Water-mediated responses of ecosystem carbon fluxes to climatic change in a temperate steppe
Water-mediated responses of ecosystem carbon fluxes to climatic change in a temperate steppe
复制标题
温带草原生态系统碳通量对气候变化的水介导响应
DOI：
10.1111/j.1469-8137.2007.02237.x
复制
发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Wan, Shiqiang
中科院分区：
文献类型：
--
作者：
Niu, Shuli;Wu, Mingyu;Wan, Shiqiang
全球变暖和降水格局的变化可能会对生态系统碳通量产生深远影响，尤其是在水资源有限的干旱和半干旱草原地区。自2005年以来，在中国北方的温带草原上进行了一项调控温度和降水的田间实验。采用了成对嵌套的实验设计，以降水增加为主要因素，以红外辐射器模拟增温为次要因素。前两年的结果显示，生态系统总生产力（GEP）高于生态系统呼吸作用，导致研究地点在生长季出现净碳汇（通过净生态系统二氧化碳交换量，即NEE来衡量）。NEE的年际变化是由年平均降水量的差异造成的。实验增温降低了GEP和NEE，而降水增加在两年中都刺激了生态系统的碳和水通量。降水增加还缓解了实验增温对NEE的负面影响。结果表明，水分有效性在中国北方温带草原调节生态系统碳和水通量及其对气候变化的响应中起着主导作用。
Global warming and a changing precipitation regime could have a profound impact on ecosystem carbon fluxes, especially in arid and semiarid grasslands where water is limited. A field experiment manipulating temperature and precipitation has been conducted in a temperate steppe in northern China since 2005.A paired, nested experimental design was used, with increased precipitation as the primary factor and warming simulated by infrared radiators as the secondary factor.The results for the first 2 yr showed that gross ecosystem productivity (GEP) was higher than ecosystem respiration, leading to net C sink (measured by net ecosystem CO2 exchange, NEE) over the growing season in the study site. The interannual variation of NEE resulted from the difference in mean annual precipitation. Experimental warming reduced GEP and NEE, whereas increased precipitation stimulated ecosystem C and water fluxes in both years. Increased precipitation also alleviated the negative effect of experimental warming on NEE.The results demonstrate that water availability plays a dominant role in regulating ecosystem C and water fluxes and their responses to climatic change in the temperate steppe of northern China.