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分别于2008和2009年夏季对南海南沙群岛永暑礁(环礁)、西沙群岛永兴岛(岛礁)和海南三亚鹿回头岸礁进行了海-气CO2交换的连续观测.结果表明:(1)南海珊瑚礁区表层海水和大气pCO2存在明显的日周期变化,白天下降,晚上上升;(2)不同礁区大气pCO2日变幅小,而表层海水pCO2日变幅较大,永暑礁潟湖为～70μmol mol-1,鹿回头及永兴岛礁坪分别为264～579μmol mol-1和420～619μmol mol-1,鹿回头礁外为324～492μmol mol-1;(3)不同礁区海-气CO2交换通量也有较大差异,永暑礁潟湖为0.4mmol CO2m-2d-1,永兴岛礁坪为4.7mmol CO2m-2d-1,鹿回头湾为9.8mmol CO2m-2d-1,表明南海珊瑚礁在夏季是大气CO2的源.在水深较浅的礁坪,生物代谢是海水pCO2变化的主要驱动因素,而较深的潟湖或礁外,水动力条件和生物代谢共同作用影响海水pCO2的变化.相对于大洋区,无机碳代谢对珊瑚礁区海水pCO2的变化有更显著的影响.
Continuous observation of sea-air CO2 exchange was carried out on Yongshuo Reef (atoll) in the Nansha Islands of the South China Sea, Yongxing Island (reefs) in the Xisha Islands and Luhuitou Head Reef in Sanya of Hainan Island in the summer of 2008 and 2009. The results show that: 1) There is a significant diurnal variation of pCO2 in the surface seawater and atmosphere in the coral reefs of the South China Sea, decreasing during the day and rising at night; (2) The pCO2 in the reefs varies day by day, while the pCO2 in the surface seawater shows a large daily variation. Was ~70μmol mol-1, and Luhuitou and Yongxing Island reefs were 264-579μmol mol-1 and 420-619μmol mol-1, respectively, and 324-492μmol mol-1 outside Luhuadiao reef. (3) - CO2 fluxes are also quite different, Yongzhu Reef lagoon is 0.4mmol CO2m-2d-1, Yongxing Island reef 4.7mmol CO2m-2d-1, Luhuitou Bay 9.8mmol CO2m-2d-1, Indicating that the South China Sea Coral Reef is the source of atmospheric CO2 in the summer.At shallow depths of the reef, the biological metabolism is the main driving force for pCO2 changes in seawater, while the deep lagoons or reefs, hydrodynamic conditions and biological metabolism affect seawater pCO2 Compared with the oceanic area, inorganic carbon metabolism had a more significant effect on the change of pCO2 in the coral reefs.