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Interactions of Greenhouse Gases, Dissolved Organic Carbon and Hydrological Regime of the Old Woman Creek wetland

Onyango, Yvette
http://rave.ohiolink.edu/etdc/view?acc_num=osu1713185443014746

Abstract Details

2024, Master of Science, Ohio State University, Civil Engineering.
Estuarine marshes occur at the interface of terrestrial riverine flows and oceans or lakes. As such, they play a crucial role in the movement, storage, and fluxes to the atmosphere, of carbon. We monitored CH4 fluxes, and the concentration of dissolved organic carbon (DOC) in the Old Woman Creek (OWC) estuary, Ohio. Gas exchange chamber measurements and sampling of surface water for DOC concentration were conducted simultaneously at three locations with distinct hydraulic characteristics: the outflow, mid-flow, and backflow areas, and at three different relative depths (deep, intermediate, and shallow) within each location. Samples were conducted monthly, over the summer and autumn of 2023 (i.e., month 1 to month last). We investigated the temporal and spatial correlation between DOC and CH4 fluxes in OWC, with a focus on the inflow dynamics from nearby rivers and the wetland’s hydrological regime. We hypothesized that the high CH4 flux levels observed in OWC are driven by the wetland’s intake of DOC, and short-term depth changes (due to barrier opening and closing) and long-term depth changes (due to changes in water levels and inundation) influences methane emissions. We found that DOC in the wetland’s inflow positively correlates with the river stage, but contrary to our initial hypothesis, elevated DOC levels within the wetland did not significantly contribute to methane emissions. However, we found that DOC concentrations varied by depth, but not temporally when other factors (temperature, depth, river stage) were considered. Spatially, the outflow area had the highest DOC concentration, with deep depths in each hydrological location exhibiting higher DOC concentrations. CH4 fluxes varied spatially, with the outflow area recording the least methane emissions, while the mid-flow area exhibited higher methane concentrations. Intermediate depths in each hydrological location recorded higher methane emissions. Interestingly, we found that long-term trends of CH4 fluxes indicated a decrease over time, potentially linked to increasing water levels in the wetland. Based on our findings, there needs to be an understanding of the complex interactions between carbon dynamics and hydrology to monitor emissions of greenhouse gases within a wetland. These relationships are significant towards the understanding of a wetland’s functioning as greenhouse gas sources and sinks, and in wetland management and conservation.
Gil Bohrer (Advisor)
Andy May (Committee Member)
James Stagge (Committee Member)
58 p.
Atmospheric Sciences; Biogeochemistry; Climate Change; Environmental Engineering; Environmental Science; Freshwater Ecology
wetland functioning systems, methane from wetlands, dissolved organic carbon, wetland hydrology influence on greenhouse gases, methanogenesis

Recommended Citations

Citations

  • Onyango, Y. (2024). Interactions of Greenhouse Gases, Dissolved Organic Carbon and Hydrological Regime of the Old Woman Creek wetland [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1713185443014746

    APA Style (7th edition)

  • Onyango, Yvette. Interactions of Greenhouse Gases, Dissolved Organic Carbon and Hydrological Regime of the Old Woman Creek wetland. 2024. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1713185443014746.

    MLA Style (8th edition)

  • Onyango, Yvette. "Interactions of Greenhouse Gases, Dissolved Organic Carbon and Hydrological Regime of the Old Woman Creek wetland." Master's thesis, Ohio State University, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=osu1713185443014746

    Chicago Manual of Style (17th edition)

osu1713185443014746
103
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This open access ETD is published by The Ohio State University and OhioLINK.