Marine habitats are habitats that support marine life (the plants, animals, and other organisms that live in the saltwater of the sea or ocean, or the brackish water of coastal estuaries). Marine life depends in some way on the saltwater that is in the sea (the term marine comes from the Latin mare, meaning sea or ocean). The marine environment supports many kinds of habitats that can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends from as far as the tide comes in on the shoreline out to the edge of the continental shelf. Most marine life is found in coastal habitats, even though the shelf area occupies only 7% of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into pelagic and demersal zones. Pelagic habitats are found near the surface or in the open water column, away from the bottom of the ocean. Demersal habitats are near or on the bottom of the ocean. Marine habitats can be modified by their inhabitants. Some marine organisms, like corals, kelp, mangroves, and seagrasses, are ecosystem engineers which reshape the marine environment to the point where they create further habitat for other organisms. By volume, the ocean provides most of the habitable space on the planet.