Widespread production of nonmicrobial greenhouse gases in soils. (6th June 2017)

• Record Type: Journal Article
• Authors: Wang, Bin; Lerdau, Manuel; He, Yongli
• Is Part Of: Global change biology. Volume 23:Number 11(2017)
• Page Start: 4472
• Page End: 4482
• Publication Date: 2017-06-06
• Subjects: carbon cycling -- extracellular oxidative metabolism -- greenhouse gas -- nitrous oxide -- nonmicrobial -- photodegradation -- soil organic matter -- thermal degradation; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.13753
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O) are the three most important greenhouse gases (GHGs), and all show large uncertainties in their atmospheric budgets. Soils of natural and managed ecosystems play an extremely important role in modulating their atmospheric abundance. Mechanisms underlying the exchange of these GHGs at the soil–atmosphere interface are often assumed to be exclusively microbe‐mediated (M‐GHGs). We argue that it is a widespread phenomenon for soil systems to produce GHGs through nonmicrobial pathways (NM‐GHGs) based on a review of the available evidence accumulated over the past half century. We find that five categories of mechanistic process, including photodegradation, thermal degradation, reactive oxidative species (ROS) oxidation, extracellular oxidative metabolism (EXOMET), and inorganic chemical reactions, can be identified as accounting for their production. These pathways are intricately coupled among themselves and with M‐GHGs production and are subject to strong influences from regional and global change agents including, among others, climate warming, solar radiation, and alterations of atmospheric components. Preliminary estimates have suggested that NM‐GHGs could play key roles in contributing to budgets of GHGs in the arid regions, whereas their global importance would be enhanced with accelerated global environmental changes. Therefore, more research should be undertaken, with a differentiation between NM‐GHGs and M‐GHGs, to further elucidate the underlying mechanisms, to investigate the impacts of various global change agents, and to quantify their contributions to regional and global GHGs budgets. These efforts will contribute to a more complete understanding of global carbon and nitrogen cycling and a reduction in the uncertainty of carbon‐climate feedbacks in the Earth system. Abstract : It is a widespread phenomenon for soils (plant residues) to produce GHGs through nonmicrobial pathways (NM‐GHGs). Five categories of mechanistic process (photodegradation, thermal degradation, reactive oxidative species oxidation, extracellular oxidative metabolism, and inorganic chemical reactions) are currently identified. Preliminary estimates have suggested that these pathways could play key roles in regulating the regional budget of GHGs. Their global importance would be enhanced with accelerated global environmental changes.