干旱半干旱区CO_2浓度升高对生态系统的影响及碳氮耦合研究进展

Effect of Elevated CO_2 on Ecosystem and C-N Coupling in Arid and Semi-arid Region

大气CO2浓度升高已成为全球备受关注的环境问题。CO2排放量的增加加剧了地球表层的温室效应,也对生态系统的结构和功能产生了重要影响。生态系统对CO2浓度升高的响应是一个长期的过程。在干旱半干旱区,CO2浓度的升高对生态系统生产力、植物、土壤和微生物等都有影响,尤其改变了生态系统中的碳循环,并加剧了生态系统对氮的需求。碳循环是生态系统重要的能量流通渠道;氮是生态系统最重要的营养元素之一,也是生态系统固碳能力的限制因子。因此,加强碳氮耦合关系的探讨对研究全球气候及生态系统变化具有重要意义。对干旱半干旱区CO2浓度升高对生态系统的影响及碳氮耦合的研究进展进行了综述和讨论,为进一步研究干旱半干旱区碳、氮循环提供参考。

Atmospheric CO2 concentrations had increased from approximately 280 μmol/mol in the late 19th century to over 360 μmol/mol today.Elevated CO2 not only pricked up global greenhouse effect,but also changed the C balance of global ecosystems,which led to the changes of ecosystem structure and function.Alterations in microbial mineralization and nutrient cycling may control the long-term response of ecosystems to elevated CO2.Elevated CO2 concentrations influenced carbon cycle,ecosystem productivity,plant,soil,microbe,and other environmental factors.The effects of elevated CO2 on growth were highly dependent on interactions with N cycling.Particularly important was the effect of elevated CO2 on N cycling and availability because shortages in N could eventually attenuate the increased plant biomass production seen in short-term elevated CO2 studies.Changes in microbial biomass C and N,microbial activity and inorganic N could indicate the effects of elevated CO2 on N dynamics.Increases in N-use efficiency tended to increase the C/N ratio of plant materials grown in elevated CO2.The purpose of this paper is to summarize the changes of ecosystems and C-N coupling due to the increasing atmospheric CO2 concentration in order to lucubrate to carbon cycle and nitrogen cycle in arid and semi-arid region.