The community abundance and diversity of mRNA transcripts for sulfate-reducing prokaryotes were investigated in parallel with rate measurements of sulfate reduction activity in marine subsurface sediments of Aarhus Bay, Denmark. Solid phase and porewater chemistry and sulfate reduction rates were determined on subsamples from sediment cores to 5 m below the sediment surface. Molecular analysis of the dissimilatory (bi) sulfite reductase (dsrAB) mRNA transcripts and 16S rRNA were performed by quantitative reverse transcription real-time PCR and traditional clonal analysis. The distribution of dsrA transcripts was directly linked to both sulfate reduction rates and rRNA content. Quantitative analysis of dsrA gene transcripts indicated the presence of active sulfate reduction at 465 cm below the sediment-water interface, where high methane concentrations persist in regions of near sulfate depletion. These results suggest an abundance of active bacteria in zones of high sulfate reduction and a marked decrease in zones of low sulfate reduction rates. Archaeal communities showed a constant distribution in the sediment profile in zones of intermediate and low sulfate reduction rates, indicating their predominance in sediments where low sulfate and high methane concentrations were observed. Substantiated by biogeochemical and rRNA analysis, the analysis of mRNA gene transcripts serves as a versatile molecular proxy for the study of sulfate reducing communities in marine subsurface sediments. / A Thesis submitted to the Department of Oceanography in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester, 2009. / September 5, 2008. / PCR, Microbial Ecology, Sufate Reduction / Includes bibliographical references. / Joel E. Kostka, Professor Directing Thesis; Markus Huettel, Committee Member; Kuki Chin, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_181707 |
| Contributors | Humphrys, Michael (authoraut), Kostka, Joel E. (professor directing thesis), Huettel, Markus (committee member), Chin, Kuki (committee member), Department of Earth, Ocean and Atmospheric Sciences (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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