Water can absorb all colors except for a couple. However, there are two major wavelengths of light that aren’t absorbed. Those colors are Blue and Green. In fact, water acts as a reflector against Blue and Green, thus causing the water to appear in a turquoise color.

The ocean is blue because water absorbs colors in the red part of the light spectrum. Like a filter, this leaves behind colors in the blue part of the light spectrum for us to see. The ocean may also take on green, red, or other hues as light bounces off of floating sediments and particles in the water.

Water is blue because it absorbs red, yellow and green light, but scatters blue light. The reason a small amount of water appears clear is because not much light is scattered. In larger bodies of water there are more water molecules for light to collide with, resulting in more blue light being scattered.

Water is colorless and transparent because ALL except a tiny bit of blue (for pure water) are reflected back. Since water reflects all colors together it looks colorless.

Green

Technically, pure white is the absence of color. In other words, you can’t mix colors to create white. Therefore, white is the absence of color in the strictest sense of the definition.

Some consider white to be a color, because white light comprises all hues on the visible light spectrum. And many do consider black to be a color, because you combine other pigments to create it on paper. But in a technical sense, black and white are not colors, they’re shades.

There is no color to darkness. Darkness is just absence of light. The objects hidden by darkness would still be the same color if you could see them. Objects do not change color with darkness, you just cannot see the color because there is no white-light.