Biology Ph.D. Dissertations

Analysis and Characterization of Microbes from Ancient Glacial Ice

Date of Award

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biological Sciences

First Advisor

Scott Rogers

Second Advisor

Kurt Panter (Committee Chair)

Third Advisor

Carmen Fioravanti (Committee Member)

Fourth Advisor

Vipaporn Phuntumart (Committee Member)

Fifth Advisor

John Castello (Committee Member)

Abstract

The objective of this research was to study the bacterial and fungal composition of icecores from Arctic and the Antarctic regions to understand their geographical and temporal distribution. Cosmopolitan microbes dominate these environments and have been deposited primarily by winds, birds, Ocean currents and mammals. Atmospheric currents play a significant role in the transport of these microorganisms to the polar regions. We hypothesize that the geographical isolation of the Antarctic region from other land masses, compared to the Arctic region, affects the transport of the microorganisms to the Antarctic region, resulting in lower number of microbes entrapped in the Antarctic ice. Four ice cores each were analysed from the Arctic (GISP2D core) and the Antarctic (Vostok 5G core) regions dating back to 10,000 YBP, 57,000 YBP, 105,000 YBP and 155,000 YBP using culturing, PCR, sequencing and SEM techniques. We report the isolation of fungi and bacteria from six of the eight ice cores analysed. Fungi most closely related to Rhodotorula, Penicillium, Cladosporium, Alternaria, Aspergillus and Cryptococcus, and bacteria related to Caulobacter and Bacillus were identified. The ice cores from Arctic had higher number of microorganisms and species richness than the core sections from the Antarctic region. Phylogenetic studies were done to compare the organisms with one another and also with the conspecifics. Some sequences showed high similarity to contemporary species, while some did not group closely with the present day organisms. Fungi isolated from the different locations, and closely related to the same genus, did not show high similarity with one another.

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