Permafrost response to temperature rise in carbon and nutrient cycling: Effects from habitat-specific conditions and factors of warming

文献类型： 外文期刊

第一作者： Gao, Wenlong

作者： Gao, Wenlong;Sun, Weimin;Gao, Wenlong;Gao, Wenlong;Sun, Weimin;Sun, Weimin;Xu, Xingliang

作者机构：

关键词： carbon cycling; climate warming; meta-analysis; permafrost; progressive nitrogen limitation

期刊名称：ECOLOGY AND EVOLUTION （ 影响因子：2.881； 五年影响因子：3.252 ）

ISSN： 2045-7758

年卷期： 2021 年 11 卷 22 期

页码：

收录情况： SCI

摘要： Permafrost is experiencing climate warming at a rate that is two times faster than the rest of the Earth's surface. However, it is still lack of a quantitative basis for predicting the functional stability of permafrost ecosystems in carbon (C) and nutrient cycling. We compiled the data of 708 observations from 89 air-warming experiments in the Northern Hemisphere and characterized the general effects of temperature increase on permafrost C exchange and balance, biomass production, microbial biomass, soil nutrients, and vegetation N dynamics through a meta-analysis. Also, an investigation was made on how responses might change with habitat-specific (e.g., plant functional groups and soil moisture status) conditions and warming variables (e.g., warming phases, levels, and timing). The net ecosystem C exchange (NEE) was found to be downregulated by warming as a result of a stronger sensitivity to warming in respiration (15.6%) than in photosynthesis (6.2%). Vegetation usually responded to warming by investing more C to the belowground, as belowground biomass increased much more (30.1%) than aboveground biomass (2.9%). Warming had a minor effect on microbial biomass. Warming increased soil ammonium and nitrate concentrations. What's more, a synthesis of 70 observations from 11 herbs and 9 shrubs revealed a 2.5% decline of N in green leaves. Compared with herbs, shrubs had a stronger response to respiration and had a decline in green leaf N to a greater extent. Not only in dry condition did green leaf N decline with warming but also in wet conditions. Warming in nongrowing seasons would negatively affect soil water, C uptake, and biomass production during growing seasons. Permafrost C loss and vegetation N decline may increase with warming levels and timing. Overall, these findings suggest that besides a positive C cycling-climate feedback, there will be a negative feedback between permafrost nutrient cycling and climate warming.

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