陆地生态系统碳-氮-水循环的关键耦合过程及其生物调控机制探讨

陆地生态系统碳循环、氮循环和水循环是全球变化科学研究的三大主题,而陆地生态系统碳氮水耦合循环过程及其生物调控机制则是全球变化生态学研究的前沿性科学问题。目前,对陆地生态系统碳氮水耦合循环过程及其调控机制认识的不足是制约评估陆地增汇/减排效果,预测分析全球变化对生态系统生产力和固碳功能影响的瓶颈性问题。本文在综合分析陆地生态系统碳氮水循环的耦合过程基础上,论述了制约生态系统碳氮水循环空间格局耦联关系的生物地理学机制,制约典型生态系统碳氮水循环耦合关系的生物生理生态学机制,以及典型生态系统碳氮水耦合循环的关键生物物理和生物化学过程。重点评述了生态系统碳氮水耦合循环的主要过程及其生物调控机制研究进展,包括:(1)植物叶片冠层生物学过程和根系冠层生物学过程及其对生态系统碳氮水耦合循环控制机制,以及二者之间的关联与互作关系;(2)土壤微生物功能群网络及其对碳氮循环过程的影响;(3)生态系统碳氮水交换通量的时空变化规律,以及生态系统的生态化学计量学理论与实践。本文最后还简要介绍了国家基金委重大研究项目"森林生态系统碳氮水耦合循环的生物控制机制"的研究思路及其主要研究内容。期望能够通过这些探讨对推动我国该研究领域的基础理论建设和新技术发展有所贡献。

Discussion on the key processes of carbon-nitrogen-water coupling cycles and biological regulation mechanisms in terrestrial ecosystem

Carbon, nitrogen and water cycles in terrestrial ecosystem are three critical subjects in global change science. The coupling modes of these cycles and their biological regulation mechanisms had been frontier issues in global change ecology. At present, lack of knowledge on the processes of carbon-nitrogen-water coupling cycles and the regulation mechanisms had limited assessment of terrestrial carbon sink enhancement and emission reduction. This had become a major problem in predicting the effects of global change on the productivity and carbon sequestration of ecosystems. Based on synthetic analysis of terrestrial ecosystem carbon, nitrogen and water cycles, this paper expounded biogeography mechanisms that limited spatial patterns of coupling cycles. It also discussed biological and physio-ecological mechanisms that limited the coupling cycles and the key biophysical and biochemical processes. The main processes and biological regulation mechanisms of carbon-nitrogen-water coupling cycles discussed included: 1) biological processes of plant leaf canopy/root canopy and its regulation mechanism on carbon-nitrogen-water coupling cycles and the interactions among them; 2) soil microbial functional group network and its effects on carbon, nitrogen and water cycles; 3) spatial and temporal variations in carbon, nitrogen and water fluxes in terrestrial ecosystem along with the theory and practice of ecosystem stoichiometry. Finally, the paper briefly introduced the strategic schemes and main contents of the key programs of National Natural Science Foundation of China-Biological Control Mechanisms of the Coupling Cycles of Carbon, Nitrogen, and Water in Forest Ecosystem. This had the potential to promote the theory and technique of developing related fields.