Hawaiian Trough the Hawaiian Arch. The Hawaiian Arch extends about 200 meters above the surrounding ocean floor, and contains tilted coral reefs. The coral reefs in the Hawaiian Tough are described as mesophotic coral ecosystems, which can be found between 100 and 500 feet below sea level. 43 percent of fish species documented at the mesophotic reefs are unique to the Hawaiian Islands. At Maui’s ‘Au’au channel the largest uninterrupted mesophotic coral ecosystem was discovered, with an area larger than 3 square miles. These reefs contained many stony, reef building coral that belong to the genus Leptoseris, which are adapted for deep
Endemism in the Hawaiian Islands island some 28 million years ago. Kure Atoll, a little further to the northwest, is near the Darwin point—defined as waters of a temperature that allows coral reef development to "just" keep up with isostatic sinking. And extending back in time before Kure, an even older chain of islands spreads northward nearly to the Aleutian Islands; these former islands, all north of the Darwin point, are now completely submerged as the Emperor Seamounts. The islands are well known for the environmental diversity that occurs on high mountains within a trade winds field. On a single island, the climate can differ