Fieldwork conducting "extreme winter warming" and "icing" events at Latnjajaure Field Station in northern Sweden
Photo: Louise C. Andresen

Arctic browning

Research project

Short description

The occurrence of extreme winter weather events has increased in the sub-Arctic. Rapid temperature increase during these events can result in a marked reduction or total loss of snow cover leading to stress responses or dieback of plants causing ‘browning’. Shifts in the biogeochemical processes driving ecosystem carbon and nitrogen (N) dynamics are possible consequences. However, very few studies have connected plant responses with responses in the biological soil crusts (BSC) consisting of a network of lichen, mosses, cyanobacteria and their symbiotic and decomposing bacteria and fungi.

The aims of the project are to:

  1. Assess the effects of field scale extreme winter weather events and ‘browning’ on the plant and microbe community composition of BSCs coupled with N cycling capabilities;
  2. Measure the direct effects of increased freezing intensity and frequency on BSC microbial activity and protein depolymerization, in a controlled environment;
  3. Visualize the organic N cycling at the nanoscale by further developing the ‘traditional’ 15N method for protein depolymerization to include nanoSIMS imaging;
  4. Develop a method that couples the depolymerization rate measured with 15N technique with the rate measured by fluorescence within a soil chips, to obtain a high tempo-spatial resolution of the N cycling, and its involved organisms;
  5. Utilize models to upscale future conditions (CoupModel) in order to understand if climate warming will drive an enhanced C and N loss or support a stable balance, while Arctic browning is happening, and to test correlations in a structural equation model.