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Wind Cave: Direct Access to a Deep Subsurface Aquifer Reveals a Diverse Microbial Community and Unusual Manganese Metabolism

Hershey, Olivia Suzanne
http://orcid.org/0000-0002-6987-6217
http://rave.ohiolink.edu/etdc/view?acc_num=akron1637328119634443

Abstract Details

2021, Doctor of Philosophy, University of Akron, Integrated Bioscience.
Caves provide a unique environment for studying microbial ecology, providing a portal to the microbial communities of the terrestrial subsurface. Despite the geologic isolation and nutrient limitation of growth in the subsurface, caves contain remarkably diverse microbial communities, with unique adaptations that allow community subsistence and growth. At Wind Cave National Park, South Dakota, a series of lakes are formed at the intersection of Wind Cave and the regionally important Madison aquifer. These lakes (WCL), provide a rare natural window into the aquifer, and my research has demonstrated that they allow us to examine the microbial community of a karst aquifer without the sources of contamination often associated with surface drilling. Though the isolation (125 m below the surface) and long residence time (~25 years) of water en route to the lakes results in ultraoligotrophic conditions (0.29 mg L-1 TOC), the lakes support a stable and diverse community of microbes, albeit with cell numbers lower than almost any body of water on Earth (~2,300 cells mL-1). This low biomass, combined with a reduced cell size as an adaptive strategy to survival in these nutrient limited conditions, made collecting sufficient cell mass for DNA based analyses problematic. I therefore optimized the standard techniques used to sample aquatic communities, using tangential flow filtration to filter more than 1,000 L of water from the Madison aquifer, through a 45 nm-pore size membrane allowing the capture of even the smallest cells within this microbial ecosystem. Metagenomic sequencing combined with comparative filtration revealed that WCL was enriched in ultrasmall cells, such as those found in the Patescibacteria and Nitrospirota. Evidence of integron-facilitated genetic plasticity suggests that metabolic flexibility is an important mechanism for adaptation and survival in WCL. Finally, our metagenomic and phylogenetic data suggest that manganese plays a central role in primary production and carbon turnover in WCL, and that primary production in the community is based on chemolithotrophic Mn(II) oxidation. Not only could this be the first Mn(II)-based microbial community described, but may provide a unique ecosystem in which to understand the important drivers of the Mn biogeochemical cycle within the subsurface.
Hazel Barton (Advisor)
John Senko (Committee Member)
Michael Konopka (Committee Member)
Zhong-Hui Duan (Committee Member)
R. Joel Duff (Committee Member)
161 p.
Biogeochemistry; Biology; Microbiology
karst; aquifer; manganese oxidation; integrons; oligotrophic; microbial community; Wind Cave; bacteria; cave; freshwater

Recommended Citations

Citations

  • Hershey, O. S. (2021). Wind Cave: Direct Access to a Deep Subsurface Aquifer Reveals a Diverse Microbial Community and Unusual Manganese Metabolism [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1637328119634443

    APA Style (7th edition)

  • Hershey, Olivia. Wind Cave: Direct Access to a Deep Subsurface Aquifer Reveals a Diverse Microbial Community and Unusual Manganese Metabolism. 2021. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1637328119634443.

    MLA Style (8th edition)

  • Hershey, Olivia. "Wind Cave: Direct Access to a Deep Subsurface Aquifer Reveals a Diverse Microbial Community and Unusual Manganese Metabolism." Doctoral dissertation, University of Akron, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1637328119634443

    Chicago Manual of Style (17th edition)

akron1637328119634443
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This open access ETD is published by University of Akron and OhioLINK.