عنوان

A Combined Microbiome and Geochemical Approach, Assessing Drivers of Microbial Diversity, Distribution and Activity

Number

TL55600

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

A Combined Microbiome and Geochemical Approach, Assessing Drivers of Microbial Diversity, Distribution and Activity

General Material Designation

[Thesis]

First Statement of Responsibility

Howells, Alta Emily Gessner

Subsequent Statement of Responsibility

Shock, Everett

Name of Publisher, Distributor, etc.

Arizona State University

Date of Publication, Distribution, etc.

2020

Text of Note

250 p.

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Arizona State University

Text preceding or following the note

2020

Text of Note

Evaluations of chemical energy supplies for redox reactions used by chemotrophs in water-rock hosted ecosystems are often done separately from evaluations of chemotroph diversity. However, given that energy is a fundamental and unifying parameter for life, much can be gained by evaluating chemical energy as an ecological parameter of water-rock hosted ecosystems. Therefore, I developed an approach that combines evaluation of chemical energy supplies with 16S and 18S rRNA gene amplicon sequencing. I used this approach to assess drivers of microbial distribution, diversity and activity in serpentinized fluids of the Samail Ophiolite of Oman and in hot springs in Yellowstone National Park. Through the application of the approach, microbiological interactions in serpentinized fluids were found to be more complex than anticipated. Serpentinized fluids are hyperalkaline and pH is often considered the driving parameter of microbial diversity, however hydrogenotrophic community composition varies in hyperalkaline fluids with similar pH. The composition of hydrogenotrophic communities in serpentinized fluids were found to correspond to the availability of the electron acceptor for hydrogenotrophic redox reactions. Specifically, hydrogenotrophic community composition transitions from being dominated by the hydrogenotrophic methanogen genus, Methanobacterium, when the concentration of sulfate is less than ~10 μm. Above ~10 μm, sulfate reducers are most abundant. Additionally, Methanobacterium was found to co-occur with the protist genus, Cyclidium, in serpentinized fluids. Species of Cyclidium are anaerobic and known to have methanogen endosymbionts. Therefore, Cyclidium may supply inorganic carbon evolved from fermentation to Methanobacterium, thereby mitigating pH dependent inorganic carbon limitation. This approach also revealed possible biological mechanisms for methane oxidation in Yellowstone hot springs. Measurable rates of biological methane oxidation in hot spring sediments are likely associated with methanotrophs of the phylum, Verrucomicrobia, and the class, Alphaproteobacteria. Additionally, rates were measurable where known methanotrophs were not detected. At some of these sites, archaeal ammonia oxidizer taxa were detected. Ammonia oxidizers have been shown to be capable of methane oxidation in other systems and may be an alternative mechanism for methanotrophy in Yellowstone hot springs. At the remaining sites, uncharacterized microbial lineages may be capable of carrying out methane oxidation in Yellowstone hot springs.

Subject Term

Ecology

Subject Term

Geochemistry

Subject Term

Microbiology

Howells, Alta Emily Gessner

Shock, Everett

Arizona State University

Electronic name

p

[Thesis]

276903

a

Y