Define hydrosphere and
mean sea level.
Write two importance of oceans.
plz give correct answer.
It is urgent.
Answers
Explanation:
The hydrosphere (from Greek ὕδωρ hydōr, "water"[1] and σφαῖρα sphaira, "sphere"[2]) is the combined mass of water found on, under, and above the surface of a planet, minor planet or natural satellite. Although Earth's hydrosphere has been around for about 4 billion years,[3][4] it continues to change in shape. This is caused by seafloor spreading and continental drift, which rearranges the land and ocean.[5]
It has been estimated that there are 1,386 million cubic kilometres (333,000,000 cubic miles) of water on Earth.[6] This includes water in liquid and frozen forms in groundwater, oceans, lakes and streams. Saltwater accounts for 97.5% of this amount, whereas fresh water accounts for only 2.5%. Of this fresh water, 68.9% is in the form of ice and permanent snow cover in the Arctic, the Antarctic and mountain glaciers; 30.8% is in the form of fresh groundwater; and only 0.3% of the fresh water on Earth is in easily accessible lakes, reservoirs and river systems.[6]
The total mass of Earth's hydrosphere is about 1.4 × 1018 tonnes, which is about 0.023% of Earth's total mass. At any given time, about 20 × 1012 tonnes of this is in the form of water vapor in the Earth's atmosphere (for practical purposes, 1 cubic meter of water weighs one tonne). 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%).[
An ocean is a body of water that composes much of a planet's hydrosphere.[1] 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.[2][3] The phrases "the ocean" or "the sea" used without specification refer to the interconnected body of salt water covering the majority of the Earth's surface.[2][3] As a general term, "the ocean" is mostly interchangeable with "the sea" in American English, but not in British English.[4] Strictly speaking, a sea is a body of water (generally a division of the world ocean) partly or fully enclosed by land.[5]
Saline seawater covers approximately 361,000,000 km2 (139,000,000 sq mi) and is customarily divided into several principal oceans and smaller seas, with the ocean covering approximately 71% of Earth's surface and 90% of the Earth's biosphere.[6] The ocean contains 97% of Earth's water, and oceanographers have stated that less than 20% of the World Ocean has been mapped.[6] The total volume is approximately 1.35 billion cubic kilometers (320 million cu mi) with an average depth of nearly 3,700 meters (12,100 ft).[7][8][9]
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 species, but because much of it is unexplored, the number of species that exist in the ocean is much larger, possibly over two million.[10] The origin of Earth's oceans is unknown; oceans are thought to have formed in the Hadean eon and may have been the cause for the emergence of life.
Extraterrestrial oceans may be composed of water or other elements and compounds. The only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan, although there is evidence for the existence of oceans elsewhere in the Solar System. Early in their geologic histories, Mars and Venus are theorized to have had large water oceans. The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, and a runaway greenhouse effect may have boiled away the global ocean of Venus. Compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice. Unconfirmed oceans are speculated beneath the surface of many dwarf planets and natural satellites; notably, the ocean of the moon Europa is estimated to have over twice the water volume of Earth. The Solar System's giant planets are also thought to have liquid atmospheric layers of yet to be confirmed compositions. Oceans may also exist on exoplanets and exomoons, including surface oceans of liquid water within a circumstellar habitable zone. Ocean planets are a hypothetical type of planet with a surface completely covered with liquid.[11][12]
Answer:
hydrosphere is the part of planet that's made of water. ocean,river,lakes and clouds are all typically included in hydrosphere.
mean sea level is an average level of the surface of one or more of earth's water bodies from which heights such as elevation may be measured.
Two importance of ocean are :
1.)Ocean produces over half of the world's oxygen and absorbs 50 times more carbon dioxide than our atmosphere.
2.)Ocean provides at least one sixth of animal protein that people eat.