2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
6/06/2017 | 12:00 PM - 12:15 PM | TOWARDS PREDICTING SPATIAL VARIATION IN NITRATE RETENTION AND DENITRIFICATION AT THE GROUNDWATER-SURFACE WATER INTERFACE IN SANDY STREAMS | 306A
TOWARDS PREDICTING SPATIAL VARIATION IN NITRATE RETENTION AND DENITRIFICATION AT THE GROUNDWATER-SURFACE WATER INTERFACE IN SANDY STREAMS
Groundwater-surface water ecotones present opportunities for nitrate retention because changes in organic carbon availability, redox potential and nitrate demand often occur at these locations. We identified spatial variation in nitrate retention and denitrification in shallow groundwater associated with sandy streams in Wisconsin, towards the ultimate goal of predicting the locations of nitrate removal. We hypothesized that groundwater nitrate removal would be optimized at intermediate rates of groundwater discharge, where microbes are exposed to suitable redox conditions for nitrate reduction and where groundwater delivers a moderate supply of nitrate to reaction sites. Three study streams were chosen that spanned an order of magnitude in groundwater nitrate concentration (2 to 20 mg NO3-N/L). Groundwater discharge was estimated by applying Darcy’s Law to standard measurements at piezometer locations. Nitrate and N2 concentrations were measured at discrete points along 60 cm groundwater flow paths using MINIPOINT samplers. Nitrate retention and denitrification (MIMS) were quantified by determining how nitrate and N2 fluxes changed along the flow paths. Nitrate retention and denitrification rates were nonlinearly related to DO concentration and groundwater discharge rate but patterns were site-specific.
- C14 Hydroecology
- C36 Water Resource Management
- C10 Biogeochemistry
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Presenters/Authors
Robert Stelzer
(), Department of Biology, University of Wisconsin Oshkosh, stelzer@uwosh.edu;
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Thad Scott
(), Baylor University, Thad_Scott@baylor.edu ;
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