What does the ninth sea mean?

The ninth sea has no special meaning, it is the name of a song.

The sea is at the edge of the ocean, and it is a subsidiary part of the ocean. The area of the sea accounts for about 1 1% of the ocean, and the water depth of the sea is relatively shallow, with an average depth of several meters to 3000 meters.

Because the ocean is close to the mainland, influenced by the mainland, rivers, climate and seasons, the temperature, salinity, color and transparency of water have changed obviously. In some sea areas, seawater sometimes freezes in winter, and the salinity of seawater near the estuary will become weak and the transparency will be poor.

Compared with the ocean, the ocean has no independent tides and currents. There are many famous oceans in the world, mainly distributed in the marginal zone of the ocean.

note:

For example, East China Sea, South China Sea, Sea of Japan, North Sea, Mediterranean Sea, Arabian Sea, Bay of Bengal, Red Sea, Gulf of Aden and so on. They are important sea areas for people's production and life.

As far as water is concerned, the sea is a subsidiary part of the ocean, but in essence, Shanghai is an underwater continent, with the main body on the continental shelf and the lower crust being the continental crust. Below the ocean is the ocean crust. This has produced a series of differences. Of course, with the geological movement, the sea and the ocean can be transformed into each other.