Marine ecosystems are among the largest of Earth's aquatic ecosystems. They include oceans, salt marsh and intertidal ecology, estuaries and lagoons, mangroves and coral reefs, the deep sea and the sea floor. They can be contrasted with freshwater ecosystems, which have a lower salt content. Marine waters cover two-thirds of the surface of the Earth. Such places are considered ecosystems because the plant life supports the animal life and vice-versa. See food chains.
Marine ecosystems are very important for the overall health of both marine and terrestrial environments. According to the World Resource Center, coastal habitats alone account for approximately 1/3 of all marine biological productivity, and estuarine ecosystems (i.e., salt marshes, seagrasses, mangrove forests) are among the most productive regions on the planet. In addition, other marine ecosystems such as coral reefs, provide food and shelter to the highest levels of marine diversity in the world.
Marine ecosystems usually have a large biodiversity and are therefore thought to have a good resistance against invasive species. However, exceptions have been observed, and the mechanisms responsible in determining the success of an invasion are not yet clear.
Famous quotes containing the word marine:
“People run away from the name subsidy. It is a subsidy. I am not afraid to call it so. It is paid for the purpose of giving a merchant marine to the whole country so that the trade of the whole country will be benefitted thereby, and the men running the ships will of course make a reasonable profit.... Unless we have a merchant marine, our navy if called upon for offensive or defensive work is going to be most defective.”
—William Howard Taft (1857–1930)