Have you ever wondered
Clear water is colored blue mainly due to absorption of red wavelengths more strongly than blue, an effect even seen in swimming pools. Secondarily there is scattering of blue by the same mechanism that colors the sky blue.
Some people know the fact and some think why the ocean water is different colors?
Generally we can say : Ocean water containing phytoplankton will be some shade of green due to chlorophyll. Near the shore ocean color is also influenced by runoff, tide-induced resuspension of fine particles from the bottom, and a number of other substances that may change the water’s color.
This information comes from Wikipedia “Ocean color” and “Color of water.But here’s the science behind the color of the sea.
The Answer Is in the Light and Depth
There are a some reasons why the ocean is blue. The best answer is that the ocean is blue because it is mostly water, which is blue in most quantities. When light strikes water, like sunlight, the water filters the light so that red is absorbed and some blue is reflected. Blue also travels farther through water than light with longer wavelengths (red, yellow, and green), though very little light reaches deeper than 200 meters (656 feet), and no light at all penetrates beyond 2,000 meters (6,562 feet).
The other reason, ocean appears blue is because it reflects the color of the sky. Tiny particles in the ocean act as reflective mirrors, so a large part of the color you see depends on what is around the ocean.
The ocean may appear gray under a cloudy sky or brown when the water contains a lot of sediment, as when a river empties into the sea or after the water has been stirred up by a storm.