摘要
由温室气体排放所造成的气候变化已成为人们最为关注的问题之一,而目前对梯级水库温室气体的源-汇关系及其影响因素的系统研究相对较少。为厘清梯级水库水化学特征及其对水体CO_(2)分压(pCO_(2))及通量的影响,于2019年5~11月对澜沧江6个梯级水库进行定点采样,测定水体理化参数并计算水体离子来源、CO_(2)分压及释放通量(FCO_(2))。结果表明,澜沧江流域水体中的主要离子来源于碳酸盐岩、硅酸盐和蒸发岩的风化,而大气输入的贡献比例相对较低;澜沧江流域梯级水库pCO_(2)的大小受到多方面因素的影响,主要包括生物新陈代谢作用、水动力学条件以及水库库龄等。澜沧江梯级水库FCO_(2)范围为-12.99 mmol/(m2·d)至334.08 mmol/(m2·d)之间,平均值为43.38 mmol/(m2·d),总的来说澜沧江梯级水库是一个大气CO_(2)源。与pCO_(2)值类似,FCO_(2)值也呈现出明显的空间变化与季节性变化,具有较强的时空异质性。
Climate change caused by greenhouse gas emissions has recently become one of the most concerned research issues, but only relatively few studies were performed on the impact of cascade reservoirs on the carbon exchange flux between water and air and on the evaluation of the system as a source or a sink of atmospheric CO_(2). In this study, surface water samples were collected in 6 cascade reservoirs along the Lancangjiang River from May to November 2019, in order to determine the physical and chemical parameters of these water body, and to evaluate the ion source, the CO_(2)flux(FCO_(2)) released from the water body by calculating CO_(2)partial pressure(pCO_(2)), with the aim of clarifying the impact of the cascade reservoirs on the partial pressure and flux of CO_(2)between water-air interface. Our results showed that the main ions in the water bodies of these cascade reservoirs were mainly derived from the weathering of carbonate, silicate and evaporite in the catchment, while the contribution of atmospheric input was relatively limited. Considering the geochemical characteristics of all water samples, the magnitude of pCO_(2)in the investigated reservoirs might be affected by the biological metabolism, hydrodynamic conditions, and the age of the cascade reservoirs as well. The calculation gave a FCO_(2)range of-12.99-334.08 mmol/(m~2·d) for the Lancangjiang River cascade reservoirs, with an average value of 43.38 mmol/(m~2·d), much larger than 0, suggesting that the Lancangjiang River cascade reservoirs are definitely a source of atmospheric CO_(2), which needs to be taken into account while investigating the global carbon cycling and the relative climate change. The obvious temporal and spatial changes of FCO_(2)value in these reservoirs signifies the strong temporal and spatial variability of released CO_(2), warranteeing further indeep investigation.
作者
杜琪琪
李伯根
蔡虹明
邓玥
王雨春
DU Qiqi;LI Bogeng;CAI Hongming;DENG Yue;WANG Yuchun(School of Earth System Science,Tianjin University,Tianjin 300072,China;Yunnan Bureau of Hydrology and Water Resources,Kunming 650106,China;Yunnan Qidi Industrial Development Co.Ltd.,Kunming 650228,China;Department of Water Environment,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)
出处
《地球与环境》
CAS
CSCD
北大核心
2023年第1期36-46,共11页
Earth and Environment
基金
国家自然科学基金项目(U1612442、U1802241、92047204)。
关键词
澜沧江
梯级水库
水化学特征
CO_(2)分压
CO_(2)通量
Lancangjiang River
cascade reservoirs
hydrochemical characteristics
CO_(2)partial pressure
air-water CO_(2)flux
