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Relict Mountain Permafrost Area (Loess Plateau, China) Exhibits High Ecosystem Respiration Rates and Accelerating Rates in Response to Warming
Author(s) -
Mu Cuicui,
Wu Xiaodong,
Zhao Qian,
Smoak Joseph M.,
Yang Yulong,
Hu Lian,
Zhong Wen,
Liu Guimin,
Xu Haiyan,
Zhang Tingjun
Publication year - 2017
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg004060
Subject(s) - permafrost , global warming , environmental science , ecosystem , terrestrial ecosystem , plateau (mathematics) , physical geography , carbon cycle , climate change , hydrology (agriculture) , atmospheric sciences , geology , ecology , oceanography , geography , mathematical analysis , mathematics , geotechnical engineering , biology
Relict permafrost regions are characterized by thin permafrost and relatively high temperatures. Understanding the ecosystem respiration rate (ERR) and its relationship with soil hydrothermal conditions in these areas can provide knowledge regarding the permafrost carbon cycle in a warming world. In this study, we examined a permafrost area, a boundary area, and a seasonally frozen ground area within a relict permafrost region on the east edge of the Qinghai‐Tibetan Plateau, China. Measurements from July 2015 to September 2016 showed that the mean annual ecosystem CO 2 emissions for the boundary area were greater than the permafrost area. The Q 10 value of the ERRs in the seasonally frozen ground area was greater than the permafrost area, indicating that the carbon emissions in the nonpermafrost areas were more sensitive to warming. The 1 year open‐top chamber (OTC) warming increased soil temperatures in both the permafrost and seasonally frozen ground areas throughout the year, and the warming increased the ERRs by 1.18 (0.99–1.38, with interquartile range) and 1.13 (0.75–1.54, with interquartile range) μmol CO 2 m −2 s −1 in permafrost and seasonally frozen ground areas, respectively. The OTC warming increased annual ERRs by approximately 50% for both permafrost and seasonally frozen ground areas with half the increase occurring during the nongrowing seasons. These results suggest that the ERRs in relict permafrost are high in comparison with arctic regions, and the carbon balance in relict permafrost areas could be greatly changed by climate warming.