Linking Transcriptional Dynamics of Peat Microbiomes to Methane Fluxes during a Summer Drought in Two Rewetted Fens

Abstract

Rewetted peatlands are reestablished hot spots for CH4 emissions, which are subject to increased drought events in the course of climate change. However, the dynamics of soil methane-cycling microbiomes in rewetted peatlands during summer drought are still poorly characterized. Using a quantitative metatranscriptomic approach, we investigated the changes in the transcript abundances of methanogen and methanotroph rRNA, as well as mcrA and pmoA mRNA before, during, and after the 2018 summer drought in a coastal and a percolation fen in northern Germany. Drought changed the community structure of methane-cycling microbiomes and decreased the CH4 fluxes as well as the rRNA and mRNA transcript abundances of methanogens and methanotrophs, but they showed no recovery or increase after the drought ended. The rRNA transcript abundance of methanogens was not correlated with CH4 fluxes in both fens. In the percolation fen, however, the mcrA transcript abundance showed a positive and significant correlation with CH4 fluxes. Importantly, when integrating pmoA abundance, a stronger correlation was observed between CH4 fluxes and mcrA/pmoA, suggesting that relationships between methanogens and methanotrophs are the key determinant of CH4 turnover. Our study provides a comprehensive understanding of the methane-cycling microbiome feedbacks to drought events in rewetted peatlands.

An Outsized Contribution of Rivers to Carbon Emissions From Interconnected Urban River‐Lake Networks Within Plains

“…In aquatic ecosystems, CH 4 emissions are jointly regulated by methanogen (16S rDNA) generation and methanotroph ( p moA) consumption, as the produced CH 4 undergoes oxidative consumption before being released into the atmosphere (Cai et al., 2018; Wang et al., 2023). In this study, 16S rDNA and p moA gene abundances were analyzed using a quantitative PCR (qPCR) method, and the 16S rDNA/ p moA was calculated to elucidate the mechanisms underlying CH 4 emissions.…”

Belowground plant traits and hydrology control microbiome composition and methane flux in temperate fen mesocosms

“…2022).The CH 4 ux was measured similarly as in the eld according toWang et al (2023). During the measurement, an opaque circular chamber made from polyurethane was xed on each pot for 3 min.…”

“…CH 4 concentrations were measured biweekly using either a GasScouter (Picarro, Santa Clara) or an Ultra-Portable Greenhouse Gas Analyzer (Los Gatos Research, Mountain). The calculation of the CH 4 ux was described inWang et al (2023).…”

“…The below-ground (micro-)biome and interactions therein are central to peatland C and N cycling(Robinson et al 2023). Rewetting changes the peat microbiome (bacteria, archaea, fungi, protists;Weil et al 2020;Wang et al 2021Wang et al , 2022Wang et al , 2023) as compared to drained fens(Emsens et al 2020;Jurasinski et al 2020;Kreyling et al 2021…”