Examination of relationships between bacterial communities, urease activity, and environmental variables over space and time in Gulf of Mexico wetlands

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dc.contributor Cherry, Julia A.
dc.contributor Mortazavi, Behzad
dc.contributor Findlay, Robert H.
dc.contributor Phipps, Scott
dc.contributor.advisor Olson, Julie B.
dc.contributor.author Lee, Philip Oscar
dc.date.accessioned 2018-06-04T14:58:31Z
dc.date.available 2018-06-04T14:58:31Z
dc.date.issued 2017
dc.identifier.other u0015_0000001_0002911
dc.identifier.other Lee_alatus_0004D_13216
dc.identifier.uri http://ir.ua.edu/handle/123456789/3587
dc.description Electronic Thesis or Dissertation
dc.description.abstract Urea is an organic form of nitrogen that has seen enormous commercial growth as agricultural fertilizer. With this expansion, ecosystems such as wetlands are more likely to experience elevated concentrations of urea via runoff. Once in the environment, the enzyme urease, produced by plants, fungi, bacteria, and archaea, controls the degradation of urea. However, within wetlands, little is known about how these organisms or their urease will respond to increased urea levels. These dissertation studies were conducted in coastal wetlands along the northern Gulf of Mexico to better understand spatial and temporal patterns of bacterial communities and urease activity in wetland soils. To examine urea removal pathways, microcosm experiments found removal of urea via denitrification in wetland soils to be limited. Microcosms supplemented with urea were not capable of hydrolyzing all added urea within 5 days. A survey of wetland soils showed urease activity varied considerably over space and time, with urease rates at the intermediate site significantly lower than sites with the lowest and highest elevation. Along with the lowest urease rates, the highest concentrations of inorganic nitrogen were also measured at the intermediate site, a parameter that has previously been linked to inhibition of bacterial ureases. To explore the differences in urease activity between sampling sites, soil bacterial communities were monitored over space and time using culture independent methods. The composition of soil bacterial communities differed over space, time, and depth at the four sampling sites. Using cultivation approaches, soil ureolytic bacteria were isolated and identified as being affiliated with eight genera, all of which were prevalent in sequence libraries prepared from the four sites. As environmental urea concentrations are expected to increase in coming years, information on the distribution and activity of ureolytic bacteria will be critical to better predict the ability of affected ecosystems to manage the additional nitrogen. Furthermore, if elevated ammonium levels inhibit urease activity, the capacity of ammonium-rich wetland soils to hydrolyze additional urea may be limited.
dc.format.extent 244 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Ecology
dc.subject.other Biogeochemistry
dc.subject.other Microbiology
dc.title Examination of relationships between bacterial communities, urease activity, and environmental variables over space and time in Gulf of Mexico wetlands
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Biological Sciences
etdms.degree.discipline Biological Sciences
etdms.degree.grantor The University of Alabama
etdms.degree.level doctoral
etdms.degree.name Ph.D.


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