Dep. of Physical Geography and Ecosystem Sciences, Lund

For the 37th year in a row, the research group from Lund University has carried out active layer monitoring in the Abisko area. The last summer was very warm and especially in the degraded peat plateaus the warm summer was directly reflected in a thicker active layer. The active layer data is submitted to the CALM database. In addition, ground temperatures from five boreholes have been downloaded and submitted to the GTN-P database.

A snow manipulation experiment has been running for 9 years now. In 2010, PAR sensors were added to the monitoring and data from these measurements have now been compiled and published in Bosiö, J., C. Stiegler, M. Johansson, H.N. Mbufong and T.R. Christensen 2014. Increased photosynthesis compensates for shorter growing season in subarctic tundra - eight years of snow accumulation manipulations. Climatic Change 127 (2): 321-334. DOI 10.1007/s10584-014-1247-4. Results showed higher PAR absorption, together with almost 35 % higher light use efficiency, in treated plots (with added snow) compared to untreated plots. Estimations of GPP suggested that the loss in early season photosynthesis, due to the shortening of the growing season in the treatment plots, was well compensated for by the increased absorption of PAR and higher light use efficiency throughout the whole growing seasons, most likely due to increased soil moisture and nutrients together with a shift in vegetation composition associated with the accelerated permafrost thaw in the treated plots.

Report prepared by Margaretha Johansson, Torben Christensen, Jonas Åkerman ( jonas.akerman@nateko.lu.se).