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Elevated CO 2 does not stimulate carbon sink in a semi‐arid grassland
Author(s) -
Song Jian,
Wan Shiqiang,
Piao Shilong,
Hui Dafeng,
Hovenden Mark J.,
Ciais Philippe,
Liu Yongwen,
Liu Yinzhan,
Zhong Mingxing,
Zheng Mengmei,
Ma Gaigai,
Zhou Zhenxing,
Ru Jingyi
Publication year - 2019
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/ele.13202
Subject(s) - arid , carbon sink , environmental science , ecosystem , grassland , carbon cycle , terrestrial ecosystem , climate change , sink (geography) , nitrogen cycle , ecology , soil respiration , ecosystem respiration , global change , primary production , nitrogen , biology , chemistry , geography , cartography , organic chemistry
Elevated CO 2 is widely accepted to enhance terrestrial carbon sink, especially in arid and semi‐arid regions. However, great uncertainties exist for the CO 2 fertilisation effects, particularly when its interactions with other global change factors are considered. A four‐factor ( CO 2 , temperature, precipitation and nitrogen) experiment revealed that elevated CO 2 did not affect either gross ecosystem productivity or ecosystem respiration, and consequently resulted in no changes of net ecosystem productivity in a semi‐arid grassland despite whether temperature, precipitation and nitrogen were elevated or not. The observations could be primarily attributable to the offset of ecosystem carbon uptake by enhanced soil carbon release under CO 2 enrichment. Our findings indicate that arid and semi‐arid ecosystems may not be sensitive to CO 2 enrichment as previously expected and highlight the urgent need to incorporate this mechanism into most IPCC carbon‐cycle models for convincing projection of terrestrial carbon sink and its feedback to climate change.