Ocean Ocean An ocean () is a body of saline water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. The word "ocean" is often used interchangeably with "sea" in American English. Strictly speaking, a "sea" is a body of saline water (generally a division of the world ocean) partly or fully enclosed by land, though "the sea" refers also to the oceans. Saline water covers approximately and is customarily divided into
Lamont–Doherty Earth Observatory a collection of academic and research units within the university that together address complex environmental issues facing the planet and its inhabitants, with particular focus on advancing scientific research to support sustainable development and the needs of the world's poor. To support its research and the work of the broader scientific community, Lamont–Doherty operates the research vessel, the R/V "Marcus Langseth", which is equipped to undertake a wide range of geological, seismological, oceanographic and biological studies. Lamont–Doherty also houses the world's largest collection of deep-sea and ocean-sediment cores as well as many specialized research laboratories. The Lamont–Doherty Earth Observatory at