Borders of the oceans seas it contains) as follows: Note that these definitions exclude any marginal waterbodies that are separately defined by the IHO (such as the Kara Sea and East Siberian Sea), though these are usually considered to be part of the Arctic Ocean. The CIA defines the limits of the Arctic Ocean differently, as depicted in the map comparing its definition to the IHO's definition. The Atlantic Ocean separates the Americas from Europe and Africa. It may be further subdivided by the equator into northern and southern portions. The 3rd edition, currently in force, of the International Hydrographic Organization's (IHO) "Limits of
Ocean area and volume – are defined in part by the continents, various archipelagos, and other criteria. Oceans are fringed by smaller, adjoining bodies of water such as seas, gulfs, bays, bights, and straits. The mid-ocean ridges of the world are connected and form a single global mid-oceanic ridge system that is part of every ocean and the longest mountain range in the world. The continuous mountain range is long (several times longer than the Andes, the longest continental mountain range). The total mass of the hydrosphere is about 1.4 quintillion metric tons ( long tons or short tons), which is