Characteristics of δ13CDIC in lakes on the Tibetan Plateau and its implications for the carbon cycle |
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| Authors: | Yanbin Lei Tandong Yao Yongwei Sheng Enlou Zhang Weicai Wang Junli Li |
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| Institution: | 1. Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China;2. Department of Geography, University of California, Los Angeles, CA 90095‐1524, USA;3. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China |
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| Abstract: | Dissolved inorganic carbon isotope (δ13CDIC) is an important tool to reveal the carbon cycle in lake systems. However, there are only few studies focusing on the spatial variation of δ13CDIC of closed lakes. Here we analyze the characteristics of δ13CDIC of 24 sampled lakes (mainly closed lakes) across the Qiangtang Plateau (QTP) and identify the driving factors for its spatial variation. The δ13CDIC value of these observed lakes varies in the range of ? 15·0 to 3·2‰, with an average value of ? 1·2‰. The δ13CDIC 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 δ13CDIC value of closed lakes is mainly attributed to the significant contribution of carbonate weathering in the catchment and the evasion of dissolved CO2 induced by the strong evaporation of lake water. The δ13CDIC value of closed lakes has a logarithmic correlation with water chemistry (TDS, DIC and pCO2), also suggesting that the evapo‐concentration of lake water can influence the δ13CDIC value. The δ13CDIC value shows two opposite logarithmic correlations with lake size depending on the δ13CDIC range. This study suggests that the δ13C in carbonates in lacustrine sediments can be taken as an indicator of lake volume variation in closed lakes on QTP. Copyright © 2011 John Wiley & Sons, Ltd. |
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| Keywords: | Tibetan Plateau δ 13CDIC closed lakes carbon cycle spatial variation |
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