Scientists explored effects of soil organic matter decomposability to temperature sensitivity of wetland carbon emissions
Wetlands store 29-45% of terrestrial soil organic carbon (SOC). Methane (CH4) and carbon dioxide (CO2) are the dominant gaseous products of wetland SOC decomposition as well as the main causes of climate change primarily characterized by global warming. Since the global warming potential of CH4 is at least 28 times greater than that of CO2, determining the difference in temperature sensitivity (EM:C) between CH4 and CO2 emissions in the context of continued warming is critical for predicting future wetland carbon emissions. The temperature dependence of CH4 and CO2 emissions can be described by the apparent activation energy (EM and EC), and their difference can be expressed as EM:C. A positive EM:C implies that CH4 emissions are more sensitive to temperature change than CO2 emissions, which indicates that the relative emissions of CH4 to CO2 increase under warming conditions. Most of the previous studies focused on the effect of hydrological changes on EM:C, indicating that wetland hydrological conditions may be the most important factor driving EM:C changes. However, EM:C in wetlands is not only influenced by hydrological conditions, but also fundamentally by the availability of carbon matrix. However, how soil organic matter availability affects EM:C remains to be further revealed.
The research team led by Prof. LIANG Yuting, researcher at the Institute of Soil Science, Chinese Academy of Sciences, in collaboration with Aarhus University, Denmark, University of Oklahoma, Swiss Federal Institute of Technology Zurich, Tsinghua University, Peking University, Fudan University, Institute of Earth Environment, Chinese Academy of Sciences, Institute of Genetics and Developmental Biology and other domestic and foreign research units, studied the temperature sensitivity of soil organic matter regulation of wetland carbon emissions Important progress has been made. The relevant research results are described as “Relative increases in CH4 and CO2 emissions from wetlands under global warming dependent on soil carbon substrates”, published online in Nature Geoscience.
Using a global database, the team showed that global wetland EM:C depends on the soil C:N stoichiometric ratio and that EM:C varies with soil C:N under different hydrological conditions. Combined with continental scale experimental studies, the relevant experimental evidence and the study of its mechanism are given. Finally, the study found that only 23% of wetlands around the world will experience a reduction in relative methane emissions with global warming. This study provides support for predicting the strength of the global wetland warming CH4 feedback.
Fig. Global distribution pattern of the difference in temperature sensitivity of
CH4 and CO2 emissions (Image by LIANG Yuting's research team)
Contact:
LIANG Yuting
Institute of Soil Science, Chinese Academy of Sciences
Tel: 86-025-86881568
Email: ytliang@issas.ac.cn
Web: http://english.issas.cas.cn/
