Carbonate production by scleractinian corals not only maintains coral reef growth, but also represents an important source of atmospheric carbon dioxide. In this paper the carbonate production by scleractinian corals at Luhuitou fringing reef, Sanya, Hainan Island, China, is investigated with an ecological census-based method. Averaged carbonate production is 1.16 ± 0.55 kg·m −2 ·a −1 and 3.52 ± 1.32 kg·m −2 ·a -1 on the reef flat and reef slope, respectively, depending on the composition and distribution of corals and the intergeneric difference of skeletal growth. In response to the rapidly increasing human impacts, coral carbonate production has decreased by 80%-89% at this fringing reef since the 1960s; as a result, the reef accretion rate declined and became lower than the rate of sea level rise. Further development of the Luhuitou fringing reef will switch significantly from lateral extension seawards to vertical growth, reflecting a response of coral reef bio-geomorphic process to strong human impacts under the background of global sea level rise. In addition, decrease in coral carbonate production reduced CO 2 release from this fringing reef. In the future, it is likely that the role played by coral reefs, especially of fringing reefs, in the ocean and even in the global carbon cycle will be modified or weakened by the increasing human impacts.coral reefs, scleractinian coral, carbonate production, sea level change, atmospheric carbon dioxide, Sanya, Hainan Island Coral reefal carbonate production is the carbonate precipitating process while the reef-building organisms dominated by scleractinian corals grow and reef develops, and it is a key factor controlling the geological and geomorphic development of coral reefs [1] . Because of releasing CO 2 during the carbonate production, coral reefs have been considered as one of global atmospheric CO 2 sources [2][3][4][5][6] and accordingly coral reefal carbonate production is regarded as an important component of the global carbon cycle [7] . Ecological census-based method has been widely used in the investigation and study on the reefal carbonate production [8][9][10][11][12][13][14][15][16] . A recent estimate of global reefal carbonate production varied from 0.9 to 2.7 kg·m −2 ·a −1 on reef flat and reef slope, and the gross carbonate production of global coral reefs was 0.65-0.83 Gt·a −1 [7] . Released CO 2 during the carbonate production of global coral reefs was 0.02 to 0.08 Gt C·a −1 [2] . At present, the global coral reefs are dramatically declining owing to global warming and increasing human impacts [17] , such as El Niño, pollution and seawater eutrophication, which bring heavy effects on the reefal carbonate production [18,19] . On the other hand, seawater acidification resulted from atmospheric CO 2 rising is also significantly influencing carbonate production of organisms in shallow sea such as coral reefs [20][21][22][23] . Model predictions suggest that atmospheric CO 2 is expected to increase by 1-1.5 times in the middle to end of the 21th cen...