Enhanced response of soil respiration to experimental warming upon thermokarst formation

• Published in: Nature Geoscience
• Main Authors: Wang, Guanqin, Peng, Yunfeng, Chen, Leiyi, Abbott, Benjamin, W, Ciais, Philippe, Kang, Luyao, Liu, Yang, Li, Qinlu, Peñuelas, Josep, Qin, Shuqi, Smith, Pete, Song, Yutong, Strauss, Jens, Wang, Jun, Wei, Bin, Yu, Jianchun, Zhang, Dianye, Yang, Yuanhe
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; permafrost; Thermokarst
• Online Access: https://hal.science/hal-04572958; https://hal.science/hal-04572958/document; https://hal.science/hal-04572958/file/s41561-024-01440-2.pdf; https://doi.org/10.1038/s41561-024-01440-2

International audience Abstract As global temperatures continue to rise, a key uncertainty of terrestrial carbon (C)–climate feedback is the rate of C loss upon abrupt permafrost thaw. This type of thawing—termed thermokarst—may in turn accelerate or dampen the response of microbial degradation of soil organic matter and carbon dioxide (CO 2 ) release to climate warming. However, such impacts have not yet been explored in experimental studies. Here, by experimentally warming three thermo-erosion gullies in an upland thermokarst site combined with incubating soils from five additional thermokarst-impacted sites on the Tibetan Plateau, we investigate how warming responses of soil CO 2 release would change upon upland thermokarst formation. Our results show that warming-induced increase in soil CO 2 release is ~5.5 times higher in thermokarst features than the adjacent non-thermokarst landforms. This larger warming response is associated with the lower substrate quality and higher abundance of microbial functional genes for recalcitrant C degradation in thermokarst-affected soils. Taken together, our study provides experimental evidence that warming-associated soil CO 2 loss becomes stronger upon abrupt permafrost thaw, which could exacerbate the positive soil C–climate feedback in permafrost-affected regions.