Microbial Observatory: Linking Microbial Diversity With Biogeochemical Studies Throughout the Deep Greenland Ice Sheet

A grant has been awarded to Drs. Jean Brenchley, Vanya Miteva, and Todd Sowers of Pennsylvania State University to establish microbial observatory studies of microbial diversity in relation to geochemical analyses throughout a Greenland glacier ice core. These investigators have shown that ice from over 3,000 meters deep contained an abundant and diverse prokaryotic population that had survived subzero temperatures, high pressures, and limited liquid, oxygen, and nutrients for over 120,000 years. This new work will develop a low temperature microbial observatory to examine the prokaryotic populations in ice core samples selected to represent different depths/times/deposition temperatures and test whether microbial metabolism could be occurring within the ice core itself. Goals include examining the viability and number of prokaryotes in different ice samples to determine whether specific types correlate with deposition climates, comparing the microbial diversity using both culture dependent and culture independent methods, and monitoring trace gas composition using stable isotopes in ice to link the microbial diversity studies with biogeochemical processes.

Glacier ice is a harsh habitat and results from this microbial observatory will help understand the limits for survival on earth and serve as a model for possible extraterrestrial life. In addition to broad educational impacts, this work will provide a comprehensive view of the vertical distribution of microbial populations in the ice core and is likely to lead to the cultivation of numerous not-yet cultivated organisms representing novel taxa. Some isolates could produce biotechnologically important new antibiotics, chemicals, cold-active enzymes, etc. In addition, the interdisciplinary test of whether metabolism can be detected within ice is important because trace gases in ice cores record past atmospheres that are then compared with current compositions. If microbial metabolism could have altered this trace gas record, then previous results and climate predictions would have to be reevaluated.