Using culture-independent methods to link active compound-specific carbon degradation to greenhouse gas production and recycling in natural populations of permafrost microbes
Funded by the U.S. Department of Energy, SC Program Office: Office of Biological and Environmental Research, DE-FOA-0002059
This is a collaborative project between the Center for Environmental Biotechnology and Microbiology Department of the University of Tennessee, Princeton University, ORNL, and PNNL. The project also includes strong international alliances with research institutions in Russia, UK, and Germany. The project will combine specialized omics approaches, metabolic activity and geochemical measurements/models to study natural microbes, cultured and uncultured, in pristine permafrost intact cores, and develop predictive protein models for greenhouse gas emissions. Permafrost at high latitudes accounts for roughly one third of global soil organic carbon (SOC) stocks within the top 3 meters of soil. With ongoing processes of climate change and intensification of thawing, this frozen SOC will be heavily impacted and reintroduced into the carbon cycle upon permafrost thawing. The study site contains globally-prevalent mineral permafrost and is located in close proximity to a long-term monitoring field station called Bayelva on the island of Spitsbergen in Svalbard, Norway. The Svalbard archipelago that is about midway between continental Norway and the North Pole is highly glaciated and is experiencing a high level of temperature increases, glacial retreat and permafrost thaw, making it an example for future changes to the rest of the Arctic. The project includes two permafrost drilling expeditions to Nu-Alesund, Svalbard where permafrost cores will be collected. In the laboratory, we will perform intact core mesocosm studies followed by simultaneous collection of 16S rRNA gene amplicons, metagenomic binning, single cell amplified genomes, metatranscriptomes, (meta)-metabolomes, proteomes, and customized extracellular enzymatic assays. When combined with the high-time resolution gas flux and pore chemistry measurements and in situ metabolic activity measurements using 13C-labelled compounds and NanoSIMS, we will obtain an intricate and well-supported view of how individual microbial clades alter their relationship with SOC in response to changes in porewater geochemistry at elevated temperature over time.
DIMENSIONS: Genetic, phylogenetic, and functional microbial diversity in permanently frozen aquatic sediments over geological time
Funded by the National Science Foundation, Directorate for Biological Sciences, Division of Environmental Biology (DEB) – Dimensions of Biodiversity
Sediments, soils, or rocks that remain at or below 0ºC for at least 2 consecutive years are defined as permafrost. Permafrost regions are geologically and ecologically diverse and occupy over 20% of the Earth’s land surface. Conditions within permafrost are shown to be amenable for preservation of microbial communities. The current literature presents contradictory interpretations on a major unresolved question in microbial ecology – whether microbes recovered from deep sediments are living fossils, representing an ancient surface community preserved through time, or an active extant community that has been interacting and evolving continuously since becoming buried. The resolution of this debate is critically important for determining past versus present microbial diversity in deep sediments and also in determining molecular evolution within bacterial taxa.
The current project aims to document temporal evolution of taxonomic, genetic and functional biodiversity in 5 thousand years to 3 million years permanently frozen sediments collected from the Siberian Kolyma-Indigirka Lowland. These permafrost sediments of lake-alluvial or marine origin have never completely thawed since they were frozen and most likely they contain a mixture of active, dormant, and truly extinct microbes. The project will expand our understanding of the extant and extinct microbial communities in young to ancient permanently frozen sediments with respect to evolutionary trends over time and the low temperature survivability and adaptation of psychrophilic microorganisms.
The team had a successful 2015 summer field season drilling cores across permafrost sediments of lake-alluvial origin in remote sites located on the Alazeya River in Northeastern Siberia. To extend public knowledge on the Siberian permafrost area including the tundra landscape and the life of the local people, the team produced a short video of the field site, local support personnel, and music of local artists.
The 2017 summer field season was completed at Cape Chukochy along the East Siberian Sea coast. The team collected a 22 meter core of permafrost from marine sediments. This core, combined with previous cores collected during the 2015 field season from a different location, represent both freshwater and marine sediments with freezing ages between three thousand to three million years. The team produced a documentary of the field research and the permafrost collection site
“Deep Freeze” in the Tennessee Alumnus magazine
“UT Scientists Revive Microscopic Life from Frost” in the Daily Beacon newsletter
The summer 2017 field research season
For more information, contact Tatiana Vishnivetskaya at tvishniv@utk.edu or 865-974-8080
