The color of the ocean and the color of the sky are related but occur independently of each other. Everyone knows that sunlight is having different colors. That's why we are able to see rainbow. Right. So different colors of different wavelengths. There are shorter wavelength and long wavelength in both cases of sea and sky. The preferential absorption of the long wavelength, the reddish colors light gives rise to the blue, the water in the ocean and sea observes more red, Orange and yellow with longer wavelength