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Symbiotic Diversity and Mineral-Associated Microbial Ecology in Marine Microbiomes

Citation

Metcalfe, Kyle Shuhert (2020) Symbiotic Diversity and Mineral-Associated Microbial Ecology in Marine Microbiomes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ve4r-k526. https://resolver.caltech.edu/CaltechTHESIS:08122020-110818529

Abstract

This thesis investigates ecological interactions in the seafloor between microbial taxa (Chapters 1 and 2) and between these microorganisms and their mineral hosts (Chapters 2 through 4). In seafloor sediments, electron acceptors are often limited, forcing microorganisms inhabiting these sediments to acquire symbiotic partners and/or perform extracellular electron transfer to insoluble electron acceptors. Seafloor methane seeps present an endmember case wherein extremely reducing fluids charged with methane advect through sediment. In these benthic ecosystems, anaerobic methanotrophic archaea (ANME) form symbiotic partnerships with sulfate-reducing bacteria (SRB), but it remained unclear if certain ANME exhibit a preference for certain SRB partners. In Chapter 1, I present results documenting such a pattern of partnership specificity in ANME-SRB consortia. In Chapter 2, I further examine these patterns in rare ANME taxa through development and application of a density-separation protocol refined from published work. This protocol exploits the co-association of microbial taxa on mineral surfaces to aid in the detection of novel symbioses, and further is useful to detect microbial interactions with certain minerals. In Chapter 3, I focus on the interaction between ANME-SRB consortia and authigenic silicates that have been observed on consortium exteriors, finding evidence to support that the precipitation of these silicates is actively mediated by ANME-SRB. In Chapter 4, I perform geochemical modeling benchmarked by synchrotron X-ray analysis to examine the imprint of extracellular electron transport by metal-reducing microorganisms on Precambrian manganese-rich sedimentary rocks.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Microbial symbiosis; Microbial ecology; Diazotrophy; nanoSIMS; FISH; Anaerobic oxidation of methane; Biomineralization; Manganese
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geobiology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Orphan, Victoria J.
Thesis Committee:
  • Leadbetter, Jared R. (chair)
  • Fischer, Woodward W.
  • Rossman, George Robert
  • Orphan, Victoria J.
Defense Date:3 August 2020
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
United States Science Support Program Schlanger FellowshipUNSPECIFIED
Record Number:CaltechTHESIS:08122020-110818529
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:08122020-110818529
DOI:10.7907/ve4r-k526
Related URLs:
URLURL TypeDescription
https://doi.org/10.1101/2020.04.12.038331DOIArticle adapted for Ch. 1
ORCID:
AuthorORCID
Metcalfe, Kyle Shuhert0000-0002-2963-765X
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13854
Collection:CaltechTHESIS
Deposited By: Kyle Metcalfe
Deposited On:28 Aug 2020 19:40
Last Modified:01 Mar 2021 17:52

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PDF (Full Dissertation) - Final Version
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PDF (Introduction) - Final Version
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PDF (Chapter 1) - Final Version
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PDF (Chapter 2) - Final Version
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PDF (Chapter 3) - Final Version
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PDF (Chapter 4) - Final Version
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PDF (Appendix A) - Final Version
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