Environmental evolution recorded by multi-proxy evidence in Lake Chenghai sediments, Yunnan Province during recent 100 years  

作　　者：ZHU Zhengjie CHEN Jing'an REN Shicong ZENG Yan 

机构地区：[1]The State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences [2]Chongqing Key Laboratory of Exogenic Mineralization and Mine Environment, Chongqing Institute of Geology and Mineral Resources [3]Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining

出　　处：《Chinese Journal Of Geochemistry》2013年第1期47-55,共9页中国地球化学学报

基　　金：financially supported jointly by the National Basic Research Program of China (Grant No. 2006CB403201);the National Natural Science Foundation of China (Grant No. 40673068)

摘　　要：Lacustrine sediments can provide potential information about environmental changes in the past. On the basis of high-resolution multi-proxy analysis including carbon and nitrogen contents of organic matter, C/N ratios, inorganic carbon contents, and carbon and oxygen isotopic composition of carbonate, together with precise 137Cs dating, the environmental evolution of Lake Chenghai, Yunnan Province, during the past 100 years has been investigated. It is shown that the carbonate in Lake Chenghai is authigenic, and the organic matter is mainly derived from aquatic plants and algae, instead of terrestrial-source materials. The environmental evolution of Lake Chenghai can be diverged into three periods with the contrasting characteristics during the past 100 years. Before 1940, the stable carbon and oxygen isotope values, the poor correlation between them and the lower carbon and nitrogen contents of organic matter suggested that Lake Chenghai was open, and the lake water was oligotrophic during that period. During 1940-1993, the negative δ13C values and the gradual increase of carbon and nitrogen contents of organic matter and C/N ratios indicated that the eutrophication was aggravated. The closeness of Lake Chenghai and human activities may be responsible for this eutrophication. After 1993, notable increases in carbon and oxygen isotopic values of carbonate, carbon and nitrogen contents of organic matter, C/N ratios and inorganic carbon contents demonstrated that the increase of lacustrine productivity and the serious eutrophication were resulted from strong human activities. Therefore, the multi-proxy in Lake Chenghai sediments has reliably recorded the natural environmental evolution and the impacts from human activities.Lacustrine sediments can provide potential information about environmental changes in the past. On the basis of high-resolution multi-proxy analysis including carbon and nitrogen contents of organic matter, C/N ratios, inorganic carbon contents, and carbon and oxygen isotopic composition of carbonate, together with precise 137Cs dating, the environmental evolution of Lake Chenghai, Yunnan Province, during the past 100 years has been investigated. It is shown that the carbonate in Lake Chenghai is authigenic, and the organic matter is mainly derived from aquatic plants and algae, instead of terrestrial-source materials. The environmental evolution of Lake Chenghai can be diverged into three periods with the contrasting characteristics during the past 100 years. Before 1940, the stable carbon and oxygen isotope values, the poor correlation between them and the lower carbon and nitrogen contents of organic matter suggested that Lake Chenghai was open, and the lake water was oligotrophic during that period. Dur- ing 1940-1993, the negative 513C values and the gradual increase of carbon and nitrogen contents of organic matter and C/N ratios indicated that the eutrophication was aggravated. The closeness of Lake Chenghai and human activities may be responsible for this eutrophication. After 1993, notable increases in carbon and oxygen isotopic values of carbonate, carbon and nitrogen contents of organic matter, C/N ratios and inorganic carbon contents demonstrated that the increase of lacustrine productivity and the serious eutrophication were resulted from strong human activities. Therefore, the multi-proxy in Lake Chenghai sediments has reliably recorded the natural environmental evolution and the impacts from human activities.

关 键 词：湖泊沉积物 环境演变 多代理 云南省 程海 氧同位素组成 水体富营养化 人类活动影响 

分 类 号：P343.3[天文地球—水文科学]