It is believed that on earth today there are 81 sea.

All sea divided according to its location in the following areas: the Atlantic, Pacific, inland sea and the sea bordering the Southern ocean, the North-Arctic ocean, and Indian ocean.

Types of seas

The sea is traditionally subdivided into four groups:
- inter-island,
- half-closed
- marginal,

The inland sea is located "inside" of the continents, but may have a connection to the ocean or other surrounding sea. Such a sea exposed to great effect, land, water in them may have an intermittent level. Such seas are: the Dead sea, the Aral sea and the Caspian sea.

Some scientists and researchers believe coastal part of the ocean sea, and therefore the inner sea, inter-island sea and they do not belong to the General list.

The marginal seas are located at the edge of the land and have direct access to the ocean but semi-enclosed sea enclosed from the ocean to the mainland, but partially.

Inter-island sea, based on the basis of its name, are located between the various Islands. To inter-island seas could be considered the following: Fiji, new Guinea and the Java sea.

The disadvantage of the seas

Compared to land and land in General, the area of seas on the planet small. There is even trash the sea, due to the large amount of waste transformed into a floating garbage polluting the world's oceans. Such a sea of plastic and other wastes were observed in the waters of the Indian and Pacific ocean.

It is worth mentioning the rare and endangered seas. For example, the huge Aral sea due to the influence of human activities began to fade, like water evaporates. And all this happened because of the abstraction of water from other rivers, so water stopped flowing into the Aral sea. As a result, all the fauna that lived in this once vast sea, disappeared, changed the climate of the area where previously bloomed gardens and there was a breeze blowing today, only desert dunes and skeletons decayed from the time of the ships. This terrible tragedy of the region, which did not go unnoticed in the world. Attempts were made the sea to artificially raise, but they were in vain. After over half a century, it has become evident that only natural forces are able to regain the original balance between land and water, today, the sea slowly comes to life.

The question of the environment and the preservation of water resources every year becomes all the more urgent: scientists suggest that climate change and rapid expansion in the natural element will erase from the face of the planet, another the sea, and not far off a war between Nations is not over territory, but for fresh and salt water.