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SFS Annual Meeting

Monday, May 20, 2019
14:00 - 15:30

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14:00 - 14:15: / 253 AB FISH AS DRIVERS OF ZOOPLANKTON SPATIAL VARIATION ACROSS MULTIPLE SPATIAL SCALES

5/20/2019  |   14:00 - 14:15   |  253 AB

FISH AS DRIVERS OF ZOOPLANKTON SPATIAL VARIATION ACROSS MULTIPLE SPATIAL SCALES Zooplankton are a critical component in aquatic food webs because they are the primary link between basal resources and higher trophic levels. Numerous factors have been identified that can potentially influence the spatial distribution of zooplankton including fish, which alter the distribution of zooplankton by both consumption and release of kairomones (also known as infochemicals). Here, we summarize several projects describing zooplankton spatial distribution across multiple scales and what implications these mechanisms have for structuring aquatic food webs. We focus on three scales: 1) fine-scale interactions among zooplankton, macrophytes, and fish with differing diets, 2) regional-scale influences of fish on both near and offshore zooplankton, and 3) system scale changes in density from upper, riverine areas to lower, lacustrine habitats above dams in reservoirs and from lakes to streams below lakes. Our observations suggest that zooplankton spatial distribution is complex and that fish interact with several factors in determining the zooplankton distribution. Our observations also suggest that the distribution of zooplankton may have important implications for food web structure and function.

Thomas Detmer (Primary Presenter/Author), University of Illinois, tdetmer@illinois.edu;


Joseph Parkos (Co-Presenter/Co-Author), University of Illinois, parkos@illinois.edu;


David Wahl (Co-Presenter/Co-Author), University of Illinois, d-wahl@illinois.edu;


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14:15 - 14:30: / 253 AB LONG-TERM RESPONSE OF LAKE PHYTOPLANKTON TO CHANGES IN NUTRIENT AND DETRITUS SUBSIDIES FROM ITS WATERSHED AND NUTRIENT CYCLING BY FISH

5/20/2019  |   14:15 - 14:30   |  253 AB

LONG-TERM RESPONSE OF LAKE PHYTOPLANKTON TO CHANGES IN NUTRIENT AND DETRITUS SUBSIDIES FROM ITS WATERSHED AND NUTRIENT CYCLING BY FISH We examined the response of phytoplankton in eutrophic Acton Lake to changes in subsidies of nutrients and detritus (sediments) over 24 years, driven by a pronounced increase in conservation tillage in this agricultural watershed. In streams draining the watershed, flow-weighted mean concentrations (FWMC) of suspended sediment, all forms of nitrogen (N), and particulate phosphorus (P) declined over the entire period. In contrast, FWMC of soluble phosphorus declined over the first decade, then increased. Acton Lake phytoplankton biomass increased over the first decade, despite decreasing stream concentrations of P, which was then the limiting nutrient. The phytoplankton increase was driven by increased light (due to decreased suspended sediments) in the water column, and by an increase in biomass, and hence nutrient excretion by, sediment feeding fish (gizzard shad). Over roughly the second decade, phytoplankton biomass remained relatively constant; however, phytoplankton have become increasingly limited by N, relative to P. The increase in relative N limitation appears driven by decreased N:P from stream inputs, and increased nutrient cycling by fish, which excrete at low N:P. Our results illustrate how phytoplankton dynamics are regulated by watershed inputs as well as animal-mediated nutrient cycling.

Michael Vanni (Primary Presenter/Author), Miami University, vannimj@miamioh.edu;


Maria Gonzalez (Co-Presenter/Co-Author), Miami University - Oxford Ohio, gonzalmj@miamioh.edu ;


William Renwick (Co-Presenter/Co-Author), Miami University, wrenwick@miamioh.edu;


Patrick Kelly (Co-Presenter/Co-Author), Rhodes College, kellyp@rhodes.edu;


Tanner Williamson (Co-Presenter/Co-Author), Miami University of Ohio, tanner.williamson@gmail.com;


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14:30 - 14:45: / 253 AB EFFECTS OF LAKE TROUT SUPPRESSION METHODS ON AMPHIPODS IN YELLOWSTONE LAKE

5/20/2019  |   14:30 - 14:45   |  253 AB

EFFECTS OF LAKE TROUT SUPPRESSION METHODS ON AMPHIPODS IN YELLOWSTONE LAKE Invasive species alter biodiversity, ecosystem function, and food web dynamics worldwide. In Yellowstone Lake, WY, invasive Lake Trout have collapsed the native Yellowstone Cutthroat Trout population. To suppress Lake Trout, the National Park Service deposits Lake Trout carcasses on Lake Trout spawning sites to induce embryo mortality, but effects of carcass deposition on other components of the lake ecosystem are unknown. Amphipods, a dominant benthic invertebrate and major food source for Lake Trout and Yellowstone Cutthroat Trout, could respond to changes in biogeochemistry in the lake's littoral zone when carcasses are deposited. We sampled amphipod populations at three carcass deposition and three control sites in 2018. Because of challenges associated with sampling large water bodies, two sampling approaches were evaluated: a spatially quantitative diver-operated suction sampler and qualitative emergent fry traps. The number of amphipods collected in fry traps was not correlated with the density of amphipods measured in suction samples, indicating that fry traps are not an effective way to quantify amphipod abundance. Results suggest amphipod population size did not change after carcass treatment, which is likely due to the sparse carcass cover achieved at spawning sites in 2018.

Michelle Briggs (Primary Presenter/Author), Montana State University, michelle.briggs32@gmail.com;


Lindsey Albertson (Co-Presenter/Co-Author), Montana State University, lalbertson@stroudcenter.org;


Hayley Glassic (Co-Presenter/Co-Author), Montana Cooperative Fishery Research Unit, hcg0509@gmail.com;


Christopher Guy (Co-Presenter/Co-Author), U.S. Geological Survey, Montana Cooperative Fishery Research Unit, Montana State University, cguy@montana.edu;


Todd Koel (Co-Presenter/Co-Author), Yellowstone National Park, todd_koel@nps.gov;


Dominique Lujan (Co-Presenter/Co-Author), University of Wyoming, dlujan1@uwyo.edu;


Lusha Tronstad (Co-Presenter/Co-Author), University of Wyoming, Wyoming Natural Diversity Database, tronstad@uwyo.edu;


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14:45 - 15:00: / 253 AB DETERMINANTS OF RESOURCE USE BY RAINBOW TROUT IN MOUNTAIN LAKES

5/20/2019  |   14:45 - 15:00   |  253 AB

DETERMINANTS OF RESOURCE USE BY RAINBOW TROUT IN MOUNTAIN LAKES Basal sources of carbon to lake food webs flow from terrestrial, pelagic, and littoral habitats. It is well established that aquatic consumers acquire carbon from across these habitats in varying proportions, yet the factors that influence this variability are not well understood. Here, we leverage the relatively simple food webs, yet complex shorelines and bathymetries, of mountain lakes to address the question of how the relative availability of habitat determines resource use by rainbow trout. We collected samples of rainbow trout, pelagic seston, benthic-littoral periphyton, and terrestrial organic matter across 16 mountain lakes in western Washington. Samples were analyzed for the stable isotope ratios of carbon and nitrogen. We found that as proportional availability of littoral-benthic habitat in mountain lakes decreased, the littoral-benthic contribution of carbon to fish biomass decreased. Our findings suggest that despite preferential use of littoral-benthic resources, rainbow trout exhibit flexibility to adjust resource use according to lake characteristics. This suggests relative stability of the high-lakes fishery in light of the potential changes to the proportional availability of basal resources resulting from climate change and human water drawdowns.

Rebekah Stiling (Primary Presenter/Author), University of Washington, stilir@uw.edu;


Julian Olden (Co-Presenter/Co-Author), University of Washington, olden@uw.edu;


Gordon Holtgrieve (Co-Presenter/Co-Author), University of Washington, gholt@uw.edu;


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15:00 - 15:15: / 253 AB 25 YEARS OF WATER QUALITY CHANGE IN RHODE ISLAND LAKES AND PONDS

5/20/2019  |   15:00 - 15:15   |  253 AB

25 YEARS OF WATER QUALITY CHANGE IN RHODE ISLAND LAKES AND PONDS University of Rhode Island’s Watershed Watch Volunteer Monitoring Program has been collecting water quality data on Rhode Island lakes for over 25 years, allowing exploration of long-term trends in water quality parameters. Not all lakes in the study area were sampled across the time period and lakes were often added in geographic clusters (e.g. in urbanized Rhode Island). Similar to how long-term temperature records are analyzed, we centered and scaled water quality measurements on a per-station basis. This provides a robust and commonly scaled measurement to explore this data for long-term trends. Aggregation of lakes showed increasing temperature, chlorophyll a, and total nitrogen. Interestingly, total phosphorus is declining, perhaps reflecting management focus on phosphorus reductions. Additionally, while most sites track the yearly trend in decreasing water quality, there are bright spots with a few sites improving over the 25 years. Contrary to other analyses that show relatively stable quality at the regional scale, our analysis shows that long-term water quality within Rhode Island show some parameters improving while others decline. Importantly, this analysis points out the value of data from long-term monitoring programs for identifying trends in environmental condition.

Betty Kreakie (Primary Presenter/Author), Environmental Protection Agency, Kreakie.Betty@epa.gov;


Jeffrey Hollister (Co-Presenter/Co-Author), Environmental Protection Agency, Hollister.Jeff@epa.gov;


D.Q. Kellogg (Co-Presenter/Co-Author), University of Rhode Island, qkellogg@uri.edu;


Stephen Shivers (Co-Presenter/Co-Author), US EPA Office of Research and Development ORISE Fellow, Shivers.stephen@epa.gov;


Elizabeth Herron (Co-Presenter/Co-Author), University of Rhode Island Watershed Watch, eherron@uri.edu;


Linda Green (Co-Presenter/Co-Author), University of Rhode Island Watershed Watch, lgreen@uri.edu;


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15:15 - 15:30: / 253 AB META-ANALYSIS ON INTERNAL PHOSPHORUS LOADING IN LAKES AND RESERVOIRS: RESULTS AND RECOMMENDATIONS

5/20/2019  |   15:15 - 15:30   |  253 AB

META-ANALYSIS ON INTERNAL PHOSPHORUS LOADING IN LAKES AND RESERVOIRS: RESULTS AND RECOMMENDATIONS Greater attention is being devoted to internal phosphorus (P) loading in waterbodies around the world, with the recognition that this release of P from sediments can delay aquatic ecosystem recovery. Various factors have been identified as important drivers of internal P loading, but P loading studies tend to be restricted in lake size or geographic location. We examined over 1350 peer-reviewed studies on internal P loading in freshwater lakes and reservoirs around the world, and retained 27 studies from 29 lakes for meta-analysis. Principal component analyses revealed that four principal components explained approximately 75% of the variance in P release rates. Multiple linear regression models identified three important factors consistent in both total P and filtered P release rates: dissolved oxygen, incubation temperature, and latitude. Despite the considerable variability found in our analyses, it appears that dissolved oxygen and temperature are master factors influencing internal P loading. We recommend future internal P loading studies employ more consistent methods and reporting standards than currently found in published literature to facilitate comparisons. These data and recommendations are published in the forthcoming book Internal Phosphorus Loading: Causes, Case Studies, and Management.

Alan Steinman (Co-Presenter/Co-Author), Annis Water Resources Institute-Grand Valley State University, steinmaa@gvsu.edu;


Emily Kindervater (Primary Presenter/Author), Annis Water Resources Institute- Grand Valley State University, kinderve@mail.gvsu.edu;


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