氮素输入对沼泽湿地碳固定和周转的影响

Effects of Nitrogen Input on Carbon Fixation and Turnover in Swamp Wetlands

湿地是地球表层各圈层之间相互作用的一个重要界面,是陆地生态系统碳(C)、氮(N)循环的重要组成部分。目前,人口增加、工农业发展、污水排放等人类活动导致湿地生态系统的N负荷增加,N输入的持续增强已成为全球性的环境问题,对湿地各种生态过程产生深刻的影响。该文总结了外源N输入对湿地植物生长、光合C固定、有机碳矿化、呼吸作用和土壤C库的影响,在此基础之上总结了对不同湿地植物生物量和光合速率产生负面影响的N输入临界负荷值,简要分析了国内湿地之间N负荷临界值存在差异的原因,深入理解N输入对中国沼泽湿地生态系统C固持和周转的影响。

Wetland is an important interface of the earth’s surface layers interactions and an important part of the carbon(C)and nitrogen(N)cycles of terrestrial ecosystems.At present,due to the increase of populations,the development of industry and agriculture,sewage discharge and other human activities,the nitrogen load is increasing in the wetland ecosystem.The continuous increase of N input has become a global environmental problem,which has a profound impact on various ecological processes of wetlands.This paper summarizes the effects of N input on plant growth,photosynthetic C fixation,organic carbon mineralization,respiration,and soil C pool in wetland ecosystems.On this basis,the critical loading of N input value which has negative impact on the plant biomass and photosynthetic rate in different wetlands was summarized,the reasons for the difference of N load critical value among domestic wetlands were further analyzed,so as to deeply understand the impact of nitrogen input on carbon fixation and turnover in swamp wetland ecosystem in China.