Date

6-2015

Document Type

Dissertation

Degree Name

Ph.D.

Institution

Oregon Health & Science University

Abstract

Biomineral templating of Fe and Mn oxides is thought to be influenced by EPS, which determines the micro-environmental conditions for the microorganisms inhabiting the biofilm. The composition and morphology of EPS and its reactive side chains effect the porosity, density, water content, charge (i.e. reactive side chains), and mechanical stability of biofilm microbial diversity and biofilm morphology. Although it is known that microorganisms play a vital role in the biogeochemical cycling of metals, much is yet to be learned as to the mechanisms used in redox reactions. As we explore extreme environments we will gain more insight into the role microorganisms and their metabolic process play in the biogeochemical cycling of elements as well as identify novel microorganisms and unique metabolisms on Earth.

Research was conducted at two field sites selected as modern analogs to early Earth environments to the shallow seas from which ancient metalliferous deposits (i.e. banded iron and manganese formations) formed, and allows us to gain a better understanding of these novel ecosystems where unique biominerals, biosignatures and microfossils. At Soda Bay, Alaska cold-seeps represent a high Fe, low oxygen ecosystem along a salinity gradient, while Purple Pool, in Yellowstone National Park represents a Mn depositing, low oxygen ecosystem. Both sites are sourced with metalliferous oxygen deplete groundwaters and each site experiences extreme environmental conditions, which is reflected in the geochemistry and microbiology due to its influence on the composition of the microbial community inhabiting both ecosystems.

Our understanding of microbial evolution on early Earth will provide insight in how modern life will adapt to mineralizing environments. Gaining a better understating of the geochemistry, microbiology, microbial mineralization will allow us to address future important questions relating to whether these environments preserve traces of microfossil or chemofossils providing a glimpse into the history of early Earth.

Identifier

doi:10.6083/M4ZC81VZ

Division

Division of Environmental & Biomolecular Systems

School

School of Medicine

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