Damage to shallow reef corals in The Gulf is caused by periodic exposures to air during extreme low tides and low water temperatures (Tarut Bay, eastern Saudi Arabia)

Corals were exposed to air repeatedly during a cluster of extreme low spring tides from December 1991 through April 1992 on patch reefs in Tarut Bay, Saudi Arabia. Most affected were colonies occurring at the highest levels on the tops of patch reef platforms. Corals (Acropora and Stylophora) fully exposed to air apparently suffered total mortality; those not fully exposed suffered tissue damage to their upper parts. Evaporative cooling and heat radiation may have caused coral tissue temperatures to drop below their normal range of thermal tolerance. Exposure to air occurred during winter months when air and water temperatures are at their lowest in the Gulf. -from Authors