Excess primary production, calcification and nutrient fluxes of a patch reef (Tikehau atoll, French Polynesia)

Community metabolism (primary production, respiration and calcification), nutrient budgets, and export of particulate organic matter of a patch reef were investigated in the lagoon of Tikehau atoll (Tuamotu Archipelago, French Polynesia). The pinnacle studied displays strong carbonate dissolution of the top surface layer, estimated to be up to -37 g CaCO3 m(-2) d(-1). The net production is negative (-3.2 g C m(-2) d(-1)) and the gross primary production was estimated to be 4.4 g C m(-2) d(-1). So the lagoonal pinnacle appears to be a sink for particulate organic matter, which is trapped by the reef frame, and a source of nitrate for downstream lagoonal waters.