Life at the Freezing Point: Global change and permafrost microbiology
Mark Waldrop (USGS), Burt Thomas (USGS), Kimberly Wickland (USGS), and Janet Jansson (Lawrence Berkeley Laboratory), Jack McFarland (USGS)
USGS Mendenhall Research Fellowship Program
Permafrost contains a reservoir of frozen carbon, equivalent to the total carbon contained within the atmosphere. In response to climate change, permafrost is experiencing widespread thawing, which will make it's carbon much more vulnerable to microbial decomposition. However, the structural and functional responses of permafrost microbes to thaw are virtually unknown. We know that thawing permafrost can result in a rapid shift in microbial community dynamics and functional diversity, with a concurrent shift in methane cycling dynamics. To understand more about these changes, this project is studying microbial community dynamics in thawed boreal permafrost soils using nucleic acid stable isotope probing (SIP) with heavy water (H218
O), combined with phylogenetic and functional gene analyses, as well as chemical, physical, and process characterizations. Objectives are to:
- Characterize and differentiate between actively growing, dormant, and deceased microbes in permafrost after thawing.
- Elucidate how microbial diversity and activity is influenced by seasonal freeze/thaw events.
- Characterize microbial activity in frozen soils and in deep unfrozen talik to determine the contribution of winter activities to annual methane and carbon dioxide flux.