Actinobacterial Nitrate Reducers and Proteobacterial Denitrifiers Are Abundant in N2O-Metabolizing Palsa Peat ...

• Main Authors: Palmer, Katharina, Horn, Marcus A.
• Format: Text
• Language: English
• Published: Washington, DC [u.a.] : American Soc. for Microbiology 2012
• Subjects: Anoxic microcosms; Betaproteobacteria; Consumption potential; Discontinuous permafrost; Operational taxonomic units; Dewey Decimal Classification500 | Naturwissenschaften570 | Biowissenschaften, Biologie; Dewey; Ice; palsa; permafrost; Lapland
• Online Access: https://dx.doi.org/10.15488/15926; https://www.repo.uni-hannover.de/handle/123456789/16052

Palsa peats are characterized by elevated, circular frost heaves (peat soil on top of a permanently frozen ice lens) and are strong to moderate sources or even temporary sinks for the greenhouse gas nitrous oxide (N2O). Palsa peats are predicted to react sensitively to global warming. The acidic palsa peat Skalluvaara (approximate pH 4.4) is located in the discontinuous permafrost zone in northwestern Finnish Lapland. In situ N2O fluxes were spatially variable, ranging from 0.01 to -0.02 μmol of N2O m-2 h-1. Fertilization with nitrate stimulated in situ N2O emissions and N2O production in anoxic microcosms without apparent delay. N2O was subsequently consumed in microcosms. Maximal reaction velocities (vmax) of nitrate-dependent denitrification approx-imated 3 and 1 nmol of N2O per h per gram (dry weight [gDW]) in soil from 0 to 20 cm and below 20 cm of depth, respectively. vmax values of nitrite-dependent denitrification were 2- to 5-fold higher than the vmax nitrate-dependent denitrification, and vmax of ...