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Publication Date


Document Type

Honors Project


Biological Sciences


Microbial diversity, Biology, Biogeochemistry, Biogeography, Sulfur bacteria, Biosphere


Beaver ponds act as mercury sinks, exhibiting favorable conditions for the production of neurotoxic methylmercury by sulfate reducing bacteria (SRBs), a group of bacteria that are characterized by function (sulfate reduction) rather than phylogeny. This study was conducted to determine the composition and spatial divergence of SRB communities inhabiting microenvironments at the sediment-water interface in three beaver ponds. These ponds are part of Avery Brook, a stream lying within a 756- hectare watershed in West Whately, Massachusetts, USA. SRB communities of Avery Brook have been analyzed using traditional PCR, clone and sequence and denaturing gradient gel electrophoresis (DGGE), a technique that generates a genetic "fingerprint," of each site sampled, which allows for the comparison of community profiles. The results indicate spatial divergence between different ponds, as well as a few shared (core) lineages among all sampled ponds. Many novel, or previously uncharacterized, lineages are present in these ponds. These data suggest that biogeochemical fluctuation in beaver ponds and the heterogeneity of the sampled soil environment result in a complex SRB community structure.




51 p. : ill. (some col.) Honors project, Smith College, 2013. Includes bibliographical references (p. 48-51)