The sea or the sea is a calm environment with blue water floating in our eyes. The curious thing is that pure water is colorless to see, but blue to see the sea!
This is due to the light coming from the sun which is actually a combination of seven colors of light. When this ray of light enters the sea water, the red, orange, yellow light of these long wavelengths is strongly absorbed in the water. But the "blue light" of the shorter wavelength is reflected without being so absorbed. Then we see the blue water of the sea.
On the other hand, if there is a large amount of dirt, mud, algae or pollutants in the sea water, then this blue light radiation cannot happen in that water. Because mud, dirt binds all kinds of light to radiation. As a result, the sea water then takes on different colors (dark, green, light yellowish, slightly red, etc.).
If you want to constantly enjoy the infinite beauty of the blue sea, let's keep the sea pollution free!
The depth of the ocean is so deep that we can see who it looks like and there are things in science that I don't know.