2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
5/23/2019 | 2:30 PM - 2:45 PM | ASSESSMENT OF THE FORMATION CRITERIA FOR HYPORHEIC ANOXIC MICROZONES WITH COMPUTATIONAL MODELING: INTERACTIONS OF HYDRAULICS, NUTRIENTS, AND BIOCLOGGING | 251 DE
ASSESSMENT OF THE FORMATION CRITERIA FOR HYPORHEIC ANOXIC MICROZONES WITH COMPUTATIONAL MODELING: INTERACTIONS OF HYDRAULICS, NUTRIENTS, AND BIOCLOGGING
Experimental studies have detected ‘microzones’ in hyporheic zones, which form as small-scale anoxic pores volumes and biofilms embedded within oxygen-rich porous media. Microzones are anaerobic reaction sites where conditions promote production of reduction compounds such as nitrous oxide, a potent greenhouse gas. Microbes are a key control on nutrient transformation within sediments, yet microbial growth is also capable of limiting hydraulic flux in sediment, leading to potential ‘bioclogging.’ These microzone processes are difficult to detect and monitor in the field. Hence, we developed one of the first computational modeling approaches that combines hydraulic and microbial conditions to explore the presence of hyporheic microzones. We used the model to explore sediment conditions with different hydraulic flux, nutrient concentrations, and bioclogging scenarios. Results indicate that microzone formation is controlled by interactions between hydraulic flux, ambient nutrient concentrations, and bioclogging, with bioclogging strongly inhibiting stable microzone formation. Bioclogging scenarios typically produced unstable microzones, which perished a few days after formation. Overall, results show that bioclogging-induced anoxic microzones are likely to form under many realistic hyporheic conditions, but their distribution and biogeochemical function will be dynamic and difficult to measure in the field.
- Biogeochemistry
- Hotspot
- Oxygen
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Presenters/Authors
Jay Zarnetske
(), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;
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Sinchan Roy Chowdhury
(), Department of Earth and Environmental Sciences, Michigan State University, USA, sinchanrc90@gmail.com;
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Mantha Phanikumar
(), Civil and Environmental Engineering, Michigan State University, phani@egr.msu.edu;
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Martin Briggs
(), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, mbriggs@usgs.gov;
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Fred Day-Lewis
(), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, daylewis@usgs.gov;
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Kamini Singha
(), Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO, USA, ksingha@mines.edu;
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