Seasons influence methane emissions from soils

 

15.08.2022

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Methane (CH4) is a potent greenhouse gas. Whether a soil acts as a methane sink or as a methane source, i.e. absorbs or releases methane, depends on the composition of the microorganisms, i.e. the microbiome, in the soil. How the soil microbiome changes over the course of a year and what influence its composition has on methane emissions in grassland has now been studied in depth for the first time. The researchers found that methane fluxes in the soil change significantly depending on the season and that methanogen transcripts provide useful information about methane emissions in grassland. The ZALF scientist Prof. Steffen Kolb was involved in the research.

The soils studied were drained peatlands from the Schorfheide-Chorin Biosphere Reserve. Both soils emitted methane in autumn and winter, while they absorbed methane in spring and summer. During this time, the ratio of methane-utilizing (methanotrophic) microorganisms to methane-producing (methanogenic) microorganisms was also higher. This was explored using a special technique called "microbial metatranscriptomics," which examines environmental RNA to infer the activities of microorganisms in the field. The researchers concluded that a high ratio of methanotrophic microorganisms to methanogenic microorganisms indicates sink properties of a soil. In their publication, the research team hypothesizes that the abundance of methanogen transcripts may be useful in estimating changes in methane emissions from grassland soils at the surface.