METABOLIC PERFORMANCE OF A SHALLOW REEF PATCH NEAR EILAT ON THE RED-SEA

Productivity and calcification were measured across a small, represent ative patch of the fringing reef near-Eilat, Israel in early March 199 0. Measurements were made by floating an instrument package across the reef patch with the current and measuring changes in oxygen concentra tion and pH together with water temperature and light intensity (photo synthetically active radiation). Average rates of photosynthesis, resp iration, calcification and solution of reef rock were estimated for th e reef patch at different times of the day and, hence, at different li ght intensities. Light response curves were constructed for productivi ty and calcification and used, together with the diurnal light regime, to provide estimates for daily metabolic performance. Gross productiv ity for the reef patch was 12.3 gC . m-2 . d-1. The production: respir ation ratio was 1.6:1. Net calcification was 16.3 gCaCO3 . m-2 . d-1, which extrapolates to 6.0 kgCaCO3 . m-2 . year-1. Although the reef is growing at high latitude, in a hypersaline environment, and is subjec t to unnatural pressures, its metabolic performance matches the perfor mance of equivalent reefal areas in the tropical Indo-Pacific.