Indigo Waters - "Uncharted" series

Why are our oceans often thought of as blue?

When light hits the ocean, the water absorbs colours with longer wavelengths first, reflecting to our eyes those with shorter wavelengths. Like a filter, water molecules absorb the red parts of the light spectrum and leave behind colours on the blue spectrum, which are reflected to our eyes.

In the shallows the light can reach the ocean floor. It bounces off the sandy bottom, which turns the water a brilliant blue. Extremely shallow areas still have some of the green wavelengths of light, hence those beautiful turquoise shades. This creates the green-blue hues that we see in areas around islands and reefs. The ocean is also very, very deep; light can only penetrate so far below the surface of the ocean, hence creating those inky blue black hues.