ZHU Zhengjie1,2,3, CHEN Jing’an1*, ZENG Yan1,4, LI Hang2, YAN Hui5, and REN Shicong2
(1. The State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;
2. Chongqing Key Laboratory of Exogenic Minerallization and Mine Environment, Chongqing Institute of Geology and Mineral Resources, Chongqing 400042, China;
3. Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining, Chongqing 400042, China;
4.Graduate School of Chinese Academy of Sciences, Beijing 100049, China;
5. College of Urban Planning and Environment Science, Xuchang University, Xuchang 461000, China)
Abstract The carbon isotopic composition of organic matter from lake sediments has been extensively used to infer variations in productivity. In this paper, based on the study of the contents and δ13C values of organic matter in different types of lakes, it has been found that δ13C values of organic matter have different responses to lake productivity in different lakes. As to the lakes dominated by aqutic macrophytes such as Lake Caohai, organic matter becomes enriched in 13C with increasing productivity. As to the lakes dominated by aquatic algae such as Lake Chenghai, δ13C values of organic matter decrease with increasing productivity, and the degradation of aquatic algae is the main factor leading to the decrease of δ13C values of organic matter with increasing productivity. Therefore, we should be cautious to use the carbon isotopic composition of organic matter to deduce lake productivity.
Key words Lake Chenghai; Lake Caohai; δ13C value; organic matter; productivity
* Corresponding author, E-mail: chenjingan@vip.skleg.cn
CHINESE JOURNAL OF GEOCHEMISTRY Vol. 30, No. 1, 2011, page 107-133
© Science Press and Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg 2011
