Sea

The term of sea recovers several realities.

Definitions

Great salt water extent

This definition confuses the Océan S, the seas closed or opened as well as the salted big lakes. One finds it in a historical context (At the time modern, the Atlantic Ocean crossed by Christophe Colomb bears the name of sea océane ) or familiar (Opposition of the sea and of the Montagne in the holidays, the sea is good? to evoke the temperature of oceanic water as well as maritime).

Great salt water extent different from the oceans

This more geographical definition brings a classification in the salt water extents. The Océan S are the greatest salt water extents. Come then the variable seas of sizes. The seas can be open or closed i.e. in contact or not with the oceans. If it is surrounded almost on all sides by grounds, like the Black Sea, it is described as sea Intracontinentale, while a sea largely open on the ocean, like the China Sea, is a bordering Mer   ; it is known as épicontinentale when it recovers a continental shelf, like the the North Sea.

If the sea is in contact with an ocean it distinguishes from this last by its geographical position generally wedged between terrestrial masses or simply limited by the continental shelf. Ex: The Manche communicates with the Atlantic Ocean by the Celtic Mer, but it is characterized some by its median position between the southern parts from the England and the coasts north from the France. A sea in contact with an ocean can be characterized by particular physical conditions. Ex: the the Mediterranean communicates with the Atlantic Ocean by the Straits of Gibraltar. It is distinguished from the ocean by its position wedged between the Europe, the Asia (the Middle East) and the Africa and by different maritime conditions (differential of temperature between the ocean and the sea, fauna and distinct Flore, Marée of lower amplitude for the the Mediterranean…). Another example: the Sargasso Sea with its accumulation of brown algas to broad of the Florida is distinguished in a completely arbitrary way of the Atlantic Ocean.

The term of sea is also used to indicate certain large Lac S, in particular when they do not have a River in which they flow. It is the case for example of the Caspian Sea or of the Mer of Aral. One speaks then often about closed sea.

Great extent sinks on the surface of the the Moon

Lastly, the large plains lunar dark, located in majority on the visible surface of the the Moon, terrestrial Natural satellite, are by convention called " Mers" (ex: Sea of Peace). These large basaltic plains had indeed been regarded as stretches of water by the first astronomers, before the use of the glasses by Galileo for the observation of the sky.

Sea in international law

In international law, one calls " mer" the space located beyond the Leaves basic sea.

The sea includes/understands:

  • bottom and the basement
  • the water column and surface
  • superjacent airspace.

The marine salt

A characteristic of sea water is well-sure to be salted. This salinity is about 32 Gram S by Liter (or g/l) in the Mediterranean, and approximately 28 g/l in the oceans. There is thus a Kilogram salt in 30 to 35 liters of sea water.

The marine salt is a compound whose complete name in chemistry is Sodium chloride. It tightens to dissolve in water until a concentration of saturation of 359 g/l. If one tries to increase the concentration with beyond this value, by evaporation of water, part of salt returns in a solid state (Solidification or Cristallisation) and settles. The value of the salinity of the seas being largely lower, salt does not settle at the bottom of the seas. As it does not evaporate not either, it is trapped in the sea.

Certain grounds and continental rocks contain salt. When these rocks are exposed to the rain or the flows of subsoil water, part of salt will be dissolved and will join the rivers then the sea. Being given that this salt does not remain but is constantly evacuated, the salinity of the rivers will remain most of the time very low.

The salt deposits can be done naturally when the salt concentration of a sea or a Lac salted increased with by saturation. That can occur in continental zones where there does not exist any flow towards the oceans, like the Dead Sea.

Another case is that of the Mediterranean, which at certain geological times functioned like a saline Marais: its connection with the oceans Straits of Gibraltar being closer, it did not allow the exchanges of water in the two directions like that currently occurs. In addition, evaporation being stronger than precipitations and contributions of fresh water (what is always the case), it is thus a oceanic contribution which made up the deficit. There was thus a salt entry which was compensated by no export. That involved very important salt deposits at the bottom of the Mediterranean and has seems it have also an influence on the salinity of the oceans. Indeed the estimate of the salt contribution to the total ocean by the whole of the rivers during geological times is higher of at least an order of magnitude than the dissolved salt mass in the oceans.

Movements of the sea

The sea is in perpetual movement. In antiquity, this one was allotted to divinities: angers of Poséidon, plays of the Néréides, the monstrous Charybde and Scylla.

The movements of the sea are complex; for better analyzing them, they are broken up moving elementary, whose causes and laws can be studied separately.

One distinguishes from the undulatory movements , in the form of vertical oscillations:

  • the Houle is caused by the Vent; its period is of about a second or of ten second and its amplitude can reach several tens of meters.
  • the Clapotis is the movement which one notes in a port, it is the combination of the swells reflected on the walls.
  • the cuttlefish, noted in the ports and the basins; from one period varying one minute at several minutes, their amplitudes are low (a few tens of centimetres).
  • the Marée is due to the attraction of the the Moon and the Sun; its period is approximately 12 hours, and its amplitude, very variable according to the geographical place, can reach more than ten meters.

The movements of the current are horizontal displacements.

  • the large currents originate in of the differences in density of sea water (due to differences of salinity or temperature). They are regarded as constant.
  • Of the more localized currents is generated by the wind or the tides. They can take a gyratory character and to generate large swirls like celebrates it Saltstraumen (Maelstrom).

Isolated movements can be caused by catastrophic phenomena (seisms, volcanic eruptions, landslides) in the form of Tsunami S, of solitary waves or Soliton S.

List seas

By ocean

Cuttings of each ocean presented below are based on the delimitations of the international hydrographic Organization (OHI). Certain seas also present possible subdivisions.

Atlantic Ocean

The OHI cuts out the Atlantic Ocean in seas, Golfe S, and Détroit S following:

The remainder of the Atlantic Ocean is finally divided between the Northern Atlantic Ocean and the Southern Atlantic Ocean, according to the situation compared to the equator.

In addition to these seas, the following denominations are common:

Arctic Ocean

The OHI cuts out the Arctic Ocean in the following seas:

In addition to these seas, one can also quote:

  • Sea of the Prince Gustave-Adolphe
  • Sea of Wandel

Antarctic Ocean

Indian Ocean

The OHI cuts out the Indian Ocean in seas, Golfe S and Détroit S following:

Pacific Ocean

The OHI cuts out the Pacific Ocean in seas, Golfe S and Détroit S following:

The remainder of the Pacific Ocean is finally divided between the Northern Pacific Ocean and the Southern Pacific Ocean, according to the situation compared to the equator.

In addition to these seas, one can also quote:

  • Sea of Bohai
  • Sea of Amakusa
  • Sea of Ariake (or bay of Ariake)
  • Sea of Bohol
  • Sea of Camotes
  • Sea of Hibiki
  • Sea of Koro
  • Sea of Lucon
  • Sea of Mindanao
  • Sea of Shiranui
  • Sea of Sibuyan
  • Sea of the Probe
  • South Seas
  • Sea of Visayan

By type

Méditerranées seas

A Mediterranean is an almost closed sea communicating with the ocean.

The most obvious example is of course the Mediterranean.

Inland seas

A Inland sea is an almost closed sea communicating with another sea.

  • the Baltic (communicates with the North Sea)

  • Inland sea of Seto (communicates with the sea of Japan)
  • Mer of Azov (communicates with the Black Sea)
  • Mer of Kara (communicates with the Arctic Ocean)

Closed seas

A closed Mer is a sea communicating with no other sea.

References

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