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RELATING DENITRIFIER COMMUNITY COMPOSITION TO FUNCTION IN FRESHWATER WETLANDS: THE INFLUENCE OF HYDROLOGY AND INTRASPECIFIC FUNCTIONAL VARIATION

Brower, Sarah Curran
http://rave.ohiolink.edu/etdc/view?acc_num=kent1385384882

Abstract Details

2013, MS, Kent State University, College of Arts and Sciences / Department of Biological Sciences.
Wetland denitrification provides an ecosystem service by removing excess bioavailable N but also exacts a cost by producing N2O, a gas that has a global warming potential about 310 times that of CO2. Wetland hydrology is a key factor regulating denitrification rates, nitrous oxide production and the microbial communities that carry out these functions. However, it is not clear how different hydrologic regimes influence denitrifier communities and function. In this study, we used constructed freshwater wetlands with adjustable water inflow and outflow to examine the effects of short-term flood-pulsing and long-term hydrologic regimes on denitrification, N2O production, and bacterial and denitrifier community structure. We measured denitrification and N2O production using an in situ chamber method that preserves soil microsites, and used terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rDNA and nitrous oxide reductase genes (nosZ) to track changes in bacterial and denitrifier community composition. We hypothesized that short-term water draw downs would result in changes in denitrification rate and N2O production with no corresponding change in denitrifier community composition, but that soils differing in long-term hydrologic regimes would harbor different denitrifier communities and differ in denitrification rate and N2O production. We found that long-term hydrologic conditions are important for structuring denitrifying community composition, and that denitrifying communities are more sensitive to hydrology than the overall bacterial community. While short-term hydrologic changes may determine long-term hydrological patterns, we did not observe immediate shifts in community composition after short-term water draw downs. Short-term hydrologic changes did affect denitrification rate in some cases, and not surprisingly, were higher in treatments with higher water level or percent moisture. While denitrification and N2O emission rates were largely unaffected by hydrological treatment, the relative rate of N2O production was higher in treatments with more dynamic hydrology, implying that more dynamic systems may contribute more to N2O production. Despite differences in both denitrifying community composition and rN2O in relation to hydrology, rN2O was not correlated to denitrifier community composition, supporting the idea of functional redundancy among denitrifying communities.
Mou Xiaozhen (Advisor)
Laura Leff (Advisor)
Ferenc DeSzalay (Committee Member)
119 p.
Biology; Ecology; Microbiology
Denitrification, hydrology, wetlands, microbial community composition

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Citations

  • Brower, S. C. (2013). RELATING DENITRIFIER COMMUNITY COMPOSITION TO FUNCTION IN FRESHWATER WETLANDS: THE INFLUENCE OF HYDROLOGY AND INTRASPECIFIC FUNCTIONAL VARIATION [Master's thesis, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1385384882

    APA Style (7th edition)

  • Brower, Sarah. RELATING DENITRIFIER COMMUNITY COMPOSITION TO FUNCTION IN FRESHWATER WETLANDS: THE INFLUENCE OF HYDROLOGY AND INTRASPECIFIC FUNCTIONAL VARIATION. 2013. Kent State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1385384882.

    MLA Style (8th edition)

  • Brower, Sarah. "RELATING DENITRIFIER COMMUNITY COMPOSITION TO FUNCTION IN FRESHWATER WETLANDS: THE INFLUENCE OF HYDROLOGY AND INTRASPECIFIC FUNCTIONAL VARIATION." Master's thesis, Kent State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1385384882

    Chicago Manual of Style (17th edition)

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© 2013, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.