The Amazon River in South America is the largest river by discharge volume of water in the world, by some definitions it is the longest. The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon's most distant source, until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru; the Mantaro and Apurímac join, with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters at Manaus, the river's largest city. At an average discharge of about 209,000 cubic metres per second —approximately 6,591 cubic kilometres per annum, greater than the next seven largest independent rivers combined—the Amazon represents 20% of the global riverine discharge to the ocean.
The Amazon basin is the largest drainage basin in the world, with an area of 7,050,000 square kilometres. The portion of the river's drainage basin in Brazil alone is larger than any other river's basin; the Amazon enters Brazil with only one-fifth of the flow it discharges into the Atlantic Ocean, yet has a greater flow at this point than the discharge of any other river. The river was known by Europeans as the Marañón and the Peruvian part of the river is still known by that name today, it became known as the Rio Amazonas in Spanish and Portuguese, or The Amazon in English. The name Rio Amazonas was given after native warriors attacked a 16th-century expedition by Francisco de Orellana; the warriors were led by women, reminding de Orellana of the Amazon warriors, a tribe of women warriors related to Iranian Scythians and Sarmatians mentioned in Greek mythology. The word Amazon itself may be derived from the Iranian compound *ha-maz-an- " fighting together" or ethnonym *ha-mazan- "warriors", a word attested indirectly through a derivation, a denominal verb in Hesychius of Alexandria's gloss "ἁμαζακάραν· πολεμεῖν.
Πέρσαι", where it appears together with the Indo-Iranian root *kar- "make". During what many archaeologists call the formative stage, Amazonian societies were involved in the emergence of South America's highland agrarian systems; the trade with Andean civilisations in the terrains of the headwaters in the Andes, formed an essential contribution to the social and religious development of the higher altitude civilisations of among others the Muisca and Incas. Early human settlements were based on low-lying hills or mounds. Shell mounds were the earliest evidence of habitation, they are associated with ceramic age cultures. Artificial earth platforms for entire villages are the second type of mounds, they are best represented by the Marajoara culture. Figurative mounds are the most recent types of occupation. There is ample evidence that the areas surrounding the Amazon River were home to complex and large-scale indigenous societies chiefdoms who developed large towns and cities. Archaeologists estimate that by the time the Spanish conquistador De Orellana traveled across the Amazon in 1541, more than 3 million indigenous people lived around the Amazon.
These pre-Columbian settlements created developed civilizations. For instance, pre-Columbian indigenous people on the island of Marajó may have developed social stratification and supported a population of 100,000 people. In order to achieve this level of development, the indigenous inhabitants of the Amazon rainforest altered the forest's ecology by selective cultivation and the use of fire. Scientists argue that by burning areas of the forest repetitiously, the indigenous people caused the soil to become richer in nutrients; this created dark soil areas known as terra preta de índio. Because of the terra preta, indigenous communities were able to make land fertile and thus sustainable for the large-scale agriculture needed to support their large populations and complex social structures. Further research has hypothesized; some say that its effects on forest ecology and regional climate explain the otherwise inexplicable band of lower rainfall through the Amazon basin. Many indigenous tribes engaged in constant warfare.
James Stuart Olson wrote: "The Munduruku expansion dislocated and displaced the Kawahíb, breaking the tribe down into much smaller groups... first came to the attention of Europeans in 1770 when they began a series of widespread attacks on Brazilian settlements along the Amazon River." In March 1500, Spanish conquistador Vicente Yáñez Pinzón was the first documented European to sail up the Amazon River. Pinzón called the stream Río Santa María del Mar Dulce shortened to Mar Dulce sweet sea, because of its fresh water pushing out into the ocean. Another Spanish explorer, Francisco de Orellana, was the first European to travel from the origins of the upstream river basins, situated in the Andes, to the mouth of the river. In this journey, Orellana baptised some of the affluents of the Amazonas like Rio Negro and Jurua; the name Amazonas is taken from the native warriors that attacked this expedition women, that reminded De Orellana of the mythical female Amazon warriors from the
Hudson Bay is a large body of saltwater in northeastern Canada with a surface area of 1,230,000 km2. It drains a large area, about 3,861,400 km2, that includes parts of southeastern Nunavut, most of Manitoba, Ontario and indirectly through smaller passages of water to parts of North Dakota, South Dakota and Montana. Hudson Bay's southern arm is called James Bay; the Eastern Cree name for Hudson and James Bay is Wînipekw or Wînipâkw, meaning muddy or brackish water. Lake Winnipeg is named by the local Cree, as is the location for the city of Winnipeg; the bay is named after Henry Hudson, an Englishman sailing for the Dutch East India Company, after whom the river that he explored in 1609 is named. Hudson Bay encompasses 1,230,000 km2, making it the second-largest water body using the term "bay" in the world; the bay is shallow and is considered an epicontinental sea, with an average depth of about 100 m. It is 1,050 km wide. On the east it is connected with the Atlantic Ocean by Hudson Strait. Hudson Bay is considered part of the Arctic Ocean.
Other authorities include it in the Atlantic, in part because of its greater water budget connection with that ocean. Some sources describe Hudson Bay as the Arctic Ocean. Canada has claimed it as such on historic grounds; this claim is disputed by the United States but no action to resolve it has been taken. English explorers and colonists named Hudson Bay after Sir Henry Hudson who explored the bay beginning August 2, 1610 on his ship Discovery. On his fourth voyage to North America, Hudson worked his way around Greenland's west coast and into the bay, mapping much of its eastern coast. Discovery became trapped in the ice over the winter, the crew survived onshore at the southern tip of James Bay; when the ice cleared in the spring, Hudson wanted to explore the rest of the area, but the crew mutinied on June 22, 1611. They left Hudson and others adrift in a small boat. No one knows the fate of Hudson or the crew members stranded with him, but historians see no evidence that they survived for long afterwards.
In 1668, Nonsuch reached the bay and traded for beaver pelts, leading to the creation of the Hudson's Bay Company which still bears the historic name. The HBC negotiated a trading monopoly from the English crown for the Hudson Bay watershed, called Rupert's Land. France contested this grant by sending several military expeditions to the region, but abandoned its claim in the Treaty of Utrecht. During this period, the Hudson's Bay Company built several factories along the coast at the mouth of the major rivers; the strategic locations were bases for inland exploration. More they were trading posts with the indigenous peoples who came to them with furs from their trapping season; the HBC shipped the furs to Europe and continued to use some of these posts well into the 20th century. The Port of Churchill was an important shipping link for trade with Europe and Russia until its closure in 2016 by owner OmniTRAX. HBC's trade monopoly was abolished in 1870, it ceded Rupert's Land to Canada, an area of 3,900,000 km2, as part of the Northwest Territories.
Starting in 1913, the Bay was extensively charted by the Canadian Government's CSS Acadia to develop it for navigation. This mapping progress led to the establishment of Churchill, Manitoba as a deep-sea port for wheat exports in 1929, after unsuccessful attempts at Port Nelson; the International Hydrographic Organization defines the northern limit of Hudson Bay as follows: A line from Nuvuk Point to Leyson Point, the Southeastern extreme of Southampton Island, through the Southern and Western shores of Southampton Island to its Northern extremity, thence a line to Beach Point on the Mainland. North of Hudson Bay has a polar climate being one of the few places in the world where this type of climate is found south of 60 °N, going further south towards Quebec, where Inukjuak is still dominated by the tundra. From Arviat, Nunavut to the west to the south and southeast prevails the subarctic climate; this is because in the central summer months, heat waves can advance and leave the weather cool, where the average temperature of the month is above 10 °C.
At the southern end in the extension known as James Bay arises the humid continental climate with a more pronounced and hot summer. The average annual temperature in the entire bay is around 0 ° C or below. Except for the James Bay area the average water temperature is only 7° C to the south in January. Although the difference is small in summer in the extreme northeast, wintery temperatures are four to five colder degrees coming near -27 °C; the Hudson Bay region has low year-round average temperatures. The average annual temperature for Churchill at 59°N is −5 °C and Inukjuak facing cool wester
The Black Sea is a body of water and marginal sea of the Atlantic Ocean between the Balkans, Eastern Europe, the Caucasus, Western Asia. It is supplied by a number of major rivers, such as the Danube, Southern Bug, Dniester and the Rioni. Many countries drain into the Black Sea, including Austria, Belarus and Herzegovina, Croatia, Czech Republic, Germany, Moldova, Romania, Serbia, Slovenia and Ukraine; the Black Sea has an area of 436,400 km2, a maximum depth of 2,212 m, a volume of 547,000 km3. It is constrained by the Pontic Mountains to the south, Caucasus Mountains to the east, Crimean Mountains to the north, Strandzha to the southwest, Dobrogea Plateau to the northwest, features a wide shelf to the northwest; the longest east–west extent is about 1,175 km. Important cities along the coast include Batumi, Constanța, Istanbul, Novorossiysk, Ordu, Rize, Sevastopol, Sukhumi, Varna and Zonguldak; the Black Sea has a positive water balance. There is a two-way hydrological exchange: the more saline and therefore denser, but warmer, Mediterranean water flows into the Black Sea under its less saline outflow.
This creates a significant anoxic layer well below the surface waters. The Black Sea drains into the Mediterranean Sea, via the Aegean Sea and various straits, is navigable to the Atlantic Ocean; the Bosphorus Strait connects it to the Sea of Marmara, the Strait of the Dardanelles connects that sea to the Aegean Sea region of the Mediterranean. These waters separate the Caucasus and Western Asia; the Black Sea is connected, to the North, to the Sea of Azov by the Strait of Kerch. The water level has varied significantly. Due to these variations in the water level in the basin, the surrounding shelf and associated aprons have sometimes been land. At certain critical water levels it is possible for connections with surrounding water bodies to become established, it is through the most active of these connective routes, the Turkish Straits, that the Black Sea joins the world ocean. When this hydrological link is not present, the Black Sea is an endorheic basin, operating independently of the global ocean system, like the Caspian Sea for example.
The Black Sea water level is high. The Turkish Straits connect the Black Sea with the Aegean Sea, comprise the Bosphorus, the Sea of Marmara and the Dardanelles; the International Hydrographic Organization defines the limits of the Black Sea as follows: On the Southwest. The Northeastern limit of the Sea of Marmara. In the Kertch Strait. A line joining Cape Takil and Cape Panaghia. Current names of the sea are equivalents of the English name "Black Sea", including these given in the countries bordering the sea: Abkhazian: Амшын Еиқәа, IPA: Adyghe: Хы шӏуцӏэ, IPA: Bulgarian: Черно море, IPA: Crimean Tatar: Къара денъиз, Qara deñiz IPA: Georgian: შავი ზღვა, translit.: shavi zghva, IPA: Laz and Mingrelian: უჩა ზუღა, IPA:, or ზუღა, IPA:, "Sea" Romanian: Marea Neagră, pronounced Russian: Чёрное мо́рe, IPA: Turkish: Karadeniz, IPA: Ukrainian: Чорне море, IPA: Such names have not yet been shown conclusively to predate the 13th century, but there are indications that they may be older. In Greece, the historical name "Euxine Sea", which holds a different meaning, is still used: Greek: Éfxeinos Póntos.
The principal Greek name "Póntos Áxeinos" is accepted to be a rendering of Iranian word *axšaina-, compare Avestan axšaēna-, Old Persian axšaina-, Middle Persian axšēn/xašēn, New Persian xašīn, as well as Ossetic œxsīn. The ancient Greeks, most those living to the north of the Black Sea, subsequently adopted the name and altered it to á-xenos. Thereafter, Greek tradition refers to the Black Sea as the "Inhospitable Sea", Πόντος Ἄξεινος Póntos Áxeinos, first attested in Pindar; the name was considered to be "ominous" and was changed into the euphemistic name "Hospitable sea", Εὔξεινος Πόντος Eúxeinos Póntos, for the first time attested in Pindar. This became the used designation for the sea in Greek. In contexts related to mythology, the older form Póntos Áxeinos remained favored, it has been erroneously suggested that the name was derived from the color of the water, or was at least related to climatic conditions. Black or dark in this context, referred to a system in which colors represent the cardinal points of the known world.
Black or dark represented the north. The symbolism based on cardinal points was used in multiple occasions and is therefore attested. For example, the "Red Sea", a body of water reported since the time of Herodotus in fact designated the Indian Ocean, together with bodies of water now known as the Persian Gulf and the Red Sea. According to the same explanation and reasoning, it is therefore considered to be impossible
Japan is an island country in East Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asian continent and stretches from the Sea of Okhotsk in the north to the East China Sea and the Philippine Sea in the south; the kanji that make up Japan's name mean "sun origin", it is called the "Land of the Rising Sun". Japan is a stratovolcanic archipelago consisting of about 6,852 islands; the four largest are Honshu, Hokkaido and Shikoku, which make up about ninety-seven percent of Japan's land area and are referred to as home islands. The country is divided into 47 prefectures in eight regions, with Hokkaido being the northernmost prefecture and Okinawa being the southernmost one; the population of 127 million is the world's tenth largest. 90.7 % of people live in cities. About 13.8 million people live in the capital of Japan. The Greater Tokyo Area is the most populous metropolitan area in the world with over 38 million people. Archaeological research indicates; the first written mention of Japan is in Chinese history texts from the 1st century AD.
Influence from other regions China, followed by periods of isolation from Western Europe, has characterized Japan's history. From the 12th century until 1868, Japan was ruled by successive feudal military shōguns who ruled in the name of the Emperor. Japan entered into a long period of isolation in the early 17th century, ended in 1853 when a United States fleet pressured Japan to open to the West. After nearly two decades of internal conflict and insurrection, the Imperial Court regained its political power in 1868 through the help of several clans from Chōshū and Satsuma – and the Empire of Japan was established. In the late 19th and early 20th centuries, victories in the First Sino-Japanese War, the Russo-Japanese War and World War I allowed Japan to expand its empire during a period of increasing militarism; the Second Sino-Japanese War of 1937 expanded into part of World War II in 1941, which came to an end in 1945 following the Japanese surrender. Since adopting its revised constitution on May 3, 1947, during the occupation led by SCAP, the sovereign state of Japan has maintained a unitary parliamentary constitutional monarchy with an Emperor and an elected legislature called the National Diet.
Japan is a member of the ASEAN Plus mechanism, UN, the OECD, the G7, the G8, the G20, is considered a great power. Its economy is the world's third-largest by nominal GDP and the fourth-largest by purchasing power parity, it is the world's fourth-largest exporter and fourth-largest importer. Japan benefits from a skilled and educated workforce. Although it has renounced its right to declare war, Japan maintains a modern military with the world's eighth-largest military budget, used for self-defense and peacekeeping roles. Japan is a developed country with a high standard of living and Human Development Index, its population enjoys the highest life expectancy and third lowest infant mortality rate in the world, but is experiencing issues due to an aging population and low birthrate. Japan is renowned for its historical and extensive cinema, influential music industry, video gaming, rich cuisine and its major contributions to science and modern technology; the Japanese word for Japan is 日本, pronounced Nihon or Nippon and means "the origin of the sun".
The character nichi means "sun" or "day". The compound therefore means "origin of the sun" and is the source of the popular Western epithet "Land of the Rising Sun"; the earliest record of the name Nihon appears in the Chinese historical records of the Tang dynasty, the Old Book of Tang. At the end of the seventh century, a delegation from Japan requested that Nihon be used as the name of their country; this name may have its origin in a letter sent in 607 and recorded in the official history of the Sui dynasty. Prince Shōtoku, the Regent of Japan, sent a mission to China with a letter in which he called himself "the Emperor of the Land where the Sun rises"; the message said: "Here, I, the emperor of the country where the sun rises, send a letter to the emperor of the country where the sun sets. How are you". Prior to the adoption of Nihon, other terms such as Yamato and Wakoku were used; the term Wa is a homophone of Wo 倭, used by the Chinese as a designation for the Japanese as early as the third century Three Kingdoms period.
Another form of Wa, Wei in Chinese) was used for an early state in Japan called Nakoku during the Han dynasty. However, the Japanese disliked some connotation of Wa 倭, it was therefore replaced with the substitute character Wa, meaning "togetherness, harmony"; the English word Japan derives from the historical Chinese pronunciation of 日本. The Old Mandarin or early Wu Chinese pronunciation of Japan was recorded by Marco Polo as Cipangu. In modern Shanghainese, a Wu dialect, the pronunciation of characters 日本; the old Malay word for Japan, Japun or Japang, was borrowed from a southern coastal Chinese dialect Fukienese or Ningpo – and this Malay word was encountered by Portuguese traders in Southeast Asia in the 16th century. These Early Portuguese traders brought the word
Patagonia is a sparsely populated region at the southern end of South America, shared by Chile and Argentina. The region comprises the southern section of the Andes mountains and the deserts and grasslands to the east. Patagonia is one of the few regions with coasts on three oceans, with the Pacific Ocean to the west, the Atlantic Ocean to the east, the Southern Ocean to the south; the Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia. Most geographers and historians locate the northern limit of Chilean Patagonia at Huincul Fault, in Araucanía Region; the name Patagonia comes from the word patagón, used by Magellan in 1520 to describe the native tribes of the region, whom his expedition thought to be giants. It is now believed that the people he called the Patagons were Tehuelches, who tended to be taller than Europeans of the time; the Argentine researcher Miguel Doura observed that the name Patagonia derives from the ancient Greek region of modern Turkey called Paphlagonia, possible home of the patagon personage in the chivalric romances Primaleon printed in 1512, ten years before Magellan arrived in these southern lands.
The hypothesis was published in a 2011 New Review of Spanish Philology report. Argentine Patagonia is for the most part a region of steppelike plains, rising in a succession of 13 abrupt terraces about 100 metres at a time, covered with an enormous bed of shingle bare of vegetation. In the hollows of the plains are ponds or lakes of fresh and brackish water. Towards Chilean territory the shingle gives place to porphyry and basalt lavas, animal life becomes more abundant and vegetation more luxuriant, consisting principally of southern beech and conifers; the high rainfall against the western Andes and the low sea surface temperatures offshore give rise to cold and humid air masses, contributing to the ice-fields and glaciers, the largest ice-fields in the Southern hemisphere outside of Antarctica. Among the depressions by which the plateau is intersected transversely, the principal ones are the Gualichu, south of the Río Negro, the Maquinchao and Valcheta, the Senguerr, the Deseado River. Besides these transverse depressions, there are others which were occupied by more or less extensive lakes, such as the Yagagtoo and Colhue Huapi, others situated to the south of Puerto Deseado, in the centre of the country.
In the central region volcanic eruptions, which have taken part in the formation of the plateau during the Cenozoic, cover a large part of the land with basaltic lava-caps. There, caused principally by the sudden melting and retreat of ice aided by tectonic changes, has scooped out a deep longitudinal depression, best in evidence where in contact with folded Cretaceous rocks which are uplifted by the Cenozoic granite, it separates the plateau from the first lofty hills, whose ridges are called the pre-Cordillera. To the west of these, a similar longitudinal depression extends all along the foot of the snowy Andean Cordillera; this latter depression contains the richest and most fertile land of Patagonia. Lake basins along the Cordillera were excavated by ice-streams, including Lake Argentino and Lake Fagnano, as well as coastal bays such as Bahía Inútil; the geological limit of Patagonia has been proposed to be Huincul Fault which forms a major discontinuity. The fault truncates various structures including the Pampean orogen found further north.
The ages of base arocks change abruptly across the fault. There have been discrepancies among geologists on the origin of the Patagonian landmass. Víctor Ramos has proposed that the Patagonian landmass originated as an allochthonous terrane that separated from Antarctica and docked in South America 250 to 270 Ma in the Permian era. A 2014 study by R. J. Pankhurst and coworkers rejects any idea of a far-travelled Patagonia claiming it is of parautochtonous origin; the Mesozoic and Cenozoic deposits have revealed a most interesting vertebrate fauna. This, together with the discovery of the perfect cranium of a chelonian of the genus Niolamia, identical with Ninjemys oweni of the Pleistocene age in Queensland, forms an evident proof of the connection between the Australian and South American continents; the Patagonian Niolamia belongs to the Sarmienti Formation. Fossils of the mid-Cretaceous Argentinosaurus, which may be the largest of all dinosaurs, have been found in Patagonia, a model of the mid-Jurassic Piatnitzkysaurus graces the concourse of the Trelew airport.
Of more than paleontological interest, the middle Jurassic Los Molles Formation and the still richer late Jurassic and early Cretaceous Vaca Muerta formation above it in the Neuquén basin are reported to contain huge hydrocarbon reserves accessible through hydraulic fracturing. Other specimens of the interesting fauna of Patagonia, belonging to the Middle Cenozoic, are the gigantic wingless birds, exceeding in size any hitherto known, the singular mammal Pyrotherium of large dimensions. In
The sea, the world ocean or 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, 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 used to denote smaller landlocked sections of the ocean and certain large landlocked, saltwater lakes such as the Caspian Sea and the Dead Sea; the most abundant solid dissolved in sea water is sodium chloride. The water contains salts of magnesium and potassium, amongst many other elements, some in minute concentrations. Salinity varies being lower near the surface and the mouths of large rivers and higher in the depths of the ocean. Winds blowing over the surface of the sea produce waves. Winds create surface currents through friction, setting up slow but stable circulations of water throughout the oceans.
The directions of the circulation are governed by factors including the shapes of the continents and the rotation of the earth. Deep-sea currents, known as the global conveyor belt, carry cold water from near the poles to every ocean. Tides, the twice-daily rise and fall of sea levels, are caused by the rotation of the Earth and the gravitational effects of the orbiting Moon, to a lesser extent of the Sun. Tides may have a high range in bays or estuaries. Submarine earthquakes arising from tectonic plate movements under the oceans can lead to destructive tsunamis, as can volcanoes, huge landslides or the impact of large meteorites. A wide variety of organisms, including bacteria, algae, plants and animals, live in the sea, which offers a wide range of marine habitats and ecosystems, ranging vertically from the sunlit surface waters and the shoreline to the enormous depths and pressures of the cold, dark abyssal zone, in latitude from the cold waters under the Arctic ice to the colourful diversity of coral reefs in tropical regions.
Many of the major groups of organisms evolved in the sea and life may have started there. The sea provides substantial supplies of food for humans fish, but shellfish and seaweed, whether caught by fishermen or farmed underwater. Other human uses of the sea include trade, mineral extraction, power generation and leisure activities such as swimming and scuba diving. Many of these activities create marine pollution; the sea is important in human culture, with major appearances in literature at least since Homer's Odyssey, in marine art, in cinema, in theatre and in classical music. Symbolically, the sea appears as monsters such as Scylla in mythology and represents the unconscious mind in dream interpretation; the sea is the interconnected system of all the Earth's oceanic waters, including the Atlantic, Indian and Arctic Oceans. However, the word "sea" can be used for many specific, much smaller bodies of seawater, such as the North Sea or the Red Sea. There is no sharp distinction between seas and oceans, though seas are smaller, are partly or wholly bordered by land.
However, the Sargasso Sea has no coastline and lies within a circular current, the North Atlantic Gyre. Seas are larger than lakes and contain salt water, but the Sea of Galilee is 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, seen from space, our planet appears as a "blue marble" of its various forms: oceans, ice caps, clouds. Earth's 1,335,000,000 cubic kilometers of sea contain about 97.2 percent of its known water and cover more than 70 percent of its surface. Another 2.15% of Earth's water is frozen, found in the sea ice covering the Arctic Ocean, the ice cap covering Antarctica and its adjacent seas, various glaciers and surface deposits around the world. The remainder form underground reservoirs or various stages of the water cycle, containing the freshwater encountered and used by most terrestrial life: vapor in the air, the clouds it forms, the rain falling from them, the lakes and rivers spontaneously formed as its waters flow again and again to the sea.
The sea's dominance of the planet is such that the British author Arthur C. Clarke once noted that "Earth" would have been better named "Ocean"; the scientific study of water and Earth's water cycle is hydrology. The more recent study of the sea in particular is oceanography; this began as the study of the shape of the ocean's currents but has since expanded into a large and multidisciplinary field: it examines the properties of seawater. The subfield dealing with the sea's motion, its forces, the forces acting upon it is known as physical oceanography. Marine biology studies the plants and other organisms inhabiting marine ecosystems. Both are informed by chemical oceanography, which studies the behavior of elements and molecules within the oceans: at the moment, the ocean's role in the carbon cycle and carbon dioxide's role in the increasing acid