GUO Fang1,2, WANG Wenke1, JIANG Guanghui2, HUANG Siyu2
(1.School of Environmental science and Engineering, Chang’an University, Xi’an 710054, China;
2. Key Laboratory of Karst Dynamics, Institute of Karst Geology, Guilin 541004, China)
Abstract: Karst groundwater from Lingshui Lake in Southwest China is recharged in this paper. It has good water quality but the aquatic ecosystem is degrading. The environment proxy indexes including organic carbon and its isotope, total nitrogen, loss on ignition, C/N, and 210Pb dating were used to analyze the information of environment change of the lake and its drainage area. Results show that δ13Corg had ranged from -29.6‰ to -20.3‰ during 1957 and 2013, having good negative relationship with TOC. C/N indicates that organic carbon mainly originates from autochthonous organism in the lake. According to variation sequence of δ13Corg in the sediment core, the evolution of environment in the lake can be divided into six stages. Rainfall, air temperature and the highest water level had a certain corresponding relation with δ13Corg during 1960 and 1990, and they are also the main factors affected the isotope. However, they had no corresponding relation with the isotope of organic carbon during 1990 and 2013, although the source of organic carbon was not changed, suggesting that there are other factors such as human activities influencing the isotope. A conceptual model for aquatic environmental evolution is summarized, considering that human actives in regional scale is the main cause for environment change in the karst lake.
Key words: Lingshuilake; Karst lake; organic carbon isotope; environmental evolution; human activity
EARTH AND ENVIRONMENT Vol.44, No.5 Tot No.313, 2016, Page 485-491
