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Annual ecosystem respiration is resistant to changes in freeze–thaw periods in semi‐arid permafrost
Author(s) -
Wang Qi,
Lv Wangwang,
Li Bowen,
Zhou Yang,
Jiang Lili,
Piao Shilong,
Wang Yanfen,
Zhang Lirong,
Meng Fandong,
Liu Peipei,
Hong Huan,
Li Yaoming,
Dorji Tsechoe,
Luo Caiyun,
Zhang Zhenhua,
Ciais Philippe,
Peñuelas Josep,
Kardol Paul,
Zhou Huakun,
Wang Shiping
Publication year - 2020
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.14979
Subject(s) - permafrost , environmental science , ecosystem , arid , climate change , precipitation , global warming , ecosystem respiration , soil respiration , grassland , atmospheric sciences , soil water , ecology , hydrology (agriculture) , physical geography , primary production , soil science , geography , geology , biology , geotechnical engineering , meteorology
Abstract Warming in cold regions alters freezing and thawing (F–T) of soil in winter, exposing soil organic carbon to decomposition. Carbon‐rich permafrost is expected to release more CO 2 to the atmosphere through ecosystem respiration (Re) under future climate scenarios. However, the mechanisms of the responses of freeze – thaw periods to climate change and their coupling with Re in situ are poorly understood. Here, using 2 years of continuous data, we test how changes in F–T events relate to annual Re under four warming levels and precipitation addition in a semi‐arid grassland with discontinuous alpine permafrost. Warming shortened the entire F–T period because the frozen period shortened more than the extended freezing period. It decreased total Re during the F–T period mainly due to decrease in mean Re rate. However, warming did not alter annual Re because of reduced soil water content and the small contribution of total Re during the F–T period to annual Re. Although there were no effects of precipitation addition alone or interactions with warming on F–T events, precipitation addition increased total Re during the F–T period and the whole year. This decoupling between changes in soil freeze – thaw events and annual Re could result from their different driving factors. Our results suggest that annual Re could be mainly determined by soil water content rather than by change in freeze – thaw periods induced by warming in semi‐arid alpine permafrost.