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SFS Annual Meeting


S01: Finding solutions to wicked problems in urban stream management & rehabilitation

A sustainable global future capable of maintaining the goods and services provided by aquatic ecosystems must address the challenges of an increasing human population. Amplified by the synergistic effects of global climate change and social injustice, the built environment concentrates impervious cover, pollutants, high temperature, and landscape modifications resulting in potentially severe degradation of water resources. A framework for sustainably managing water resources in human-dominated landscapes requires a holistic approach that is highly adaptable, empirically based, and co-created with the communities in these urban catchments. This framework must address a complicated set of co-occurring and interacting ecological, physical, and social factors that can also act as barriers to remediation and equitable socio-ecological outcomes. Thus, urban stream management and rehabilitation represents a 'wicked problem' in need of innovative interdisciplinary design, management, and monitoring approaches. We argue that urban stream ecology requires collaboration with affected communities and the integration of natural science, social science, humanities, communication, engineering, landscape architecture, and education. This session will present the state of the science in urban stream management and rehabilitation by exploring a) in-depth case studies from the 5th Symposium on Urbanization and Stream Ecology (SUSE5) and b) other contemporary research concerning complex real-world examples of interdisciplinary management approaches in urban catchments.

S02: Transforming freshwater science through collaboration, recognition, and blending diverse knowledge systems

Freshwater ecosystems are important culturally, socially, economically, and ecologically; however importance does not spare these ecosystems from change. Conventional research is rooted in quantifying and analyzing ecological data, however this approach fails to recognize the complexity, diversity and connections between environmental and social issues. As such, there is an increasing need to approach freshwater science holistically. Increasingly, our research, data analysis and decision-making is being transformed through representation of all peoples values, balancing of Traditional, Local and Ecological Knowledge with western sciences, and celebrating the diversity of communities. Collaboration is an important step to meet this objective and can be conducted through community-based learning, partnerships, co-management, and/or co-governance. Furthermore, collaboration in research can help foster relationship building, capacity building in communities, and mutually beneficial knowledge transfer.

The goal of this session is to transform our understanding and approach to ecological research by demonstrating the importance of collaboration, and recognizing and including traditional and local ecological knowledge. This session will begin with an opening presentation discussing collaboration, shared decision-making, and traditional/local knowledge with examples from the lands of the traditional territories of Yukon First Nations, Canada. This will be followed by a series of presentations highlighting examples from a variety of locations around the world. The session will close with a presentation by the organizers summarizing the various initiatives/projects presented during the session and looking ahead to a future where all research is inclusive of social and cultural values to protect the natural resources we have left in this changing world.

S03: Scaling the effects of flow regimes over space, time, and levels of biological organization

From headwaters to estuaries, hydrologic variability is a key control of structure and dynamics in riverine ecosystems. Flow regimes combine stochastic 'noise' and periodic 'signals' spanning from diurnal to decadal scales. These fluctuations shaped life histories and behaviors of organisms, and continue to drive contemporary ecological responses—from population dynamics to ecosystem processes (e.g., drought-induced mortality, pulse-driven primary production). As climate change, dams, urbanization, and other human impacts continue to alter flow regimes, understanding how biota and ecosystem processes will be affected remains a key need. In this session we will focus on the particular challenge of scaling responses to hydrologic variability across levels of biological organization (i.e., population to ecosystems) and spatio-temporal scales. We thus welcome contributions examining relationships between hydrologic drivers and ecological responses that combine ecological endpoints (e.g., metapopulations, food webs, and ecosystem-level properties), as well as nested temporal or spatial scales (e.g., observations across seasons and years, or along reaches within a river network). We are interested in work combining methodological approaches (e.g., observation, experiments, simulations), as well as analytical tools. We are particularly interested in contributions highlighting the utility of time series methods in the time and/or frequency domains (e.g., state-space models, spectral analyses), as they can help identify the dominant scales of environmental variation, and link such scales to ecological responses. Collectively, we hope this session will advance understanding of how hydrologic regimes drive long-term change in riverine and estuarine ecosystems via changes in community composition, trophic interactions, nutrient cycling, and resulting ecosystem functioning.

S04: Animal legacies lost and found

Freshwater ecosystems host remarkable biodiversity, including one-third of all vertebrate species, which shapes the structure and function of rivers, lakes, and wetlands. Animal activities can result in patterns and processes ranging across spatio-temporal scales that influence the geomorphology, hydrology, nutrient budgets, and production of freshwater systems. In some cases, these effects can persist for years to decades after animals disappear, leaving a legacy of their influence on the system. For example, incision of riparian zones by hippos, construction of wallows and burrows by alligators, building of dams by beavers, and shell deposition by mollusks all may have legacy effects on freshwater ecosystems. As many animal species decline, particularly in freshwater ecosystems, these legacy effects are being replaced either by the influence of other more cosmopolitan species, or by human activities such as livestock farming and agriculture. These modern analogues likely differ from historical animal legacies in the degree and timing of their influence and the resulting degree of heterogeneity they introduce to the landscape. We propose this special session to bring together scientists studying freshwater ecosystems across the world to present on the historical, present and future legacy effects of animals on freshwater ecosystems. We invite participants to present research from a wide range of systems in order to examine similarities and differences in animal legacy effects across species and regions, identify general processes that may emerge from these legacy effects, and evaluate how legacy effects of native fauna may compare to those of modern analogues.

S05: "The valley rules the stream": restoring the landscape to restore the stream

Stream networks are an integral part of landscapes and cannot be understood in isolation from the surrounding terrestrial environment. Actions aimed at improving aquatic ecosystem quality must be underpinned by knowledge of interactions among ecosystems in the landscape. The development of more efficient tools to restore streams is required to protect water quality and to conserve freshwater biodiversity and ecosystem processes, which are all important societal challenges. We argue that to improve the effectiveness of stream restoration projects, a landscape perspective has to be adopted. Therefore, in our session, we aim to discuss: 1. results of restoration practices at the landscape scale; 2. evaluation of key abiotic drivers (e.g. natural or anthropogenic) affecting biotic links (e.g. structural and functional parameters) between landscape and stream; 3. Modelling and upscaling the effects of restoration on stream ecosystems. This session provides an important opportunity to discuss ways to bridge terrestrial and aquatic ecosystems to improve restoration practices through sharing and discussing methods and outcomes, including science-based policy-making.

A virtual meeting holds a chance to involve researchers and students from different biomes, and different social and cultural backgrounds. Therefore, the perspectives and discussions could be more diverse and more integrative, which is crucial to improve freshwater conservation. Being virtual, the presentation could even be given from a field site where an experiment is running.

S06: Linkages in urban aquatic systems: movements, transformations, and restoration ranging from chemical cocktails to organisms

Flowpaths inherently link freshwater systems and can be responsible for the transport of chemical cocktails and resources (such as nutrients, pollutants, organic matter) from the landscape, provide a framework for the transformation and assimilation of these compounds, and connect organisms and foodwebs. These flowpaths become increasingly complicated in urban systems while biological communities become simplified. This can potentially modify connectivity among urban water bodies and the transformation and transfer of resources between different habitats and trophic levels. Increased connectivity can allow for more successful movement of resources (e.g., nutrients, carbon) and organisms (e.g., fish, macroinvertebrates) among habitats, but also may result in elevated transport of pollutants or colonization by non-native species. Conversely, reduced connectivity may limit resource availability to foodwebs, concentrate pollutants, and prevent biotic recolonization of habitats (e.g., fish or macroinvertebrates) even after restoration otherwise improves environmental conditions. In this session we seek to explore how urban watersheds present unique linkages among aquatic ecosystems, particularly with respect to the movement of organisms (from microbes to fishes; e.g., dispersal or migration), chemical cocktails (ranging from nutrients to pharmaceuticals to microplastics), and biological transformations within these systems. As cities grapple with the management of urban streams, better understanding linkages in urban aquatic systems will inform how restoration projects and management practices can address these linkages and provide the desired ecosystem services. We invite speakers working in urban watersheds to present research on how the unique linkages present in urban systems influence ecosystem processes and the movement/transformation of resources and organisms.

S07: Biogeochemical and ecological change in Arctic lakes and rivers

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 have 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 will bring together studies that address the changes in biogeochemical pathways and their effects on the biological assemblages and ecosystem function of Arctic lakes and rivers. This virtual session will allow contributions and participation from freshwater researchers from across the circumpolar region. The session will begin with a series of presentations and conclude with a panel discussion on improving research collaboration and biomonitoring in the north, including discussion of the use of emergent technologies, citizen science, and increased engagement with Indigenous communities.

S08: Inequitable Waterscapes: Examining Environmental Justice in Aquatic Systems

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

S09: Exploring freshwater ecosystems under a changing climate via storm-driven nutrient, carbon, and sediment transport and biogeochemical cycling

There is growing evidence that extreme events, primarily as storms, are increasing due to climate change. These storms have a direct impact on nutrient, carbon, and sediment transport as well as biogeochemical cycling from watersheds to streams, rivers and lakes. Research has shown that storm-driven export makes up a large proportion of annual nutrient, carbon, and sediment loads to these ecosystems. Recent analyses suggest the impact of storm timing and intensity on retention and transport may be more pronounced as storm patterns shift under a changing climate. Thus, an improved understanding of the controls on nutrient, carbon, and sediment import, export and cycling in freshwater ecosystems during high-flow conditions is necessary to mitigate climate impacts on freshwater resources.

By looking across the freshwater continuum, our session will provide insight on how an increase in the frequency and magnitude of storms not only affects the transport and transformation of nutrients, carbon, and sediments in each individual ecosystem, but alters cross-ecosystem transport and transformation. We seek presentations that assess how nutrient, carbon, and sediment sources, quantity, and composition change in response to storms using a suite of methodological approaches in any freshwater ecosystem.

We encourage presentations that utilize high-frequency sensors, which allow researchers to capture high- resolution data during storms. The relative importance of storms in controlling nutrient, carbon, and sediment import, export, and cycling is likely to increase with predicted shifts in hydrology, highlighting a need for an increased understanding on controls of storm-driven export, transport, and retention under a changing climate.

S10: Herstory in Freshwater Sciences

The study of freshwaters is fulfilled with passionate and fascinating women, who have made vast contributions to our current understanding of freshwater ecosystems. Today, women represent more than half of the total limnologists in-training and at early-career stages. However, as in many other fields of science, there are far fewer women full professors and leading academic departments and research institutions. In this session, organized by the Biogeofeminist initiative and the Gender & Science AIL group, we aim to raise our awareness on the importance of gender equity for the freshwater community, and in particular on the role of women. We welcome contributions that discuss key vulnerabilities that challenge women's careers in freshwater ecology, and that identify activities, strategies and solution based approaches promoting their visibility and participation at all career stages. Improving the inclusivity of women in freshwater sciences is critical to face environmental challenges from different perspectives as well as to advance towards a safer and healthier community.

S11: Greenhouse gases in tropical streams, rivers, lakes and wetlands: current work and future research needs

Greenhouse gas (GHG) emissions from freshwater ecosystems is an important flux, yet there is high uncertainty with current estimates. Recent reviews have shown emissions from freshwaters have increased due to both improvements in methods and greater awareness of the importance of freshwaters to GHG cycling, and should be included in global climate models to contribute to future climate projections. However, measurements are still spatially sparse and temporally narrow. In particular, estimates from the global tropics remain understudied, and better resolution of GHG (CO 2 , CH 4 , N 2 O) fluxes from tropical freshwaters (streams, rivers, lakes, and wetlands) is needed. Tropical freshwaters host a broad range of environmental conditions that are well suited to large GHG emissions, but greater study is needed.

This special session aims to bring together a diverse and energetic team of researchers working to measure GHG from the global tropical freshwaters to update the current field of research and identify opportunities for future work. Specifically, we encourage research from streams, rivers, lakes, and wetlands to present recent work on concentrations, fluxes, emissions, and drivers of GHG dynamics. Second, we call for novel methods in measuring GHG concentrations, fluxes, and emissions, including sensor advances, gas exchange estimates, and stable isotope partitioning. Lastly, we call for research focusing on climate change influences on GHG dynamics in freshwaters, including effects of warming temperatures, altered precipitation regimes, extreme climatological events, land-use change, and hydrologic manipulation for human use to better project GHG in the future and inform global models of freshwater GHG contributions.

S12: Freshwater ecosystems in states of transformation: inclusive approaches to advance temporary stream science

Dynamic river ecosystems shift between flowing, ponded and dry conditions in space and time. From organism to landscape scale, biodiversity in these temporary streams (also termed intermittent rivers and ephemeral streams; non-perennial rivers) is structured by shifts between wet and dry states. Equally, the presence or absence of flowing water has a profound impact on human perceptions of ecosystem value. In this session, we bring together colleagues with diverse, positive experiences of advancing understanding of temporary streams within landscapes dominated by human societies. One key challenge in temporary stream ecohydrology is to know how long a channel has been dry or wet, and thus to understand the abiotic drivers structuring ecological communities. To address this, we will consider the insights brought by traditional ecological knowledge and novel approaches including mobile apps used by volunteer scientists. Such approaches can both document wet and dry instream states and assess stream health using ecological communities. A second key challenge is the public perception of dry channels as symbolic of environmental degradation. We will explore how perceptions differ among global regions and explore opportunities to improve peoples' understanding of these dynamic ecosystems. Finally, we will recognize how collaboration between academic and management partners can facilitate real-world improvements in temporary stream health. As their extent increases in our changing world, our multidisciplinary session will show how collaboration between global researchers including aquatic and terrestrial ecologists, hydrologists, social scientists, and political scientists is transforming our understanding of temporary stream ecosystems and strategies for their effective management.

S13: From boxes and arrows to big data: the future of ecological modeling in freshwater science

Advances in high-frequency environmental sensing and statistical approaches have greatly expanded the breadth of scientific tools and data sources available to the aquatic sciences. Immense volumes of data with broad spatial and temporal extent are opening a new frontier in freshwater science. Although aquatic ecosystem models have been developed and tested for decades, our ability to capitalize on the 'data revolution' and test existing models with new data is limited by conceptual and computational challenges that remain at the forefront of aquatic ecosystem research. Despite inconsistent data coverage, the integration of multiple modeling approaches with diverse data sources has improved the predictive capacity of the aquatic sciences through space and time. The goal of this session is to highlight work that uses new modeling approaches to explain and predict ecological dynamics in freshwaters. Therefore, we invite contributions that explore ecosystem modeling and statistical approaches such as bayesian hierarchical modeling, machine learning, the integration of those, or other modeling methods to address ecological questions. This session will feature early career researchers who are expanding the scope of ecological modeling approaches to advance understanding of aquatic ecosystem dynamics.

S14: Challenges in tropical stream conservation

Tropical 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 disturbances on tropical streams, up-to-date information remains limited and often scattered. This session will summarize current knowledge on tropical stream ecology and conservation and will explore research techniques and datasets used to detect the impacts of climate change and anthropogenic activities, as well as work to mitigate these effects, in stream ecosystems from Caribbean, Central and South American, African, Asian, and Australian sites. 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.

S15: The scholarship of teaching and learning in Freshwater Science: Pandemic edition

Recently, the SFS community has been increasingly interested in the crafts of teaching and student research mentoring. This is evidenced by the great reception of the special session on The scholarship of teaching and learning in Freshwater Science during our last three annual meetings, and the persistent success and growth of the INSTARS program. Last Spring semester (2019-2020 academic year), teaching and mentoring practices were significantly impacted by our current global pandemic. Most teacher- scholars had to switch from teaching and mentoring research in person to remote (online) or hybrid (in- person and online) practices. As we continue to navigate these though times, remote and hybrid practices became the standard for most academic institutions for the current 2020-2021 academic year.

This special session is targeted at highlighting and sharing the efforts that our SFS community of teacher scholars have implemented to continue to deliver high level teaching and mentoring. We welcome submissions for all types of pandemic-modified teaching and mentoring approaches, from brand new modules and/or assessments specifically designed for remote or hybrid teaching, to modifications of old approaches to incorporate this new norm. We also welcome submissions about research mentorship at all levels (undergraduate and graduate) and any other teaching-learning oriented activity that you may have developed or modified to work under our current hybrid and remote circumstances.

S16: Beyond lentic or lotic: Integrating the science of inland waters

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.

S17: Think positive: Exploring the consequence(s) of positive interspecific interactions from community structuring to ecosystem processes.

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. The session will consist of 15-minute pre-recorded oral presentations, followed by a 30-minute question answer forum focused on the future of positive interaction research.

S18: Salinization of Freshwater Ecosystems

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 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. In addition to oral platform presentations, we propose a panel session to allow engaging discussions for a meaningful virtual meeting experience.

S19: Beyond Breakdown: Detrital nutrient dynamics in freshwater ecosystems

Decomposition is more than the breakdown and disappearance of organic matter: it involves the flow of elements among the detrital-microbial matrix, animal consumers, and the surrounding environment. In comparison to soils, freshwater research lacks a comprehensive empirical theory of nutrient cycling mediated by necromass. Because detritus is ubiquitously important in freshwater systems, this research gap impedes understanding the role of detritus in animal nutrition, aquatic-terrestrial linkages, and processes such as nutrient uptake. This special session aims to synthesize knowledge and highlight research needs on freshwater detrital nutrient cycling by convening a diverse group of researchers using a variety of approaches. We invite presentations on nutrient (N, P, etc.) fluxes, transformations, and fates mediated by organic matter decomposition in freshwater ecosystems, where the focal dead organic matter may be any type and span dissolved to particulate (e.g., leaf litter, carcass, and wood) classes. Studies may examine detrital nutrients individually or in combination and may explore 1) environmental and biological controls on detrital nutrient dynamics, or 2) effects of detrital nutrient dynamics on broader ecosystem processes. This session welcomes a broad variety of evidence and processes through time, including, e.g., patterns of nutrient uptake and release from detrital-microbial complexes, isotopic tracing of detrital nutrient fates into other ecosystem compartments, or microbial ecoenzyme expression and stoichiometry during decomposition. In addition to more conventional presentation styles, we will also take advantage of the online format to invite all interested presenters and audience members to a virtual roundtable discussion concluding the special session.

S20: Securing biodiversity, functional integrity and ecosystem services in drying rivers

Rivers are among the most threatened biodiversity hot spots on Earth. They also support crucial biogeochemical cycles and provide key ecosystem services. By forming networks, rivers are metaecosystems, where aquatic communities, ecosystem functions and services are organised spatially by the interaction of local environmental constraints (e.g. physical habitat) with regional fluxes of organisms and resources.

Global change alters rivers and streams worldwide and the incidence of drying is dramatically increasing in time and space. Effects of flow intermittence on the biodiversity-function- services cascade have gained attention at the local scale, yet this phenomenon has been poorly considered at the larger spatial scales, where intermittent flow translates into river network fragmentation. The lack of knowledge how intermittent flow may shape regional-scale fluxes prevents us from predicting how global change will alter river network biodiversity, ecosystem functions and services, and how does this affect public values and perceptions of such services. Consequently, there is no effective conservation strategy or ecosystem management for drying river networks.

Arising from an interdisciplinary group of international scientists, this session investigates how global change cascades on to biodiversity, ecosystem functions and ecosystem services of rivers. Based on the most recent research of intermittent rivers, we explore ways to promote the adaptive management of drying river networks. This session welcomes presentations from eco-hydrology, biogeochemistry, community ecology, socio-economy, policy, modelling and river network management from all continents. A time dedicated to early career scientists will be considered to form a forum for further collaborations and capacity-building on intermittent river research.

S21: The social and ecological implications of wastewater in freshwater systems

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.

S22: Trash talk: Ecology of anthropogenic materials in freshwaters

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 is critical to sustain ecosystem services and 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 which 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.