Microbial Communities Associated with Phosphoclast-bearing Sediments of the Benguela Upwelling Zone
2016-09
Loading...
View/Download File
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
Microbial Communities Associated with Phosphoclast-bearing Sediments of the Benguela Upwelling Zone
Authors
Published Date
2016-09
Publisher
Type
Thesis or Dissertation
Abstract
Phosphorus is a limiting nutrient in the environment and is an important component of many biological molecules. Calcium phosphate mineral deposits, known as phosphorites, are also the primary source of P for agriculture. Understanding phosphorite formation may improve management of P resources. However, the processes that mediate calcium phosphate mineral precipitation in certain marine pore waters remain poorly understood. Phosphogenesis occurs in sediments beneath some oceanic upwelling zones that harbor polyphosphate-accumulating giant sulfur bacteria (GSB). These bacteria may concentrate phosphate in sediment pore waters, creating supersaturated conditions with respect to apatite. However, the relationship between microbes and phosphogenesis is not fully resolved. To further study this relationship, we examined microbial communities from two sources: sediment cores recovered from the shelf of the Benguela region, and DNA extracted from washed phosphoclasts recovered from those same sediments. We used iTag and clone library sequencing of the 16S rRNA gene to examine the microbial communities and their relationship with the environment. We found that many of our sediments shared large numbers of phylotypes with one another, and that the same metabolic guilds were represented at localities across the shelf. Sulfur-reducing bacteria and sulfur-oxidizing bacteria were abundant in our datasets. Phylotypes that are known to carry out nitrification and/or anammox (anaerobic ammonia oxidation) were also well-represented. Our phosphoclast extraction, however, contained a distinct microbial community from those observed in the modern sediments. We observed both an enrichment of certain common microbial classes and a complete absence of others. These results could represent an ancient microbial assemblage that was present when the apatite precipitated. While these taxa may or may not have contributed to apatite precipitation, several groups represented in the phosphoclast dataset have the genetic potential, as determined through the analysis of published genomes, to synthesize, and perhaps accumulate, polyphosphate.
Keywords
Description
University of Minnesota M.S. thesis. September 2016. Major: Earth Sciences. Advisor: Jake Bailey. 1 computer file (PDF); vi, 51 pages.
Related to
Replaces
License
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Suggested citation
Zoss, Roman. (2016). Microbial Communities Associated with Phosphoclast-bearing Sediments of the Benguela Upwelling Zone. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/183282.
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.