Where are corals found?

All corals require very salty water to survive—from 32 to 42 parts per thousand—restricting them to coastal and open ocean areas. Because of this, different types of coral communities are typically located in parts of the ocean based on their light requirements.

The red dots on the map represent the locations of reef building stony corals around the world. The majority of reef-building stony corals are found in shallow tropical and subtropical waters ranging from 35N to 35S latitude. View a large map of where reef building corals are found.

Shallow water stony corals are typically found in areas that receive a lot of light and warm water. Many grow the best in water temperatures between 23° and 29° C (73.4° and 84.2° F), but some can tolerate temperatures as high as 40° C (104° F) for short periods. These corals’ requirement for high light also explains why most reef-building species are restricted to the region in the ocean where light penetrates to a depth of approximately 30 meters (98.4 feet).

The sun is powerful, but its intensity dwindles as it passes through the depths of the sea. Yet even the ocean’s dim middle reaches—the mesophotic zone (and its deepest, sunlight-free areas—the deep sea, or deep benthic zone)—host an abundance of life. Mesophotic corals (meso meaning middle and photic meaning light) are so named because they have lower light requirements than shallow corals. But, enough sunlight still reaches the mesophotic zone to support light-dependent coral species.

Sometimes healthy deep sea corals take on a stark white appearance. Learn more and view a larger image.

Mesophotic coral reefs are usually understudied because they are too deep to reach with regular scuba gear and often too shallow for submarine expeditions. However, with the increasing safety and accessibility of technical diving and remotely operated vehicle technologies, larger areas of mesophotic coral communities are being explored.

Deep-sea corals, which include both stony and soft corals, live in dark waters as cold as 4° C. With increased deep sea exploration, scientists have discovered there are reefs in parts of the deep sea. These reefs, like shallow coral reefs, are also built by stony corals. However, they grow much slower than their shallow water counterparts.