Sunday, May 22, 2016
10:30 - 12:00

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10:30 - 10:45: / 308 DOES COMPLIANCE WITH THE BRAZILIAN FOREST CODE MITIGATE THE IMPACTS OF SUGARCANE AGRICULTURE AND ITS LEGACY ON INSTREAM NUTRIENT CONCENTRATIONS IN BRAZIL?

5/22/2016  |   10:30 - 10:45   |  308

DOES COMPLIANCE WITH THE BRAZILIAN FOREST CODE MITIGATE THE IMPACTS OF SUGARCANE AGRICULTURE AND ITS LEGACY ON INSTREAM NUTRIENT CONCENTRATIONS IN BRAZIL? Recent expansion of forest cover embedded within an agricultural landscape in the Atlantic forest region in Brazil provides unique opportunity to test the effectiveness of the Brazilian Forest Code that, among other objectives, aims at protecting Brazilian waters with riparian buffers. I hypothesized that concentrations of N and P in streams draining long-term sugarcane agriculture are high relative to those of least-disturbed streams, but the concentration levels depend on the percentage sugarcane cover and its legacy, and on the compliance with the law (re-establishment of forests within rural properties). The results show that instream concentrations of N and P can be as high as in the temperate zone ([TN]max=5.9 mgN.L-1; [TP]max=0.7 mgP.L-1). There was little evidence that the compliance with the law controlled the extent to which sugarcane agriculture affects instream N and P concentrations. Nutrient concentrations were more related to legacy (land use in 1962) than to contemporary land uses. These results are relevant to management of riverine ecosystems draining sugarcane agriculture in Brazil because land managers assume that stream water quality can be secured via riparian forest restoration.

Maíra Bezerra (Primary Presenter/Author), University of Maryland, mbezerra@umd.edu;


Solange Filoso ( Co-Presenter/Co-Author), University of Maryland Center for Environmental Sciences, filoso@umces.edu;


Margaret Palmer ( Co-Presenter/Co-Author), National Socio-Environmental Synthesis Center, mpalmer@sesync.org;


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10:45 - 11:00: / 308 LINKING AGRICULTURAL CONSERVATION EFFORT TO WATER QUALITY IN THE INDIAN CREEK WATERSHED

5/22/2016  |   10:45 - 11:00   |  308

LINKING AGRICULTURAL CONSERVATION EFFORT TO WATER QUALITY IN THE INDIAN CREEK WATERSHED We used water quality data from the Indian Creek Watershed (IL) to explore whether enrollment of >50% of the watershed land area in agricultural conservation practices has influenced nutrient loading over 6 years. We analyzed nitrate data from grab samples collected at 5 sites across the watershed from 2010-2015, and high-frequency data from a nitrate sensor deployed at the watershed outlet from 2012-2015. Surface water nitrate concentrations and export depended on discharge, and up to 80% of export occurred during large storms. High resolution data from nitrate sensors, during both low and high flow conditions, significantly improved watershed load estimation. Load estimates based on grab samples suggested that nitrate export was lowest during the 2012 drought, then increased progressively due to increasing discharge from 2013-2015. In contrast, continuous sensor data showed a decline in watershed nitrate export from 2013-2015. The signature of conservation practices on reduced nitrate export was difficult to detect, possibly due to limited site-specific conservation data. Nevertheless, this analysis provides a framework for future monitoring to detect changes over time, and with varying climatic conditions.

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


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


Steve Powers ( Co-Presenter/Co-Author), Washington State University, st3powers@gmail.com;


Matt T. Trentman ( Co-Presenter/Co-Author), University of Notre Dame, mtrentma@nd.edu;


Erik Maag ( Co-Presenter/Co-Author), University of Notre Dame, emaag1@nd.edu;


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11:00 - 11:15: / 308 DOES PHOSPHORUS FROM AGRICULTURAL TILE DRAINS FUEL ALGAL BLOOMS?

5/22/2016  |   11:00 - 11:15   |  308

DOES PHOSPHORUS FROM AGRICULTURAL TILE DRAINS FUEL ALGAL BLOOMS? Phosphorus (P) is often implicated as a contributing factor to algal blooms. Attention has been focused on P coming from surface runoff, but tile drains also can be a source, especially in agricultural areas in the US Midwest. Lake Macatawa is a hypereutrophic, drowned river mouth lake located in west Michigan. The watershed is dominated by row crop agriculture, and further research is needed to understand the influence of bioavailable P originating from tile drains. I sampled tile drain effluent monthly 1) to measure total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations and 2) conduct bioassays to determine the effect of tile drain P on algal growth and community structure. During March – December 2015, TP concentrations ranged from 10-560 µg/L, and SRP ranged from 5-447 µg/L. Four of six bioassays resulted in a positive relationship between SRP and algal growth, but results from only one bioassay were statistically significant. There was a clear change in the algal community structure, but dominance was by diatoms, not cyanobacteria. Results will inform an ongoing restoration project in the Macatawa Watershed.

Delilah Clement (Primary Presenter/Author), Grand Valley State University - Annis Water Resources Institute, clemedel@mail.gvsu.edu;


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


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11:15 - 11:30: / 308 EXPOSURE OF AQUATIC MACROINVERTEBRATES TO GENETICALLY MODIFIED CORN DEBRIS IN AN AGRICULTURAL STREAM

5/22/2016  |   11:15 - 11:30   |  308

EXPOSURE OF AQUATIC MACROINVERTEBRATES TO GENETICALLY MODIFIED CORN DEBRIS IN AN AGRICULTURAL STREAM Transgenic Bt corn debris containing endotoxic Cry proteins enter streams and may impact aquatic communities. Risk of environmental damage involves both exposure and harmful effects. Here, we asked: 1) do Cry proteins persist in corn debris after exposure to streams; 2) do Bt and non-Bt debris decompose equally; and 3) are Bt and non-Bt debris colonized equally by stream macroinvertebrates? We deployed leafpacks containing Bt and non-Bt debris in a small agricultural Maryland stream. Macroinvertebrate colonization and community metrics were compared between Bt and non-Bt varieties. Leaf degradation rates were determined from ash-free dry mass and Cry protein degradation rates from qualitative and quantitative ELISA. ELISA results indicated that aquatic communities are exposed to Cry proteins via Bt leaf debris, with all samples testing positive for Cry2A through week 12 and 15 of 17 samples testing positive for Cry1F and Cry34Ab1. We found no significant difference in colonization and community metrics nor leaf decomposition rates between Bt and non-Bt corn debris. Exposure is likely; our current research focuses on non-target effects.

Claire Hirt (Primary Presenter/Author), University of Maryland, ccregan@umd.edu;


William Lamp ( Co-Presenter/Co-Author), University of Maryland, lamp@umd.edu;


Raina Kaji ( Co-Presenter/Co-Author), University of Maryland, rainakaji@gmail.com;


Alison Post ( Co-Presenter/Co-Author), University of Maryland, akpost@comcast.net;


Galen Dively ( Co-Presenter/Co-Author), University of Maryland, galen@umd.edu;


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11:30 - 11:45: / 308 THE INTERACTION BETWEEN FLOODPLAIN RESTORATION AND CHANGING LAND COVER ON STREAM METABOLISM IN A MIDWESTERN AGRICULTURAL STREAM

5/22/2016  |   11:30 - 11:45   |  308

THE INTERACTION BETWEEN FLOODPLAIN RESTORATION AND CHANGING LAND COVER ON STREAM METABOLISM IN A MIDWESTERN AGRICULTURAL STREAM The restoration of small floodplains in formerly-channelized, agricultural streams can reduce water column turbidity during high flows (i.e. spring snowmelt and storms). Similarly, the planting of winter cover crops on bare, agricultural fields in the post-harvest period has the potential to reduce turbidity by decreasing soil erosion. Previous work in the Shatto Ditch Watershed (SDW; Kosciusko Co, IN) has shown that floodplain restoration via the two-stage ditch (0.6 km length) can significantly increase gross primary production (GPP) via increased water clarity during high flows. Subsequent implementation of watershed-scale cover crops in SDW may further reduce suspended sediments, yet its effect on stream metabolism remains unexplored. We measured daily stream metabolism from Spring 2013-Summer 2015 in order to examine the combined influence of cover crop planting and floodplain restoration on metabolism in SDW. We found that GPP was generally higher in the two-stage reach relative to the upstream control, particularly in Spring/Summer. We place these new data into context by comparing results to the previous 4-yr dataset (2007-2011) that captured changes in metabolism pre/post two-stage implementation, prior to cover crop planting.

Matt T. Trentman (Primary Presenter/Author), University of Notre Dame, mtrentma@nd.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;


Rob Davis ( Co-Presenter/Co-Author), White Rock Conservancy, davis.t.rob@gmail.com;


Kara Prior ( Co-Presenter/Co-Author), Indiana University, kprior@indiana.edu;


Sarah Roley ( Co-Presenter/Co-Author), Washington State University Tri Cities, roleysar@msu.edu ;


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


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11:45 - 12:00: / 308 VEGETATION AND CHANNEL GEOMORPHIC COMPLEXITY IN AGRICULTURAL WATERWAYS: IMPLICATIONS FOR WATER QUALITY

5/22/2016  |   11:45 - 12:00   |  308

VEGETATION AND CHANNEL GEOMORPHIC COMPLEXITY IN AGRICULTURAL WATERWAYS: IMPLICATIONS FOR WATER QUALITY Conventionally-managed agricultural waterways in California’s Central Valley transport typically poor-quality field drainage to sensitive ecosystems and groundwater recharge areas. This research asks whether riparian and channel geomorphic management can affect plant-soil-water interactions in agricultural waterways to enhance water quality. A survey of 80 sites investigated nitrate, turbidity, pH and temperature levels in waterways draining irrigated cropland throughout summer 2014. Sites were selected to represent a wide range of riparian vegetation, hydrogeomorphic features, and agricultural contexts. Using linear mixed-effects models, we tested for the interaction of upstream water quality with indices of vegetation and geomorphic complexity in an effort to predict downstream water quality. Upstream nitrate concentrations generally interacted with geomorphic complexity indices to predict downstream nitrate concentrations. Upstream turbidity levels, in contrast, interacted with vegetation complexity indices to predict downstream turbidity. Temperature and pH did not significantly interact with any indices. These findings suggest that managing agricultural waterways to increase geomorphic and vegetation complexity may enhance water quality; exact recommendations may depend on the specific water quality concern.

Alex Webster (Primary Presenter/Author), University of California Davis, ajwebster@ucdavis.edu;


Mary Cadenasso ( Co-Presenter/Co-Author), University of California, Davis, mlcadenasso@ucdavis.edu;


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