Hao Liu , Yining Zhang , Yu-Jia Cai , Zi-Yan Liu , Liang Li , Ya-Qin Wang , Xiao Shu , Royston Goodacre , Zheng Chen
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引用次数: 0
Abstract
Flooded soils play a crucial role in global carbon cycling, acting as significant reservoirs of soil organic carbon and sources of carbon emissions. Leaf litter, especially from local vegetation, is a key contributor to soil organic carbon formation in these ecosystems, with its decomposition driving the production of carbon dioxide (CO2) and methane (CH4). Although numerous studies have examined the factors influencing leaf litter decomposition and associated greenhouse gas emissions, the impact of millimeter-scale variations in leaf litter placement within the soil-water interfaces (SWI) has received little attention. This study hypothesizes that even small changes in burial depth could significantly affect the emission patterns of CO2 and CH4. To test this hypothesis, a microcosm experiment was conducted to monitor gas fluxes and physicochemical profiles in treatments with leaf litter placed uncovered at the SWI (LU) or covered by a thin (10 mm) soil layer (LC). The results demonstrated substantial shifts in emissions: cumulative CH4 emissions were more than doubled in the LC group (115.3 μgC) compared to the LU group (42.5 μgC), while cumulative CO2 emissions were reduced by 25 % in the LC group (77 mgC) versus the LU group (103 mgC). Consequently, the overall global warming potential over a 20-year horizon (GWP20) was 13.2 % lower for the LC treatment (280.7 mgCO2e) compared to the LU treatment (323.3 mgCO2e). These findings advance our understanding of wetland carbon dynamics by revealing that a millimeter-scale change in leaf litter placement significantly alters the spatiotemporal patterns and partitioning of CO2 and CH4 emissions, highlighting the critical role of micro-scale heterogeneity in regulating greenhouse gas fluxes. Moreover, our results demonstrate a decoupling of CO2 and CH4 responses to this small-scale environmental variation, ultimately leading to a reduction in overall global warming potential despite increased methane release.
期刊介绍:
Applied Geochemistry is an international journal devoted to publication of original research papers, rapid research communications and selected review papers in geochemistry and urban geochemistry which have some practical application to an aspect of human endeavour, such as the preservation of the environment, health, waste disposal and the search for resources. Papers on applications of inorganic, organic and isotope geochemistry and geochemical processes are therefore welcome provided they meet the main criterion. Spatial and temporal monitoring case studies are only of interest to our international readership if they present new ideas of broad application.
Topics covered include: (1) Environmental geochemistry (including natural and anthropogenic aspects, and protection and remediation strategies); (2) Hydrogeochemistry (surface and groundwater); (3) Medical (urban) geochemistry; (4) The search for energy resources (in particular unconventional oil and gas or emerging metal resources); (5) Energy exploitation (in particular geothermal energy and CCS); (6) Upgrading of energy and mineral resources where there is a direct geochemical application; and (7) Waste disposal, including nuclear waste disposal.