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Geomicrobial Investigations on Extreme Environments: Linking Geochemistry to Microbial Ecology in Terrestrial Hot Springs and Saline Lakes

Huang, Qiuyuan
http://rave.ohiolink.edu/etdc/view?acc_num=miami1399305277

Abstract Details

2014, Doctor of Philosophy, Miami University, Geology and Environmental Earth Science.
Terrestrial hot springs and saline lakes represent two extreme environments for microbial life and constitute an important part of global ecosystems that affect the biogeochemical cycling of life-essential elements. Despite the advances in our understanding of microbial ecology in the past decade, important questions remain regarding the link between microbial diversity and geochemical factors under these extreme conditions. This dissertation first investigates a series of hot springs with wide ranges of temperature (26-92oC) and pH (3.72-8.2) from the Tibetan Plateau in China and the Philippines. Within each region, microbial diversity and geochemical conditions were studied using an integrated approach with 16S rRNA molecular phylogeny and a suite of geochemical analyses. In Tibetan springs, the microbial community was dominated by archaeal phylum Thaumarchaeota and four bacterial phyla (Firmicutes, Proteobacteria, Cyanobacteria, Chloroflexi). In the Philippines hot springs, the archaeal community mainly consisted of phyla Crenarchaeota, Euryarchaeota, and unclassified Archaea, while the bacterial community was predominated by phyla Aquificae and Firmicutes. Sulfur metabolisms appear to be key physiological functions in these hot springs. Saline lake on high elevation represents another extreme environment where various microorganisms thrive. In this study, the taxonomic and functional diversity of the microbial community in a saline lake (Qinghai Lake, China) was characterized using metagenomes and metatranscriptomes techniques. Metagenomic data showed that microbial communities in two water columns of Qinghai Lake were mainly dominated by Bacteria (mainly phyla Cyanobacteria, Proteobacteria, Verrucomicrobia, Actinobacteria, etc), while metatranscriptomics was performed to study the functional gene expression in elemental cycles (e.g., carbon and nitrogen cycles). Lastly, an artificial extreme environment was studied, where trichloroethylene (TCE) in bedrock aquifer was a major contaminant. In situ chemical oxidation (ISCO) was a commonly used strategy to oxidize TCE, but how strong oxidants such as permanganate diffuses into solid rocks and its interaction with rock matrices remain poorly known. A series of diffusion experiments were conducted that measured the permanganate diffusion and reaction in four different types of sedimentary rocks (dark gray mudstone, light gray mudstone, red sandstone, and tan sandstone). Various Mn minerals formed as surface coatings as a result of the permanganate reduction coupled with total organic carbon (TOC) oxidation, and the extent of permanganate diffusion and reaction depended on rock properties.
Hailiang Dong (Advisor)
147 p.
Geobiology; Geochemistry
Biodiversity; hot springs; saline lakes; permanganate

Recommended Citations

Citations

  • Huang, Q. (2014). Geomicrobial Investigations on Extreme Environments: Linking Geochemistry to Microbial Ecology in Terrestrial Hot Springs and Saline Lakes [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1399305277

    APA Style (7th edition)

  • Huang, Qiuyuan. Geomicrobial Investigations on Extreme Environments: Linking Geochemistry to Microbial Ecology in Terrestrial Hot Springs and Saline Lakes . 2014. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1399305277.

    MLA Style (8th edition)

  • Huang, Qiuyuan. "Geomicrobial Investigations on Extreme Environments: Linking Geochemistry to Microbial Ecology in Terrestrial Hot Springs and Saline Lakes ." Doctoral dissertation, Miami University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1399305277

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Miami University and OhioLINK.