Characteristics of δ13CDIC in lakes on the Tibetan Plateau and its implications for the carbon cycle

✍ Scribed by Yanbin Lei; Tandong Yao; Yongwei Sheng; Enlou Zhang; Weicai Wang; Junli Li

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 348 KB
• Volume: 26
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.8152

✦ Synopsis

Dissolved inorganic carbon isotope (υ 13 C 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 υ 13 C DIC of closed lakes. Here we analyze the characteristics of υ 13 C DIC of 24 sampled lakes (mainly closed lakes) across the Qiangtang Plateau (QTP) and identify the driving factors for its spatial variation. The υ 13 C DIC value of these observed lakes varies in the range of 15Ð0 to 3Ð2‰, with an average value of 1Ð2‰. The υ 13 C 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 υ 13 C 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 υ 13 C 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 υ 13 C DIC value. The υ 13 C DIC value shows two opposite logarithmic correlations with lake size depending on the υ 13 C DIC range. This study suggests that the υ 13 C in carbonates in lacustrine sediments can be taken as an indicator of lake volume variation in closed lakes on QTP.