Climate in the Coral Reef

The climate in the Coral Reef has to be “just right”.

The dependence of reef corals on plant cells means they require light. This restricts their growth to a maximum depth of 80 metres or less depending on water clarity. For reasons less clear but probably related to their physiology of limestone secretion, coral reef formation seems to be limited to temperatures above a minimum of 18degrees C. Coral reefs are therefore a phenomenon of shallow tropical seas because of the climate in the coral reef.

Geographically they are generally limited by the tropics of Cancer and Capricorn, 23.5 (degrees) (1410 nautical miles) on either side of the Equator. However, where warm ocean currents prevail there are isolated reefs at higher latitudes. There are coral reefs at Bermuda (32.5 degrees N), Lord Howe Island (31.5 degrees S), and the islands outside Tokyo Bay (34 degrees N).

Within this broad band around the tropics, reefs are remarkably similar. There are only two major regions of differentiation, the Indo-Pacific and the tropical Atlantic. The former stretches from East Africa and the Red Sea across the Indian and Pacific oceans to the west coast of the Americas. The latter is essentially restricted to the West Indian region and the coast of Brazil. At the eastern extremity of both regions, along the west coast of the Americas and off West Africa, reef development is greatly restricted by cold currents flowing toward the Equator.

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