@article {Ohde:1999:0007-4977:559, title = "Carbon dioxide flux and metabolic processes of a coral reef, Okinawa", journal = "Bulletin of Marine Science", parent_itemid = "infobike://umrsmas/bullmar", publishercode ="umrsmas", year = "1999", volume = "65", number = "2", publication date ="1999-09-01T00:00:00", pages = "559-576", itemtype = "ARTICLE", issn = "0007-4977", url = "http://www.ingentaconnect.com/content/umrsmas/bullmar/1999/00000065/00000002/art00018", author = "Ohde, Shigeru and van Woesik, Robert", abstract = "This study investigates carbon dioxide flux associated with calcification, photosynthesis and respiration on a coral reef atoll near Okinawa, Japan. Metabolic activity and nutrient concentrations were routinely measured at three study sites: (1) on the reef flat, (2) in the lagoon, and (3) 1050 m off the reef. Sampling was undertaken during low spring tide events, when the atoll was temporarily emerged, over five periods in 199395. Two of the five sampling periods included both day and night sampling. Alkalinity, Dissolved Inorganic Carbon (DIC), Dissolved Oxygen (DO) and pH varied slightly among sampling periods, however there were no differences in the range of variation. Compared to the lagoon and open waters, the reef flat had significantly lower alkalinity and DIC, and significantly higher DO and pH during the day. DIC reached a maximum shortly before sunrise and was closely coupled with total alkalinity over the diel cycle. Rates of netorganic carbon production and calcification for the reef flat were estimated at 12 mmol m2 h1 and 9 mmol m2 h1, respectively, although calcification was low (i.e., under the detection limit) at night. The respiration rate of the reef flat was approximately 6 mmol m2 h1. A comparison of CO2 released by calcification and net organic production indicates that this reef flat acted as a sink for atmospheric carbon dioxide in the daytime, but acted as a source at night, and that the net CO2 diel budget was almost equally balanced.", }