caa a22 4500 606217835 CHVBK 20210128101109.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s11104-014-2356-6 doi (NATIONALLICENCE)springer-10.1007/s11104-014-2356-6 Nitrogen fixation in Sphagnum mosses is affected by moss species and water table level [Elektronische Daten] [Sanna Leppänen, Antti Rissanen, Marja Tiirola] Background and aims: Nitrogen (N2) fixation by moss-associated bacteria is an important N source in boreal peatlands and forests. Here we studied whether moss species, water table fluctuations, methane (CH4) availability and diazotroph community structure would affect the rate of Sphagnum-associated N2 fixation. Methods: Diazotrophy and methanotrophy were studied in parallel in a double labeling (15 N2 and 13CH4) experiment in forest and fen habitats. The role of N2-fixing methanotrophs was further characterized by the phylogenetic analysis of nifH genes encoding for dinitrogenase reductase. Results: N2 fixation rates were dependent on the moss species in a habitat level, but independent of the diazotroph community structure. Only 6% of the nifH sequences were taxonomically assigned to cyanobacteria, while the majority (82%) of genes were assigned to Alphaproteobacteria clustering with the nifH sequences of the order Rhizobiales, but without close matches to sequences of cultivated species. In the originally submerged fen mosses, water increased both N2 fixation and CH4 oxidation rates. However, such effect was not seen in forest mosses grown above the water table level. CH4 addition did not enhance N2 fixation. Conclusions: N2 fixation associated to Sphagnum mosses was controlled by the moss species and the water environment. Although most of the observed nifH sequences were related to the order Rhizobiales, methanotrophs were not responsible for the N2 fixation. Springer International Publishing Switzerland, 2014 Bryophyte nationallicence Diazotroph community nationallicence Methane oxidation nationallicence NifH nationallicence Stable isotope nationallicence Leppänen Sanna Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut Rissanen Antti Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut Tiirola Marja Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut Plant and Soil Springer International Publishing 389/1-2(2015-04-01), 185-196 0032-079X 389:1-2<185 2015 389 11104 https://doi.org/10.1007/s11104-014-2356-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11104-014-2356-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Leppänen Sanna Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut NATIONALLICENCE 700 1- Rissanen Antti Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut NATIONALLICENCE 700 1- Tiirola Marja Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland aut NATIONALLICENCE 773 0- Plant and Soil Springer International Publishing 389/1-2(2015-04-01), 185-196 0032-079X 389:1-2<185 2015 389 11104