Responses of methanogenic and methanotrophic communities to warming in varying moisture regimes of two boreal fens
journal contribution
posted on 2023-05-19, 05:25authored byPeltoniemi, K, Laiho, R, Juottonen, H, Bodrossy, L, Kell, DK, Minkkinen, K, Makiranta, P, Mehtatalo, L, Penttila, T, Siljanen, HMP, Tuittila, E-S, Tuomivirta, T, Fritze, H
Peatlands are one of the major sources of the powerful greenhouse gas methane (CH4). Our aim was to detect responses of methanogenic archaeal and methane-oxidizing bacterial (MOB) communities that control the methane (CH4) cycle to climatic warming. This study took place in two boreal fens three years after experimental warming in un-manipulated wet and drier regimes, thus simulating future climate scenarios. We determined active methanogen and MOB communities as transcripts of mcrA and pmoA genes, along with the abundance of these genes, CH4 production and oxidation potentials, and in situ CH4 fluxes. Methanogenic community remained similar, although methanogen abundance decreased after warming. In the wet regime, this decrease resulted in a small but significant reduction on the potential CH4 production in such peat layers where the average production potential was high. Drying alone, however, reduced the potential CH4 production more than warming, and this impact was strong enough to mask the small warming impact in the drier regime. Warming did not affect the MOB community or the potential CH4 oxidation in the wet regime; however, type Ib MOB abundance decreased and MOB related to genus Methylocapsa became typical after warming in the drier regime of the southern fen. The in situ measured CH4 fluxes indicated similar patterns as potential measurements; both warming and drying reduced methane emissions, drying more than warming. These results indicate that methanogens and MOB may have different controlling patterns on CH4 fluxes when facing global warming. These patterns may further differ not only between moisture regimes, but inside the same habitat type, here boreal fen. Irrespective of this variation, the in situ CH4 fluxes still seem to respond similarly across sites.
History
Publication title
Soil Biology and Biochemistry
Volume
97
Pagination
144-156
ISSN
0038-0717
Department/School
Tasmanian Institute of Agriculture (TIA)
Publisher
Pergamon-Elsevier Science Ltd
Place of publication
The Boulevard, Langford Lane, Kidlington, Oxford, England, Ox5 1Gb