Microbial activity contributes to spatial heterogeneity of wetland methane fluxes

The emission of methane from wetlands is spatially heterogeneous, as concurrently measured surface fluxes can vary by orders of magnitude within the span of a few meters. Despite extensive study and the climatic significance of these greenhouse gas emissions, it remains unclear what drives these large within-site variations, creating a knowledge-gap that impedes a mechanistic understanding of wetland fluxes. While geophysical variables including water table depth (WTD) and soil temperature are known to correlate with CH4 flux, measurable variance in these parameters declines as spatial and temporal scales become finer. Here, we leveraged depth-stratified gene abundance and gene expression measurements of methanogenesis and methanotrophy to investigate CH4 flux variance at an ombrotrophic peat bog. Our results show that the flux variance was strongly correlated to methanogen abundance and that peat depth also exerted significant control over CH4 flux, methanogen abundance, and the relati...