Xue Xian, Peng Fei, You Quangang, Xu Manhou, Dong Siyang
Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 320 West Donggang Road Lanzhou 730000 China.
Ecol Evol. 2015 Sep 1;5(18):4063-78. doi: 10.1002/ece3.1685. eCollection 2015 Sep.
Recent studies found that the largest uncertainties in the response of the terrestrial carbon cycle to climate change might come from changes in soil moisture under the elevation of temperature. Warming-induced change in soil moisture and its level of influence on terrestrial ecosystems are mostly determined by climate, soil, and vegetation type and their sensitivity to temperature and moisture. Here, we present the results from a warming experiment of an alpine ecosystem conducted in the permafrost region of the Qinghai-Tibet Plateau using infrared heaters. Our results show that 3 years of warming treatments significantly elevated soil temperature at 0-100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40-100 cm depth. In contrast to the findings of previous research, experimental warming did not significantly affect NH 4 (+)-N, NO 3 (-)-N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30-50 cm depth. This led to increased soil organic carbon, total nitrogen, and liable carbon at 30-50 cm depth, and increased autotrophic respiration of plants. Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon. Our findings suggest that future climate change studies need to take greater consideration of changes in the hydrological cycle and the local ecosystem characteristics. The results of our study will aid in understanding the response of terrestrial ecosystems to climate change and provide the regional case for global ecosystem models.
最近的研究发现，陆地碳循环对气候变化响应中最大的不确定性可能来自温度升高情况下土壤湿度的变化。变暖引起的土壤湿度变化及其对陆地生态系统的影响程度主要由气候、土壤、植被类型以及它们对温度和湿度的敏感性决定。在此，我们展示了在青藏高原多年冻土区使用红外加热器进行的高寒生态系统变暖实验的结果。我们的结果表明，3年的变暖处理显著提高了0至100厘米深度的土壤温度，降低了10厘米深度的土壤湿度，并增加了40至100厘米深度的土壤湿度。与先前研究的结果不同，实验性变暖并未显著影响铵态氮、硝态氮和异养呼吸，但刺激了植物生长，并显著增加了30至50厘米深度的根系生物量。这导致30至50厘米深度的土壤有机碳、总氮和活性碳增加，以及植物的自养呼吸增加。分析表明，实验性变暖通过重新分配土壤湿度影响了更深层的根系生产，这有利于地下碳的积累，但并未显著影响土壤有机碳的分解。我们的研究结果表明，未来的气候变化研究需要更多地考虑水文循环的变化和当地生态系统特征。我们的研究结果将有助于理解陆地生态系统对气候变化的响应，并为全球生态系统模型提供区域案例。
