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Sediment nutrient dynamics in Fondriest agricultural settling pond

Bezold, Marie Grace
http://rave.ohiolink.edu/etdc/view?acc_num=wright1622555814026793

Abstract Details

2021, Master of Science (MS), Wright State University, Earth and Environmental Sciences.
Excess loading of nitrogen (N) and phosphorus (P) is a serious global problem and has numerous negative impacts on water quality of aquatic ecosystems including eutrophication, harmful algal blooms, and hypoxia. Anthropogenic activities (such as the Haber-Bosch process, burning of fossil fuels, sewage treatment, and manure reuse) have led to excess N loading to aquatic systems. Sediment N dynamics were examined from Oct 2019 – Oct 2020 in an agricultural settling pond connected to a constructed wetland adjacent to an agricultural field. Intact sediment cores were amended with 15N for continuous-flow incubations to measure denitrification and N fixation rates, as well as net nutrient and oxygen fluxes. Net N2 consumption (N fixation > denitrification) was observed over most of the year, suggesting that pond sediments were a net N source. Denitrification was stimulated when 15N-nitrate was added, and net denitrification was observed following a N fertilizer application in May 2020. NOx entering the wetland and settling pond was rapidly transformed or assimilated. However, during winter and following fertilizer application, ambient NOx concentrations increased in the wetland, but remained lower in the settling pond, suggesting rapid N removal in the pond. Sediment oxygen demand and potential denitrification rates increased in warmer months, suggesting greater microbial activity and organic matter decomposition. Settling ponds in agricultural settings thus have the potential to supplement agricultural nutrient control practices. Further research should focus on understanding the frequency, timing, and amount of N loading that enters field-adjacent wetlands and ponds to determine if the sediments will consistently function as a net N sink and to maximize denitrification efficiency.
Silvia E. Newell, Ph.D. (Advisor)
Mark J. McCarthy, Ph.D. (Committee Member)
Rebecca E. Teed, Ph.D. (Committee Member)
96 p.
Biogeochemistry; Environmental Science
nitrogen; nutrient dynamics; settling pond; agriculture; nitrogen cycle; denitrification

Recommended Citations

Citations

  • Bezold, M. G. (2021). Sediment nutrient dynamics in Fondriest agricultural settling pond [Master's thesis, Wright State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=wright1622555814026793

    APA Style (7th edition)

  • Bezold, Marie. Sediment nutrient dynamics in Fondriest agricultural settling pond. 2021. Wright State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=wright1622555814026793.

    MLA Style (8th edition)

  • Bezold, Marie. "Sediment nutrient dynamics in Fondriest agricultural settling pond." Master's thesis, Wright State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1622555814026793

    Chicago Manual of Style (17th edition)

wright1622555814026793
702
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This open access ETD is published by Wright State University and OhioLINK.