Abstract
Due to climate warming, ice sheets and permafrost around the world are losing mass, contributing to greening of terrestrial landscapes with expected major repercussions on climate. However, these repercussions are poorly constrained mostly due to limited knowledge on microbial responses to climate change in the Arctic. Using genomic and chemical data from freshwater chronosequences in Svalbard and Norway we study the microbial trajectories in response to deglaciation and permafrost thaw. Using landscape feature resolved metagenomics we study microbial trait patterns in relation to greenhouse gas concentrations including methane, carbon dioxide and nitrous oxide. Our findings show diverse microbial succession patterns indicating multiple trajectories in carbon and nitrogen cycle processes across Arctic terrestrial landscapes under climate change. Meaning that complex community metabolism may be a reason behind “surprises” in GHG emissions from natural systems; in other words a result of rapid, non-linear responses of the microbial system to anthropogenic forcing.
In addition to environmental surveys we perform experiments to model greenhouse gas production kinetics and feed them into climate models. Both the rate and extent of greenhouse gases are the result of redox reactions, and these reactions are tightly linked to redox conditions. Here we show rapid responses in greenhouse gas production and microbial community metabolism when conditions shift from aerobic to anaerobic conditions.