Variation in methane uptake by grassland soils in the context of climate change - A review of effects and mechanisms

Adrianna Rafalska; Anna Walkiewicz; Bruce Osborne; Katja Klumpp; Andrzej Bieganowski

doi:10.1016/j.scitotenv.2023.162127

Variation in methane uptake by grassland soils in the context of climate change - A review of effects and mechanisms

Sci Total Environ. 2023 May 1:871:162127. doi: 10.1016/j.scitotenv.2023.162127. Epub 2023 Feb 9.

Authors

Adrianna Rafalska¹, Anna Walkiewicz², Bruce Osborne³, Katja Klumpp⁴, Andrzej Bieganowski¹

Affiliations

¹ Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland.
² Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland. Electronic address: a.walkiewicz@ipan.lublin.pl.
³ UCD School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, 4 Dublin, Ireland.
⁴ INRAE, University of Clermont Auvergne, VetAgro Sup, UREP Unité de Recherche sur l'Ecosystème Prairial, 63000 Clermont-Ferrand, France.

PMID: 36764535
DOI: 10.1016/j.scitotenv.2023.162127

Abstract

Grassland soils are climate-dependent ecosystems that have a significant greenhouse gas mitigating function through their ability to store large amounts of carbon (C). However, what is often not recognized is that they can also exhibit a high methane (CH₄) uptake capacity that could be influenced by future increases in atmospheric carbon dioxide (CO₂) concentration and variations in temperature and water availability. While there is a wealth of information on C sequestration in grasslands there is less consensus on how climate change impacts on CH₄ uptake or the underlying mechanisms involved. To address this, we assessed existing knowledge on the impact of climate change components on CH₄ uptake by grassland soils. Increases in precipitation associated with soils with a high background soil moisture content generally resulted in a reduction in CH₄ uptake or even net emissions, while the effect was opposite in soils with a relatively low background moisture content. Initially wet grasslands subject to the combined effects of warming and water deficits may absorb more CH₄, mainly due to increased gas diffusivity. However, in the longer-term heat and drought stress may reduce the activity of methanotrophs when the mean soil moisture content is below the optimum for their survival. Enhanced plant productivity and growth under elevated CO₂, increased soil moisture and changed nutrient concentrations, can differentially affect methanotrophic activity, which is often reduced by increasing N deposition. Our estimations showed that CH₄ uptake in grassland soils can change from -57.7 % to +6.1 % by increased precipitation, from -37.3 % to +85.3 % by elevated temperatures, from +0.87 % to +92.4 % by decreased precipitation, and from -66.7 % to +27.3 % by elevated CO₂. In conclusion, the analysis suggests that grasslands under the influence of warming and drought may absorb even more CH₄, mainly because of reduced soil water contents and increased gas diffusivity.

Keywords: Altered precipitation; Climate change; Elevated CO(2); Grassland soils; Methane uptake; Warming.

Publication types

Review