Microbial controls on, and response to, carbon release during permafrost degradation
The analytical approaches that I employ have utility that extends well beyond paleogenetics, and my lab is also interested in applying these and other tools to studies of the contemporary environment. In this context, we have studied microbial processes associated with permafrost degradation. Specifically, we have assessed whether OM stored for millennia in permafrost soils represents a significant source of degradable biopolymers for the microbiota. Given that northern high-latitude ecosystems contain about half of the world’s soil carbon, most of which is stored in permafrost, questions concerning the fate of this carbon as it is destabilized are of profound importance, as it is expected that much of this currently fixed carbon can be released as greenhouse gasses through microbial decomposition and respiration. Via microbial exoenzyme activity assays, we have shown that permafrost underlying moist acidic tundra harbors a significant amount of decomposable biopolymers, and identified prokaryotes and eukaryotes that retained viability within only 11 days upon permafrost thaw(Coolen et al., 2011). With funding through WHOI’s Arctic Research Initiative and in collaboration with Dr. Amanda Spivak (WHOI, MC&G) we are currently analyzing the transcriptome (i.e., pool of actively transcribed functional genes) of the above-described Alaskan permafrost soils using Illumina HiSeq NGS. Paired with the analysis of the geochemical composition of the soil OM, this study will reveal which microbial metabolic processes involved in the cycling of OM take place in currently frozen permafrost soils and how this will change upon permafrost thaw in a global change scenario.