Holocene variations in peatland methane cycling associated with the Asian summer monsoon system
Zheng, Y., Singarayer, J., Cheng, P., Yu, X., Liu, Z., Valdes, P. J. and Pancost, R. D. (2014) Holocene variations in peatland methane cycling associated with the Asian summer monsoon system. Nature Communications, 5. 4631. ISSN 2041-1723
To link to this article DOI: 10.1038/ncomms5631
Atmospheric methane concentrations decreased during the early to middle Holocene; however, the governing mechanisms remain controversial. Although it has been suggested that the mid-Holocene minimum methane emissions are associated with hydrological change, direct evidence is lacking. Here we report a new independent approach, linking hydrological change in peat sediments from the Tibetan Plateau to changes in archaeal diether concentrations and diploptene delta C-13 values as tracers for methanogenesis and methanotrophy, respectively. A minimum in inferred methanogenesis occurred during the mid-Holocene, which, locally, corresponds with the driest conditions of the Holocene, reflecting a minimum in Asian monsoon precipitation. The close coupling between precipitation and methanogenesis is validated by climate simulations, which also suggest a regionally widespread impact. Importantly, the minimum in methanogenesis is associated with a maximum in methanotrophy. Therefore, methane emissions in the Tibetan Plateau region were apparently lower during the mid-Holocene and partially controlled by interactions of large-scale atmospheric circulation.