CBSE Class 9 Answered

The visible part of sunlight is made up of a spectrum of many colors,ranging in colour from red to blue and violet. This light is scattered by particles suspended in the water. The shorter blue wavelengths scatter more effectively and are absorbed less quickly than the longer red and orange wavelengths. Once the reddish end of the spectrum is absorbed by the water, the remains are the bluish components that we see. Thus the blue to green coloration of the oceans. Seawater appears blue for about 100 feet under the surface. But a small percentage of undetectable blue light remains in the water down to the 600 foot level.