Seawater carbonate chemistry, community calcification and photosynthesis during experiments with coral reefs at Shiraho reef, Ishigaki Island, southwest Japan, 2009

• Main Authors: Nakamura, T, Nakamori, T
• Format: Dataset
• Language: English
• Published: PANGAEA 2009
• Subjects: Alkalinity; total; Alkalinity anomaly technique (Smith and Key; 1975); Aragonite saturation state; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification rate of calcium carbonate; Calcite saturation state; Calculated; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Date/time end; Date/time start; Entire community; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; EXP; Experiment; Field experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Net photosynthesis rate; NN_08; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH meter (Radiometer; PHM; 240); Photon flux sensor (MDS MkV/L; Alec Electronics Co.; Ltd); Potentiometric open-cell titration; Primary production/Photosynthesis; Radiation; photosynthetically active; Rocky-shore community; Salinity; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.721856; https://doi.org/10.1594/PANGAEA.721856

Seven coral reef communities were defined on Shiraho fringing reef, Ishigaki Island, Japan. Net photosynthesis and calcification rates were measured by in situ incubations at 10 sites that included six of the defined communities, and which occupied most of the area on the reef flat and slope. Net photosynthesis on the reef flat was positive overall, but the reef flat acts as a source for atmospheric CO2, because the measured calcification/photosynthesis ratio of 2.5 is greater than the critical ratio of 1.67. Net photosynthesis on the reef slope was negative. Almost all excess organic production from the reef flat is expected to be effused to the outer reef and consumed by the communities there. Therefore, the total net organic production of the whole reef system is probably almost zero and the whole reef system also acts as a source for atmospheric CO2. Net calcification rates of the reef slope corals were much lower than those of the branching corals. The accumulation rate of the former was approximately 0.5 m kyr?1 and of the latter was ~0.7-5 m kyr?1. Consequently, reef slope corals could not grow fast enough to keep up with or catch up to rising sea levels during the Holocene. On the other hand, the branching corals grow fast enough to keep up with this rising sea level. Therefore, a transition between early Holocene and present-day reef communities is expected. Branching coral communities would have dominated while reef growth kept pace with sea level rise, and the reef was constructed with a branching coral framework. Then, the outside of this framework was covered and built up by reef slope corals and present-day reefs were constructed.