Elevated CO2 is widely accepted to enhance terrestrial carbon sink, especially in arid and semi-arid regions. However, great uncertainties exist for the CO2 fertilisation effects, particularly when its interactions with other global change factors are considered. A four-factor (CO2, temperature, precipitation and nitrogen) experiment revealed that elevated CO2 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 CO2 enrichment. Our findings indicate that arid and semi-arid ecosystems may not be sensitive to CO2 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.
1.Henan Univ, Sch Life Sci, Int Joint Res Lab Global Change Ecol, Kaifeng 475004, Henan, Peoples R China 2.Hebei Univ, Coll Life Sci, Baoding 071002, Hebei, Peoples R China 3.Peking Univ, Coll Urban & Environm Sci, Sinofrench Inst Earth Syst Sci, Beijing 100871, Peoples R China 4.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Alpine Ecol & Biodivers, Beijing 100085, Peoples R China 5.Chinese Acad Sci, Ctr Excellence Tibetan Earth Sci, Beijing 100085, Peoples R China 6.Tennessee State Univ, Dept Biol Sci, Nashville, TN 37209 USA 7.Univ Tasmania, Sch Nat Sci, Biol Sci, Private Bag 55, Hobart, Tas 7001, Australia 8.UVSQ, CNRS, CEA, Lab Sci Climat & Environm, Gif Sur Yvette, France 9.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Alpine Ecol & Biodivers, Beijing 100101, Peoples R China
Recommended Citation:
Song, Jian,Wan, Shiqiang,Piao, Shilong,et al. Elevated CO2 does not stimulate carbon sink in a semi-arid grassland[J]. ECOLOGY LETTERS,2019-01-01,22(3):458-468