水布垭水库水体碳时空变化特征及其影响因素分析

为了评估大型水库对河流碳循环的拦截作用,选择清江流域最上游水布垭水库为典型案例,采用德国元素公司vario TOC分析仪对定期采集水样进行分析,研究新建大型水库水体碳时空分布特征及其影响因素。结果表明,水布垭水库表层水体总碳、总无机碳、溶解有机碳和颗粒有机碳平均含量分别为26.665、24.089、2.141和0.438 mg/L,在水库年内蓄水阶段呈现显著的峰值,其空间分布格局在支流库湾和坝前典型断面表现出显著的差异,在水体碳中总无机碳占据主导地位,与湖泊水体碳时空分布特征极为相似。由于受到人类活动和自然环境的双重影响,水体无机碳则与水体电导率指标具有较强的相关性,溶解有机碳则与水体温度具有直接的关系,而数量最少的颗粒有机碳则与水体叶绿素含量具有弱相关关系。研究成果可以为理解水库碳循环过程机制提供数据支持,对于开展大坝建设的河流碳循环影响评估具有重要参考意义。

SPATIAL AND TEMPORAL DISTRIBUTION OF CARBON CONCENTRATION IN SURFACE WATER FROM THE SHUIBUYA RESERVOIR

The Shuibuya Reservoir over the Qingjiang River Basin was selected as a typical reservoir to analyze the spatial and temporal distribution of carbon cycle in large hydropower reservoir intercepting rive eco-system in this study.The spatial and temporal distribution of carbon in surface water were obtained by analyzing water sampling using vario TOC analyzer in laboratory and other aquatic environment parameters was attained by HACH hydro-lab multi-parameters water quality analyzer in field experiments.The results showed that the monthly mean concentration of total carbon,total inorganic carbon,dissolved organic carbon and particulate organic carbon in surface water from the Shuibuya Reservoir were 26.665 mg/L,24.089 mg/L,2.141 mg/L and 0.438 mg/L,respectively during measurement.The carbon concentrations peaked in spring and autumn,while valleyed in summer and winter.Inorganic carbon accounts for most of total carbon and the spatial variation of all carbon parameters mentioned above over the whole reservoir was very different at measurement stations,which is similar with that of lakes.The Shuibuya Reservoir was affected by both human activities and natural environment.Inorganic concentration was strongly related with water conductivity,dissolved organic carbon in water was strongly related with water temperature and chlorophyll concentration in surface water exerted more influences on the spatial and temporal heterogeneity of less particulate organic carbon in surface water over the Shuibuya Reservoir.This study is expected to provide more supports and in-situ data for understanding aquatic carbon cycle of reservoir and play a pivotal role to evaluate the effects of dam construction on aquatic ecosystem.