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Isolation of Bacteria and Fungi from Lake Vostok Accretion Ice

D'Elia, Tom V.

Abstract Details

2008, Doctor of Philosophy (Ph.D.), Bowling Green State University, Biological Sciences.
Lake Vostok, located below the 4000 m thick Antarctic Ice Sheet, is the largest subglacial lake in Antarctica. The lake water has not been sampled due to concerns of forward contamination. However, ice cores available from the Vostok 5G well of depths greater than 3538 m represent lake water that has accreted to the overhead glacier from various regions across Lake Vostok. Here, we report the characterization of bacteria and fungi from ten accretion ice sections (15,000 to 18,000 years old), and two deep glacial ice sections (1 to 2 million years old) from the Vostok, Antarctica 5G ice core. Fungi, as well as bacteria, were characterized by fluorescence microscopy, scanning electron microscopy, culturing, and sequence analyses of ribosomal DNA. A total of 703 bacteria and fungi were cultured from the accretion ice of subglacial Lake Vostok. Mean cell concentrations were from 2.3 to 12.3 cells per ml of ice meltwater, of which 5 to 84% were viable. These cell counts are substantially lower than previously reported values. A total of 54 unique ribosomal DNA sequences were determined and compared to recent taxa, of which 36 were fungi and 18 were bacteria. Fungi most closely related to Rhodotorula, Aureobasidium, Cryptococcus, Cladosporium and Penicillium, and bacteria related to Carnobacterium spp., Bacillus spp., Caulobacter and Micrococcus were identified based on sequence analysis from cultured isolates. These findings, plus tests for growth at low temperatures, indicate that Lake Vostok contains a mixture of heterotrophic psychrotolerant and psychrophilic species. The results revealed new genera of microorganisms not previously reported in Lake Vostok accretion ice, lower abundances of microorganisms, and demonstrated the necessity to use multiple methods to thoroughly characterize environmental ice.
Scott Rogers, PhD (Advisor)
George Bullerjahn, PhD (Committee Member)
R. Michael McKay, PhD (Committee Member)
Paul Morris, PhD (Committee Member)
127 p.

Recommended Citations

Citations

  • D'Elia, T. V. (2008). Isolation of Bacteria and Fungi from Lake Vostok Accretion Ice [Doctoral dissertation, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1224865593

    APA Style (7th edition)

  • D'Elia, Tom. Isolation of Bacteria and Fungi from Lake Vostok Accretion Ice. 2008. Bowling Green State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1224865593.

    MLA Style (8th edition)

  • D'Elia, Tom. "Isolation of Bacteria and Fungi from Lake Vostok Accretion Ice." Doctoral dissertation, Bowling Green State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1224865593

    Chicago Manual of Style (17th edition)