World Ocean

The World Ocean or Global Ocean (colloquially the sea or the ocean) is the interconnected system of the oceanic waters of the sea, and comprises the bulk of the hydrosphere, covering 361,132,000 square kilometres or 139,434,000 square miles (70.8%) of Earth's surface, with a total volume of roughly 1,332,000,000 cubic kilometres (320,000,000 cubic miles).[1]

"Ocean Sea" redirects here. For the novel, see Ocean Sea (novel).
Not to be confused with Ocean World, Ocean, or Sea.
World Ocean
The image by Rosetta shows mostly a part of the Water Hemisphere, with Indian Ocean at the left and Pacific at the right
Surface area361,132,000 km2 (139,434,000 sq mi)
Average depth3,688 m (12,100 ft)
Max. depth10,911 m (35,797 ft)
Water volume1,332,000,000 km3 (320,000,000 cu mi)
IslandsLists of islands
Earth's oceans
World Ocean
Animated map exhibiting the world's oceanic waters. A continuous body of water encircling Earth, the World Ocean is divided into a number of principal areas with relatively uninhibited interchange among them. Five oceanic divisions are usually defined: Pacific, Atlantic, Indian, Arctic, and Southern; the last two listed are sometimes consolidated into the first three.
The Atlantic, one component of the system, makes up 23% of the "global ocean".

Organization

The unity and continuity of the World Ocean, with relatively free interchange among its parts, is of fundamental importance to oceanography.[2] 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 an estuary of the Atlantic), Indian Ocean, Pacific Ocean, and the Southern Ocean, defined by the International Hydrographic Organization (IHO) in 2000, based on evidence that this region of the World Ocean has a distinct ecosystem and a unique impact on global climate.[3] In turn, oceanic waters are interspersed by many smaller seas, gulfs, and bays.

A global ocean has existed in one form or another on Earth for eons, and the notion dates back to classical antiquity in the form of Oceanus. The contemporary concept of the World Ocean was coined in the early 20th century by the Russian oceanographer Yuly Shokalsky to refer to the continuous ocean that covers and encircles most of Earth.[4]

If viewed from the southern pole of Earth, the Atlantic, Indian, and Pacific Oceans can be seen as lobes extending northward from the Southern Ocean. Farther north, the Atlantic opens into the Arctic Ocean, which is connected to the Pacific by the Bering Strait, forming a continuous expanse of water.

Plate tectonics, post-glacial rebound, and sea level rise continually change the coastline and structure of the world ocean.

Overview
Main article: Ocean
#OceanLocationArea
(km2)
(%)		Volume
(km3)
(%)		Avg. depth
(m)		Coastline
(km)
1Pacific OceanSeparates Asia and Australasia from the Americas[5][NB]168,723,000
46.6		669,880,000
50.1		3,970135,663
2Atlantic OceanSeparates the Americas from Europe and Africa[6]85,133,000
23.5		310,410,900
23.3		3,646111,866
3Indian OceanBorders southern Asia and separates Africa and Australia[7]70,560,000
19.5		264,000,000
19.8		3,74166,526
4Southern OceanEncircles Antarctica. Sometimes considered an extension of the Pacific, Atlantic and Indian Oceans,[8][9]21,960,000
6.1		71,800,000
5.4		3,27017,968
5Arctic OceanBorders northern North America and Eurasia and covers much of the Arctic. Sometimes considered a sea or estuary of the Atlantic.[10][11] [12]15,558,000
4.3		18,750,000
1.4		1,20545,389
Total – World Ocean 361,900,000
100		 1.335×10^9
100		 3,688 377,412[13]

Anthropogenic presence and impact
See also: Sea level rise, Marine pollution, Oceanic carbon cycle, Environmental dumping, Toxic colonialism, Plastic pollution, Marine debris, Garbage patch, Human impact on marine life, Overfishing, Holocene extinction, Anthropocene, World Oceans Day, Maritime transport, Sea lane, Ocean development, Aquaculture, Mariculture, Offshore aquaculture, Offshore geotechnical engineering, Land reclamation, Offshore construction, Artificial island, Offshore platform, Underwater habitat, Maritime history, Maritime timeline, Timeline of maritime migration and exploration, Ocean exploration, and Deep-sea exploration
Global cumulative human impact on the ocean[14]

Human activities affect marine life and marine habitats through overfishing, pollution, acidification and the introduction of invasive species. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.[15]

See also
  • Superocean – An ocean that surrounds a supercontinent
  • World Ocean Atlas – A data product of the Ocean Climate Laboratory of the National Oceanographic Data Center (U.S.)
  • Panthalassa – Prehistoric superocean that surrounded Pangaea
  •  Geography portal
  •  Oceans portal

References
  1. "WHOI Calculates Volume and Depth of World's Oceans". Ocean Power Magazine. Archived from the original on July 13, 2012. Retrieved February 28, 2012.
  2. Spilhaus, Athelstan F. 1942 (Jul.). "Maps of the whole world ocean." Geographical Review (American Geographical Society). Vol. 32 (3): pp. 431-5.
  3. Rosenberg, Matt (May 1, 2005). "Do You Know the World's Newest Ocean?". ThoughtCo. Retrieved December 16, 2017.
  4. Bruckner, Lynne and Dan Brayton (2011). Ecocritical Shakespeare (Literary and Scientific Cultures of Early Modernity). Ashgate Publishing, Ltd. ISBN 978-0754669197.
  5. "Pacific Ocean". Encyclopedia of Earth. Retrieved 2015-03-07.
  6. "Atlantic Ocean". Encyclopedia of Earth. Retrieved 2015-03-07.
  7. "Indian Ocean". Encyclopedia of Earth. Retrieved 2015-03-07.
  8. "Southern Ocean". Encyclopedia of Earth. Retrieved 2015-03-10.
  9. "Limits of Oceans and Seas, 3rd edition" (PDF). International Hydrographic Organization. 1953. Archived from the original (PDF) on 8 October 2011. Retrieved 28 December 2020.
  10. Tomczak, Matthias; Godfrey, J. Stuart (2003). Regional Oceanography: an Introduction (2 ed.). Delhi: Daya Publishing House. ISBN 978-81-7035-306-5. Archived from the original on 2007-06-30. Retrieved 2006-04-10.
  11. "'Arctic Ocean' – Encyclopædia Britannica". Retrieved 2012-07-02. As an approximation, the Arctic Ocean may be regarded as an estuary of the Atlantic Ocean.
  12. "Arctic Ocean". Encyclopedia of Earth. Retrieved 2015-03-07.
  13. "Recommendation ITU-R RS.1624: Sharing between the Earth exploration-satellite (passive) and airborne altimeters in the aeronautical radionavigation service in the band 4 200–4 400 MHz (Question ITU-R 229/7)" (PDF). ITU Radiotelecommunication Sector (ITU-R). Retrieved 2015-04-05. The oceans occupy about 3.35×108 km2 of area. There are 377412 km of oceanic coastlines in the world.
  14. Halpern, B.S.; Frazier, M.; Afflerbach, J.; et al. (2019). "Recent pace of change in human impact on the world's ocean". Scientific Reports. 9 (1): 11609. Bibcode:2019NatSR...911609H. doi:10.1038/s41598-019-47201-9. PMC 6691109. PMID 31406130.
  15. Human impacts on marine ecosystems GEOMAR Helmholtz Centre for Ocean Research. Retrieved 22 October 2019.

Further reading
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