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
Evolution of Hawaiian volcanoes Waialeale, and Niihau volcanoes are in this stage of development. Eventually, erosion and subsidence break the volcano down to sea level. At this point, the volcano becomes an atoll, with a ring of coral and sand islands surrounding a lagoon. All the Hawaiian islands west of the Gardner Pinnacles in the Northwestern Hawaiian Islands are in this stage. Atolls are the product of the growth of tropical marine organisms, so these islands are only found in warm tropical waters. Eventually, the Pacific Plate carries the volcanic atoll into waters too cold for these marine organisms to maintain a reef by