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SFS Annual Meeting


S01: Dams, big data, and meta-analyses
Keywords: Biodiversity, conservation, flow, hydropower, river ecology

Dams represent one of the most extensive and significant threats to freshwater biodiversity and ecosystem health globally. By altering physical river properties, such as flow, connectivity, sediment transport, and temperature, dams impede dispersal, modify productivity, and cause species extirpations and replacements. Despite these negative effects, as a pervasive human legacy and integral component of our energy future, dams are not going to disappear from the landscape anytime soon. Therefore, we need to advance our understanding of how dams affect biodiversity and how to better manage dams to minimize their ecological impact. Yet, although dams are ubiquitous, associated data (e.g., geographic, ecological, physicochemical, hydrological) is patchy. The question therefore arises whether we can use big data and meta-analyses to understand and influence current and future dam operations and management. There is evidence to suggest both big data and meta-analytical approaches can indeed provide the science to support dam-operating policies. In this special session, speakers will expand upon these ideas to discuss how they've utilized big data and/or meta-analyses to characterize and interpret patterns of dam impacts on the ecology and evolution of aquatic organisms. Speakers will also discuss how they have used this type of data to provide useable information to managers and/or policy makers. Discussions after the special session will explore the applicability of results outside study areas and how best to direct future data gathering efforts.

S02: The Great Lakes Restoration Initiative: Interdisciplinary Approaches to Assessing Beneficial Use Impairments in Areas of Concern
Keywords: Great Lakes restoration initiative, beneficial use impairment, area of concern, monitoring and assessment, remediation

The United States and Canada committed to restoring the physical, chemical, and biological integrity of the Great Lakes under the Great Lakes Water Quality Agreement in 1972 and identified 43 Areas of Concern (AOC) in 1987. The Great Lakes Restoration Initiative first funded the U.S. Environmental Protection Agency and numerous partners in 2010 to strategically restore or remediate contamination, habitat degradation, and ecological impairments that led to various Beneficial Use Impairments (BUIs) in AOCs. Relatively independent Remedial Action Committees (RACs) designated specific BUIs and associated criteria that needed to be met to remove individual BUIs within each AOC. Though some removal criteria for BUIs attempt to establish unaffected or nontoxic conditions, many rely on comparison of BUI data from inside the AOC with like data from areas outside AOC boundaries to determine if conditions are unique to the AOC or if they do not differ significantly from regional norms. The cumulative effects of the 1972 Clean Water Act, natural attenuation of contaminated sediments, and numerous restoration and habitat improvement projects driven by RACs appear to have remediated selected BUIs in many AOCs. The wide range in BUI-removal criteria (established by individual RACs) and the impractical nature of some criteria, however, make the effectiveness of remedial actions and removing BUIs problematic in many AOCs. Results from some recent interdisciplinary studies, however, illustrate how various RACs and federal, state/provincial, non-profit, private, academic, and Native American entities are working to successfully assess and remove BUIs from AOCs throughout the Great Lakes.

S03: Death and Decomposition in Aquatic Ecosystems
Keywords: carrion, mass mortality, organic matter, decomposition, resource subsidy, disturbance, pulse, necrobiome

Resource subsidies affect food webs, nutrient cycling, and community interactions, but their effects depend on the history, magnitude, and recurrence frequency of the subsidies. In aquatic ecosystems, plant detritus is considered the predominant form of such subsidies; however, while often less abundant in many ecosystems, carrion represents subsidies with relatively rapid turnover and highly concentrated nutrient and energy release that can have strong and lasting effects on ecosystems. Carrion subsidies can come in the form of phenology-based frequency (e.g., salmon spawning and death) or stochastic and episodic (e.g., mass fish kills). Some aquatic ecosystems have a natural history of carrion resource subsidies (e.g., natural salmon-bearing streams), while others have only recently been exposed to phenology-based carrion subsidies (e.g., salmon introductions around the world). Others only experience episodic subsidies in the form of unexpected mass mortalities (e.g., eutrophication- or disease-related fish kills). The responses of ecosystems to these different histories and frequencies of carrion subsidies have often been investigated independently, with little effort to compare and bridge research boundaries in the broader context of resource subsidies. The proposed session will provide a common platform for presenting diverse studies of carrion subsidies to provide a extensive ecological understanding of how pulsed carrion nutrient and energy releases have widespread and lasting impacts on many aquatic ecosystems. This session will increase the awareness of carrion importance to aquatic ecosystems by bringing together aquatic scientists discovering ecosystem effects of carrion resource subsidies from different habitat contexts, subsidy history and frequency, and research approaches.

S04: Expanding regulatory frameworks to include detrital responses in streams.
Keywords: environmental regulation, detritus, brown web, trophic dynamics, organic matter

Detritus, an important terrestrial energy subsidy to aquatic ecosystems, can change in magnitude and form with landscape alterations that reduce inputs and retention. Those same alterations often introduce excess nutrients (e.g., [nitrogen and phosphorus] and salts) that can become stressors that change the base of the food web through alteration of detrital quantity and quality. Detrital pathways have not been well integrated into the regulatory framework despite their importance in aquatic systems where habitat or human alterations limit primary productivity even though they can be sensitive to nutrients and salts and many of our most altered streams occur in forested highlands where detritus can be essential for aquatic life. Detrital endpoints are especially needed to identify ecosystem alterations prior to species loss or significant changes to aquatic community composition in light-limited streams to protect biological integrity. We aim to join a diversity of investigators to present approaches on how to expand regulatory frameworks to include detrital variables.

S05: Damming the Amazon – hydropower proliferation in the world's largest river system
Keywords: hydropower, Amazon Andes, tropical rivers, dams, connectivity

The rapid proliferation of new hydropower projects is a critical emerging issue confronting some of the largest and most biodiverse river systems of the world. In this special session, we will examine hydropower expansion in the Amazon Basin, where more than 500 dams have been proposed, in addition to some high-profile projects that have been recently completed or are currently under construction. The main objectives of this proposed session are to: 1) provide an overview of the current status of hydropower expansion in different regions of the Amazon, 2) examine potential ecological and social impacts of Amazon dams, and 3) explore basic considerations relevant to the hydropower planning in the Amazon Basin. One goal of the session is to raise awareness among SFS members of some of the current changes occurring in the Amazon with respect to hydropower, and potential consequences to the structure, function, and social dynamics of this magnificent river system.

S06: Social-Ecological Systems and Ecosystem Services
Keywords: social values, trade-offs, water quality assessment, biodiversity, conservation

There is a global concern about future water supplies because of growing human populations and increases in drought frequency and magnitude linked to climate change. Tradeoffs between water security for human needs and freshwater ecosystem health will only become more challenging in the future with increasing human demand for freshwater coupled with impending shifts in the duration and frequency of extreme climatic events and associated alterations in stream flows. This current social-ecological crises requires of new interdisciplinary and holistic conceptual approaches. Freshwater social-ecological systems provide essential contributions or ecosystem services that benefit society and support human wellbeing. These include contributions such as drinking water and irrigation, habitat for species and air quality, and nonmaterial benfits through spiritual enrichment such as recreation and esthetic values. The ecosystem service framework is useful for decision making in conservation actions and natural resource management of freshwater systems because it enables focusing on ecosystems- human well-being interlinkages by translating ecosystem properties into human needs. This session aims to advance knowledge of the complex dynamics of social-ecological freshwater systems by both understanding the relationships existing between freshwater ecosystems and societies, and analyzing either the contributions (i.e., ecosystem services) made by freshwater biodiversity to human wellbeing or the human actions that, through institutions, affect the integrity of freshwater biodiversity.

S07: Landscape Influences on Freshwater Habitats and Biological Assemblages
Keywords: landscape ecology, aquatic ecosystems, aquatic communities, land use

This session will focus on the multi-scale influences of landscape factors on aquatic habitats and fish, macroinvertebrate, and algal assemblages. It will highlight novel analytical techniques for addressing hierarchical relationships in factors and the usefulness of landscape-scale studies for more effective management and conservation of river systems, particularly the influences of anthropogenic land uses on river systems and the importance of enhanced landscape-scale datasets. We will include presentations involving the landscape approach for understanding influences on streams, rivers, wetlands, and lakes in North America and globally.

S08: Re-eutrophication of Lake Erie: Causes, consequences, and possible solutions
Keywords: Lake Erie, nutrients, cyanobacteria, agriculture, human land use

The re-eutrophication of Lake Erie over the past two decades has culminated in vast harmful algal blooms (HABs) in the western basin, a seasonal hypoxic zone in the central basin, and extensive growth of benthic algae in the eastern basin. In recent years, these HABs have been receiving additional attention because of the 2014 drinking water ban in Toledo, the record- breaking bloom in 2015, and the intense HAB on the Maumee River in downtown Toledo in 2017. The interplay of land, riverine, and lake dynamics that influence the exact response of Lake Erie to re-eutrophication are often simplified and brief in the current public narrative. Yet the reasons for the blooms and hypoxia, causes of toxicity, effects on food webs and people, and practices that will improve lake health are far more interesting and nuanced. We invite contributions that address any aspect of eutrophication along the land-river-lake continuum, including the potential influence of wetlands or examples from other watersheds. The overall goal of this session is to provide a cohesive and broad look at why Lake Erie and other similar water bodies have eutrophied, the consequences, and hopefully a glimpse into the future of possible recovery.

S09: Spatial aspects of freshwater ecology: understanding, managing, predicting
Keywords: spatial, patterns, anthropogenic, management, prediction

The environmental properties of freshwater ecosystems show strong spatial patterns, some at the large scale and mostly related to climate or geology, others at the small scale and often linked to topography. These, and many other environmental properties along spatial gradients, define the distribution of freshwater habitat types within vast networks of streams and rivers, creating highly variable and dynamic ecosystems. In addition, different pathways of human impairment impacting freshwater ecosystems also show spatial patterns, adding a further level of complexity. Our understanding of freshwater ecosystems is therefore highly dependent on the spatial arrangement of environmental properties and anthropogenic impairments, but also on the location of the sites where sampling is performed. Space is therefore one of the most challenging dimensions of freshwater research and management. This session will bring together approaches advancing our understanding of the impact of spatial patterns on abiotic and biotic components, their effect on freshwater communities, their application for management and their prediction for conservation purposes.

S10: Land-water boundaries: towards harmonizing hydrological and biogeochemical concepts in riparian zones across ecoregions
Keywords: near-stream zone, terrestrial-aquatic interface, biogeochemistry, watershed hydrology, catchment science

In natural and semi-natural areas, freshwater quality is primarily determined by substances mobilized from the surrounding land. The land-water boundary, i.e. the riparian zone, is therefore a pivotal landscape element from both scientific and management perspectives. Understanding riparian zone function, the central theme of this session, is thus of primary importance to support science-based, sustainable management of river networks that preserves the diverse and essential services provided by aquatic ecosystems. Riparian zones are traditionally conceptualized as "hot spots" that activate during "hot moments". However, most riparian studies are site-specific and have only modest value for generalization as riparian zone hydrological and biogeochemical processing differ along fluvial networks and among ecoregions. A conceptual framework that synthesizes our fundamental understanding of riparian zone processes controlling solute transformation and transfer between land and water within drainage basins and across ecoregions is therefore needed for a science-based, sustainable management of rivers. We welcome contributions on riparian studies with a catchment perspective from any ecoregion (boreal, temperate, Mediterranean, tropical), that investigate hydrology (how water and solutes are mobilized from lands to surface waters) and/or biogeochemistry (any chemical element cycle) with focus on the influence of riparian zones on freshwater quality.

S11: At the Confluence of Freshwater Science and the Humanities
Keywords: Communication, arts, collaborations, humanities, videography

This session will highlight collaborations between colleagues in aquatic sciences and the humanities as they explore science in creative ways and engage diverse audiences. We hope to address what James Gustave Speth, Yale School of Forest and Environmental Studies, called "the wellsprings of human motivation" to communicate our science more effectively. Presenters will showcase innovative ways for raising awareness about and becoming active in solving ecological problems particularly in aquatic ecosystems. Evaluation of project effectiveness will be encouraged to enhance our abilities to meet these challenges. We will be soliciting for participation by scientists and artists involved with diverse media, including writing, visual arts, videography, theater and music. An important goal of the session will be to develop new connections between scientists and artists working on place-based programs in freshwater science.

S12: Status and Trends in Arctic Freshwater Biodiversity Across the Circumpolar Region
Keywords: arctic, freshwater, climate change, biodiversity, monitoring

The freshwater group of the Circumpolar Biodiversity Monitoring Plan (Arctic Council: Conservation of Arctic Flora and Fauna) has completed regional and circumpolar assessments of freshwater flora and fauna to determine the state of Arctic freshwaters. This evaluation, the most extensive assessment of freshwater monitoring data from the Arctic to date, included examination of data from both historical (paleolimnological data and records from 1800 to 1950) and contemporary (post-1950) time scales, as well as Indigenous Knowledge of Arctic peoples. Presentations in this session will highlight multiple-stressor scenarios that act on the biodiversity and biogeochemistry of Arctic freshwaters and cause change in biological communities of lakes and streams. Assessments compare and contrast the regional state of Arctic freshwater ecosystems in North America, Greenland, Iceland, Fenno-Scandia, and Russia. Circumpolar assessments for specific focal ecosystem components, namely fish, benthic invertebrates, benthic algae, macrophytes, and plankton, provide novel analyses of how climate change and associated environmental drivers affect these biological components. For example, presenters will explore driver-response relationships across latitudinal and longitudinal spatial scales to determine whether similar patterns are evident throughout the sub-, low-, and high- Arctic. This study represents the first circumpolar assessment of trends in Arctic freshwater biodiversity.

S13: Ecoacoustic methods for continuous freshwater monitoring
Keywords: continuous monitoring, assessment, new methods, bioacoustics

Traditional aquatic survey techniques a) often bear risks to the health of the organisms, b) introduce fright bias and c) only asses populations at single times instead of continuously and d) incur high costs, particularly in remote areas. All of these disadvantages can be dealt with by modern methods of remote observation, such as passive acoustic surveys. This special session will discuss conceptual advances and case studies on how sound enables continuous observation in environments such as rivers, lakes and wetlands where populations are notoriously hard to monitor. Simple underwater microphones can be used to detect species of interest, and track ecosystem health through sounds produced by fish, invertebrates or the physical habitat. Sound can also be used to detect human disturbance through mechanical noises in the water. In this session we cover the conceptual basis of ecoacoustics, followed by an introduction to freshwater applications. The following talk will cover study design, followed by three examples of applications.

S14: Crossing Brook Trout Boundaries: Interdisciplinary Approaches to Salvelinus fontinalis Research, Management, and Outreach
Keywords: brook trout, conservation, interdisciplinary, management, restoration

Brook trout (Salvelinus fontinalis) are many things: central nodes in environmental conflict; primary foci of conservation and removal plans; and iconic symbols of North American angling. From historic conceptions as the "gentlemen's fish" to the 2017 feature film, Finding Fontinalis, brook trout are produced, reproduced, and embroiled in a complicated existence. They are transplanted, stocked, extirpated. Experimented on in hatcheries and shocked by electrical currents in native streams. Introduced, removed, worshipped, and reviled. In their native range, brook trout are under increasing pressure from stocking, land use shifts, and climate change, which drives the urgency of conservation efforts in the brook trout triangle from Maine to Wisconsin to the southern Appalachians. Meanwhile, in the American West, resource managers struggle to control and remove brook trout populations that are often publicly beloved. Researching and managing brook trout in the midst of these complexities and pressures demands deep disciplinary understandings and wide-ranging interdisciplinary integration. This special session gathers an interdisciplinary panel bridging biological sciences, social sciences, critical theory, and science communication. Participants range from California to Maine, from masters students to full professors, and from academia to management. We propose a series of presentations about our individual work--on dams and culvert fragmentation; stocked and wild salmonid interactions; habitat restoration projects; removal efforts; and innovative methodological approaches--and close the session by synthesizing across the boundaries of these fields and approaches. Collectively, we address the complex challenges and opportunities of brook trout research, management, and outreach in the 21st century.

S15: Crossing boundaries: watershed-tributary-lake exchanges in the Great Lakes region
Keywords: restoration, migration, loading, subsidy, biogeochemistry

Although the watersheds of the Great Lakes are very small relative to the size of the lakes, each lake has multiple large tributary rivers, hundreds of smaller tributaries, and extensive coastal and watershed wetlands that mediate exchanges between ecosystems. These fluxes of water, sediment, and organisms represent ecologically-important transfers of nutrients and energy. Moreover, the biodiversity and ecosystem services of these enormous lakes is concentrated in their nearshore zones, where tributary and wetland interfaces allow bidirectional exchange with watersheds and provide unique habitat and food resources. Coastal development, tributary fragmentation, species invasions, and numerous other anthropogenic stressors threaten these ecosystem linkages, yet research and management often focus on either a specific watershed or internal dynamics of the lakes while ignoring their exchanges. In this session, we will explore the nature of biological, hydrologic, biogeochemical, and human linkages between the Great Lakes and their watersheds, and the benefits of including ecosystem exchanges in efforts to restore and manage the Great Lakes system as an integrated whole.

S16: Ecological Stoichiometry as a Bridge Across Disciplinary Boundaries in Freshwater Science
Keywords: nitrogen, phosphorous, biogeochemistry, evo-eco dynamics, nutrient recycling

Interdisciplinary research approaches are required to solve complex environmental problems, but an issue with these approaches is the difficulty in finding common ground among disciplines. Ecological stoichiometry has the potential to unite disparate disciplines by making predictions based on a common currency, i.e., individual chemical elements and energy. By utilizing a common currency, its application can also reveal lessons applicable across boundaries. As a result, ecological stoichiometry has been used in studies of ecosystem ecology, organismal evolution, disease ecology, and population biology, among others. This session will gather speakers from these various fields to 1) highlight opportunities to apply lessons across disciplinary boundaries, 2) identify gaps in our existing knowledge, and 3) reveal chances to improve translation of scientific results into freshwater conservation. Speakers working on diverse questions and from diverse backgrounds in this session will highlight a variety of research approaches using ecological stoichiometry to link disparate areas of freshwater science.

S17: Bridging the Gap between Freshwater and Disease Ecology
Keywords: disease ecology, disease vectors, vector control, waterborne pathogens, interdisciplinary research

Many human, animal, and plant diseases are linked to fresh water ecosystems. Some pathogens are waterborne, some are affected by changing hydrologic regimes, and some are vectored by organisms that complete all or some of their life cycle in fresh water habitats. Freshwater ecological theory, therefore, can help inform our understanding of the transmission, persistence, and impact of these diseases around the world. In turn, biological and chemical methods of pathogen or vector control can impact the structure and function of freshwater ecosystems. This session will feature research exploring the intersection of freshwater ecology and disease ecology. It will highlight specific ways in which freshwater ecological theory or methodology is advancing our understanding of disease systems and the implications of disease control for freshwater ecosystems. Topics may include assessing the role of freshwater habitats in pathogen spread and viability, vector production, and disease prevalence as well as the consequences of vector or pathogen control methods for freshwaters at the organismal, population, community, and ecosystem levels. We welcome field, laboratory, and modeling studies relating to any human, domestic animal, wildlife, or plant disease. Research investigating how human-driven alterations to freshwater ecosystems (i.e. land use change, climate change, loss in freshwater biodiversity) are impacting disease dynamics is particularly encouraged. The goal of this session is to emphasize existing links between freshwater and disease ecology, to promote discussion of trade-offs between disease control measures and environmental impacts, and to explore new opportunities for interdisciplinary research.

S18: Aquatic Biodiversity Surveillance Using Environmental Genomics

Genetic and genomic tools and their applications continue to mature as technological advances decrease costs while increasing the accessibility of these tools to researchers and end users. The further development of environmental DNA methods and DNA metabarcoding techniques provides many avenues of research for various aspects of measuring aquatic biodiversity. These tools can be used in a targeted approach, detecting one or a few species, or in broader ways to capture large portions of the biodiversity within aquatic habitats. This session will focus on the latest accomplishments in the use of environmental genomics in such applications as detecting rare and invasive species, monitoring endangered, threatened, or keystone species, and finding and tracking parasites and pathogens. The session will present opportunities to describe successes while outlining existing and future challenges to the growing field of environmental genomics.

S19: Aquatic Invasive Species in the Laurentian Great Lakes Region Organizers
Keywords: invasion, Great Lakes, aquatic invasive species, freshwater

Aquatic invasive species (AIS) are expanding their ranges across the globe, and left unchecked, can dramatically impair freshwater ecosystems, and the goods and services they provide. In the Laurentian Great Lakes ecosystem of North America (known colloquially as 'the Great Lakes')184 documented exotic species have been tallied to date; many of these have become highly abundant and caused catastrophic impacts to ecosystems and fisheries, with repercussions for societal wellbeing. Given that the Great Lakes contain 20% of Earth's liquid freshwater, minimizing the impacts of AIS should be a global conservation priority. Detroit -- host of the 2018 SFS Meeting -- has a close historical, economic, cultural and ecological connection to the Great Lakes, and we propose a special session focused on Great Lakes AIS. The session will draw from diverse perspectives including AIS prevention, early detection (e.g., eDNA), eradiation, control, forecasting future invasions, and quantification of ecological impacts. Examples will be drawn from plants (watermilfoil, Phragmites), protists (Microcystis), vertebrates (sea lamprey, round goby), and invertebrates (quagga mussels, New Zealand mudsnails). By hosting this special session we hope to provide a platform for disseminating current information on AIS in the Great Lakes and for networking among stakeholders from diverse backgrounds including resource managers, educators, students, non-profits, and academics.

S20: Emerging Approaches to Modeling Population and Community Dynamics in Fresh Waters
Keywords: community dynamics, quantitative modeling, stochasticity, biodiversity

Characterized by predictable, seasonal signal and stochastic, aseasonal environmental noise, freshwater ecosystems are inherently difficult to model. Climate change is poised to affect both components of environmental variation via shifts in the timing, magnitude, and frequency of hydrologic events. However, anticipating how ongoing and expected changes in flow regimes will affect biota across levels of biological organization is challenging and requires alternative approaches to traditional niche-based ones. This acknowledges the fact that environmental variation is as important, if not more important, than mean environmental conditions. This session will bring together speakers using quantitative approaches to understand population and community dynamics, including the interaction between local and regional spatio-temporal variation, in both lotic and lentic ecosystems. Research can therefore span various spatial and temporal scales, ranging from local population and community dynamics through to regional biodiversity dynamics. Of particular interest are studies that bridge this local-regional divide, helping to understand the role that small-scale spatially-heterogeneous variability and large-scale regional variability can have on the regional stability of metapopulations and metacommunities. Habitat simplification, fragmentation, and climate change-induced extremes are different facets of global change that may interact in poorly-known ways. A better mechanistic understanding of how spatio-temporal environmental variability controls freshwater biodiversity will thus increase our ability to forecast and potentially mitigate the effects of global environmental change in freshwater ecosystems.

S21: Navigating between Ecosystem Structure and Functioning in Research and Management
Keywords: ecosystem process species composition, water quality assessment, structure, function

Ecological water quality is traditionally assessed using point-in-time measurements of ecosystem structure, such as community composition. However, these structural parameters do not capture the functional properties of an ecosystem, and structure might not always be linked to function. This has resulted in recent interest to also directly assess dynamic processes in aquatic ecosystems, including measures of decomposition, metabolism, nutrient cycling, and productivity. These structural and functional approaches often provide complementary information on the impact of stressors on the health of an aquatic ecosystem, and there might thus be need to navigate between them. This session aims to highlight research that combines measurements of both ecosystem structure and function in freshwater ecosystems. Speakers are encouraged to compare the use of structural and functional approaches in their ability to identify the impacts of various stressors. We will reflect on whether either measures, or a combined approach, would be more useful in ecological water quality assessment.

S22: Transcending Aquatic-terrestrial Boundaries: Ecology, Conservation and Management of Temporary Freshwaters
Keywords: drying, reciprocal subsidies, aquatic-terrestrial linkage, spatio-temporal dynamics, biodiversity

Temporary freshwaters are globally prevalent, yet scientific research in these ecosystems has lagged behind that devoted to their permanent counterparts. Intermittent rivers and ephemeral streams (IRES)cease to flow at some point in time and may lose all surface water seasonally. Temporary wetlands dry seasonally but differ in their hydrologic connectivity compared to riverine systems. Despite differences in hydrologic connectivity, aquatic-terrestrial linkages are apparent in both IRES and temporary wetlands in the form of reciprocal subsidies, and of aquatic, riparian, and terrestrial biota that depend on seasonal wet/dry phases to feed, reproduce, and disperse. Here we will explore how aquatic-terrestrial linkages influence the unique characteristics of temporary freshwaters, their biodiversity dynamics, and their contribution to key ecosystem functions such as nutrient dynamics and carbon cycling. We are particularly interested in contributions that advance our understanding of the natural dynamics of temporary freshwaters at different spatial and temporal scales. We also call for contributions that could enhance conservation and management of these ecosystems, including policy-relevant case studies.This session will highlight the ecological importance of temporary freshwaters by emphasizing their aquatic-terrestrial linkages and natural dynamics and thus help change their perception from 'second-class' freshwaters to biodiverse and functionally-important ecosystems.

S23: The Evolving Science Supporting Biological Assessments and Criteria
Keywords: bioassessment, biological criteria, aquatic life, metagenomics, diagnostic indices, conservation science

Biological assessments and criteria have been used worldwide for over three decades to measure the biological condition of streams and rivers. Over this time, the original methods devised for conducting biological assessments have been incrementally improved and refined. And, the science continues to evolve. For example, in 2014-2015, a review of the scientific foundations supporting biological assessment and criteria was conducted by the USEPA. Top technical challenges identified include issues such as new approaches expanding biological assessment beyond streams and rivers, scaling assessments to characterize biological conditions and identify dominant stressors across reach, watershed and regional scales, incorporating new sources of biological data (e.g., genetic data) when assessing condition, defining management thresholds that are strongly linked to the protection of aquatic life, and streamlining methods for identifying the causes of poor biological condition. At the same time, new technical advances will challenge how science is used to develop, modify, and implement water resources policy. In this special session, we will describe some of the major technical challenges we now face and new ideas and approaches for addressing these challenges.

S24: Advancing Freshwater Science: A Discussion with the National Science Foundation
Keywords: population ecology, community ecology, ecosystems ecology, cross-disciplinary initiatives, early career scientists

The National Science Foundation (NSF) provides opportunities for funding basic research and training in ecology and related disciplines. The Foundation supports researchers at all career stages, including undergraduate and graduate students, post-doctoral researchers and early career faculty. The purposes of this session are to inform Society for Freshwater Science (SFS) members about funding opportunities at NSF and to receive comments and suggestions on how the Foundation can best advance freshwater science and related disciplines. NSF representatives will include program officers from programs broadly relevant to ecology and environmental research. We will begin the session with a 10-minute overview of relevant programs, followed by a town-hall type Question & Answer session and discussion (1 hour) with SFS members. Discussion topics will include basic research proposals and the review process, new and continuing special competitions, cross-cutting programs, alternative funding mechanisms, and network and observatory infrastructure support. We will also discuss opportunities at different career stages and supplemental funding opportunities. Audience members are encouraged to bring questions.

S25: Effects of Multi-stressors in Stream Ecology Across Regional Landscapes and Mesocosm Studies
Keywords: multi-stressors, landscape, mesocosm, bioassessment, models

In general, national- or large regional-scale models typically focus on large-scale natural landscape features, such as climate, topography, elevation, and geology, as the most important discriminating variables, with disturbance variables, such as land use, nutrients, sediments, and contaminants, usually of lower predictive importance. Large data sets recently have become available. These data sets enable researchers to build stream bioassessment models across a range of spatial scales (Feld 2013, Waite et al. 2014, May et al. 2015) and to incorporate more types of stressors, such as hydrological alteration and water quality (Norton et al. 2002, Kennen et al. 2010, Wiley et al. 2010, Riseng et al. 2011, Esselman et al. 2015, Villeneuve et al. 2015). In addition, experiment approach in the field or in laboratory conditions using mesocosms helps to elucidate some interactions of reduced number of stressors acting together (De Castro et al, 2017...). This Special Session will highlight research on the effects of multiple stressors on stream biota across large regional or laboratory studies with various objectives. Regional studies will highlight the issues of multi-stressors from agricultural and urban land use, while laboratory studies will allow more detail focus on select stressor variables in a control setting.

S26: Ecological Perspectives on the Movement and Transformation of Anthropogenic Materials in Freshwaters
Keywords: ecosystem disruptors, nanomaterials, microplastic, community ecology, ecosystem ecology

The diversity and abundance of anthropogenic materials entering freshwaters is increasing and will persist for centuries. Anthropogenic materials span a size gradient including dissolved compounds (e.g., personal care products and pharmaceuticals), nanoparticles, fine particles (i.e., microplastic; particles < 5mm), and coarse materials (i.e., anthropogenic litter; trash). While a ubiquitous component of freshwater ecosystems globally, the impact of these novel materials on the structure and function of ecosystems remains poorly defined. In addition, measurements of anthropogenic materials' abundance, movement, and biological interactions in lotic ecosystems are urgently needed to inform assessments of their environment 'life cycle' and develop budgets of anthropogenic materials at a global scale. In this session we will bring together disparate studies examining the ecological dynamics of anthropogenic materials in freshwater ecosystems that range across scales and impacts. Speakers will present work that bridges fields in community, ecosystem, and restoration ecology, along with ecotoxicology. The session will stress research using fundamental ecological approaches from the molecular to landscape scales, and in watersheds flowing through a variety of landscapes. These presentations will call attention the need to generate an overarching paradigm that can connect research on a diversity of anthropogenic contaminants on freshwater ecosystems. All participants are invited to consider how ongoing and future research can be incorporated with management strategies at the local, regional, and global scales for innovative approaches to conservation.

S27: Green meets Brown: Ecological Significance of Interacting Autotrophy and Heterotrophy in Freshwaters
Keywords: algae, organic matter, carbon cycling, periphyton, food webs

Overview: Many approaches in ecosystem ecology focus on separate pathways of energy flow based on either autotrophy or heterotrophy ("green" or "brown" systems, respectively). While these two pathways are easily separated by concept and methodology, recent research from freshwaters suggests autotrophy and heterotrophy often occur in close proximity and interact in complex ways. Studies investigating algal-bacterial and algal-fungal interactions, for example, point to a range of possible interactions including competition, mutualism, and priming effects that depend on environmental factors and can alter organic matter processing. Further blurring the distinction between trophic pathways, studies increasingly suggest primary consumers do not feed exclusively in either brown or green food webs. This omnivory complicates trophic classification, and its nutritional significance is important to discern roles of autotrophs, heterotrophs, and non-living detritus as the basis of consumer growth and fitness. In the proposed session, we solicit investigations crossing the boundary between green and brown to understand organism- to ecosystem-level implications of interacting autotroph and heterotroph biomass and activity in freshwaters. These studies will advance understanding of how autotrophs and heterotrophs can interactively shape ecosystem responses to light regime, nutrient availability, temperature, and other environmental factors under anthropogenic change. Studies in the session may use a variety of approaches to address the autotroph-heterotroph interface from microbial, consumer-resource, or ecosystem perspectives. This session will bring together a diversity of aquatic scientists around a shared interest, identifying common themes and providing direction for future inquiry at the interface between green and brown trophic systems.

S28: Reframing the Science of Urbanized Headwater Streams
Keywords: biogeochemistry, diversity, watershed management

Headwaters comprise a majority of stream length in urbanized watersheds. Thus, due to sheer number, urbanized headwater streams hold significant ecological and social importance in human dominated landscapes. The expansive habitat of urban headwaters can, in some cases, has the potential to harbor diverse biotic communities. Further, as the boundary between urbanized watersheds and fluvial networks, urbanized headwaters mediate the transfer of nutrients and other materials from landscapes to waterways. Owing to their ubiquity across the landscape, many people interact with urbanized headwater streams as part of their daily lives. Yet, this close association between people and urbanized headwaters means that these waterways are also often the most impacted by management and development activity. How urbanized headwaters are managed has changed over time and differs between regions. The result of this mosaic of land use practices is that urbanized headwaters are often even more heterogeneous than their natural counterparts. This heterogeneity has challenged ecologists, but also presents opportunities to reframe understanding of urbanized headwaters to incorporate concepts important to scientists, managers, and stakeholders. We invite a broad spectrum of research on urbanized headwaters, including work emphasizing community ecology, management, biogeochemistry, restoration ecology, hydrology, public health, and environmental economics. Recognizing the important feedbacks between ecosystem processes and management activities in urbanized settings, the session will place a special emphasis on research that approaches urbanized headwaters from an interdisciplinary perspective.

S29: Scholarship of Teaching and Learning in Freshwater Science
Keywords: Communication, arts, collaborations, humanities, videography, vision and change, education, outreach, practitioner research

Typical science courses emphasize memorizing facts when learning is actually driven by being observant, thinking, linking concepts, and asking good questions. As a response to our nation's "leaky STEM pipeline," and the subsequent AAAS Report: Vision and change in undergraduate biology education: a call to action (2011), the science class room is changing. Biology education is making more connections across curriculum, clarifying relevance to the 'real-world,' and placing less emphasis on memorization (AAAS 2011). Further, there has been a rise of practitioners (discipline specific experts) who are now contributing their best teaching practices as a recognized form of scholarship. Those with discipline specific research are now developing inquiry based activities that increase intellectual engagement and foster deep understanding. We propose a special session focused on teaching (e.g. techniques, goals, troubleshooting, modules, experiences) all levels of freshwater science. We hope to encourage SFS members to contribute inquiry activities and resources to be used in the classroom/lab, and ultimately, increase the availability of educational outreach materials that we offer as a society (which are currently scarce). Additionally, we'd like to promote the Scholarship of Teaching and Learning in our field and society so that freshwater science can be represented and explored in all levels of education and outreach. Engaging and effectively educating students in the classroom and laboratory about freshwater science can help navigate the boundaries between teachers-students, as well as freshwater science research-teaching.

S30: Environmental and Ecological Roles of Dissolved Organic Matter in Freshwater Ecosystem

Dissolved organic matter (DOM) is ubiquitous and heterogeneous in natural waters, containing biopolymers and geopolymers with different molecular sizes and functionalities. Due to the plenty of active organic components and functional groups, DOM in aquatic ecosystems will definitely have substantial role for carbon cycling, contaminant behavior, and ecological balances. The following topic would be included in this special session: 1) Detailed structural information on DOM, including the compositions, molecular weights, surface charges, etc., and the dynamic variations under changing environments (e.g., salinity, specific conductivity, pH, etc); 2) Insights into the behavior of DOM in freshwater environment, including aggregation/disaggregation, photo-/microbial degradation, and transformation; 3) Interaction between DOM and inorganic/organic contaminants (such as heavy metals, POPs, emerging contaminants, etc), including the interaction process and mechanism; 4) The coating/adsorption of DOM on some natural colloidal particles or the engineering nanoparticles, and its subsequent influence on the environmental behavior of these small-sized particles; 5) Influence of DOM on the aquatic biomass/microorganism, phytoplankton/zooplankton and the ecological structure.

S31: Putting your science "In the Room": Communicating Science to Inform Environmental Policy and Management Decisions

Environmental managers and policy-makers at all levels of government rely upon rigorous scientific research and analysis to inform their decisions on natural resource management. Their decisions, and thus the science, not only impact the natural resource itself, but often a wide range of stakeholders – the public, regulated and non-regulated industries. This combination workshop and special session focus on the transactions that occur between scientists and environmental managers and policy-makers "in the room" where natural resource management decisions are made. Scientists will have an opportunity to broker these transactions by communicating the scientific research they are presenting at the conference to a panel of state and federal water quality managers who operate in Clean Water Act implementation programs. Communication will occur through the preparation of a one-page briefing document that will be provided to the panelists and registered attendees prior to the conference. Scientists will be asked to deliver a five-minute brief to the panel in which they describe the environmental problem or issue, their scientific research, and the action they are seeking. A five-minute question and answer period will follow with additional feedback from a science communication specialist. A follow-up special session will repeat this exercise and give scientists an opportunity to hone their communication skills. This workshop/special session has three objectives:

  1. To mutually increase awareness of relevant science and the potential application of that science in environmental policy and management,
  2. To enhance science communication, and
  3. To connect science practitioners to specific environmental policy and management programs.