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SFS Annual Meeting

Thursday, May 24, 2018
14:00 - 15:30

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14:00 - 14:15: / 430 B HIPPOPOTAMUS POOL BIOGEOCHEMISTRY REVEALS TWO ALTERNATIVE STATES: AEROBIC AND ANAEROBIC

5/24/2018  |   14:00 - 14:15   |  430 B

HIPPOPOTAMUS POOL BIOGEOCHEMISTRY REVEALS TWO ALTERNATIVE STATES: AEROBIC AND ANAEROBIC Hippopotami have long been recognized as ecosystem engineers, capable of transforming their environment, yet their influence on the biogeochemistry of aquatic ecosystems is not well known. Hippopotami load 36,000 kg per day of feces into the Mara River of East Africa, primarily into pools occurring along the main river channel and tributaries that can harbor 1-130 individuals each. Water samples were taken upstream, downstream, and at the surface and bottom of pools of varying volume, discharge, and hippopotamus densities, both before and after flushing flows. Multivariate analysis reveals that hippopotamus pools exist in two alternative states depending upon the density of hippopotamus loading and the time since flushing. Low-density hippopotamus pools remain aerobic and can be a source or sink for nutrients. High-density hippopotamus pools quickly become anaerobic between flushing flows and export nutrients and microbial byproducts. Transitions between these states are influenced by river discharge; episodic flushing of pools resets them back to the aerobic state. The frequent shifts between these alternative states create heterogeneity in space and time in pools as well as for downstream receiving waters.

Amanda Subalusky (Co-Presenter/Co-Author), Cary Institute of Ecosystem Studies, asubalusky@gmail.com;


Stephen Hamilton (Co-Presenter/Co-Author), Michigan State University, hamilton@kbs.msu.edu;


Ella C. Jourdain (Co-Presenter/Co-Author), Florida International University, jourdain.ella@gmail.com;


Emma Rosi (Co-Presenter/Co-Author), Cary Institute of Ecosystem Studies, rosie@caryinstitute.org;


David Post (Co-Presenter/Co-Author), Yale University, david.post@yale.edu;


Christopher Dutton (Primary Presenter/Author), Yale University, cldutton@gmail.com;


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14:15 - 14:30: / 430 B LITERATURE-BASED SYNTHESIS OF NUTRIENT STRESSOR-RESPONSE RELATIONSHIPS TO INFORM ASSESSMENT, MONITORING, AND CRITERIA DEVELOPMENT IN RIVERS AND STREAMS

5/24/2018  |   14:15 - 14:30   |  430 B

LITERATURE-BASED SYNTHESIS OF NUTRIENT STRESSOR-RESPONSE RELATIONSHIPS TO INFORM ASSESSMENT, MONITORING, AND CRITERIA DEVELOPMENT IN RIVERS AND STREAMS Eutrophication from nitrogen and phosphorus pollution is a major stressor of freshwater ecosystems globally. Despite recognition of this problem by scientists and stakeholders, synthesis of scientific evidence is still needed to inform nutrient-related management decisions and policies, especially for streams and rivers. A rigorous assessment of what is known about nutrient-stressor response relationships and modifying factors is a critical first step for identifying, managing, and restoring aquatic resources impaired by eutrophication. We conducted systematic reviews of the literature that asked: “What are the responses of chlorophyll-a, diatoms, and macroinvertebrates to TN and TP concentrations in lotic ecosystems,” and “how are these relationships affected by other factors?” We describe the reviews and discuss preliminary results based on the ~300 publications documenting cause-effect relationships between relevant nutrients and endpoints that were obtained after screening >22,000 publications from academic databases, and >4000 from other sources, for relevance, duplication, and quantitative effect sizes. These reviews provide a state-of-the-science body of evidence for assessing nutrient impacts to the most widely-used indicators of biological responses to nutrients. Disclaimer: Views expressed are the authors’ and not views or policies of the U.S.EPA.

Susan Norton (Co-Presenter/Co-Author), U.S.Environmental Protection Agency, norton.susan@epa.gov;


Micah Bennett (Primary Presenter/Author), U.S. Environmental Protection Agency, Office of Research and Development, bennett.micah@epa.gov;


Kate Schofield (Co-Presenter/Co-Author), U.S. Environmental Protection Agency, Office of Research and Development, schofield.kate@epa.gov;


Sylvia Lee (Co-Presenter/Co-Author), U.S. EPA, lee.sylvia@epa.gov;


Caroline Ridley (Co-Presenter/Co-Author), U.S. EPA, ridley.caroline@epa.gov;


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14:30 - 14:45: / 430 B SETTING SITE-SPECIFIC EUTROPHICATION STANDARDS FOR RESERVOIRS AND RUN-OF-THE-RIVER LAKES

5/24/2018  |   14:30 - 14:45   |  430 B

SETTING SITE-SPECIFIC EUTROPHICATION STANDARDS FOR RESERVOIRS AND RUN-OF-THE-RIVER LAKES When adopted in 2008, Minnesota’s lake eutrophication standards defined the need to develop standards on a case-by-case basis for many reservoirs and run-of-the-river lakes. The development of site-specific standards in these waterbodies is required because there is greater variability in the response of trophic status to nutrient enrichment compared to natural lakes. Challenges to developing standards for reservoirs and run-of-the-river lakes include: atypical water chemistry relationships, greater temporal and spatial variability in water quality parameters, and limited biological assessment tools for directly assessing attainment of aquatic life uses (e.g., indices of biotic integrity). The state of Minnesota has developed site-specific standards for several reservoirs and run-of-the-river lakes in the last decade, but to date, they have largely been limited to high-profile waters and those with extensive data sets. The development and implementation of these standards reveal commonalities among these waterbodies that can be used to streamline this process and reduce data needs for determination of nutrient levels that are protective of recreation and aquatic life beneficial uses.

R. William Bouchard, Jr. (Primary Presenter/Author), Minnesota Pollution Control Agency, Will.Bouchard@state.mn.us;


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14:45 - 15:00: / 430 B SIMILAR PROCESSES EXPLAIN WATER QUALITY IN ARTIFICIAL AND NATURAL US LAKES

5/24/2018  |   14:45 - 15:00   |  

SIMILAR PROCESSES EXPLAIN WATER QUALITY IN ARTIFICIAL AND NATURAL US LAKES In 2007 and 2012, the US EPA sampled approximately 1,000 US lakes, reservoirs, and ponds for its National Lakes Assessment. Scientists sampled different lakes between years; each year included roughly half manmade lakes and half lakes of geologic origin. They assessed up to 30 standard biological, physical, chemical, and recreational indicators of water quality. In the EPA's first report based on 2007 data only, authors stressed the low quality of artificial lakes relative to natural lakes, without parsing causes. Their later report including 2012 data focused on the limited changes between years, and still did not account for the causes of the disparity. We wanted to know if the processes leading to worse average outcomes in artificial lakes were the same as in natural lakes, with the artificial lakes simply subjected to greater stress, or if ecosystem processes in artificial lakes actually differed. We assessed this question with structural equations models, and found that artificial and natural lakes go through indistinguishable processes of eutrophication, leading to turbidity and lowered dissolved oxygen, in response to nutrient loading. Thus, reasons for problems in these natural and artificial lakes appear similar.

Chelsea Clifford (Primary Presenter/Author), Duke University (Nicholas School of the Environment), chelsea.clifford@duke.edu;


Jim Heffernan (Co-Presenter/Co-Author), Duke University, james.heffernan@duke.edu;


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15:00 - 15:15: / 430 B AMERICAN FALLS RESERVOIR, IDAHO, USA 2001-2016: TIDBITS OF WISDOM GARNERED FROM A FLOOD OF DATA

5/24/2018  |   15:00 - 15:15   |  

AMERICAN FALLS RESERVOIR, IDAHO, USA 2001-2016: TIDBITS OF WISDOM GARNERED FROM A FLOOD OF DATA American Falls Reservoir, in southeast Idaho, was created in 1927 to provide flood control, irrigation and recreation. Water quality issues have been documented since the 1960s. To address these issues, the Idaho Department of Environmental Quality established a total phosphorus target on tributaries and point sources to the reservoir. A chlorophyll a target for the reservoir was also set based on the mean value from July to August. To document changes resulting from efforts to reduce total phosphorous, data have been collected from 2001 through the present to characterize water quality, including physical and chemical parameters (i.e. dissolved oxygen, pH, temperature), and phytoplankton communities. Reductions in tributary total phosphorous concentrations have resulted in reductions in the reservoir. The chlorophyll a target was exceeded in 11 of 13 years data was collected but did not necessarily follow total phosphorous concentrations. Chlorophyll a concentrations are more related to reservoir level than to phosphorus concentrations. Phytoplankton communities vary spatially and temporally with cyanobacteria dominating the community in the summer. This long term data set contributes to further understanding the many factors affecting water quality.

Jennifer Cornell (Primary Presenter/Author), Idaho Department of Environmental Quality, cornjenn@isu.edu;


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