World Ocean

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World Ocean
Earth in True Color - Rosetta.jpg
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)
Islands Lists of islands
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. World ocean map.gif
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 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 (139,434,000 square miles) or 70.8% of Earth's surface, with a total volume of roughly 1,332,000,000 cubic kilometres (320,000,000 cubic miles). [1]

Contents

Concept

The notion can be found in the root of the concept of ocean, though 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. [2]

System

The unity and continuity of the World Ocean, with relatively free interchange among its parts, is of fundamental importance to oceanography. [3]

Plate tectonics, post-glacial rebound, and sea level rise continually change the coastline and structure of the world ocean. That said a global ocean has existed in one form or another on Earth for eons.

Oceanic division

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, the latter being a relatively new addition identified with a distinct ecosystem and a unique impact on global climate. [4] In turn, oceanic waters are interspersed by many smaller seas, gulfs, and bays.

Anthropogenic presence and impact

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. [5]

See also

Related Research Articles

Mediterranean Sea Sea between Europe, Africa and Asia, connected to the Atlantic Ocean

The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant. Although the sea is sometimes considered a part of the Atlantic Ocean, it is usually referred to as a separate body of water. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago.

Marine biology The scientific study of organisms that live in the ocean

Marine biology is the scientific study of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.

Oceanography The study of the physical and biological aspects of the ocean

Oceanography, also known as oceanology, is the study of the physical and biological aspects of the ocean. It is an important Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within: astronomy, biology, chemistry, climatology, geography, geology, hydrology, meteorology and physics. Paleoceanography studies the history of the oceans in the geologic past. An oceanographer is a person who studies many matters concerned with oceans including marine geology, physics, chemistry and biology.

Underwater environment The aquatic or submarine environment

The underwater environment refers to the region below the surface of, and immersed in, liquid water in a natural or artificial feature, such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation.

Ocean current Directional mass flow of oceanic water generated by external or internal forces

An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents are primarily horizontal water movements.

Continental shelf A portion of a continent that is submerged under an area of relatively shallow water known as a shelf sea

A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an insular shelf.

Natural environment All living and non-living things occurring naturally, generally on Earth

The natural environment encompasses all living and non-living things occurring naturally, meaning in this case not artificial. The term is most often applied to the Earth or some parts of Earth. This environment encompasses the interaction of all living species, climate, weather and natural resources that affect human survival and economic activity. The concept of the natural environment can be distinguished as components:

Ocean gyre Any large system of circulating ocean currents

In oceanography, a gyre is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect; planetary vorticity, horizontal friction and vertical friction determine the circulatory patterns from the wind stress curl (torque).

Biogeochemistry is the scientific discipline that involves the study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment. In particular, biogeochemistry is the study of the cycles of chemical elements, such as carbon and nitrogen, and their interactions with and incorporation into living things transported through earth scale biological systems in space through time. The field focuses on chemical cycles which are either driven by or influence biological activity. Particular emphasis is placed on the study of carbon, nitrogen, sulfur, iron, and phosphorus cycles. Biogeochemistry is a systems science closely related to systems ecology.

Atlantic Oceanographic and Meteorological Laboratory

The Atlantic Oceanographic and Meteorological Laboratory (AOML), a federal research laboratory, is part of National Oceanic and Atmospheric Administration's (NOAA) Office of Oceanic and Atmospheric Research (OAR), located in Miami, Florida. AOML's research spans tropical cyclone and hurricanes, coastal ecosystems, oceans and human health, climate studies, global carbon systems, and ocean observations. It is one of seven NOAA Research Laboratories (RLs).

Marine ecosystem Ecosystem in saltwater environment

Marine ecosystems are the largest of Earth's aquatic ecosystems and are distinguished by waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Marine ecosystems include nearshore systems, such as the salt marshes, mudflats, seagrass meadows, mangroves, rocky intertidal systems and coral reefs. They also extend outwards from the coast to include offshore systems, such as the surface ocean, pelagic ocean waters, the deep sea, oceanic hydrothermal vents, and the sea floor. Marine ecosystems are characterized by the biological community of organisms that they are associated with and their physical environment.

The following outline is provided as an overview of and introduction to Oceanography.

Sea Large body of salt water

The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers over 70 percent of the Earth's surface. It moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. Humans harnessing and studying the sea have been recorded since ancient times, and evidenced well into prehistory, while its modern scientific study is called oceanography. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, as well as certain large, entirely landlocked, saltwater lakes, such as the Caspian Sea.

Ocean the body of salt water which covers the majority of the surface of the Earth

An ocean is the body of salt water which covers approximately 71% of the surface of the Earth. It is also "any of the large bodies of water into which the great ocean is divided". These five oceans are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans.

Arctic Ocean Ocean in the north polar region

The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately 14,060,000 km2 (5,430,000 sq mi) and is also known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea. It is sometimes classified as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing World Ocean.

Marine habitats A habitat that supports marine life

Marine habitats are habitats that support marine life. Marine life depends in some way on the saltwater that is in the sea. A habitat is an ecological or environmental area inhabited by one or more living species. The marine environment supports many kinds of these habitats.

Effects of climate change on oceans Effects of climate change on oceans

Effects of climate change on oceans provides information on the various effects that climate change has on oceans. Climate change can affect sea levels, coastlines, ocean acidification, ocean currents, seawater, sea surface temperatures, tides, the sea floor, weather, and trigger several changes in ocean bio-geochemistry; all of these affect the functioning of a society.

The poleward migration of coral species refers to the phenomenon brought on by rising sea temperatures, wherein corals are colonising cooler climates in an attempt to circumvent coral bleaching, rising sea levels and ocean acidification. In the age of Anthropocene, the changing global climate has disrupted fundamental natural processes and brought about observable changes in the submarine sphere. Whilst coral reefs are bleaching in tropical areas like the Great Barrier Reef, even more striking, and perhaps more alarming; is the growth of tropical coral species in temperate regions, which has taken place over the past decade. Coral reefs are frequently compared to the "canaries in the coal mine," who were used by miners as an indicator of air quality. In much the same way, "coral reefs are sensitive to environmental changes that could damage other habitats in the future," meaning they will be the first to visually exhibit the true implications of global warming on the natural world..

Human impact on marine life

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

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. Bruckner, Lynne and Dan Brayton (2011). Ecocritical Shakespeare (Literary and Scientific Cultures of Early Modernity) . Ashgate Publishing, Ltd. ISBN   978-0754669197.
  3. Spilhaus, Athelstan F. 1942 (Jul.). "Maps of the whole world ocean." Geographical Review (American Geographical Society). Vol. 32 (3): pp. 431-5.
  4. Rosenberg, Matt (May 1, 2005). "Do You Know the World's Newest Ocean?". ThoughtCo. Retrieved December 16, 2017.
  5. Human impacts on marine ecosystems GEOMAR Helmholtz Centre for Ocean Research. Retrieved 22 October 2019.