"and some of its mass merged with Earth. Between approximately 4.1 and , numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic activity and outgassing. Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids, protoplanets, and comets. In this model, atmospheric ""greenhouse gases"" kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity. By , Earth's magnetic field was established, which"
"Sea The sea, the world ocean or simply the ocean is the connected body of salty water that covers over 70 percent of the Earth's surface. It moderates the Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. It has been travelled and explored since ancient times, while the scientific study of the sea—oceanography—dates broadly from the voyages of Captain James Cook to explore the Pacific Ocean between 1768 and 1779. The word ""sea"" is also used to denote smaller, partly landlocked sections of the ocean. The most abundant solid dissolved in sea water"
"from which life first arose, should now be threatened by the activities of one form of that life. But the sea, though changed in a sinister way, will continue to exist: the threat is rather to life itself"". Sea The sea, the world ocean or simply the ocean is the connected body of salty water that covers over 70 percent of the Earth's surface. It moderates the Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. It has been travelled and explored since ancient times, while the scientific study of the sea—oceanography—dates broadly from"
"in oceans and other large bodies of water, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds, and precipitation. Oceans hold 97% of surface water, glaciers, and polar ice caps 2.4%, and other land surface water such as rivers, lakes, and ponds 0.6%. Additionally, a minute amount of the Earth's water is contained within biological bodies and manufactured products. An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface (an area of some 361 million square kilometers) is covered by ocean,"
"Approximately 71% of Earth's surface, an area of some 361 million square kilometers (139.5 million square miles), is covered by ocean. The average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5%). The water cycle refers to the transfer of water from one state or reservoir to another. Reservoirs include atmospheric moisture (snow, rain and clouds), streams, oceans, rivers, lakes, groundwater, subterranean aquifers, polar ice caps and saturated soil. Solar energy, in the form of heat and light (insolation), and gravity cause the transfer from one state to another over periods from hours"
"or another natural kind of body of water. An ocean is a major body of saline water, and a component of the hydrosphere. Approximately 71% of the Earth's surface (an area of some 362 million square kilometers) is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas. More than half of this area is over 3,000 meters (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt. Though generally recognized as"
"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"
"several principal oceans and smaller seas, with the ocean covering approximately 71% of Earth's surface and 90% of the Earth's biosphere. The ocean contains 97% of Earth's water, and oceanographers have stated that less than 5% of the World Ocean has been explored. The total volume is approximately 1.35 billion cubic kilometers (320 million cu mi) with an average depth of nearly . As the world ocean is the principal component of Earth's hydrosphere, it is integral to life, forms part of the carbon cycle, and influences climate and weather patterns. The World Ocean is the habitat of 230,000 known"
"about 0.023% of Earth's total mass. Less than 3% is freshwater; the rest is saltwater, almost all of which is in the ocean. The area of the World Ocean is about 361.9 million square kilometers (139.7 million square miles), which covers about 70.9% of Earth's surface, and its volume is approximately 1.335 billion cubic kilometers (320.3 million cubic miles). This can be thought of as a cube of water with an edge length of . Its average depth is about , and its maximum depth is at the Mariana Trench. Nearly half of the world's marine waters are over deep."
"land surface (119,000 - 74,200 = 44,800 km/year) represents the total runoff of the Earth's rivers (42,700 km/year) and direct groundwater runoff to the ocean (2100 km/year). These are the principal sources of fresh water to support life necessities and man's economic activities."" Water is a basic necessity of life. Since 2/3 of the Earth is covered by water, the Earth is also called the blue planet and the watery planet. Hydrosphere plays an important role in the existence of the atmosphere in its present form. Oceans are important in this regard. When the Earth was formed it had only"
"a freshwater lake. The United Nations Convention on the Law of the Sea states that all of the ocean is ""sea"". Earth is the only known planet with seas of liquid water on its surface, although Mars possesses ice caps and similar planets in other solar systems may have oceans. It is still unclear where Earth's water came from, but, seen from space, our planet appears as a ""blue marble"" of its various forms: oceans, ice caps, clouds. Earth's of sea contain about 97.2 percent of its known water and cover more than 70 percent of its surface. Another 2.15%"
". At the other extreme, the slowest-moving plate is the Eurasian Plate, progressing at a typical rate of . The total surface area of Earth is about . Of this, 70.8%, or , is below sea level and covered by ocean water. Below the ocean's surface are much of the continental shelf, mountains, volcanoes, oceanic trenches, submarine canyons, oceanic plateaus, abyssal plains, and a globe-spanning mid-ocean ridge system. The remaining 29.2%, or , not covered by water has terrain that varies greatly from place to place and consists of mountains, deserts, plains, plateaus, and other landforms. Tectonics and erosion, volcanic"
"Southern Hemisphere The Southern Hemisphere is the half of Earth that is south of the Equator. It contains all or parts of five continents (Antarctica, Australia, about 90% of South America, the southern third of Africa, and several southern islands off the continental mainland of Asia), four oceans (Indian, South Atlantic, Southern, and South Pacific) and most of the Pacific Islands in Oceania. Its surface is 80.9% water, compared with 60.7% water in the case of the Northern Hemisphere, and it contains 32.7% of Earth's land. Owing to the tilt of Earth's rotation relative to the Sun and the ecliptic"
"the Maritime Southeast Asia, and the Southern Cone of the Americas. Antarctica is solely within the water hemisphere, though sources differ as to whether it is considered land for the purposes of calculation. Most of the Pacific Ocean and the Indian Ocean are on the water hemisphere. Proportionately, the Water Hemisphere is approximately 89% water, 6% dry land and 5% polar ice cap. The below table follows the assignments of Alphonse Berget of land to the two hemispheres. Land and water hemispheres The land and water hemispheres of Earth, sometimes capitalised as the Land Hemisphere and Water Hemisphere, are the"
"the Moon causes ocean tides, stabilizes Earth's orientation on its axis, and gradually slows its rotation. Earth is the densest planet in the Solar System and the largest of the four terrestrial planets. Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans. The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earth's polar regions are covered"
"Atlantic Ocean The Atlantic Ocean is the second largest of the world's oceans, with an area of about . It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the ""Old World"" from the ""New World"". The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and the Americas to the west. As one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast,"
"of the regions most vulnerable to the effects of climate change, the Asia-Pacific region needs more public-private partnerships (PPPs) to successfully implement its sustainable development initiatives. Oceans cover 71 percent of the Earth's surface. They are essential for making the planet livable. Rainwater, drinking water and climate are all regulated by ocean temperatures and currents. Over 3 billion people depend on marine life for their livelihood. Oceans absorb 30 percent of all carbon dioxide produced by humans. The oceans contain more than 200,000 identified species, and there might be thousands of species that are yet to be discovered. Oceans are"
"is approximately which is about 29.2% of its total surface. Water covers approximately 70.8% of Earth's surface, mainly in the form of oceans and ice formations. Creation myths in many religions recall a story involving the creation of the world by a supernatural deity or deities, including accounts wherein the land is separated from the oceans and the air. The Earth itself has often been personified as a deity, in particular a goddess. In many cultures, the mother goddess is also portrayed as a fertility deity. To the Aztecs, Earth was called ""Tonantzin""—""our mother""; to the Incas, Earth was called"
"is characterized by different kinds of crust, oceanic crust and continental crust. Oceans cover 70% of the Earth's surface. Because oceans lie lower than continents, the former serve as sedimentary basins that collect sediment eroded from the continents, known as clastic sediments, as well as precipitation sediments. Ocean basins also serve as repositories for the skeletons of carbonate- and silica-secreting organisms such as coral reefs, diatoms, radiolarians, and foraminifera. Geologically, an oceanic basin may be actively changing size or may be relatively, tectonically inactive, depending on whether there is a moving plate tectonic boundary associated with it. The elements of"
"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"
"Marine ecosystem Marine ecosystems are among 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,"
"an area of with a mean depth of , resulting in an estimated volume of . If all of Earth's crustal surface was at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km. About 97.5% of the water is saline; the remaining 2.5% is fresh water. Most fresh water, about 68.7%, is present as ice in ice caps and glaciers. The average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5% salt). Most of the salt in the ocean comes from the"
"coastlines, frequently washing aground where it is known as beach litter. Atlantic Ocean The Atlantic Ocean is the second largest of the world's oceans, with an area of about . It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the ""Old World"" from the ""New World"". The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and the Americas to the west. As one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean, to the"
"the co-Chairs stated that the Commission is ""inspired by the opportunity that exists for the high seas to play a regenerative role in restoring whole ocean health, and by the potential of a small number of bold proposals to stimulate a cycle of recovery."" The high seas constitute 45% of the Earth’s surface and are essential to the health of the planet. Five key ""drivers of ocean decline"" were identified by the Commission: rising demand for resources; technological advances; decline of fish stocks; climate change (including ocean acidification), biodiversity and habitat loss; weak high seas governance. The mandate of the"
"Water distribution on Earth Water is distributed across earth. Most water in the Earth's atmosphere and crust comes from the world ocean's saline seawater, while freshwater accounts for only 2.5% of the total. Because the oceans that cover roughly 78% of the area of the Earth reflect blue light, the Earth appears blue from space, and is often referred to as the ""blue planet"" and the ""Pale Blue Dot"". An estimated 1.5 to 11 times the amount of water in the oceans may be found hundreds of miles deep within the Earth's interior, although not in liquid form. The oceanic"
"zone. Subtropical gyres make up 40% of the Earth’s surface and play critical roles in carbon fixation and nutrient cycling. This particular gyre covers most of the Pacific Ocean and comprises four prevailing ocean currents: the North Pacific Current to the north, the California Current to the east, the North Equatorial Current to the south, and the Kuroshio Current to the west. Its large size and distance from shore has caused the NPSG to be poorly sampled and thus poorly understood. The life processes in open-ocean ecosystems are a sink for the atmosphere’s increasing. Gyres make up a large proportion,"
"the global community. Perhaps one of the most recent adverse effects of climate change to be explored is that of ocean acidification. Our oceans cover approximately 71 percent of the Earth's surface and support a diverse range of ecosystems, which are home to over 50 percent of all the species on the planet. Oceans regulate climate and weather as well as providing nutrition for a vast variety of species, humans included. Covering such an extensive part of the planet has allowed the oceans to absorb a large portion of the carbon dioxide () from the atmosphere. This process is part"
"Sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the"
"smoothly into oceans of supercritical hydrogen. The atmosphere of Venus is 96.5% carbon dioxide, which is a supercritical fluid at its surface. On other bodies: 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"
"Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south and is bounded by Asia and Australia in the west and the Americas in the east. At in area (as defined with an Antarctic southern border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about one-third of its total surface area, making it larger than all of Earth's land area combined. The centers of"
"several 'separate' oceans, these waters comprise one global, interconnected body of salt water often referred to as the World Ocean or global ocean. The deep seabeds are more than half the Earth's surface, and are among the least-modified natural environments. The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean. A river is a natural watercourse, usually freshwater, flowing toward an ocean, a lake, a sea or another river. A"
"ecosystem services. Marine ecosystem Marine ecosystems are among 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"
"in the oceans as a result of evaporation returning the fresh water to land as rain and snow. As a result, the vast bulk of the water on Earth is regarded as ""saline"" or ""salt water"", with an average salinity of 35‰ (or 3.5%, roughly equivalent to 34 grams of salts in 1 kg of seawater), though this varies slightly according to the amount of runoff received from surrounding land. In all, water from oceans and marginal seas, saline groundwater and water from saline closed lakes amount to over 97% of the water on Earth, though no closed lake stores"