Flux of organic carbon burial and carbon emission from a large reservoir: implications for the cleanliness assessment of hydropower

作     者：Fushun Wang Yunchao Lang Cong-Qiang Liu Yong Qin Ningxiao Yu Baoli Wang 

作者机构：School of Environmental and Chemical EngineeringShanghai University Institute of Surface-Earth System SciencesTianjin University 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2019年第64卷第9期

页      面：603-611页

核心收录：

学科分类：07[理学] 08[工学] 070602[理学-大气物理学与大气环境] 0815[工学-水利工程] 0706[理学-大气科学] 

基　　金：supported by the National Key Research and Development Program of China (2016YFA0601003) the National Natural Science Foundation of China (41573064) 

主　　题：The Hongfeng Reservoir Sediment Carbon sink Underwater seismology method 

摘      要：Accurately quantifying the budget of carbon sources and sinks in hydropower reservoirs is important for evaluating the cleanliness of hydroelectricity. However, current research on carbon emissions from reservoirs has rarely taken into account the organic carbon(OC) buried in sediment. Only greenhouse gas emissions from the water-air interface at reservoirs have been examined, which would result in an overestimation of the greenhouse effect of reservoirs. In November 2017, this study investigated the distribution of sediment in the Hongfeng Reservoir(HFR) in southwest China, a typical large hydropower reservoir, by using an underwater seismology monitoring system. We estimated the flux of OC into sediment using the results of a sediment survey and a dataset compiled from references. Our results show that, the HFR retained 200,715 t of OC in the sediment since its impounding after dam construction to the sampling year of 2017, when the average burial flux was 3,521 t-C aà1(106 g C aà1) and the modern burial flux was 5,449 t-C aà1. After excluding the exogenous OC, the modern valid carbon sink of the sediment was 4,632 t per year. Under the current state of the reservoir, taking the modern valid carbon sink value, the carbon emissions from the reservoir s surface, and the discharge water from the dam into consideration, the net carbon sink of the HFR is found to be 1,098.9 t-C aà1. If the hydroelectricity generated by the reservoir is converted to a carbon sink, then the total net carbon sink becomes 12,972.9 t-C aà1.This work argues that both reservoir sediment and hydroelectricity are important carbon sinks and both should be included in assessments of the greenhouse effects of reservoirs.