The study of high temperature extreme environments challenges our understanding of the upper tolerances of microbial life and may provide a window to understanding how life originated on earth. The Tramway Ridge geothermal site on Mt. Erebus, an active volcano in Antarctica, is the most geographically isolated geothermal site on earth. The extreme isolation of Erebus makes it an excellent system for studies of microbial speciation, biogeography, and evolution of thermal adaptation. An earlier genetic survey of the Tramway Ridge subsurface microbial community conducted by our group revealed an unprecedented diversity of extremely novel microbes distantly related to known bacteria and provided the impetus for this current Marsden funded research effort.
Ice chimneys dot the landscape surrounding Tramway ridge and present another unique geothermal habitat for comparisons of geothermal soils. Ice chimneys are formed when geothermal steam condenses to form an ice vent surrounding hot soils. Microbes being transported by steam may be deposited on the walls of an ice chimney and become sealed in ice over time. Thus, an ice chimney core may hold a record of changes in the microbial community of the underlying geothermal soil over time. The use of Lower Erebus Hut during 2010/2011 field season enabled our team to sample geothermal soils and ice cores from ice chimneys for microbial characterization. We collected one such core during the 2009/2010 field season and collected an additional two cores during the 2010/2011 field season. Portions of the core will be melted and used for DNA extraction, and other portions will be used for geochemical characterization. Together these data will provide a detailed history of the biology and chemistry of the ice chimney over time.