The World Ocean is a continuous watery shell of the earth's crust (oceanosphere) that surrounds the continents. It is 70.8% (361 million km 2) earth surface, it contains 96.5% (1370 million km 3) of all the waters of the planet. Depending on the structure of the bottom, the outlines of the continental shores, the movement of waters, the structure of the World Ocean consists of oceans, seas, bays and straits.
The open ocean to the north is uniformly bright and appears blue due to strong winds making the surface rough. Although the map shows disputed areas, it also shows the floor of the Arctic Ocean. The lower features of the Arctic Ocean are displayed on the map above.
Mean sea level is a measure of the average height of the ocean surface used as a standard when calculating land height. The upper figure on the right shows the change in mean sea level averaged over 23 geologically stable ebb and flow sites with long term records selected by Douglas. The thick dark line represents the 3-year moving average of the instrumental records. the limited geographic coverage of these records, it is unclear if the apparent decadal fluctuations are true global sea level changes or simply variations in regions that are not allowed.
The ocean is the largest part of the World Ocean, bounded by continents. The oceans are divided into 4 oceans: Pacific (area 178,700,000 km 2, water volume 710 million km 3, average depth 3,984 m). Atlantic (91.6; 330; 3 602), Indian (76.2; 283; 3736), Arctic (14.7; 18; 1220). The boundaries of the oceans are drawn along the continents and islands, and in water areas - along the meridians of the capes: Cape Horn (about. Tierra del Fuego) between the Pacific and Atlantic, Cape Agulhas between the Atlantic and Indian, Cape South (Tasmania) between the Indian and Pacific. The boundaries of the Arctic Ocean with the Atlantic - submarine rise north of the Arctic Circle, the Pacific - the Bering Strait. Some researchers call the fifth - the Southern Ocean, which includes the waters of the Southern Hemisphere between Antarctica and the southern ends of the continents of South America, Africa and Australia. But at the International Hydrographic Congress in Monaco in 1952, it was decided not to separate the Southern Ocean into an independent one. At the same time, the Arctic Ocean was "liquidated" there, which was joined to the Atlantic Ocean as the internal Polar Sea. But not all scientists of the world agreed with this decision, and therefore on many maps the Arctic Ocean appears as an independent one, and also on some maps the name of the Southern Ocean is restored.
These data indicate a slightly higher rate of increase than the tide scale data, but the source of this discrepancy is not obvious. The spread over months by satellites is measured approximately along the thickness of the graphical curve. These documents collected data from various reports and adjusted them for subsequent vertical geological movements, primarily those associated with the postglacial continental and hydroisostatic rebound. The former refers to deformations caused by the weight of continental ice sheets pressing against the ground, with the latter referring to the rise in coastal areas as a result of increased water weight associated with sea level rise.
The sea is a part of the World Ocean, separated from it by land, by an underwater rise or by islands, and has a peculiar hydrometeorological regime. In terms of the degree of separation and mode, the internal seas are those that are deep in the land and are combined with the ocean by one or several channels. For example, Azov, Black, Mediterranean. The marginal seas are those that are not far in land and are separated from the ocean by islands, peninsulas and irregularities in the bottom, for example, Beringovo. Javanskoe, Sulawesi, etc. belong to the inter-island seas. In total, there are up to 60 seas on the planet. They occupy about 60% of the world's oceans.
It should be noted that due to the latter effect and associated uplift, many islands, especially in the Pacific Ocean, exhibited higher local sea levels in the mid-Holocene than they do today. Uncertainty about the magnitude of these corrections is the dominant uncertainty in many measurements of Holocene-scale level change.
The black curve is based on minimizing the sum of the squared errors, weighted by the distance between this curve and the plotted data. It was constructed by adjusting a set of predetermined tie points, which are usually placed every 1 kir and are forced to go to 0 in the modern day.It should be noted that some authors have suggested the existence of significant short-term sea level fluctuations, so that the sea level curve can fluctuate up and down. approximately in this average state ~ 1 Kir.
A bay is a part of the sea (or ocean) water area, submerged in land and has free water exchange with the main water basin. By origin, ocean and sea bays are distinguished, funnel-shaped, elongated, branched in shape, desalinated, brackish, salty in terms of water properties, shallow and deep-water in depth. For example, Odessa, Biscay, Bengal Bay.
Other controversies argue that sea level change was a smooth and gradual process throughout essentially the entire length of the Holocene. Regardless of such perceived fluctuations, data presented by Morhang et al. Indicate that sea level has never been higher in the last 10 Kirov than it is now.
No other events can be seen in the data presented above. The time of the lowest sea level is more or less equivalent to the last glacial maximum. The Bay of San Sebastian is shown above. The two fjords in this painting are Barry Arm on the left and Fiord College on the right, in Prince William Sound, Alaska.
A strait is a relatively narrow strip of water that separates some land areas and connects adjacent water basins or parts of them. For instance, Kerch Strait connects the Azov and Black seas.
> Dry in the ocean
The relief of the bottom of the World Ocean is the surface of the ocean floor, developed within the framework of various types of the earth's crust: continental, transitional and oceanic. The main structural elements this relief: a) the plain of the underwater margin of continents and large islands (continental shelf) b) continental slope; c) continental foot; d) ocean floor with mid-oceanic and folded-block ridges, oceanic swells, hills and plateaus.
Usually a fjord is understood as a glacial valley that has been invaded by the sea. The two fjords in this painting are Barry Arm on the left and Fiord College on the right, in Prince William Sound, Alaska. The delayed "long, narrow, deep entrance between the rocks" is called a fjord.
The Persian Gulf is the deep entrance to the sea between Arabia and Western Asia. A delayed deep entrance to the sea, almost surrounded by land, with a narrow mouth is called a bay. The delayed "part of the ocean or sea extending into the land, partly landlocked sea" is called a bay.
The continental shelf has a relatively flat and flat surface with an inclination angle of less than one degree. It stretches gently to a depth of 200 m. The shelf width is different - from 1 to 1500 km.
The continental slope stretches on average to a depth of at least 2000 m. The slope of the slope surface increases to 4-7 °, and sometimes much more. It is characterized by a sharp dissection of the relief: the presence of frequent and deep canyons, terraces, landslides. Submarine canyons begin mainly on the outer shelf. Many of them are continuation of terrestrial river valleys: Congo, Niger, Amazon, Mississippi, Columbia, Colorado.
The delayed "narrow channel of water connecting two large bodies of water" is called a strait. The Atlantic Ocean, the Strait of Gibraltar and the Albor Sea divide Spain into Morocco. The harbor of Algeciras is a prominent notch carved from the eastern end of the north bank of the strait, and Gibraltar is the tiny arrowhead that separates the notch from the Alboran Sea. The difference in elevation between the Sierra Morena and the Guadalquivir Valley is well emphasized by cumulus clouds. Tangier, Morocco can be seen as a bright spot on south bank strait, near the entrance to the Atlantic Ocean.
Some canyons run along the bottom of the oceans without a shelf origin; they are called mid-oceanic. They are very different in size. For example, in the North Atlantic, the Northwest runs from the Davis Strait to a parallel of 40 ° N. sh. and stretches for 3200 km, skirting the continental slope North America... Its width is from 2 to 9 km, and the incision depth reaches 200 m.
The estuary mouth is in the center. A delayed coastal body of water where ocean tides and river water merge, or an ocean entry also fed by fresh river water, is called an estuary. A delayed "large, landlocked stretch of water" is called a lake.
This is an image of Landsat Lake Superior in North America. Of all the freshwater lakes in the world, the great lakes of North America are unique. Their five basins merge into a single watershed with one common outlet to the ocean. The Huron Moon and Michigan Moth are at the same elevation and are linked by the Mackinac Sound by 120 feet, also at the same elevation. The lakes are separated from each other by streams and rivers. Strait of Makinats is not a river. It has a width of 6 to 5 miles, wider than most lakes, long.
The continental foot is the boundary of the transitional and oceanic crust, where a thick layer of loose rocks is deposited. It is a slightly sloping plain.
The ocean floor occupies the lowest level of the earth's surface - from 4000 to 5000-6000 m depth between the continental foot and the mid-ocean ridges. The bed is folded crust oceanic type and is characterized by weak vertical movements. Along with flat areas, underwater ridges occur on it, extensive uplifts - plateaus, rapids stretching from one coast of the ocean to another.
In fact, this is just a narrowing, not a separation of the two lobes of Lake Michigan-Huron. The flow between the two lakes can vary. Due to the large connection channel, they can quickly equalize whenever an imbalance in the water level occurs. The calibration figures for the lakes clearly show that they have the same water level regimes and average long-term characteristics; that is, they are hydrologically considered one lake.
These teapots were freshly formed on the remote plain of the retreating Bering Glacier in southern Alaska. This teapot lake is located in the Ysungua Highlands, Greenland. The lakes in the image on the right are freshly formed on the remote plain of the retreating Bering Glacier in southern Alaska.
Mid-ocean ridges - these are underwater mountain structures, mainly in the middle of the oceans. They consist of several longitudinal strands. They contain transverse faults, which are also associated with deep submarine canyons. The most ridges are the Mid-Atlantic and the East Pacific. The Mid-Atlantic Ridge extends 20,000 km from the Spitz Bergen Islands to Antarctica. South of Africa, it connects with the African-Antarctic Ridge and passes into the West Indian Ridge, which is called the Central Indian Ridge in the middle of the ocean. Further, the Central Indian Ridge passes through the Austral-Antarctic Uplift into the South Pacific Uplift, and the last into the East Pacific Uplift.
The image on the left is a lake with a kettle in the Ysungua Mountains, Greenland. Lacustrine sediments are the only permanent archives in the area that can record both local and regional changes. environment including emissions to tephra. The area is abundant in lakes, and the strategy is to create at least three different lakes with different settings: being connected, thanks to the impact of glacial melt water, with the current glacier, as well as with major wave events, which means that it should be the main one. sedimentary basin within the main extra-lattic river system, one lake should be connected only with the glacial system of melt water during the surges, and one basin should be without direct contact with the glacial system, but register regional ecological and climate change including local and regional tephras.
In the relief of the ocean floor there are also volcanic cones and large hollows. On the large uplifts of the ocean floor, rich volcanic mountains are located, which protrude to the surface in groups of islands. These are, for example, the Marshalls. Hawaiian, Polynesian, Aleutian, Kuril Islands.
At the bottom of the oceans there are many flat or slightly sloping parts of the bottom of the oceans, isolated by the villas of the basins with performances. They are called plateaus. They differ from the shelves in that they are located at a depth of 1 to 2 km and more. For example, the Falkland Plateau east of the Falkland Islands.
The delayed "water found in unfrozen zones in permafrost" is called intergranular water. The delayed “lake occupying a closed depression formed by the settlement of the earth after the melting of icy permafrost or the melting of massive ice” is called a thermokarst lake.
It is located in the Northern Highland Province, which is the southernmost extension of the Canadian Shield. This province is characterized primarily by pre-Cambrian rocks covered with a thin layer of sedimentary rocks left behind by the Paleozoic seas. The summit of this formation includes the glacial deposits left by the glacial and Valdera uplifts of the Wisconsinia glaciers, the glacial deposits are young and the drainage system is poorly developed. Surface sediments are characteristic of glacial retreat, consisting of barren, sandy, pitted glacial washed out or boulder and clay moraines. As a result of their composition, soils have a reduced capacity for cation exchange, which makes them very susceptible to acidification.
Islands are small (in comparison with continents) areas of land, surrounded by water on all sides. There are several thousand islands on Earth. There are single islands, groups of islands (archipelagos) and a chain. There are sea, ocean, river and lake islands. By origin, they are continental and independent (volcanic and coral).
Many of the lakes in this region are kettle lakes, others are due to irregular depressions in the land moraine or washed out as glaciers passed. All water entering Pola Lake comes from atmospheric deposition and groundwater seepage.
Two largest lakes, Seneca and Cayuga, are so deep that the base of their lake firewood is below sea level. Lakes Kawarta in central Ontario, Canada, are indicated. For this reason, it has gained prominence as a vital historical trade route. Smaller political areas also border the Arabian Sea, including Socotra off the coast of Yemen, the Huriyai Muriyya Islands, and the Lakshadweep Islands.
Mainland islands - land areas separated from the mainland as a result of land subsidence. They are located on the underwater basis of the continents (Greenland, New Guinea, New Zealand, Great Britain, Novaya Zemlya).
Volcanic Islands - Islands that have arisen as a result volcanic eruptions at the bottom of oceans and seas. Volcanic islands are small; they often rise to considerable heights above the water and have the shape of a volcano. Volcanic islands are located in groups, forming chains of mountains (Kuril, Hawaiian).
View of the Arabian Sea from Fort San Angelo in the Kannur region of Kerala, southern India. The Arabian Sea is connected to the surrounding bodies of water by a series of bays and straits that provide a stable avenue out to sea. The largest and most visible of the bays that feed into the sea are the Gulf of Oman, which connects the Arabian Sea to the Persian Gulf, and the Gulf of Aden, which connects the Arabian Sea to the Red Sea. The bays are not the only access point to the Arabian Sea, however, as two significant rivers flow into its borders.
Arabian is supplemented by water flowing along the Indus and Narmada rivers, which are the main means of access to the Arabian Sea. The Arabian Sea has a surprisingly deep water level, which is often maintained close to land masses. Deep sea water levels are believed to be one of the reasons that there are no significant island events in the center of the Arabian Sea, despite the fact that islands are fairly common on the outer borders. The floor of the Arabian Sea, far below the surface, exhibits an astonishing complexity similar to standard terrestrial formations.
Coral islands are formed by the structures of coral polyps. Coral polyps live in large clusters at a depth of up to 50 m. Attaching to the hard bottom of the sea, they grow from above, spreading in width. They form elongated reefs and small ring-shaped low-lying islands - atolls. Coral polyps can live in ocean water with a temperature not lower than 20 ° С, therefore coral islands found only in the seas of the hot zone, between 30 ° N. sh. and 30 ° S. sh. (Great Barrier Reef).
Perhaps the most notable of the underwater features is the Maldives Ridge, which runs along the ocean floor from the Arabian Sea to the Indian Ocean. This ridge, which is essentially similar to mountain range on land, it eventually rises above the water level to become the Maldives.
The Maldives Ridge, along with other seabed formations in the Arabian Sea, is believed to be the result of seismic activity approximately 50 million years ago. During this time, according to geologists, Asia collided with the subcontinent of India, forming the Arabian Sea and its unique underground ridges. After the initial collision of the two land masses, the Arabian Sea was shaped by many influential factors, including erosion from water currents. One of the deepest areas of the seabed is where the Indus River meets the Arabian Ocean.
TO largest islands include: Greenland (2176 thousand km 2), New Guinea (829 thousand km 2), Kalimantan (734 thousand km 2), Madagascar (590 thousand km 2).
Peninsulas are land areas surrounded by water on three sides, and connected to land on the fourth. Peninsulas are formed mainly under the influence of tectonic movements of the earth's crust, which cause the subsidence of certain parts of the land or the uplift of individual parts of the seabed. Small peninsulas are formed by the accumulation of loose material. Largest peninsula on Earth - Arabian - located in Southwest Asia. For more than 1000 km, the Indian subcontinent runs into the Indian Ocean. In the northwest of Europe is the Scandinavian Peninsula.
Geogr. shell of the Earth. Hydrosphere. MO as part of Mr.
Geographic envelope, landscape shell,
epigeosphere - a complex shell, consisting
from the earth's crust (lithosphere), the lower parts of the atmosphere
(troposphere and parts of the stratosphere), hydrosphere and
biosphere (vegetation and soil cover and
animal world). Characterized by a complex composition
and structure. The upper boundary of the geographic
shells are drawn along the stratopause, the border
geographic envelope in the lithosphere is often combined with
the lower limit of the region of hypergenesis. Geographic
shell completely
covers the hydrosphere, sinking 10-11 km in the ocean
below the surface of the Earth, the upper zone of the earth's crust and
the lower part of the atmosphere (layer 25-30 km thick).
The greatest thickness of the geographic envelope is close to 40 km.
Hydrosphere- intermittent water shell of the earth,
located between the atmosphere and the solid earth
crust (lithosphere) and representing a set
oceans, seas and surface waters land, water atmosphere
and water in living organisms. The bulk of G.
concentrated in the seas and oceans. G.'s waters are in
constant interaction with the atmosphere, the earth's crust
and the biosphere. Life on earth was first conceived in Georgia.
World Ocean- continuous water shell of the Earth,
surrounding continents and islands and having a common
salt composition... Makes up most of the hydrosphere (94%)
and occupies about 70.8% of the earth's surface. As part of
hydrosphere The oceans are in continuous
interactions with the atmosphere and the earth's crust, which determine
many of its essential features. MO presents
is a huge accumulator of solar heat and moisture.
The oceans are the richest source of food
also a source of energy, chemical and
mineral resources which are partially already in use
human. There are separate oceans in the oceans,
seas, bays, bays and straits.
Thermohaline circulation of MO.
2. Halina - salinity.
3. Thermal convection (circulation) - immersion
4.waters of the surface layer until it reaches
5. of a certain density - downwering.
6. Thermohaline conditions explain mainly
7.convective movements of water (lowering cold heavy
8. water in the polar regions and its subsequent flow to the tropics).
9. When water freezes, a significant part of the contained
10. Salts are not included in newly formed ice. As a result
11. The salinity and density of the remaining unfrozen water increase.
12. This heavy water sinks to the bottom.
13. Other important feature thermohaline circulation
14.Related to ocean density stratification and its influence
15. for mixing. The density of water in the ocean increases with depth,
16. and lines of constant density run almost horizontally.
17. Water with different characteristics is much easier to mix
Subdivisions of the World Ocean. Oceans and their boundaries.
Seas, bays, straits.
The oceans are subdivided into separate oceans. The ocean is a vast part of the MO, located between the continents, with an independent system of water circulation and specific features of the hydrological regime.
Quiet-178.7. million km per sq., borders with the North Ice Island - in the Bering Strait. Indian Ocean- along the northern edge of the Strait of Malacca and along the western part of the Bass Strait, and along the meridian from Cape South in Tasmania to Antarctica. WITH Atlantic Ocean- from the island of Tierra del Fuego along the meridian to Antarctica. Antlantic-91.7 million km per sq. limited to Europe and Africa from the east and North and South America from the west. Indian-76.2 million km per sq. Sev Ledov-th-14.7 million km per sq.
In the last time, the 5th ocean is often distinguished. Yuzhny, which is also an independent object with a specific regime. In the south, it extends to the coast of Antarctica, northward or northward. The boundary of the Antarctic circumpolar current, or along the line connecting the southern ends of the continents (Africa, Tasmania, South America, New Zealand) -S-80 million km per sq.
Inside the oceans, seas are distinguished. Sea- a relatively small part of the ocean, jutting into the land or isolated from its other parts by the coast of the continent, bottom rises (rapids) or islands and having specific features of the hydrological regime. S seas make up about 10% of the entire area of the sea. Inland seas usually go deep into the land and have a difficult connection with the ocean.
The total number of seas classified by UNESCO is about 60. Strait- body of water. which separates two land areas and connects separate oceans and seas or parts of them-the Bering Strait of the Pacific and North Ice oceans. And separating Asia and Se America. Bay- a part of the ocean or sea jutting into the land and not separated from it by islands or bottom uplifts. Examples are the Bays of Guinea and Biscay in the Atlanta Ocean. Bengal (the largest in S-2.2 million km in sq.)
2.2 Main currents in MO-
Gulf Stream, Antarctic circumpolar,
South trade wind, Brazilian, North Atlantic,
current of the Western winds, East Greenland, Kuroshio,
Labrodorskoe, Kuril. The current systems of the Northern and Southern hemispheres at the equator they are separated by a zone of inter-trade (equatorial) countercurrents moving from west to east. Inter-trade countercurrents are seasonal and exist only in the Pacific Ocean all year round. In the monsoon regions of the ocean, currents change with the seasons The transfer of water in these systems from low to high latitudes and from high to low latitudes determines the presence in the ocean of warm and cold currents that differ in temperature from the surrounding waters.
