Where can coral and coral reefs be found?
Corals can be found throughout the world’s oceans, but reef-building corals are limited to oligotrophic (low nutrient) subtropical and tropical seas. Temperature and light are the primary factors which limit the growth of coral reefs. Coral reefs are restricted to a seawater temperature range of 65F to 97F and optimal reef growth occurs between 79F-82F. Light intensity decreases exponentially with depth in seawater, and, likewise, so does coral symbiont photosynthesis and coral calcification. Coral reefs are thus limited to depths of less than 20 meters assuming water clarity is satisfactory. At depths greater than 20 meters light intensity is not sufficient to promote necessary growth rates for reef development. Salinity, wave energy, water column nutrient levels, and sedimentation are also important factors which limit reef development. Optimal coral calcification occurs at normal oceanic salinities of 33-36 parts per thousand, in low nutrient level water, and in areas where sediment
