Air–water CO2 flux in an algae bloom year for Lake Hongfeng,Southwest China:implications for the carbon cycle of global inland waters

作     者：Faxiang Tao 

作者机构：State Key Laboratory of Environmental GeochemistryInstitute of GeochemistryChinese Academy of Sciences99Lincheng West RoadGuanshanhu DistrictGuiyang 550081GuizhouChina 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2017年第36卷第4期

页      面：658-666页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 081501[工学-水文学及水资源] 0708[理学-地球物理学] 0815[工学-水利工程] 

基　　金：carried out with funding from the National Key Research and Development Project provided by the Ministry of Science and Technology of China through Grant 2016YFA0601000 

主　　题：CO2 flux Algae bloom Carbon cycle Inland waters Lake Hongfeng 

摘      要：The carbon cycle of global inland waters is quantitatively comparable to other components in the global carbon budget. Among inland waters, a significant part is man-made lakes formed by damming rivers. Manmade lakes are undergoing a rapid increase in number and size. Human impacts and frequent algae blooms lead to it necessary to make a better constraint on their carbon cycles. Here, we make a primary estimation on the air–water CO_2 transfer flux through an algae bloom year for a subtropical man-made lake—Hongfeng Lake, Southwest China. To do this a new type of glass bottles was designed for content and isotopic analysis of DIC and other environmental parameters. At the early stage of algae bloom,CO_2 was transferred from the atmosphere to the lake with a net flux of 1.770 g·C·m^(-2). Later, the partial pressure(pCO_2) of the aqueous CO_2 increased rapidly and the lake outgassed to the atmosphere with a net flux of 95.727 g·C·m^(-2). In the remaining days, the lake again took up CO_2 from the atmosphere with a net flux of 14.804 g·C·m^(-2). As a whole, Lake Hongfeng released 4527 t C to the atmosphere, accounting for one-third of the atmosphere/soil CO_2 sequestered by chemical weathering in the whole drainage. With an empirical mode decomposition method, we found air temperature plays a major role in controlling water temperature, aqueous pCO_2 and hence CO_2 flux. This work indicates a necessity to make detailed and comprehensive carbon budgets in man-made lakes.