Arctic microbial ecology

Over 20% of Earth’s terrestrial surface is underlain by permafrost that represents one of the largest terrestrial carbon pools with an estimated 1330-1580 Pg of carbon, resulting in as much as half of the Earth’s below ground C.

The soil organic matter (SOM) has accumulated in cold conditions that limit its decomposition. However, climate change is affecting the arctic dramatically as the warming is fastest in higher latitudes. Previously frozen ground is thawing and releasing substantial quantities of carbon which microbes can decompose. Microbes mineralize the carbon fraction and convert it to carbon dioxide (CO2) and methane (CH4). Climate change models estimate that C released from thawing arctic permafrost might represent the largest future transfer of C from the biosphere to the atmosphere resulting in a positive feedback loop. In addition to temperature, oxygen and moisture affect the microbial activity.

In a project funded by the Academy of Finland and the University of Helsinki we will study the function and role of the microbial community in production of greenhouse gases in the arctic on a temporal and spatial scale. As a model for future climate change scenarios with annual freeze-thaw cycles, altering vegetation and increased formation of bogs, we use arctic site in northern Finland, Kilpisjärvi (69°03’ N, 20°50’ E). Use of the model field site is ideal for the analysis of cause and effect of changing conditions to the microbial community relations and for the environmentally contextualized reconstruction of novel genomes that will lead to better understanding of the metabolic and environmental potential of uncultured microbes.

Group members:

PI Jenni Hultman

Postdoc Igor Pessi

MSc student Sirja Viitamäki

MSc student Aino Rutanen