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Name: Personal
Name: Personal
Name: Personal
Name: Personal
Name: Personal
Name: Corporate
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Note: thesis: Thesis (Ph. D.)--Brown University, 2016
Genre (aat): theses
Abstract: Oceans cover 70% of the Earth's surface and each liter of seawater contains billions of microbes. These microbes account for most of the biomass in the oceans, driving biogeochemical cycles that govern marine food webs and the global carbon cycle. While recent advances in molecular biology have greatly increased our understanding of marine microbial assemblages, the ocean remains an undersampled and poorly understood environment. This is especially true of remote Antarctic waters where microbes reflect and influence strong seasonal, interannual and climate change-driven ecosystem variability. This research uses small subunit (SSU) rRNA gene amplicon sequencing to examine microbial diversity across different temporal and spatial scales in the coastal waters west of the Antarctic Peninsula (WAP), with a focus on phytoplankton-derived dissolved organic matter (DOM) as a driver of bacterial activity and community structure. Research findings were interpreted using ecological theory, particularly community assembly rules. A survey of microbial diversity across all three domains of life revealed similar bacterial communities in winter surface waters and summer deep waters, habitats that share the common feature of reduced light and primary production. A fine-scale analysis of WAP bacterial succession during the winter-to-summer transition found increased bacterial production, decreased richness, and changes in community composition concurrent with a major phytoplankton bloom. Expanding this analysis to multiple years suggested that interannual variability in large-scale climatic forces may indirectly structure bacterial communities through phytoplankton dynamics. DOM amendments in the form of phytoplankton exudates altered bacterial production, abundance, and community composition in mesocosm experiments, demonstrating the significance of phytoplankton-derived carbon. Likewise, DOM-rich filtered sea ice amendments enhanced bacterial production. While most results emphasized the importance of environmental forcing and niche-based processes in community assembly, priority effects were evident, suggesting that interannual variability in the timing of phytoplankton blooms is critical to bacterial community responses. This research advances our understanding of the role of bacterial communities in the WAP and informs a growing body of ecological theory pertaining to microbes.
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01239992")
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01746286")
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00864229")
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01110497")
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01753801")
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01110029")
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Identifier: DOI: 10.7301/Z0DR2SXR
Access Condition: rights statement (href="http://rightsstatements.org/vocab/InC/1.0/"): In Copyright
Access Condition: restriction on access: Collection is open for research.
Type of Resource (primo): dissertations