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Relating spatial patterns of denitrification and bacterial community structure to environmental conditions in streams

Baxter, Alyssa M.
http://rave.ohiolink.edu/etdc/view?acc_num=kent1285447715

Abstract Details

2010, MS, Kent State University, College of Arts and Sciences / Department of Biological Sciences.
Land use is a key factor influencing the health of a stream. Agricultural land use, in particular, can have detrimental effects on water quality, habitat, and biological assemblages. Artificially high nitrogen loading from fertilizer runoff can lead to eutrophic conditions in affected streams, and may significantly alter the composition of aquatic vertebrate, invertebrate and microbial communities. In this study, six streams of varying land use type (three impacted by high intensity agriculture and three in mixed-use watersheds) in Indiana and Ohio were sampled in summer and fall for a variety of chemical, physical and biotic factors. Nested ANOVAs determined differences in these factors longitudinally within each stream, and subsequent one-way ANOVAs determined significant differences in these factors based on season and land use type. The abundance and diversity of the whole bacterial community and the denitrifying community were examined using quantitative PCR and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA gene (all bacteria) and the nosZ gene (specific to denitrifiers). Detrended canonical correspondence analysis and multiple linear regression were used to elicit possible predictive relationships between various factors and denitrification rate and denitrifier abundance. Streams impacted by high intensity agriculture were found to have significantly higher nitrate, soluble reactive phosphorus and dissolved oxygen concentrations than mixed-use streams during both seasons. These streams also contained a significantly higher proportion of pollution tolerant macroinvertebrate taxa. Mixed-use streams had significantly higher dissolved organic carbon concentrations and higher total bacterial abundances than agricultural streams. Multivariate analyses suggested nitrate concentration was an important predictor variable for both denitrification rate and denitrifier abundance. Denitrification rates and denitrifier abundance were significantly higher in agricultural streams than mixed-use streams, and generally higher in summer than fall. Redundancy analysis of T-RFLP data suggested that a larger portion of the variation among stream bacterial communities was explained when streams of differing land use type were compared. Overall, the data suggested possible relationships between denitrifier community abundance, diversity, and function, as well as the possibility to predict stream denitrification rates using chemical, physical and community factors.
Laura Leff, PhD (Advisor)
Ferenc De Szalay, PhD (Committee Member)
Darren Bade, PhD (Committee Member)
151 p.
Ecology; Environmental Science; Microbiology; Molecular Biology
denitrification; bacteria; bacterial community structure; TRFLP; nosZ; bacterial abundance; stream; land use; agriculture; macroinvertebrate; nitrogen

Recommended Citations

Citations

  • Baxter, A. M. (2010). Relating spatial patterns of denitrification and bacterial community structure to environmental conditions in streams [Master's thesis, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1285447715

    APA Style (7th edition)

  • Baxter, Alyssa. Relating spatial patterns of denitrification and bacterial community structure to environmental conditions in streams. 2010. Kent State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1285447715.

    MLA Style (8th edition)

  • Baxter, Alyssa. "Relating spatial patterns of denitrification and bacterial community structure to environmental conditions in streams." Master's thesis, Kent State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1285447715

    Chicago Manual of Style (17th edition)

kent1285447715
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© 2010, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.