A habitat is a place/territory where animal or plant lives and calls it home. Temperature, ocean depth, and distance from the shore determine the types of plants and animals living in an area of the ocean. Marine habitat is made up of variety of environments: from warm tropical waters, freezing polar regions, shorelines, canyons, and hydrothermal vents, to coral reefs. It provides the necessities of life for many species. It is home to various marine plants like kelp, seaweed and animals from smallest plankton and krill to biggest whales and sharks. The main ocean habitats are,
Shore - A great abundance of life is found in the shores. Some species spend part of their life in the water and another out of the water. They adapt to shifting water levels and wave impacts. So many of them like mussels may have hard shells.
Reefs - Made up of corals and other animals that deposit the mineral calcium carbonate to make rock formations in oceans closer to the shore. They support complex ecosystem of diverse ocean species that live in these coral reefs. One species support another; they interact with one another; harm to one species has domino effect on other species. So when reefs are destroyed or polluted, it affects the entire ecosystem.
Open Ocean - Large open expanses of ocean water. It is packed with ocean life because of the sunlight that penetrates the surface. Larger marine animals like whales, groupers, dolphins etc., to smaller species like Krill, plankton etc., and plants like seaweed live in the open ocean. These animals may also come close to the shore for foods.
Deep Sea including Trenches - These are long, narrow canyons and deepest areas of the ocean. It has high pressure, it is darker and colder. No sunlight penetrates here. Some species have adapted to live in these conditions. Large animals like whales, sharks cannot live here. Most of them here are gelatinous. Some species like Anglerfish produce their own living light (i.e.) bioluminescence to attract prey, mate or protect themselves from predators.