Holocene variations in peatland methane cycling associated with the Asian summer monsoon system

• Published in: Nature communications Vol. 5; no. 1; p. 4631
• Main Authors: Zheng, Yanhong, Singarayer, Joy S., Cheng, Peng, Yu, Xuefeng, Liu, Zhao, Valdes, Paul J., Pancost, Richard D.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-08-2014; Nature Publishing Group; Nature Pub. Group
• Subjects: 704/106/413; 704/106/47; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• 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 δ
13
C 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.
Although it has been widely suggested that the mid-Holocene minimum methane emissions are associated with hydrological change, direct evidence is missing. Here, the authors present evidence from the Tibetan Plateau using tracers of methanogenesis and methanotrophy, in combination with climate simulations.