摘要
随着经济飞速发展与能源消耗快速攀升,中国已成为全球酸沉降最严重的地区之一.酸沉降能够引起地表植被破坏、土壤酸化等一系列的环境问题,在全球范围受到普遍关注.作为全球最重要的生态系统之一,森林生态系统受到酸沉降的深刻影响.本文通过分析国内外已发表的相关文章,综述酸沉降对森林生态系统碳循环关键过程的影响及可能的机理.(1)对植物光合作用的影响:酸沉降通过改变叶绿素含量、气孔导度及酶活性等影响叶片光合作用,而且叶片光合功能受损程度与酸沉降强度和类型有关;(2)对林木生长的影响:酸沉降通过改变叶片结构和诱导土壤酸化影响林木生长,通常酸沉降会抑制林木生长,但会因酸沉降强度和类型有所差异;(3)对凋落物分解的影响:酸沉降通过改变土壤酶活性、微生物群落结构等对不同森林类型凋落物分解产生影响,其影响程度和方向与土壤的酸缓冲能力和酸沉降类型有关;(4)对土壤呼吸(Rs)的影响:酸沉降对Rs的影响受到根系生物量、微生物、酶活性及温度等多种因素共同作用,Rs的不同组分对酸沉降的响应机制不同;(5)对土壤有机碳(SOC)的影响:通常情况下,酸沉降抑制水溶性有机碳(DOC)的溶解,降低微生物活性及生物量从而有利于SOC的积累与稳定.通过探讨森林生态系统碳动态对酸沉降响应的不确定性因素,建议今后加强以下几方面研究:(1)干湿酸沉降比较;(2)酸沉降对树干呼吸、地下碳分配等其他关键生态过程的影响;(3)酸沉降与其他全球变化因子的耦合;(4)酸沉降对森林生态系统碳循环的长期影响.
With rapid economic development and energy consumption,acid deposition has become increasingly serious in China.Acid deposition can cause a series of environmental problems,such as vegetation degradation and soil acidification.Therefore,increasing attention is being paid to the harmful effects of acid deposition.The forest ecosystem is one of the most important ecosystems in the world that is profoundly affected by acid deposition.In this study,we reviewed the influence of acid deposition on the key processes in the carbon cycle of forest ecosystems and their possible mechanisms.(1)Acid deposition influences leaf photosynthesis by altering chlorophyll content,stomatal conductance,and enzymatic activity.Photosynthetic activity is related to the severity and type of acid deposition.(2)The biomass of forest vegetation is altered by acid deposition through direct damage to the leaf structure and indirect effects on soil acidification.Acid deposition usually inhibits tree growth,but it varies with the severity and type of acid deposition.(3)Acid deposition influences the litter decomposition rate by altering soil enzyme activity and microbial composition,and the degree and direction of the acid deposition effect are related to the soil buffering capacities and the type of acid deposition.(4)The effect of acid deposition on soil respiration(Rs)is regulated by various factors,including root biomass,microorganisms,enzyme activity,and temperature.The different components of Rs(autotrophic and heterotrophic respiration)may respond differently to acid deposition.(5)In general,acid deposition reduces dissolved organic carbon levels,microbial activity,and microbial biomass and,thus,contributes to soil organic carbon accumulation and stabilization.Finally,based on the uncertainties surrounding the response of forest ecosystem carbon dynamics to acid deposition,four directions were proposed for consideration in future research:(1)comparison of the effects on forest ecosystems between dry and wet acid deposition;(2)the response of other ecological processes,including stem respiration and belowground carbon allocation,to acid deposition;(3)the effects of the coupling of acid deposition and other environmental change factors on forest ecosystems;and(4)the long-term effect of acid deposition on the carbon cycle of forest ecosystems.
作者
王娇
关欣
黄苛
朱睦楠
宿秀江
杨庆朋
WANG Jiao;GUAN Xin;HUANG Ke;ZHU Munan;SU Xiujiang;YANG Qingpeng(CAS Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;Huitong National Research Station of Forest Ecosystem of Chinese Academy of Sciences,Hunan Key Laboratory for Structure and Ecosystem Service of Subtropical Forest,Huitong 418307,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 101408,China;Baiyunshan National Nature Reserve Administration,Baojing 416500,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2021年第3期776-785,共10页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金项目(31570402,41977092)
湖南省科技计划项目(2017TP1040)资助。
关键词
酸沉降
森林生态系统
林木生长
光合作用
凋落物
土壤呼吸
有机碳
acid deposition
forest ecosystem
forest tree growth
photosynthesis
litter
soil respiration
soil organic carbon
