Publication Date:
2011-05-19
Description:
Dissolved inorganic carbon isotope (δ 13C DIC) is an important tool to reveal the carbon cycle in lake systems. However, there are only few studies focusing on the spatial variation of δ 13C DIC of closed lakes. Here we analyze the characteristics of δ 13C DIC of 24 sampled lakes (mainly closed lakes) across the Qiangtang Plateau (QTP) and identify the driving factors for its spatial variation. The δ 13C DIC value of these observed lakes varies in the range of - 15·0 to 3·2‰, with an average value of - 1·2‰. The δ 13C DIC value of closed lakes is close to the atmospheric isotopic equilibrium value, much higher than that in rivers and freshwater lakes reported before. The high δ 13C DIC value of closed lakes is mainly attributed to the significant contribution of carbonate weathering in the catchment and the evasion of dissolved CO 2 induced by the strong evaporation of lake water. The δ 13C DIC value of closed lakes has a logarithmic correlation with water chemistry (TDS, DIC and pCO 2), also suggesting that the evapo-concentration of lake water can influence the δ 13C DIC value. The δ 13C DIC value shows two opposite logarithmic correlations with lake size depending on the δ 13C DIC range. This study suggests that the δ 13C in carbonates in lacustrine sediments can be taken as an indicator of lake volume variation in closed lakes on QTP. © 2011 John Wiley & Sons, Ltd.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
