Microbial Ecology of Dry Permafrost from Elephant Head, Antarctica

Abstract

The objective of this thesis is to determine if a viable, active microbial community could persist in cold, oligotrophic, dry permafrost soils from Elephant Head, Antarctica. Low amounts of microbial activity were measured in some microcosm samples at 5, 0, and -5C, as assessed using radiorespiration assays with radiolabeled acetate as a carbon source. Microbial communities were similar to other Antarctic environments and appear adapted for survival to cold, dry, oligotrophic conditions based on metagenomic, bacterial and fungal amplicon sequencing. The presence of viable microorganisms was confirmed through cultivation which isolated ~20 psychrotrophic organisms including Arthrobacter agilis strain Ant-EH-1 which is capable of cell division at -5C. The genome of A. agilis Ant-EH-1 was sequenced and was found to contain many genes for adaptation to cold, oligotrophic conditions. Together these results show that dry permafrost environments do not exclude active microbial life at sub-zero temperatures.