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Warming effects on permafrost ecosystem carbon fluxes associated with plant nutrients
Author(s) -
Li Fei,
Peng Yunfeng,
Natali Susan M.,
Chen Kelong,
Han Tianfeng,
Yang Guibiao,
Ding Jinzhi,
Zhang Dianye,
Wang Guanqin,
Wang Jun,
Yu Jianchun,
Liu Futing,
Yang Yuanhe
Publication year - 2017
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1002/ecy.1975
Subject(s) - ecosystem , environmental science , permafrost , nutrient , global warming , growing season , ecosystem respiration , ecology , vegetation (pathology) , carbon dioxide , climate change , agronomy , primary production , biology , medicine , pathology
Large uncertainties exist in carbon (C)‐climate feedback in permafrost regions, partly due to an insufficient understanding of warming effects on nutrient availabilities and their subsequent impacts on vegetation C sequestration. Although a warming climate may promote a substantial release of soil C to the atmosphere, a warming‐induced increase in soil nutrient availability may enhance plant productivity, thus offsetting C loss from microbial respiration. Here, we present evidence that the positive temperature effect on carbon dioxide ( CO 2 ) fluxes may be weakened by reduced plant nitrogen (N) and phosphorous (P) concentrations in a Tibetan permafrost ecosystem. Although experimental warming initially enhanced ecosystem CO 2 uptake, the increased rate disappeared after the period of peak plant growth during the early growing season, even though soil moisture was not a limiting factor in this swamp meadow ecosystem. We observed that warming did not significantly affect soil extractable N or P during the period of peak growth, but decreased both N and P concentrations in the leaves of dominant plant species, likely caused by accelerated plant senescence in the warmed plots. The attenuated warming effect on CO 2 assimilation during the late growing season was associated with lowered leaf N and P concentrations. These findings suggest that warming‐mediated nutrient changes may not always benefit ecosystem C uptake in permafrost regions, making our ability to predict the C balance in these warming‐sensitive ecosystems more challenging than previously thought.