World Ocean World Ocean The World Ocean or Global Ocean (colloquially the sea or the ocean) is the interconnected system of Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering (70.8%) of Earth's surface, with a total volume of roughly . The unity and continuity of the World Ocean, with relatively free interchange among its parts, is of fundamental importance to oceanography. It is divided into a number of principal oceanic areas that are delimited by the continents and various oceanographic features: these divisions are the Atlantic Ocean, Arctic Ocean (sometimes considered a sea of the Atlantic), Indian Ocean, Pacific
Indian Ocean point of Tasmania. The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf. The Indian Ocean covers , including the Red Sea and the Persian Gulf but excluding the Southern Ocean, or 19.5% of the world's oceans; its volume is or 19.8% of the world's oceans' volume; it has an average depth of and a maximum depth of . The ocean's continental shelves are narrow, averaging in width. An exception is found off Australia's western coast, where the shelf width exceeds . The average depth of the ocean is . Its deepest point is Sunda