BENTHIC RESPIRATORY AND PHOTOSYNTHETIC QUOTIENTS IN A TROPICAL LAGOON

Carbon dioxide and oxygen fluxes were measured in 0.2 m(2) enclosures placed at the water sediment interface in the SW lagoon of New Caledon ia. Experiments, performed at several stations in a wide range of envi ronments, were carried out both in darkness to estimate respiration an d at ambient light, to assess the effects of primary production. The c ommunity respiratory quotient (CRQ = CO2 production rate/O-2 consumpti on rate) and the community photosynthetic quotient (CPQ = gross O-2 pr oduction rate/gross CO2 consumption rate) were calculated by functiona l regressions. The CRQ value, calculated from 61 incubations, was 1.14 (S.E. 0.05) and the CPQ value, obtained from 18 incubations, was 1.03 (S.E. 0.08). The linearity of the relationship between the O-2 and th e CO2 fluxes suggests that these values are representative for the who le lagoon.