Carbon cycle in coral reefs and its change with environment

珊瑚礁通过光合作用和钙化作用与全球碳循环有关。近几千年来，随着环境的变化，珊瑚礁地貌的形成改变了其碳循环模式。我们研究了大堡礁和帕劳群岛这两个典型的大陆和海洋堡礁系统近1万年来的珊瑚礁地貌/生物地带性和生产速率、海洋-珊瑚礁-泻湖系统的海水和碳通量以及珊瑚礁的形成。研究结果表明：1)堡礁系统分为礁滩和礁湖，礁滩从海到洋分为礁前、礁顶、排列的珊瑚铺装层和沙滩，具有地貌特征和珊瑚群落结构；2)通过卫星和航空遥感数据可以识别这些珊瑚礁分区；(3) 8000 ~ 4000年前随着海平面上升形成了堡礁体系，4000年前随着海平面稳定形成了礁带；4)礁滩的净有机产量为167 mmol C m^<-2> day^<-1>，超过了碳酸钙净产量130 mmol C m^<-2> day^<-1>；有机产品随着潮流以溶解和颗粒的形式被输送到外海洋。

Coral reefs are related with global carbon cycles through photosynthesis and calcification. The mode of carbon cycles in reefs have been changed with formation of reef geomorphology accompanying with environmental changes for the last several thousand years. We have made researches on reef geomorphological/biological zonations and production rates, sea water and carbon fluxes across ocean-reef-lagoon system and formation of coral reefs for the last 10,000 years in the Great Barrier Reef and Palau Islands-typical continental and oceanic barrier reef systems. We have obtained the following results : 1) Barrier reef system is divided into the barrier reef flat and lagoon : the barrier reef flat is subdivided into reef front, reef crest, aligned coral pavement and sand flat from sea to ocean with geomorphological features and coral community structure ; 2) These reef zonation can be identified by satellite and aerial remote sensing data ; 3) The barrier reef systems have been formed with the rising sea from 8,000 to 4,000 years ago and reef zonation have been formed with the stabilized sea since 4,000 years ago ; 4) Net organic production 167 mmol C m^<-2> day^<-1>, which exceeds net calcium carbonate production 130 mmol C m^<-2> day^<-1>, exists on barrier reef flat ; 5) Organic products are delivered to outer ocean as dissolved and particulate forms accompanying with tidal currents.