Air-Sea Gas Exchange and CO 2 Fluxes in a Tropical Coral Reef Lagoon

Abstract

Coral reefs are found predominately in tropical and subtropical areas and are sites of active carbon cycling. Knowledge of gas transfer velocities is necessary for carbon cycle studies in coral reef environments, and past studies in these environments have used wind speed/gas exchange parameterizations intended for the open ocean. In order to determine the relationship between wind speed and gas exchange, and to assess the suitability of open ocean wind speed/gas exchange parameterizations for this environment, two 3 He/SF 6 tracer release experiments were conducted during two separate years in a tropical coral reef lagoon in Kaneohe Bay, Hawaii. The results show that because water depth is relatively deep in much of Kaneohe Bay, some parameterizations intended for the open ocean can be used to predict gas transfer velocities in that environment. The bay was a source of CO 2 to the atmosphere during both studies, and the residence times of water in the bay during the two studies differed by a factor of two.