MEPS 232:129-140 (2002)  -  doi:10.3354/meps232129

ABSTRACT: Organic carbon flux and community production rates were estimated on Shiraho coral reef (Ishigaki Island, Japan) from 19 to 26 September 1998. The daily net community production (P_n) and respiration rate (R) during the study period were 3 to 79 and 596 mmolC m^-2 d^-1, respectively. This resulted in a daily gross community production (P_g) of 599 to 675 mmolC m^-2 d^-1. The variation of P_n associated with the uncertainty of the curve fitting parameters of light response curves for photosynthesis was estimated using an error propagation formula. The averaged P_n ± SE was 36 ± 12 mmolC m^-2 d^-1 (n = 23), indicating that the P_n was significantly positive (t-test, p < 0.05). The apparent fluxes of dissolved organic carbon (DOC) and particulate organic carbon (POC) on the reef were estimated as 30 to 36 and 5 to 7 mmolC m^-2 d^-1, respectively; The sum of which was comparable with the P_n during the study period. The sediment trap study conducted at 1 km off the reef and 40 m depth showed that the vertical flux of POC was 1.0 mmolC m^-2 d^-1. The results indicated that 6 to 7 % of the P_g was exported to offshore and about 14 to 20% of the POC exported from the reef flat and 0.2% of the P_g reached 1 km off and 40 m depth.

KEY WORDS: Coral reef · Shiraho · Community production · Carbon flux · DOC · POC · Sediment trap