge variation control nutrient pulses, biodiversity, and food-web structure. In wetlands and lakes, hydroperiod length and timing are also critical drivers of biota and a variety of ecosystem processes, such as primary and secondary production. As the global hydrologic cycle is increasingly altered by human activities and climate change, understanding how hydrologic regimes influence ecosystem structure and function, and their change over time, will be necessary to anticipate ecosystem responses to future scenarios and inform management accordingly. In this session we will examine variation in hydrologic regimes (e.g., floods, lake water level, reservoir operations, glacial outflow, storm surges), and how these regimes control organismal to ecosystem-level responses. We welcome contributions combining levels of biological organization (e.g., population and ecosystem ecology), methodological approaches (e.g., observation and experiments), and analytical tools (e.g., stable isotope analyses, analysis of high-frequency sensor data). We are also interested in contributions highlighting the applied implications of the hydrology-ecosystem dynamics link—from monitoring to conservation planning and reserve design. Collectively, this session will advance our understanding of the links between hydrologic variation and the flow of energy through ecosystems, via changes in community composition, trophic interactions, nutrient cycling, and ecosystem production.

SS24 How changing thermal regimes influence stream ecology and resilience

Valerie Ouellet, University of Birmingham, [email protected]
Stefan Krause, University of Birmingham, [email protected]

Water temperature is recognized as a highly sensitive key environmental variable which directly and indirectly influences and regulates numerous aquatic ecological processes. For instance, there is a strong positive relationship between water temperature and bacterial and algal development. Water temperature influences the rates and efficiency of biochemical reaction, as well as inducing physiological or behavioural responses in aquatic organisms. Therefore, water temperature is a crucial variable when assessing overall aquatic ecosystem health. Rising atmospheric temperatures and modification of hydrological regimes due to climate change are increasing river temperatures worldwide. In addition, human use of water resources exacerbates climate-driven thermal effects to river ecosystems. This has resulted in modified thermal regimes, with warmer temperatures being observed globally under climate warming. Increased river temperatures may lead to reduced gas solubility and increased biogeochemical processing rates. Elevated temperature can negatively affect the metabolism and functioning of aquatic organisms, reduce habitat suitability and induce changes in species distribution. Therefore, changes in thermal regimes can cascade through a wide range of stream ecological processes and influence aquatic ecosystems resilience under global changes. This session invites contributions that explore different aspects of how changing thermal regimes influence (1) stream productivity and biochemical processes, (2) induce changes in aquatic organism metabolisms, behaviour and community structure, habitat and distribution and (3) how thermal stress interacts with other stressors in their combined impact on ecosystem functioning and health.

SS25 Think positive: Exploring the consequence(s) of positive interspecific interactions from community structuring to ecosystem processes

Benjamin Tumolo, Montana State University, [email protected]
Scott Collins, Texas Tech University, [email protected]

Positive interspecific interactions such as species mutualisms (i.e., both species benefit) and species facilitation (i.e., one species alters conditions to the benefit of another species) are prevalent in nature and comparable in strength to negative interactions (e.g., predation, competition). Yet, these processes are generally underrepresented in the published literature when compared to competition and predation, despite their importance in shaping food web architecture and driving the productivity of ecosystems. The means by which one species confers benefits to another species are diverse and usually entail some form of habitat or resource modification. Indeed, as plants and animals modify physical habitat structure and/or food resource availability, such changes can ameliorate otherwise harsh ecological conditions for other species. Given unprecedented rates of global biodiversity loss, especially so in aquatic habitats, there is an urgent need to better understand which positive interactions will be lost or gained from a community or ecosystem as well as the broader ecological consequences. This special session serves to highlight the prevalence of positive interspecific interactions in aquatic ecosystems, the mechanisms through which they occur, and their importance for restoration, conservation, and management. A clearer understanding of the role of positive interactions in aquatic communities should better inform such efforts, particularly when mitigating for the growth of human populations, the protection of endangered species, and the imminent effects of global climate change.

SS26 Salinization of Freshwater Ecosystems

Sarah Orr, North Carolina State University, [email protected]
David Buchwalter, North Carolina State University, [email protected]
Sally Entrekin, Virginia Polytechnic Institute and State University, [email protected]
Tony Timpano, Virginia Polytechnic Institute and State University, [email protected]

Freshwater salinization is an emerging global ecological issue. Many anthropogenic activities such as agriculture, road de-icing, and resource extraction are changing salinity regimes of freshwater ecosystems. Additionally, these land use practices can interact with changes in climate that affects precipitation and water withdrawals. Unfortunately, many freshwater species and habitats have been adversely affected as a result. Regulatory approaches in ion-specific water quality standards vary among countries and are typically focused narrowly on one or two ions, if at all. A better understanding of how salinity changes affect freshwater biota and their associated functions is necessary to avoid lost biodiversity and ecosystem services and support actions towards protection and mitigation. This Salinization of Freshwater Ecosystems session welcomes the opportunity to integrate disciplinary perspectives on freshwater salinization, including geochemistry, spatial distributions of salinity regimes, osmoregulation, toxicity, and ecosystem effects. We aim to bring together researchers, regulators, and practitioners across SFS and ASLO to discuss these important issues. The overarching goals of this session are to share new information and illuminate potential future research and collaborations for research aimed at understanding and addressing ecological impacts of freshwater salinization.

SS27 Aquatic greenhouse gas dynamics in the face of global change

Tonya Delsontro, University of Geneva, [email protected]
Jake Beaulieu, United States Environmental Protection Agency, [email protected]
Erin Hotchkiss, Virginia Tech, [email protected]

Biogeochemical cycling in aquatic ecosystems results in the production and consumption of the greenhouse gases (GHG) methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O). Although freshwater aquatic ecosystems cover a small proportion of the earth’s surface, GHG emissions from these systems are globally significant, reflecting high biogeochemical transformation rates. Aquatic GHG dynamics are complex involving aerobic and anaerobic transformations, physical transport via diffusion and advection, and multiple emission mechanisms. Furthermore, the processes are controlled by multiple interacting drivers that vary across a range of spatial and temporal scales. The objective of this session is to review studies that attempt to understand, predict, or mitigate GHG biogeochemistry/emissions across all freshwater ecosystems including lakes, reservoirs, wetlands, rivers and streams. We invite abstracts discussing any aspect of aquatic GHG biogeochemistry, including those that consider how a changing climate and expanding human population may influence local to global scale GHG emission patterns.

SS28 Social-Ecological Systems as a Framework for Freshwater Conservation

Chelsey Neiman, Carey Institute of Ecosystem Studies, [email protected]
Christopher Solomon, Cary Institute of Ecosystem Studies, [email protected]
Stuart Jones, University of Notre Dame, [email protected]

Freshwater ecosystems are facing severe anthropogenically-induced threats causing them to become some of the most imperiled ecosystems in the world. As these systems support a variety of social and economic systems as well as ecological systems, it is essential to consider the conservation of these systems in the context of this greater landscape. Social-ecological systems thinking can provide managers and agencies with the tools for management of ecological systems that also support human endeavors, particularly in freshwater systems and recreational fisheries. Integration of social-ecological systems thinking with management strategies can increase understanding of adaptive responses to global change, but also relies heavily on engagement of stakeholders. As freshwater systems continue to face human-induced rapid environmental change, innovative solutions are of increasing importance to increase resilience across the freshwater landscape. Stakeholder engagement can provide essential links to conservation practices within these systems, however, engagement can be varied across the landscape. This session will highlight research on freshwater systems within a social-ecological systems framework, including, but not limited to recreational fisheries, urban water quality, energy production, and other freshwater landscapes. In particular, we want to include research that emphasizes practical stakeholder engagement for conservation and management of social-ecological systems.

SS29 From metabolites to management: Applying environmental metabolomics to bioassessment

Jessica Orlofske, University of Wisconsin-Parkside, [email protected]
Nicholas Bielski, University of Arizona, [email protected]
Jason Kowalski, Marian University, [email protected]

Sustaining aquatic ecosystems requires sensitive, diagnostic tools that can offer early detection of environmental degradation and indicate subsequent improvement from management action and intervention. Traditional structural and functional measures of biotic condition are broadly applied for regulatory monitoring; however, molecular approaches, such as the rapidly developing field of environmental metabolomics, have the potential to enhance and improve bioassessment. Metabolomics is the study and analysis of molecules involved in biochemical reactions within an organism. Environmental metabolomics applies these analyses to questions concerning individuals or groups of organisms and their habitats. Environmental metabolomics has been applied broadly to aquatic systems. This session provides a venue to present diverse examples of environmental metabolomics in aquatic systems and organisms, illustrating different questions, applications, and molecular and analytical approaches. The session combines the expertise of aquatic ecologists, molecular biologists, and chemists to address environmental challenges from impacts due to climate change and habitat alteration to pollution and contamination. In addition to providing an interdisciplinary forum, the outcomes of this session include synthesizing relevant tools and techniques for field and laboratory applications, conceptualizing how to integrate environmental metabolomics with traditional bioassessment approaches, and prioritizing future research needs to inform sustainable management and policy decisions.

SS30 Trash talk: Ecology of anthropogenic materials in freshwaters

Rae McNeish, California State University, [email protected]
Emma Rosi, Carry Institute of Ecosystem Studies, [email protected]
Timothy Hoellein, Loyola University Chicago, [email protected]

Anthropogenic materials (e .g., anthropogenic litter, plastic, nanoparticles, pharmaceuticals) are ubiquitous pollutants across freshwater ecosystems and a signature of global change. Advancements in chemical engineering have diversified the number and variety of anthropogenic materials in the environment. Understanding their sources, fates, and biological interactions are critical to sustaining ecosystem services and the environmental health of valuable freshwater resources. While monitoring the presence of anthropogenic materials in the environment has been ongoing for decades, research advancements in the field require placing anthropogenic materials in a dynamic ecological context by considering their biological and chemical transformations across multiple spatial and temporal scales. Moreover, consideration of the interactions of these materials with each other and other drivers of global change will be necessary to understand the future of freshwater ecosystems. Ecological approaches that explicitly consider fate, transport, and multiple interactions will generate results most useful for management and policy frameworks that support conservation. This session will focus on ecological research that spans different types of anthropogenic materials, aquatic ecosystems, habitats, scales of inquiry, and interactions. All participants are welcome to consider how current and future research can support aquatic ecosystems under global change.

SS31 Littoral Greening: Uncovering physical, chemical, and biological drivers of attached filamentous algal blooms (FABs) in pristine lakes

Yvonne Vadeboncoeur, Wright State University, [email protected]
Sudeep Chandra, University of Nevada, Reno, [email protected]
Simon Stewart, Cawthron Institute, [email protected]

Throughout the world, clear lakes with high water quality are suddenly experiencing unexplained proliferations of attached filamentous algae and cyanobacteria. Littoral benthic habitats are ‘greening’ yet this phenomena remains undetected by established indicators of eutrophication. Excessive growths of filamentous green algae and cyanobacteria represent a shift away from the cryptic, thin biofilms of benthic diatoms that typically fuel nearshore food webs. Filamentous algal blooms (FABs) alter the function of littoral habitats - habitats that support a majority of lake biodiversity and are instrumental in transforming landscape nutrients. FABS are well documented in Lake Baikal, Lake Tahoe, and oligotrophic montane lakes in the USA and New Zealand, but we have only rudimentary understanding of the links between these outbreaks and climate variability, groundwater pollution, and loss of top- down control. In addition to case studies, the session will include talks exploring potential drivers of littoral FABS and the appropriate scientific and public outreach responses to this emerging threat to clear-water lakes. Potential topics include 1) How do climatically-induced changes in physical conditions affect nutrient and sediment dynamics in the nearshore zone? 2) Are remote lakes experiencing increased nutrient loading from anthropogenic groundwater pollution? 3) Is top-down control by the littoral zone grazer assemblage weakening? 4) Do even moderate increases in nitrogen availability associated with lakeshore development and atmospheric loading favor the growth of filamentous green algae and filamentous cyanobacteria? We strongly encourage early career scientists to contribute to our understanding of this emerging threat to pristine lakes.

SS33 Ecology of groundwater systems: Where do we go from here?

Weston Nowlin, Texas State University, [email protected]
Benjamin Schwartz, Edwards Aquifer Research and Data Center, Texas State University, [email protected]
Benjamin Hutchins, Texas State University, [email protected]

Groundwater resources are highly exploited and are being depleted rapidly across the globe. The ecology of groundwater ecosystems (e.g., aquifers, cave streams, hyporheic zones) have been studied over the last 40+ years, but these systems are still poorly understood. Previous studies of groundwater systems have focused on patterns of organism occurrence, site-specific species richness, and the description of physical habitat characteristics. In general, many of these studies are descriptive and have not addressed larger ecological or evolutionary questions. However, in the last decade groundwater community and ecosystem data sets have become larger and more robust and have been used to examine macroecological questions, test ecology – evolutionary biology hypotheses, and examine the role of organisms in ecosystem functioning. Groundwater systems are ideal for the examination of basic ecological and evolutionary biology questions because when compared to surface water systems, groundwater food webs tend to be simple, species richness is low, the number of environmental covariates is limited, and sites are spatially constrained, highly replicated, and isolated by aquifer or hydrogeomorphic unit. The purpose of the proposed special session will bring together ecologists and evolutionary biologists who have focused research efforts on groundwater systems. The session’s main goals will be to review the status of groundwater ecology, present current research on the ecology and evolutionary biology of groundwater systems, demonstrate how groundwater systems can be used to address basic ecological and evolutionary biology questions, and to propose future research areas and data gaps in the study of groundwater systems. The session will start with a 30-minute tutorial/review of the current status of groundwater systems ecology and then move onto a series of standard 15 minute talks. The session will conclude with a panel discussion, with a number of the speakers in the session being the members of the panel.

SS34 Inequitable Waterscapes: Examining Environmental Justice in Aquatic Systems

Mitchell Owens, Indiana University Bloomington, [email protected]
Rachel Scarlett, Purdue University, [email protected]

Changing climate and its effects on water regimes influence the ecological integrity of our aquatic systems. These changes expose all of society to many risks, however it is well-established that the marginalization of communities based on sociodemographic factors, such as race, gender, income, and/or nationality, systematically exposes certain groups more than others to environmental disamenities-- such as vulnerability to floods and impaired water quality. However, these kinds of environmental injustices not only relate to unequal distributions of environmental quality, amenities, and services, but also manifest themselves in the lack of diverse representation and inclusion in decision-making processes and a lack of recognition of marginalized groups as stewards of the environment. Substantial evidence has supported the prevalence of environmental injustices in landscapes; for example, several case studies illustrate the unequal siting of United States’ pollution and polluting industries in poor and often African American communities and the consequences for aquatic systems on which they depend. However, waterscapes have only recently been studied through the lenses of social equity and environmental justice. This session will highlight a small but growing body of work on or related to: 1) Distribution of amenities and disadvantages in waterscapes 2) Inequitable participation in social processes that govern waterscapes 3) How pre-existing social inequalities and environmental processes work simultaneously to produce inequitable waterscapes 4) Opportunities for streamlining environmental justice into management and conservation of aquatic systems

SS35 Drying in freshwater systems: merging lotic and lentic perspectives in an era of global change

Daniel Allen, University of Oklahoma, [email protected]
Rachel Stubbington, Nottingham Trent University, [email protected]
Meryl Mims, Virginia Tech, [email protected]
Thibault Datry, IRSTEA, [email protected]
Nathan Jones, University of Alabama, [email protected]

Drying is an important abiotic factor in non-perennial freshwaters, influencing organismal biology and ecosystem processes at local and landscape scales. Despite the ecological importance and growing awareness of drying in lotic and lentic ecosystems, the majority of freshwater research focuses on systems that do not dry. Furthermore, drying regimes in both lentic and lotic ecosystems are changing due to climate change and human water use, with drying expected to increase in many parts of the world. In this session, we seek to bridge traditional boundaries across disciplines and scales (e.g., lentic–lotic, organismal–ecosystem, aquatic–terrestrial, ecology-hydrology) to help advance the broad science of drying in freshwater systems. This session will focus on fundamental and applied research exploring population dynamics, community composition, ecosystem functions, and ecohydrology in aquatic systems that regularly dry. First, we will aim to characterize principal drivers of drying regimes in freshwaters. Second, we will explore the role that drying plays in processes across levels of biological organization, from organisms to ecosystems. Third, we will investigate shifts in drying regimes in an era of global change and their implications for freshwater ecosystems. The overall aim of this session is to identify common objectives and approaches that span lentic and lotic research, and how research in these areas could better inform management, restoration, and policy related to freshwater systems that regularly dry.

SS36 Tracing change in food webs: current and emergent methods to determine impacts of anthropogenic change on ecosystem structure and function

Ariana Chiapella, University of Vermont, [email protected]
Jason Stockwell, University of Vermont, [email protected]
Ellen Marsden, University of Vermont, [email protected]

Humans activities cause direct and indirect change to aquatic food webs, and this change continues to accelerate. From the introduction of non-native aquatic species, to brownification and warming, such changes can have devastating ecological consequences and create serious management challenges for freshwater and marine waterbodies. The consequences often include shifts in nutrient cycling and trophic cascades, which can induce major changes in ecosystem function that have both ecological and economic impacts such as harmful algal blooms, reduced biodiversity, and loss of recreational and commercial fisheries. The ability to anticipate the ecological consequences of such major ecosystem changes, so that scientists and managers can work together to mitigate the impacts, is imperative. One of the most effective ways to understand and anticipate the consequences of ecosystem change is to understand the flow of energy in the food web. Such approaches provide an opportunity to retroactively understand how anthropogenic stressors have affected food webs, and use that information to anticipate changes to food webs in at-risk waterbodies. This session highlights current and emergent methods in food web ecology – for example, bulk and compound-specific stable isotope analysis and fatty acid analysis – that allow us to trace energy pathways. Such knowledge can be used to develop management and policy solutions that may mitigate the effects of future anthropogenic change, and sustain the health of our freshwater and marine ecosystems.

SS37 Regulated reservoirs and rivers: How can we manage hydrology to meet society and ecosystem needs?

Allison Roy, U.S. Geological Survey, [email protected]
Katrine Turgeon, Université du Québec en Outaouais, [email protected]
Jason Carmignani, University of Massachusetts, [email protected]

Reservoir and river management commonly includes the regulation of flows and water-level fluctuations to provide hydropower; for flood control, water supply and irrigation; and to manage invasive species, among other human services. These direct manipulations alter the natural hydrologic regime of aquatic ecosystems, with varied risks to native flora and fauna and potential impacts on critical ecosystem functions. An understanding of the spatial and temporal extent of impacts is critical for quantifying mechanisms by which flow regulation and water- level fluctuations impair aquatic ecosystems. In this session, presenters will share results of empirical studies describing the impacts of different dam and reservoir flow management approaches on lake and river ecosystems. Talks in the session will also explore approaches to better manage flow and water levels to meet societal needs while minimizing impacts to aquatic ecosystems.

SS38 Twenty-five years since The Freshwater Imperative: What have we accomplished and where do we go from here?

Catherine O'Reilly, Illinois State University, [email protected]
Steven Sadro, UC Davis, [email protected]
Kathryn Cottingham, Dartmouth College, [email protected]
Michael Vanni, Miami University, [email protected]

The theme of the joint aquatic sciences meeting this year “Sustaining Aquatic Ecosystems Under Global Change” speaks to the heightened urgency about the impacts of environmental change on ecosystem services. The focus of this theme further highlights the complexity of these impacts, alluding to not just the scientific knowledge, but also the policy tools that are needed to accomplish effective management of freshwater resources in this era of rapid change. Three decades ago, concern about the need for sustainable management of freshwater resources led to The Freshwater Imperative (FWI), published as a book by Naiman et al. (1995) and highlighted in Science. The FWI was a comprehensive research agenda designed to lead to a predictive understanding of freshwater ecosystems, through improving detection, assessment, and forecasting, as well as developing management and mitigation scenarios for potential environmental change. On the 25 th anniversary of its publication, we reflect on what aquatic ecologists have accomplished, what we have missed, and what lessons we have learned that can be applied to preparing for future environmental crises. How have predictions of the FWI been borne out? What current threats and challenges were not predicted? What would a new FWI look like? In this session we solicit talks that are 1) reflective, retrospective summaries of research and/or policy in freshwater environments, or 2) describe emerging tools and approaches that will improve our understanding and management of aquatic environments. This session will include a period for interactive discussion and synthesis about future directions. We request a combination format: Standard 15-minute talk formats, starting with a 30-minute tutorial talk, and with a final block as period for discussion. We request 3 blocks: 1) introduce the session with a tutorial and some retrospective talks, 2) focus on emerging tools and approaches, and 3) an interactive discussion/synthesis period. We would report back this discussion to the broader community through publications in the L&O Bulletin, In the Drift and/or Making Waves.

SS39 Living on the edge: What can we learn from comparing waterbodies in remote locations?

Angela Strecker, Western Washington University, [email protected]
Steven Sadro, University of California, Davis, [email protected]
Adrianne Smits, University of California Davis, [email protected]

Remote or inaccessible waterbodies have provided valuable insight for aquatic ecology and biogeochemistry, in part because they have historically been viewed as pristine. However, they face a multitude of stressors, many of which are increasing in frequency and severity over time. These waterbodies may represent the last refuge for some species given forecasted climate shifts and habitat destruction in more populated regions. Despite these threats, remote waterbodies often retain a level of natural heterogeneity that is absent from more impacted systems. Yet we lack a synthetic understanding of the factors driving environmental change within and across these systems, as well as how their spatial organization affects their response to environmental stress. Thus, it is vital to understand the processes that govern these systems and determine if there is a synthesis that can emerge from comparing different regions, such as mountain, polar, desert, and boreal biomes. We welcome submissions that consider topics such as ecosystem processes, landscape connectivity, cross-scale interactions, and biotic interactions in aquatic systems that operate at the edges. We are especially interested in submissions that integrate lentic and lotic perspectives, which will be critical for advancing our understanding of global environmental change over the next century

SS40 Challenges in Neotropical stream conservation

Carissa Ganong, Missouri Western State University, [email protected]
Pablo Gutierrez Fonseca, Universidad de Costa Rica, [email protected]

Neotropical stream ecosystems are at the forefront of global climate change effects and are facing impacts from changing precipitation patterns and extreme weather events, in addition to other anthropogenic stressors such as land use changes and contamination. Despite several studies demonstrating the influence of these natural and anthropogenic stressors on Neotropical streams, up-to-date information remains limited and scattered. This session will summarize current knowledge of tropical stream conservation and will explore research techniques and datasets used to detect anthropogenic effects on stream ecosystems from Caribbean, Central American, and South American sites as well as work to mitigate these effects. Speakers will summarize the state of knowledge for their particular tropical study sites, identify actual and emerging ecological trends, and describe threats associated with global change and anthropogenic activities.

SS41 Showering the Earth with carbon: The implications of CO2 as an unbalanced stoichiometric driver to organism, ecosystem and human health

James Cotner, University of Minnesota- Twin Cities, [email protected]
Jessica Corman, University of Nebraska-Lincoln, [email protected]

Human use of fossil fuels and changes in land use are contributing about 10 Pg of additional carbon to the atmosphere annually, mostly as carbon dioxide. The two main issues that aquatic science has focused on related to this perturbation are climate change and ocean acidification, both of which are extremely relevant to the condition of organisms, aquatic systems and their sustainability. However, there is a less well-understood aspect of 'the CO2- problem' which is related to the fact that carbon can be a limiting element to both autotrophs and heterotrophs. Furthermore, even when it is not limiting, the degree to which it is in excess or 'out of balance' could have important implications for how organisms and ecosystems function. For example, microbes are able to store excess carbon in various forms when they are limited by nutrients such as nitrogen and phosphorus, but they can also increase metabolic rates. Does the extent to which carbon is in excess when it is not limiting have implications for metabolism of organisms and ecosystems as well as other biogeochemical cycles such as iron and oxygen that are influenced by carbon? Can carbon excess lead to increased greenhouse gas production in aquatic ecosystems. We will use stoichiometry to explore whether ecosystems are 'healthier' when biogeochemical cycles are balanced, similar to how humans are healthier when they eat a balanced diet.

SS42 Strain level variation of cyanobacteria

Bastiaan Ibelings, University of Geneva, [email protected]
Michele Burford, Griffith University, [email protected]
David Hamilton, Griffith University, [email protected]
Man Xiao, Griffith University, [email protected]

The environment is changing and becoming less predictable. This unpredictability provides a challenge for all species in nature, even for those that have been around as long as cyanobacteria and have always found ways to adapt. An important mechanism that buffers the impact of environmental variability and provides long-term stability for species is genetic and phenotypic - trait - population level variation. Developments like high throughput sequencing, flow cytometry and image analysis have allowed scientists to slowly open up the black box on individual-level variation, which is present within populations. In this session we aim to explore what we know about genomic and functional variation within populations of cyanobacteria that cause (harmful) blooms, how this variation promotes persistent bloom formation, how it affects toxicity, and the outcome of interactions with the competitors, grazers and parasites of cyanobacteria. We seek to understand how study over extended periods of years of a limited number of cyanobacterial isolates may have biased our understanding of bloom dynamics and the drivers of blooms. The genes and traits that will be discussed during this session will vary from toxins, like the widespread microcystins, to cellular nutrient uptake mechanisms, carbon concentrating mechanisms and others. At a fundamental level we are interested to explore the eco-evolutionary mechanisms that have led to cyanobacterial diversification and that contribute to this diversity being maintained within populations, despite the counteracting effects of competition between strains. Additionally, at the applied level, we aim to discuss how a deeper understanding of strain-level variation could contribute to successful design and implementation of bloom control and mitigation measures.

SS43 Physiological and Environmental Drivers of HAB Formation and Toxicity

Nicole Wagner, Baylor University, [email protected]
Thad Scott, Baylor University, [email protected]
Dedmer van de Waal, NIOO-KNAW, [email protected]
Bryan Brooks, Baylor University, [email protected]

Harmful algal blooms (HABs), including cyanobacteria and eukaryotic species, have been increasing in magnitude and intensity as result of eutrophication and climatic changes. Although blooms may continue to expand and become more prominent/toxic, the environmental drivers and mechanism(s) of bloom formation and toxin production remain elusive due to the multifaceted nature of HABs. The focus of this session will be to examine how phytoplankton physiological traits interact with environmental factors to promote HAB formation and/or toxin production. Revealing these mechanisms of bloom formation and toxin production are urgently needed to offer better predictions on where and when HABs will form. We invite both poster and oral presentations from laboratory, field, and/or modeling approaching that examine physiological traits of HABs to environmental stressors from molecular to ecosystem scale.

SS44 Emerging technologies for improved spatial and temporal observations of HAB and ecosystem change

Errera Reagan, NOAA, [email protected]
Steve Ruberg, NOAA GLERL, [email protected]

Our ability to understand harmful algal blooms (HABs) formation and demise is limited by our ability to make accurate and timely observations within the ecosystem, which includes collection of environmental and biological data when weather conditions may not be ideal. Beyond ecosystem and human health threats posed by HABs, ecosystems are experiencing unprecedented changes from anthropogenic pressures, invasive species, and global climate change. These challenges hinder our ability to assess and predict HA growth, expanse, and toxicity. Significant progress has been made based on the development and use of remote and passive samplers, vehicles and traps, toxin and optical sensors, imaging systems, and microfluidic analyzers; these emerging technologies have provided the opportunity to address these challenges within aquatic and coastal systems. The goal of the session is to discuss successes and difficulties of incorporating prototypes and novel technologies to investigate HABs. Since multiple factors influence bloom development and senescence, our aim is to focus on sensor and platform designs that analyze multiple environmental and biological aspects of bloom events, such as the biogeochemistry, chemistry, toxicity, allelochemicals, and genetic diversity. As well as, prompt discussion on possible gaps in technology and system development that could improve scientific research and provide critical information to ecosystem based models, industry, and resource managers.

SS45 Brainstorming Beyond the Edge of Field: Mitigating the impacts of nutrient pollution on harmful algal blooms

James Larson, U.S. Geological Survey, [email protected]
Rebecca Kreiling, U.S. Geological Survey, [email protected]
Lynn Bartsch, U.S. Geological Survey, [email protected]

Harmful algal blooms (HABS) impact the ability of nearshore and freshwaters to support the provisioning of ecosystem services, and therefore have substantial impacts to the economies of surrounding communities. While agricultural runoff of fertilizers is often thought to be responsible for creating conditions that favor HABS formation, agricultural production itself contributes to the economic well-being of large communities. This on-going tension has made reduction of HABS frequency and intensity difficult. Conventional approaches to reducing nutrient runoff have had mixed success. Are there great ideas that have not yet been attempted or seen the light of day? Are there things that have only been attempted at small spatial or temporal scales? What great ideas are we not trying? Here we solicit lightning talks and discussion on all aspects of the causal network that leads to HABS. For example, management of aquatic processes, effectiveness of landscape management, models for predicting toxicity, better forecasting of ecosystem service impacts and any other topics that explore solutions beyond “less fertilizers”.

SS46 Open access sensor-based monitoring networks as foundations to water resources sustainability

Bobby Hensley, NEON, [email protected]
Kaelin Cawley, NEON, [email protected]
Guy Litt, NEON, [email protected]

Water resources data (e.g. streamflow, chemistry, metabolism) provided by long-term, spatially expansive monitoring networks can provide useful insights into understanding responses to long-term change from regional to global scales. In addition to enabling higher sampling frequencies, the supplanting of grab sampling by in- situ sensors as the primary mode of data collection potentially allows near real-time monitoring of many water quality parameters. Coupled with predictive models, whose power also benefits from the expansive datasets these networks provide, this allows managers to take prompt or even proactive action in response to changing conditions. Many of these monitoring networks (e.g. USGS NWIS, NEON, GLEON, Stream Pulse) or data repositories (CUAHSI) are openly available, providing external users access to these databases. This allows cross-validation of models and pooling of datasets which can provide broader understandings. This session is intended to highlight the role open-access monitoring networks can play in characterizing diverse threats to water resource sustainability (e.g. climate change, over-appropriation, extreme hydrologic events, eutrophication, invasive species) and developing sustainable solutions. We actively solicit submissions highlighting the potenatial for "networking of networks". Additionally, given the public’s role as the critical stakeholder, we also encourage submissions which highlight ways in which public contributions to, and utilization of, new and existing monitoring networks can be encouraged.

SS47 Open data in the era of global change: the role of networks in water resources sustainability science

Eric Sokol, NEON, [email protected]
Stephanie Parker, National Ecological Observatory Network (NEON), [email protected]
Lee Stanish, National Ecological Observatory Network (NEON), [email protected]

In the Anthropocene, the sustainability of freshwater resources are under threat due to both climate change and non-climate drivers, such as changes in land use and the introduction of invasive species. Long-term research and observatory networks, including the National Ecological Observatory Network (NEON), the US Long Term Ecological Research program (US LTER), and Global Lake Ecological Observatory Network (GLEON), have and will continue to play an important role in freshwater science by providing data streams necessary to differentiate between historical/natural variability and anthropogenic disturbance. Importantly, the field of ecology is in the midst of a data revolution with increased investment in infrastructure and coordination of large-scale programs to collect long-term data. This investment in data-gathering infrastructure has been accompanied by a community-wide push to publish open and FAIR (Findable, Accessible, Interoperable, and Reusable) data. The increasing availability of FAIR data has the potential to democratize ecology, and provide opportunities for a much more diverse pool of researchers to study global change, even when they might not have the resources to conduct large scale field campaigns themselves. We invite contributions that highlight novel perspectives for freshwater sustainability that have arisen from the synthesis of open and FAIR data from one or multiple ecological observatory, experimental, and/or collaborative networks. We especially encourage speakers to highlight how open data has provided unique opportunities to assess challenges to freshwater resource sustainability in the face of global change.

SS48 Data science for aquatic discovery and prediction: building a community of practice

Jacob Zwart, U.S. Geological Survey, [email protected]
Charuleka Varadharajan, Lawrence Berkeley National Laboratory, [email protected]
Matthew Ross, Colorado State University, [email protected]
Erin Schliep, University of Missouri, [email protected]
Alison Appling, U.S. Geological Survey, [email protected]

Data science combines mathematics and statistics, computer science, and domain expertise to enable prediction and insight for problems that are otherwise too computationally demanding or data-intensive to be analyzed with traditional tools - in other words, many current and inevitably future water resources issues. Although data science solutions are frequently applied to freshwater problems, these solutions may seldom be labeled "data science" due to a lack of a community supporting aquatic data science, limited formal training in data science for aquatic scientists, and few explicit examples of how data science is used in aquatic fields. This session seeks to make more commonplace the role of data science in aquatic fields by showcasing contributions that utilize data science tools to address issues ranging from large-scale aquatic biogeochemistry to within-system metagenomics across all aquatic systems. This includes, but is not restricted to, research that utilizes 1) information extracted from big data such as satellites, in-situ sensors, or genomic sequences, 2) statistical or data-driven analytical tools such as Bayesian inference, data assimilation, or deep learning, or 3) modeling techniques that are applied at regional to global-scales.

SS49 Beyond lentic or lotic: Integrating the science of inland waters

Megan Fork, Cary Institute of Ecosystem Studies, [email protected]
John Gardner, University of North Carolina, [email protected]
Erin Hotchkiss, Virginia Tech, [email protected]
Stuart Jones, Notre Dame University, [email protected]
Chris Solomon, Cary Institute of Ecosystem Studies, [email protected]

To understand how ongoing global change will alter water and biogeochemical cycles at local to global scales, collaboration of aquatic scientists from disparate disciplines is essential. This session will bring together researchers bridging or blurring traditional divides between landscape, catchment, lotic, and lentic paradigms. Further, many aquatic ecosystems do not neatly fit into the “lentic” or “lotic” dichotomy, highlighting opportunities to merge traditionally lentic and lotic perspectives to advance freshwater research. Advances in limnology require data and models that cross ecosystem boundaries and integrate across ecosystem types. In this session, we seek to integrate perspectives across the lentic-lotic continuum to improve understanding of freshwater ecosystems. We invite researchers whose questions and methods bridge flowing and non-flowing inland waters across space and/or time. Examples of potential topics include, but are not limited to, hydrology and physical limnology, community ecology, and ecosystem processes (e.g., metabolism) across lentic-lotic transitions and ecosystem mosaics or comparing along a gradient of lentic to lotic conditions. We welcome submissions from a broad range of freshwater researchers interested in integrating perspectives across lentic and lotic systems.

SS50 The importance of long-term monitoring for detecting and understanding human impacts on aquatic systems from past and emerging environmental issues

Jason Lynch, US EPA, [email protected]
William McDowell, University of New Hampshire, [email protected]
Scott Riley, US EPA, [email protected]

Long-term monitoring of lakes and streams has been critical for detecting and understanding human-driven environmental changes as well as the effectiveness of the environmental policies enacted to protect aquatic ecosystems. For example, the U.S. Environmental Protection Agency’s Long-term Monitoring (LTM) program has been fundamental to our understanding of the impact of acid rain and acidification on surface waters, watershed processes, and aquatic biota. It has also been essential for tracking improvements in water quality and aquatic ecosystems due to improving air quality and declining deposition related to the 1990 Amendments to the Clean Air Act. As past environmental issues, like acid rain, improve other environmental drivers emerge such as temperature, precipitation, discharge regimes, atmospheric CO 2 levels, carbon dissolution, nutrient enrichment, etc. The interactions among these drivers pose new risks and challenges for researchers and policymakers to address. Data from long-term monitoring will be essential to understand these new threats, to track changes in environmental conditions and help to determine the effectiveness of pollution reduction policies. This session provides an opportunity for researchers to disseminate recent work that uses long-term monitoring measurements to demonstrate the success of past policies to better protect and sustain aquatic ecosystems and to detect emerging aquatic environmental issues related to but not limited to nutrient enrichment, climate change, CO 2 , algal blooms, and microplastics.

SS51 Contextualising abrupt change using computational limnology

Xavier Benito, SESYNC, [email protected]
Eric J Pedersen, Department of Biology, Concordia University, Canada, [email protected]
Trisha Spanbauer, University of Toledo & Lake Erie Center, USA, [email protected]
Gavin L Simpson, University of Regina, [email protected]
Jessica Burnett, U.S. Geological Survey, [email protected]

Human activities are causing diverse and unprecedented changes in many of Earth’s ecosystems. Freshwater ecosystems have been in the spotlight because their economic and ecological values are among the highest of any biome. Understanding how accelerating environmental stressors in freshwater ecosystems will produce regime shifts, the changes in the underlying structure and function of the system, requires an understanding of the local and regional environments, as well as a long-term view on the range of past environmental change and variability. However, evidence linking environmental variation to regime shifts is largely restricted to relatively small spatio-temporal scales. The explosion of large volumes of ecological 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). We welcome contributions focused on regime shifts in freshwater ecosystems across different spatial (local to regional) and/or temporal (decades to millennia) scales, with focus on possible synchronisation across large, disconnected areas. We aim to highlight studies that use disparate sources of data and novel synthesis-related statistical and visualisation techniques to advance in the understanding of which variables or combinations of variables (natural and anthropogenic) may lead to different ecosystems with undesirable states. Given that societies rely heavily on freshwater ecosystem services, and these can be jeopardized when a critical threshold is crossed, a better knowledge to forecast these scenarios is crucial for well- informed management practices.

SS52 Synthesizing across time: Bridging the gap between long-term and high-frequency data

Jonathan Stetler, Rennselaer Polytechnic Institute, [email protected]
Emily Stanley, University of Wisconsin, [email protected]
Kevin Rose, Rennselaer Polytechnic Institute, [email protected]

The collection of long-term ecological data is irreplaceable and has enabled the discovery of long-standing and often unexpected patterns in all types of aquatic ecosystems. Long-term data is often collected at the monthly time scale (or even less frequently), which often enables sustained monitoring over years to decades. However, ecosystems often exhibit changes at much shorter time scales. Essential changes in key ecological processes can occur within minutes to hours. These changes have the potential to play a large role in driving long-term changes and can often be difficult to detect with low-frequency long-term data. With the technological advances over the past decade, high-frequency data collection is now not only possible, but also affordable for many aquatic researchers. Coupling traditional long-term data collection with high-frequency sensor data, surveys, models, and experiments offers a path forward for researchers to synthesize drivers of environmental change across time scales from seconds to hours to decades. Here, we strive to bring together a community of researchers whose research crosses time scales to offer new insight into the drivers and patterns of environmental change in aquatic systems. We invite researchers from both lentic and lotic systems across physical, chemical, and biological domains to share projects derived from the use of both long-term and high frequency data, surveys, experiments, and/or modeling efforts.

SS53 Too much, not enough, or just right: Understanding productivity and eutrophication in large rivers

Jeffrey Houser, USGS, [email protected]
KathiJo Jankowski, USGS Upper Midwest Environmental Sciences Center, [email protected]
Joanna Carey, Babson College, [email protected]

Our understanding of riverine primary productivity and eutrophication, especially that of the world’s largest rivers, lags behind that of lakes. Often, we focus on the effects riverine nutrient inputs on productivity in receiving marine environments, rather than on primary production and ecological consequences within the rivers themselves. Natural hydrogeomorphic complexity and anthropogenic alterations (e.g., dams, levees) of large floodplain rivers and their tributaries translate to dynamic patterns in riverine primary productivity and eutrophication that we do not fully understand, and which present unique opportunities and challenges to their long-term sustainability. In this session, we will explore an array of basic and applied questions focused on primary productivity in large rivers. This includes the role of primary production in the carbon cycle of large rivers, the spatial and temporal frequency of excessive eutrophy and its implications for riverine food webs, approaches to measuring and monitoring river productivity and metabolism at the large scale (e.g., remote sensing techniques), and considerations on how to manage the potentially increasing prevalence of harmful algal blooms and other consequences of anthropogenic eutrophication as high nutrient input persists and the climate warms.

SS54 Linking freshwaters across ecosystem boundaries

Janine Rüegg, University of Lausanne, [email protected]
Sarah Winikoff, University of Minnesota, [email protected]

Freshwaters are among the most imperiled ecosystems, and can act as sentinels of environmental changes including altered nutrient inputs, flow modifications, and climate change. Widespread focus on the effects of catchments on recipient freshwater systems (e.g., streams, lakes, reservoirs) have largely overlooked the interactions between lotic and lentic systems, such as areas of transition between flowing and standing water or the freshwater continuum in its entirety. For example, lakes and their streams are seldom studied in tandem, especially in relation to the transition zones between the lentic and lotic ecosystems, despite their inherent linkage via flowing water. Furthermore, geographically isolated wetlands are often linked to one another and larger bodies of water via ephemeral overland flow and more often via subsurface flow, yet the impact of these linkages are not well understood. Since resource management generally occurs at scales that include multiple linked freshwater ecosystems, it is critical to understand the behavior of transitional zones between water bodies and interactions between surface and sub-surface waters, especially as aquatic systems are increasingly altered by anthropogenic modification (e.g., wetland drainage, reservoir construction, water extraction) and climate change. To understand how anthropogenic alterations impact freshwater ecosystems and their linkages, we must first better understand the structure, function and relative importance of current linkages to freshwater ecosystems. The proposed session aims to start bridging the gap between different aquatic disciplines toward a holistic understanding of the freshwater continuum.

SS55 It's Not Easy Being Green: The Ecology of Hypereutrophic Waterbodies

Amy Burgin, University of Kansas, [email protected]
Grace Wilkinson, Iowa State University, [email protected]

Approximately one in four US lakes and reservoirs are impaired under the Clean Water Act for excess algal growth due to eutrophication, resulting in thousands of high-nutrient, “green” lakes. As a consequence of eutrophication and excess algal growth, many of the ecosystem services provided by inland waters have been greatly diminished, with some surface waters even becoming unsafe due to the increasing prevalence of algal toxins. We know excessive nutrients alter aquatic ecosystem structure and function in streams and lakes. However, our ability to understand and predict these changes is limited by our current paradigms, most of which were developed in low- nutrient (oligotrophic) systems. The "textbook” predictions that we use to comprehend aquatic ecosystems are likely not robust in highly-impacted, eutrophic waterbodies. Hypereutrophic systems are often dismissed by the scientific community as not “real aquatic ecosystems” because of their highly-impacted, modified characteristics and manmade or manipulated physical and chemical properties. Yet these waterbodies are abundant in agricultural regions of the US and Europe, where humans rely on them for drinking water, irrigation, flood control and recreation. These systems face unique challenges (e.g., harmful algal bloom prediction and management in lakes, nitrate loading and saturation in streams) that may result from their emergent properties and ecosystem dynamics that do not conform to traditional paradigms. We seek to build a synthesized, theoretical understanding of the structure and function of hypereutrophic surface waters. To that end, we invite studies aimed at understanding how hypereutrophy affects aquatic ecosystem biogeochemistry, metabolism, foodweb structure, resilience, aquatic-terrestrial linkages, and any other aspect of ecosystem structure and function. Of particular interest are studies that examine how hypereutrophic lakes may depart from traditional limnological paradigms in terms of predicting ecosystem structure and function or how high nutrient loading streams may depart from traditional nutrient spiraling or ecosystem metabolism predictions. Understanding how hypereutrophic waterbodies function is crucial given how much humans interact with and rely on surface waters.

SS56 Microbial Interfaces in the Urban Water Cycle

Ryan Newton, University of Wisconsin-Milwaukee, [email protected]
Sandra McLellan, University of Wisconsin-Milwaukee, [email protected]

Globally, human populations are becoming more urbanized. Storm intensity is also increasing with a changing climate, often bringing increased precipitation to urban areas. As these processes intensify, greater stress is put upon the quality and quantity of natural and built aquatic system resources in urban areas. Many of the valued resources in cities, including clean drinking water, wastewater treatment, stormwater mitigation, recreational water quality, and landscape nutrient processing are influenced both positively and negatively by microbial activities. This session brings together researchers across the urban water cycle who identify and quantify microbial transport and activities within and between engineered and natural water systems and measure impacts on system processes or human and ecosystem health.

SS57 The power of time series for unraveling aquatic microbial community interactions and functions

Katherine McMahon, University of Wisconsin Madison, [email protected]
Ryan Newton, University of Wisconsin Milwaukee, [email protected]

Time series sampling of aquatic ecosystems is a powerful approach to detecting and perceiving ecosystem change, and the drivers contributing to that change. The concept of the "Invisible Present" states that some changes cannot be observed without extended and sufficiently dense sampling. Microbial communities are sensitive response variables and therefore sentinels of change. Freshwater and marine microbial time series are being used to unravel microbial community dynamics and understand the implications of change with respect to community function. They can also be used to infer terrestrial contributions to aquatic communities, including contaminant organisms delivered in storm water inputs. Attendees will leave the session able to explain why time series are important for understanding microbial ecology and evolution, and what we can (and can't) learn from them. They will also be able to identify major roadblocks preventing advances on this topic, along with proposed near-term next steps.

SS58 Big data ecology: leveraging large scale data sets to understand aquatic ecosystem structure and dynamics at macrosystem scales

McArd Mlotha, Rensselear Polytechnic Institute, [email protected]
Max Glines, Rensselear Polytechnic Institute, Troy, NY, [email protected]
Kevin C. Rose, Rensselear Polytechnic Institute, Troy, NY, [email protected]
Whitney Beck, U.S. Environmental Protection Agency, [email protected]
Kelly Hondula, University of Maryland College Park and National Socio-environmental Synthesis Center, [email protected]

Aquatic ecosystems are experiencing substantial pressure in many regions from population growth, urbanization, changing land use, invasive species, and climate change, among other drivers. To address these challenges, researchers are increasingly using large volumes of compiled field, model, and remotely sensed data, including from programs such as the EPA National Aquatic Resource Surveys (NARS), the USGS National Water Quality Assessment (NAWQA), the National Ecological Observatory Network (NEON), the Lake multi-scaled geospatial and temporal database (LAGOS), and satellites such as Landsat and Sentinel series. Analysis of these large datasets enable characterization and attribution of environmental patterns, variability, and change at macrosystem scales. In this session, we invite contributions that improve understanding of spatial and temporal patterns and dynamics in aquatic ecosystems at regional to continental scales. We also encourage contributions that describe improvements in analytical techniques (e.g., algorithms or software packages) for generating insights into aquatic ecosystems at these broad scales. We seek to highlight novel applications and advancements in using these tools and data sets to understand aquatic ecosystems and to synthesize similarities and differences in lotic, lentic, wetland, and coastal ecosystem responses to climate, land use, hydrogeomorphic, and other key drivers.

SS59 Molecular Genetic Tools for Monitoring & Sustaining Aquatic Ecosystems

Erik Pilgrim, US EPA, [email protected]
Eric Stein, Southern California Coastal Water Research Project, [email protected]
Agnes Bouchez, Institut National de la Recherche Agronomique, [email protected]
Michael Pfrender, University of Notre Dame, [email protected]
Nate Smucker, US EPA, [email protected]

Aquatic ecosystems across the globe face varied and constant challenges from multiple stressors such as land use, pollution, and climate effects. The ability to monitor aquatic habitats in a quick, precise, and cost-effective manner is a critical element for preserving existing resources and for evaluating restoration efforts. Molecular genetic techniques continue to develop, evolve, and improve, potentially providing a variety of those tools necessary for measuring the health and condition of our aquatic resources. Recent advances in the field include means for detecting and quantifying target taxa such as invaders or endangered species, for biomonitoring of traditional assessment groups like fishes and diatoms through environmental DNA and DNA metabarcoding, for detecting harmful algae species and toxins, and for investigating microbial communities and their responses to nutrients, antibiotics, and other chemicals. This session aims to provide an opportunity for researchers from various aquatic disciplines to highlight their research endeavors and discuss their successes to a broader scientific audience as these molecular genetic tools move beyond proof-of-concept and to become relevant and useful tools for end users and decision makers.

SS60 Exploring the sources, fate, transport and impacts of plastics in the aquatic environment

Kathryn Schreiner, University of Minnesota Duluth, [email protected]
Peter Lenaker, U.S. Geological Survey, [email protected]
Stefan Krause, University of Birmingham, [email protected]
Steve Allen, University of Lyon, [email protected]

Plastic garbage in the world’s oceans has received a lot of attention by the public and scientific communities over the last two decades, however, much less is known about the environmental fate, abundance, distribution and ecological effects of microplastics in freshwater and terrestrial ecosystems. Coupled with this are critical knowledge gaps related to standardization of environmental sampling approaches, extraction and identification protocols (from micro to nanoplastics), and laboratory analysis and characterization methods, which combined do limit our understanding of potential effects on environmental and public health. Additional questions such as how microplastics may distribute within the water column and sediment, the ability of plastics to act as transport vectors for other pollutants in freshwaters, their ability to be degraded, and their chemistry post-degradation are just beginning to be explored.

In this session, we invite submissions from studies pushing the boundaries on field sampling approaches, and laboratory and analytical protocols for the collection, identification, characterization and quantification of microplastics across the landscape, including also fate and transport modelling studies. Research investigating plastic transport processes in and across aquatic - terrestrial interfaces, coupled with plastics property dependent transformations, aging, accumulation and leaching of harmful contaminants are also welcome. Further we solicit submissions related to the identification of plastic exposures and related risks of uptake and propagation in aquatic - terrestrial food-webs, and the quantitative analyses of environmental impacts of microplastics in freshwater and terrestrial ecosystems.

SS61 Beyond contaminant-specific effects: Interactions with global change drivers and cumulative effects of complex chemical mixtures.

Roxanne Razavi, SUNY ESF, [email protected]
Steven Corsi, U.S. Geological Survey, [email protected]
Elena Nilson, U.S. Geological Survey, [email protected]

The pollution of freshwaters by legacy and emerging contaminants affects the health of food webs globally and impairs water for human and ecological uses. With thousands of chemicals in production and analytical methods capable of lower detection limits, identifying which chemicals are most likely to pose an ecological hazard is a challenge. To add to the complexity of this task, many of these chemicals are present as complex mixtures with biological effects influenced by drivers of global change such as invasive species, eutrophication, hypoxia, browning, and/or climate change. Chemicals and chemical mixtures need to be placed in context for resource managers and policy makers to prioritize those most likely to degrade ecological health and therefore to be prioritized in management efforts. We welcome contributions across all scales, ranging from uptake into plankton, to studies on individual lakes and rivers, to contrasting systems across large spatial scales and diverse chemical influences.

SS62 Linking microbes and biogeochemistry to understand change across the aquatic continuum

Amy Marcarelli, Michigan Technological University, [email protected]
Katherine McMahon, University of Wisconsin Madison, [email protected]
Stephen Techtmann, Michigan Technological University, [email protected]
Patricia Tran, University of Wisconsin Madison, [email protected]

Biogeochemical processes are driven by microorganisms, yet understanding the mechanistic relationships between nutrient and carbon pools and fluxes and microbial assemblages in aquatic ecosystems has been hamstrung by our ability to link microbial composition to function. Moreover, most quantitative models used to predict biogeochemical processes and water quality in aquatic ecosystems do not explicitly include microbes. Emerging technologies are rapidly expanding the possible spatial and temporal coverage of biogeochemical and microbial community datasets while also increasing the detail with which we can characterize both. These advances create challenges and opportunities associated with handling ever-expanding volumes of data, the need to integrate multiple data streams, and building models that explicitly integrate microbial community dynamics. These observational, data science, and modeling advances are now allowing aquatic scientists to explore the ways that diverse consortia of microbes cooperate and interact to transform and process nutrients and carbon across aquatic continua. This session will bring together those working at the interface of microbial ecology and biogeochemistry to elucidate the mechanisms of these linkages, to understand how these relationships vary across scale, and to model how they change in response to natural and artificial disturbances including nutrient loading, habitat modification, and global change.

SS63 Finding solutions to wicked problems in urban stream management and rehabilitation

Leslie Rieck, Lycoming College, [email protected]
Mateo Scoggins, City of Austin, [email protected]
Robert Smith, Lycoming College, [email protected]
Megan Fork, Umeå University, [email protected]

A sustainable global future capable of maintaining the goods and services provided by aquatic ecosystems must address the challenges of an increasing human population. The built environment concentrates impervious cover, pollutants, high temperature, and landscape modifications resulting potentially severe degradation of water resources that may be amplified by synergistic effects of global climate change and social and environmental injustice. A framework for sustainably managing water resources in human-dominated landscapes requires a holistic approach that is highly adaptable, empirically based, and cuts across physical and social-science disciplines. Any framework for managing urban stream catchments will need to address a complicated set of co-occurring and interacting ecological, physical and social factors that drive ecosystem impairment but may also act independently as barriers to remediation. Thus, urban stream management and rehabilitation represents a ‘wicked problem’ in need of innovative design, management, and monitoring approaches. We argue that urban stream ecology requires expertise and collaboration among natural science, social science, humanities, communication, engineering, landscape architecture, and education. We invite those working in urban stream management and rehabilitation to present research on the state of the science in this special session, and invite contributions exploring outcomes from the 5th Symposium on Urbanization and Stream Ecology and other research concerning complex real-world problems in urban catchment management.

SS64 Ecosystem-scale questions tackled by mesocosms approach in aquatic systems

Meryem Beklioglu, Midle East Technical University, [email protected]
Lisette De Senerpont Domis, Netherland Institute of Ecology, Wagenningen, The Netherlands, [email protected]
Maria Stockenreiter, Ludwig Maximilians Universität München, [email protected]

Globally unprecedented disruptions (e.g. biodiversity loss, nutrient and pollutant inputs, climate crises etc.) are taking place in freshwater ecosystems with major consequences of losing biodiversity and ecosystem services. Obtaining quantitative mechanistic understanding of aquatic ecosystem structure and functioning is ever more curial for taking sound measures of adaptation and mitigation. Well controlled and highly replicated empirical approaches from small-scale laboratory microcosm experiments have been used to relate changes in food webs to altered environments, however, their realism is limited and the extrapolation to natural systems is often difficult. Large-scale mesocosm (or enclosure) experiments allow a more realistic setting by including a higher complexity in terms of trophic levels, and thus potential interactions. Thus, mesocosms experiments is a powerful approach to obtain such mechanistic quantitative understanding. To this session we therefore welcome researchers to present their ecosystem-scale empirical work where scientific questions about various aspects of aquatic ecosystem functioning has been tested through using mesocosms.

SS65 Macroscale stoichiometry: assessing elemental ratios from ecosystems to the globe

Patrick Kelly, Rhodes College, [email protected]
Jessica Corman, University of Nebraska - Lincoln, [email protected]
Jake Zwart, US Geological Survey, [email protected]

Ratios of key elements are important in structuring and influencing ecosystem processes and services, including the productivity and community composition of primary producers, and growth rates of consumers. These ratios may vary systematically in space and time as a function of landscape characteristics or seasonality, providing geographic or temporal context for patterns in ecosystem responses. This may be especially pronounced in areas of significant environmental change, with alterations in land use or climate causing shifts in the relative availability, use, or flux of certain elements. In this session, we seek to bring together researchers interested in better understanding this variability in stoichiometric ratios of elements across broad spatial or temporal scales in aquatic systems. We welcome contributions that 1) use experiments or surveys to assess biogeochemical cycles at the ecosystem scale, 2) scale up stoichiometric patterns from the ecosystem to landscape, continental, or even global scales, and/or 3) identify links between elemental ratios and ecosystem processes at broad spatial or temporal scales. We particularly encourage participation from those interested in understanding those patterns in the context of widespread environmental changes.

SS66 Modelling aquatic ecosystems and food webs under global change

Sherri Johnson, USDA Forest Service, [email protected]
Christina Murphy, Oregon State University, [email protected]
Matt Whiles, University of Florida, [email protected]

Climate change and increased frequency of extreme events have the potential to alter ecological relationships, from physical to chemical to biological interactions. Evaluating climate change impacts on aquatic ecosystems and trophic relationships can highlight vulnerable processes and dynamics that may be crucial to in the stability of these systems. Models can facilitate evaluation of alternative scenarios and changes in strengths of interactions. In this session, we will be exploring a variety of types of modelling of aquatic ecosystem dynamics and food webs across local, regional or global scales. We will focus on the uses of modelling to evaluate food web and ecosystem dynamics, energy flow within or across trophic levels, responses of biota to extreme events and responses to scenarios of climate change. Talks that evaluate the interactions of climate change and potential management, including remediation actions, are especially welcome. The goal of this session is to exchange ideas on potential climate change impacts and solutions as well as to showcase the many modelling techniques that can be employed to better understand dynamics in streams, lakes and reservoirs.

SS67 Response to threat of loss of cold water habitats in lakes and streams

Lucinda Johnson, University of MN Duluth, [email protected]
Sherri Johnson, US Forest Service, [email protected]

Cold water habitats in both streams and lakes are among the most endangered of aquatic habitats in temperate regions as a result of changing climate and changing land use/cover patterns. In streams, restoration activities to mitigate warming temperatures are plentiful, but their effectiveness is not yet fully understood. In contrast, management options for lakes are more limited. We will highlight research addressing current distributions of temperatures, influences of climate and land use forcing, and describe management options, including showing tools and analyses relevant to lake and stream temperature regimes in changing landscapes.

SS68 Understanding reservoir function in a changing world

Joseph Conroy, Ohio Dept of Natural Resources, [email protected]
Nicole Hayes, University of Minnesota, [email protected]
Maria Gonzalez, Miami University, [email protected]
Michael Vanni, Miami University, [email protected]
Bridget Deemer, USGS, [email protected]

Reservoirs are ubiquitous in the landscape. These human-made lakes and ponds provide many essential services, including flood control, water supply, irrigation, navigation, and hydropower, in addition to recreational opportunities. Yet reservoirs also directly influence ecological processes, including carbon cycling, sediment retention, nutrient transformation, and methane emissions, biodiversity, animal migration patterns, among others. Given the generally quick aging of reservoirs due to their high sedimentation rates and their large watersheds (compared to natural lakes), these systems may be critically affected by ongoing and coming environmental challenges such as climate change and the development of divergent human demands on these systems. With this symposium we seek, generally, (1) to identify those who are currently working in the fields of reservoir limnology and all aspects of reservoir ecology in an effort to build connections and collaborations within this group, and (2) to identify the critical research themes and approaches which may provide avenues to building sustainability in these—by definition—temporary aquatic ecosystems. A particularly useful approach might include comparing reservoir ecosystems with other aquatic systems, including lakes, rivers, and estuaries. We encourage contributions on all aspects of reservoir limnology and ecology, especially those contributions by early career scientists, those studying reservoirs throughout the world, and those from self- nominating participants.

Education and Policy Sessions

EP01 Scholarship of Teaching and Learning in Freshwater Science

Petra Kranzfelder, University of California Merced, [email protected]
Alyssa Anderson, Southwest Minnesota State University, [email protected]

Today’s students will be tomorrow’s decision and policymakers. Therefore, informing and engaging students from all disciplines in the field of freshwater sciences is essential, especially considering the rate, magnitude, and impacts of current environmental changes. This is particularly important considering the range of public awareness and acceptance to current environmental issues. We propose a special session focused on pedagogy, research, and assessment of teaching and learning in the freshwater sciences. The goal of this session is to support educators in improving STEM instruction by promoting the adoption of best practices of teaching and learning in our field. This special session will support our Society’s mission of promoting further understanding of freshwater ecosystems and fostering the exchange of scientific information among the membership, especially educators. We encourage session contributors to share specific STEM teaching practices, techniques, goals, modules, and experiences. Pedagogical techniques related to all areas of biology that could be applied to the freshwater science classroom are welcome to participate in the session. We also encourage participants to contribute inquiry-based activities and resources used in the classroom/lab to build and enhance educational materials offered to our membership. Ultimately, we hope that the information shared in this session will help educators to better engage students, creating better scientists, active advocates for environmental issues, and better-informed decision and policymakers.

EP02 Scott Wissinger: Homage to a Scientist, Mentor, and Teacher

Amanda Klemmer, University of Maine, Orono, [email protected]
Jared Balik, North Carolina State University, [email protected]
Howard Whitman, Murray State University, [email protected]
Hamish Greig, University of Maine, [email protected]

Scott Wissinger, freshwater ecologist for ~40 years and mentor to over 240 undergraduate students researching freshwaters, leaves a lasting legacy in freshwater science. Scott worked at a primarily undergraduate university, Allegheny College, since 1986, and through his mentorship of undergraduate research projects, had a prolific research career in freshwater science, with 31 of his 53 peer-reviewed articles having undergraduate co-authors. Of his undergraduate mentees, >32 went on to pursue PhDs and >85 went on to pursue MSs in related fields, highlighting the strength of his influence on freshwater science through training the next generation of scientists.

Scott’s research, studying benthic habitats in lentic ecosystems, perfectly highlights the connections between ASLO and SFS. By tactfully piecing together short 1-2 year undergraduate research projects and co-advising graduate students at other institutions, Scott accumulated long-term datasets in Colorado Rocky Mountain ponds (>30 years), Pennsylvania streams and wetlands (~23 years), and New Zealand high elevation ponds (19 years) that are crucial for understanding climate and other anthropogenic changes in these systems. His timely research on climate-induced range shifts of caddisfly species in the Rocky Mountains of Colorado is some of the first to explore ecosystem-level consequences of documented range shifts.

This session will present Scott’s long-term research in Colorado, Pennsylvania, and New Zealand, while highlighting his legacy in freshwater science through his mentorship of undergraduate students.

Contributed Sessions

CS01 Human and Social Dimensions

Session Chair TBD. Volunteers welcome.

CS02 Management and Conservation of Aquatic Systems

Session Chair TBD. Volunteers welcome.

CS03 Restoration

Session Chair TBD. Volunteers welcome.

CS04 Urban Ecosystems

Session Chair TBD. Volunteers welcome.

CS05 Valuation of Aquatic Ecosystems and Resources

Session Chair TBD. Volunteers welcome.

CS06 Acidification

Session Chair TBD. Volunteers welcome.

CS07 Trace metals

Session Chair TBD. Volunteers welcome.

CS08 Hypoxia

Session Chair TBD. Volunteers welcome.

CS09 Stable Isotopes

Session Chair TBD. Volunteers welcome.

CS10 Gas Fluxes

Session Chair TBD. Volunteers welcome.

CS11 Nitrogen biogeochemistry and cycling

Session Chair TBD. Volunteers welcome.

CS12 Phosphorus biogeochemistry and cycling

Session Chair TBD. Volunteers welcome.

CS13 Carbon fluxes in FW & marine environment

Session Chair TBD. Volunteers welcome.

CS14 Dissolved organic matter - DOC, DON, DOP, fDOM, cDOM

Session Chair TBD. Volunteers welcome.

CS15 Sediment dynamics

Session Chair TBD. Volunteers welcome.

CS16 Environmental Change

Session Chair TBD. Volunteers welcome.

CS17 Extreme Events

Session Chair TBD. Volunteers welcome.

CS18 Harmful blooms

Session Chair TBD. Volunteers welcome.

CS19 Novel methods

Session Chair TBD. Volunteers welcome.

CS20 Regime shifts

Session Chair TBD. Volunteers welcome.

CS21 Success through science

Session Chair TBD. Volunteers welcome.

CS22 Fish and fisheries

Session Chair TBD. Volunteers welcome.

CS23 Aquatic food webs

Session Chair TBD. Volunteers welcome.

CS24 Biodiversity

Session Chair TBD. Volunteers welcome.

CS25 Community Ecology

Session Chair TBD. Volunteers welcome.

CS26 Microbial ecology and physiology

Session Chair TBD. Volunteers welcome.

CS27 Phytoplankton ecology and physiology

Session Chair TBD. Volunteers welcome.

CS28 Primary production

Session Chair TBD. Volunteers welcome.

CS29 Viruses

Session Chair TBD. Volunteers welcome.

CS30 Zooplankton ecology and physiology

Session Chair TBD. Volunteers welcome.

CS31 Aquatic Landscape Ecology

Session Chair TBD. Volunteers welcome.

CS32 Benthic and Littoral Ecology and Physiology

Session Chair TBD. Volunteers welcome.

CS33 River and Stream Ecology

Session Chair TBD. Volunteers welcome.

CS34 Aquatic Invasion Ecology

Session Chair TBD. Volunteers welcome.

CS35 Coral Reef Ecosystems

Session Chair TBD. Volunteers welcome.

CS36 Estuarine Ecosystems

Session Chair TBD. Volunteers welcome.

CS37 Antarctic Ecosystems

Session Chair TBD. Volunteers welcome.

CS38 Arctic Ecosystems

Session Chair TBD. Volunteers welcome.

CS39 Coastal Ecosystems

Session Chair TBD. Volunteers welcome.

CS40 Aquatic Education: K12 to Postgraduate

Session Chair TBD. Volunteers welcome.

CS41 Communicating Science to the Public

Session Chair TBD. Volunteers welcome.

CS42 Successes in/through Education

Session Chair TBD. Volunteers welcome.

CS43 Undergraduate Research Projects

Session Chair TBD. Volunteers welcome.

CS44 Big data in aquatic systems

Session Chair TBD. Volunteers welcome.

CS45 Global oceanography and limnology

Session Chair TBD. Volunteers welcome.

CS46 Models and modelling

Session Chair TBD. Volunteers welcome.

CS47 Physical dynamics

Session Chair TBD. Volunteers welcome.

CS48 Physical-Biological Coupling

Session Chair TBD. Volunteers welcome.

CS49 River and Stream Ecology

Session Chair TBD. Volunteers welcome.

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