SFS Annual Meeting

5/21/2018  |   14:00 - 14:15   |  420 B

RESTORING STREAM ECOSYSTEM FUNCTION ON WORKING LANDS TO IMPROVE WATER QUALITY Stream restoration often focuses on returning stream habitat features to their historic configuration via intensive channel engineering. Targeted restoration of selected ecosystem functions (e.g., nutrient retention) has become more prevalent given goals to improve water quality in systems where traditional habitat restoration is infeasible (e.g., urban, agricultural). For example, ten years ago, we restored connectivity in 600m of an agricultural stream by adding small inset floodplains to the formerly channelized system. Floodplain restoration immediately increased sediment, phosphorus, and nitrogen retention by increasing bioreactive surface area and improved storm resilience by decreasing water velocity. Other improvements emerged years later, including increased floodplain denitrification and a shift from silt-dominated to sand- and gravel-dominated substrate, the latter having potential positive consequences for macroinvertebrates, but potentially reducing high-denitrification habitat. The short length of the restored reach limited its watershed-scale effects, but model results suggest that floodplain restoration could decrease nitrogen and phosphorus export by 10 and 30%, respectively, if all headwaters reaches in the sub-watershed were restored. We conclude that restoring stream ecosystem function through targeted strategies (e.g., floodplain construction) offers a low-cost but effective approach to improving water quality in working agricultural lands.

Sarah S. Roley (Primary Presenter/Author), Washington State University, sarah.roley@wsu.edu;


Jennifer L. Tank (Co-Presenter/Co-Author), University of Notre Dame, tank.1@nd.edu;


Brittany Hanrahan (Co-Presenter/Co-Author), USDA Agricultural Research Service, br.hanrahan@gmail.com;


Matt Trentman (Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, matt.trentman@flbs.umt.edu;


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5/21/2018  |   14:15 - 14:30   |  420 B

EVALUATION OF EUTROPHICATION MITIGATION MEASURES AT FINE SPATIAL AND TEMPORAL RESOLUTION Combating eutrophication is difficult and exposes gaps in the scientific understanding of hydrological and biogeochemical processes in streams. One example of such a knowledge gap is understanding of the hydrological and biogeochemical effects of mitigation measures aimed to reduce eutrophication. To address this gap, we implemented high-frequency monitoring in a Swedish headwater watershed (7.4 km2) subjected to intensive crop production and high phosphorus and sediment losses from clay soils. To reduce the negative effects of agriculture on stream water quality and ecology, a number of mitigation measures have been implemented in the watershed, including: improved drainage, lime filters, buffer zones, a two-stage ditch and a sedimentation pond. The experimental setup includes hydrochemical measurements at the watershed outlet and along the stream network, using optical sensors and wet-chemistry analyzers for continuous determination of phosphorus, nitrogen, carbon and suspended sediments. In this paper, we show how our high-frequency experimental setup helps to evaluate combined and individual effects of mitigation measures and provides a collaborative dialogue between scientists, water authorities and the farmers, all interested in reducing eutrophication at watershed-scale.

Magdalena Bieroza (Primary Presenter/Author), Swedish University of Agricultural Sciences, magdalena.bieroza@slu.se;


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5/21/2018  |   14:30 - 14:45   |  420 B

LAND COVER CHANGE THROUGH THE PLANTING OF COVER CROPS REDUCES PHOSPHORUS LOSS FROM AN AGRICULTURAL WATERSHED Tile drainage systems in the agricultural Midwestern US facilitate the transport of soluble reactive phosphorus (SRP) to adjacent streams and ditches, contributing to harmful and nuisance algal blooms. Winter cover crops increase nutrient retention in watersheds by retaining nutrients when fields would otherwise be fallow. However, previous studies on the effect of cover crops on SRP loss have been inconsistent at the field-scale and are understudied at the watershed-scale. In this study, cover crops were planted on >65% of croppable land in the Shatto Ditch Watershed (13.3km2) for 3yrs. Before and during cover crops, we quantified SRP loss from tile drains and the watershed outlet. We found that median SRP loss was 75-92% lower from tiles draining fields with cover crops compared to those without. Across multiple tile drains, the magnitude of SRP loss was controlled by tile flows. Watershed SRP yields were temporally variable, but were 18-20% lower at elevated flows (>60th percentile) during years with watershed-scale planting of cover crops. Results suggest that cover crop planting has the potential to increase SRP retention in agricultural fields and effectively decrease SRP export to downstream waters.

Brittany Hanrahan (Primary Presenter/Author), USDA Agricultural Research Service, br.hanrahan@gmail.com;


Jennifer L. Tank (Co-Presenter/Co-Author), University of Notre Dame, tank.1@nd.edu;


Sheila Christopher (Co-Presenter/Co-Author), University of Notre Dame, sheila.christopher@nd.edu;


Matt Trentman (Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, matt.trentman@flbs.umt.edu;


Ursula H. Mahl (Co-Presenter/Co-Author), University of Notre Dame, umahl@nd.edu;


Todd V. Royer (Co-Presenter/Co-Author), Indiana University Bloomington, troyer@iu.edu;


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5/21/2018  |   14:45 - 15:00   |  420 B

COMPARING THE ROLE OF BIOTIC AND ABIOTIC FACTORS INFLUENCING PHOSPHORUS CYCLING IN CONSTRUCTED FLOODPLAINS OF MULTIPLE AGRICULTURAL STREAMS Maximizing nutrient removal from agricultural streams is one mechanism for alleviating eutrophication to downstream water bodies such as Lake Erie. The construction of inset floodplains in agricultural streams/ditches can increase nutrient removal, yet the impact of floodplains on phosphorus (P) dynamics is understudied compared to nitrogen. We examined the role of biotic and abiotic processes influencing P pools and fluxes on inset floodplains of three agricultural streams in northern Indiana. We predicted that P dynamics would be driven by both P assimilation via soil microbial activity (i.e., respiration; R) and Fe-associated sorption influencing P during soil drying and rewetting. Soil respiration was significantly different among floodplains and was correlated with soil organic matter content, linking microbial P assimilation with carbon availability. The Fe pools also varied significantly among sites, and we found that Fe and available P were significantly correlated, suggesting that Fe-associated P adsorption may vary substantially. Overall, both biotic P assimilation and a strong potential for abiotic P sorption exist in these floodplains; however, the ability of any individual floodplain to remove water column P will vary with soils and their associated physiochemical characteristics.

Matt Trentman (Primary Presenter/Author), Flathead Lake Biological Station, University of Montana, matt.trentman@flbs.umt.edu;


Jennifer L. Tank (Co-Presenter/Co-Author), University of Notre Dame, tank.1@nd.edu;


Todd V. Royer (Co-Presenter/Co-Author), Indiana University Bloomington, troyer@iu.edu;


Sara McMillan (Co-Presenter/Co-Author), Iowa State University, swmcmill@iastate.edu;


Alex Johnson (Co-Presenter/Co-Author), Purdue University, john1963@purdue.edu;


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5/21/2018  |   15:00 - 15:15   |  420 B

SHORT-TERM IMPACTS OF PHRAGMITES MANAGEMENT ON NUTRIENT RETENTION IN LAKE ERIE COASTAL MARSHES Invasive plant management is a key focus of wetland managers, and considerable resources are devoted to control of non-native Phragmites australis in many Great Lakes coastal wetlands. This study examined short-term impacts of herbicide management by comparing changes in wetland plant productivity, nutrient availability, and plant communities before and after herbicide treatment in two coastal wetlands. In the year after treatment, annual aboveground net primary production and plant nitrogen and phosphorus uptake decreased dramatically (by an average of 88%, 80% and 89% respectively; p < 0.05), and some, but not all, porewater and surface water nutrients increased significantly. Despite large reductions in Phragmites biomass following herbicide treatment, short-term floristic quality did not improve. When scaled to the area surrounding Lake Erie’s Western Basin treated with herbicide in 2012, plant nutrient uptake was reduced by 159 mt nitrogen and 24 mt phosphorus. This amount, potentially available for export to coastal waters, was small relative to average annual riverine loading but similar in magnitude to 2012 summer loading (57% of total nitrogen and 478% of SRP loading from the Maumee River). Our results highlight the trade-offs inherent in managing invasive plants.

Kristi Judd (Primary Presenter/Author), Eastern Michigan University, kjudd2@emich.edu;


Steven Francoeur (Co-Presenter/Co-Author), Eastern Michigan University, sfrancoeu@emich.edu;


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5/21/2018  |   15:15 - 15:30   |  420 B

OPENING THE BIOGEOCHEMICAL BLACK BOX: NUTRIENT REMOVAL IN A GREAT LAKES COASTAL WETLAND (OLD WOMAN CREEK, OH) AT WHOLE-ECOSYSTEM AND MECHANISTIC SCALES Wetlands, in particular along Great Lakes coasts, are valued for their nutrient removal capabilities. However, the ability to demonstrate whole-ecosystem nutrient removal by mass balance is limited in natural wetlands. In one of few remaining intact freshwater estuary wetlands along the Lake Erie coast (Old Woman Creek, Huron, OH), we calculate whole-ecosystem annual nutrient mass balance. In parallel, we assess indicators of nutrient removal processes (P fractionation, denitrification assays) in eight hydrologically and ecologically distinct zones (“ecozones”) to understand the biogeochemical mechanisms underlying whole-ecosystem accounting. For the October 2016-September 2017 water year, mass balance calculations indicate net removal of nutrient forms including total phosphorus, soluble reactive phosphorus, nitrate-nitrogen, and total kjeldahl nitrogen. The relative distribution of sediment P among chemical forms varied among ecozones, and the magnitude of easily mobilized fractions was seasonally variable. Potential denitrification was highest in vegetated ecozones with highly organic soils, and actual denitrification was highest in spring when nitrate loading was high. Continued work in future years combining whole-ecosystem monitoring with spatially resolved mechanistic studies will provide insights into how hydrologic change in Great Lakes coastal wetlands will shape their biogeochemical function.

Lauren Kinsman-Costello (Primary Presenter/Author), Kent State University, lkinsman@kent.edu;


Bree Richardson (Co-Presenter/Co-Author), Kent State University, bricha34@kent.edu;


Kristin Arend (Co-Presenter/Co-Author), Ohio Department of Natural Resources, kristin.arend@dnr.state.oh.us;


Laura Johnson (Co-Presenter/Co-Author), Heidelberg University, ljohnson@heidelberg.edu;


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