This project studies the microbial processes that alter volcanic glass, which is critical to understanding the earliest life on earth. To understand the environmental controls on these processes, this project uses the extreme environments of the McMurdo region of Antarctica as a natural laboratory. Volcanic glass substrates are placed in hydrothermal systems, lakes, and other areas for two to four years to identify colonizing microbial consortia and the chemical processes of microbe-glass interaction. Recovered experiments are analyzed to explore the role of eukaryotic and prokaryotic organisms, and the relevance of autotrophs during colonization and biofilm formation using microscopic, molecular and culture techniques.
The broader impacts include graduate and undergraduate student participation in research and K-12 outreach and teacher training.
The Earth’s crust may host a deep, dark, and oligotrophic biosphere with a biomass comparable to that on Earth’s surface. Production of biomass in the subsurface is believed to be supported primarily by organic matter derived from the surface. Inorganic chemicals and reduced gases may also contribute additional sources of energy for subsurface microorganisms, however, the organisms or mechanisms by which chemical energy is derived from the lithosphere are not well understood. Fumarolic ice caves near the summit of Mt. Erebus (Antarctica) offer dark oligotrophic volcanic ecosystems (DOVEs) in an extremely organic-poor environment. Amongst a variety of extreme environments in the McMurdo area, these DOVEs provide an excellent model system for microbe-volcanic rock and gas interactions analogous to those occurring in deep, oligotrophic and oxic subsurface environments. We explored prokaryotic and eukaryotic microbial communities and found pristine bacterial communities and some contaminated fungal consortia for some caves, probably due to their use as shelters from the extreme weather conditions on Mt Erebus. However, we recognized a number of pristine caves and some fumarolic vents within a larger cave allowing us to explore the microbial diversity and their functions. Fungal communities display very high species diversity in clone libraries with many species in common with oligotrophic soils in Antarctica. A metagenomic library of the microbial communities from fumarolic sediments shows relatively low diversity community dominated by Chloroflexi along with lesser proportions of Actinobacteria, Acidobacteria, and Alphaproteobacteria. Eukaryotes and Archaea composed less than 0.1% of the community. The Calvin Cycle was the only carbon fixation pathway. Lithotrophic metabolisms identified in the metagenome include aerobic carbon monoxide oxidation and "Group 5" high-affinity [Ni-Fe]-hydrogenases. Together, these metabolisms represent important insights into microbial communities in highly oligotrophic volcanic environments, and may provide a greater understanding of primary production in other oxic, oligotrophic systems such as desert and alpine soils.
