长江口溶解无机碳循环的地球化学研究  

A Geochemical Study on Carbon Cycling in the Changjiang Estuary

作　　者：Sivaji Patra 刘丛强[1] 李思亮[1] 王宝利[1] 汪齐连[1] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550002 [2]中国科学院研究生院,北京100039

出　　处：《地球与环境》2010年第4期409-413,共5页Earth and Environment

基　　金：国家自然科学基金重点项目(90610037);国家自然科学基金创新群体项目(40721002)

摘　　要：于2005年6月对长江口23个站点的溶解性无机碳及其同位素组成进行了采样调查。结果发现长江河流区水体的pCO2均处于过饱和状态,但在进入河口区后发生大幅度的下降;δ13CDIC为-10.0‰～-0.9‰,且随盐度发生梯度性变化;DIC和δ13CDIC值偏离河水、海水混合线,显示了长江河口碳的复杂生物地球化学过程,包括内部碳酸盐岩体系及外部生物的作用:河流区主要受水-气界面CO2逸散的影响;河口区主要受光合作用的影响;海岸区则主要受碳酸盐类矿物沉淀作用的影响。Water samples collected along the Changjiang River estuary in June 2005 were studied for their dissolved inorganic carbon （DIC） contents and their isotopic composition. We found that CO2 super-saturation significantly occurred in the riverine zone and decreased sharply in the coastal zone. The δ13CDIC values are within the range of -10.0‰ and -0.9‰, and vary along the salinity gradient. The deviation of observed DIC concentrations and δ13 CDIC from the mixing equation between riverine and marine water indicates multiple processes controlling the carbon cycling in different zones. Degassing of CO2 mainly occurred in the riverine zone, photosynthesis in the estuary zone and carbonate mineral precipitation in the coastal zone.

关 键 词：长江 河口 溶解无机碳 同位素 CO2 

分 类 号：P595[天文地球—地球化学]