Methane emissions from an alpine fen in central Switzerland

Abstract

Methane emissions and below ground methane pore water concentrations were determined in an alpine fen at 1,915 m a.s.l. in central Switzerland. The fen represented an acidic (pH 4.5-4.9), nutrient-poor to mesotrophic habitat dominated by Carex limosa, Carex rostrata, Trichophorum caespitosum and Sphagnum species. From late fall to late spring the fen was snow-covered. Throughout winter the temperatures never dropped below 0°C at 5 cm below the vegetation surface. Methane emissions in June, July, August and September were in the range of 125 (±26)-313 (±71) mg CH 4 m -2 day -1 with a tendency to decrease along the summer season. Mean methane pore water concentrations at a depth of 20-40 cm below the vegetation surface were 526 (±32) lM in June and in the range of 144 (±10)-233 (±7) lM in July, August and September. At a depth of 0-20 cm the mean methane pore water concentrations dropped back to \20 lM with an almost linear decrease between 0 and 15 cm. Oxygen pore water concentrations were close to air saturation in the first few centimeters and dropped back below detection limit at a depth of 20 cm. In July and August the pore water concentrations of dissolved organic carbon (DOC) were in the range of 7.2-10.1 mg C l -1 at all depths. The pore water concentrations of acetate, formate and oxalate were in the range of 2.0-8.2 lM at all depths. Methanotrophic and methanogenic communities were quantified using pmoA and mcrA, respectively, as marker genes. The abundances of both communities showed a distinct peak at a depth of 10-15 cm below the vegetation surface.

Simple Absolute Quantification Method Correcting for Quantitative PCR Efficiency Variations for Microbial Community Samples

“…n microbial ecology, real-time quantitative PCR (qPCR) is used to measure the number of copies of a gene of interest in a community or an environmental sample (24,25,41,42). The presence of specific phylogenetic groups can be quantified by targeting the 16S rRNA gene (1,10).…”

Environmental Transcription of mmoX by Methane-Oxidizing Proteobacteria in a Subarctic Palsa Peatland

“…In addition, determinations of plot-scale methane emissions were conducted in triplicate per site. The procedures for sampling and analyzing pore water and for methane emission measurements are described in detail elsewhere (18). Ammonium concentrations were determined by an analytical laboratory (TosLab, Tromsø, Norway).…”

Methanotrophic and Methanogenic Communities in Swiss Alpine Fens Dominated by Carex rostrata and Eriophorum angustifolium

“…Fig. S1a in the supplemental material) were used to determine CH 4 emissions as described previously (32,33). In brief, the chambers were carefully placed in standing water, which provided a complete sealing.…”

“…Pore water sampling was carried out as described in detail elsewhere (32,33). In brief, a series of brass tubes (inside diameter [i.…”

“…These studies focused mainly on in situ measurements of CH 4 emissions and concentrations in pore water, reporting spatial and seasonal variability in emissions. In particular, two C. rostratadominated, permanently submerged fens in the Swiss Alps, at the Oberaar and the Göschener Alp, have been studied in detail (33,39,40). Analyses of physicochemical pore water properties, and of the abundances of methanotrophs and methanogens in the subsurface along the depth profile, were performed.…”