From single cells to ecosystem functioning: uncovering the decomposition potential of freshwater fungi in a thawing Arctic

Climate change-driven thawing of permafrost in northern landscapes is leading to the formation of thaw ponds.

These water bodies are hotspots in the carbon cycle, as they receive large inputs of terrestrial organic matter that has been stored for millennia. This organic matter is degraded by microorganisms, releasing greenhouse gases as putative products.

Fungi are notorious for their ability to break down organic compounds, but their functional role in aquatic environments remain largely unknown.

This project aims to study the functional potential of fungal communities with regards to carbon cycling in Arctic freshwaters in two ways: a) by analyzing metagenomic sequencing and carbon quality data across a permafrost thaw gradient from pristine to degraded areas; and b) by conducting in-depth functional studies in a thawing Swedish permafrost site, combining single cell genomics and carbon assimilation assays via DNA/RNA stable-isotope probing.

The project will start in Sweden, where a new sampling campaign in Abisko will be completed in July 2022 and carbon assimilation assays will be performed for the fresh samples. The following two years will be spent in Germany in Dr.

Christian Wurzbacher´s group, where single cell sequencing and bioinformatic analyses of all sequencing data will be performed.

This is the first study on the functional role of fungi from permafrost ponds, shedding light on the potential fate of the organic matter in Arctic ecosystems upon climatic changes.