Nitrogen Fixation in Wet Minerotrophic Moss Communities of a Subarctic Mire

This is the authors' abstract. We don't add key points for this paper.

Nitrogen fixation by blue-green algae associated with Sphagnum and Drepanocladus mosses growing in wet depressions and pools was studied in minerotrophic parts of the Stordalen mire in Swedish Lapland. Nitrogen fixation rates of 0.5-6.4 g m2 yr-1 were estimated on Sphagnum riparium with the acetylene reduction method. Fixation varied considerably along moss plants and for Sphagnum was found to be lower on apical and non-green parts. Fixation was higher at the periphery of a moss community. Activity was strongly light dependent and seemed little affected by pH-variations between pH 4.3-6.8. A daily fixation maximum around noon, and an annual maximum around the middle of the growing season, were indicated.