外源碳输入对陆地生态系统碳循环关键过程的影响及其微生物学驱动机制

外源碳输入对土壤碳源可利用性的改变不仅直接影响着微生物参与陆地生态系统的碳循环过程,而且也制约着微生物对其它营养元素的需求。在大气氮沉降持续增加的全球变化背景下,部分地区已出现生态系统氮养分条件的显著变化甚至土壤中活性氮素的过量积累,进而带来微生物对碳源需求的增加。通过人为调控碳源的可利用性,改善微生物的碳限制状况,将对科学的增加陆地生态系统固碳能力具有极为重大的意义。综述了国内外有关外源碳输入对土壤碳排放、凋落物分解以及土壤碳库影响及其主要的微生物作用机制的相关研究结果,以期能够为未来氮沉降持续增加情景下,如何科学有效地提高生态系统的碳汇潜力提供一定的参考。

Effects of external carbon on the key processes of carbon cycle in a terrestrial ecosystem and its microbial driving mechanism

External carbon input to soil influences the available carbon content and the microbial carbon cycle, as well as the microbial utilization of other nutritional elements in the terrestrial ecosystem. With globally increasing nitrogen deposition, the nitrogen content of soil in some regions has changed significantly and now exceeds microbial demand. This in turn increases the need for available carbon. Therefore, artificial regulation of available carbon sources might be essential for relieving microbial carbon limitation and improving carbon sequestration capacity of terrestrial ecosystem. In this paper, previous studies concerning the influences of external carbon input on soil carbon emission, litter fall decomposition, soil carbon pools, and the functional microbial mechanisms in these processes were reviewed. This work will provide a reference for improving the carbon sink capacity of terrestrial ecosystems.