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

Productivity and calcification were measured across a small, representative patch of the fringing reef near-Eilat, Israel in early March 1990. Measurements were made by floating an instrument package across the reef patch with the current and measuring changes in oxygen concentration and pH together with water temperature and light intensity (photosynthetically active radiation). Average rates of photosynthesis, respiration, calcification and solution of reef rock were estimated for the reef patch at different times of the day and, hence, at different light intensities. Light response curves were constructed for productivity and calcification and used, together with the diurnal light regime, to provide estimates for daily metabolic performance. Gross productivity for the reef patch was 12.3 gC . m-2 . d-1. The production: respiration 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 subject to unnatural pressures, its metabolic performance matches the performance of equivalent reefal areas in the tropical Indo-Pacific.