<P> Color is not removed by typical water filters; however, slow sand filters can remove color, and the use of coagulants may also succeed in trapping the color - causing compounds within the resulting precipitate . </P> <P> Other factors can affect the color seen: </P> <Ul> <Li> Particles and solutes can absorb light, as in tea or coffee . Green algae in rivers and streams often lend a blue - green color . The Red Sea has occasional blooms of red Trichodesmium erythraeum algae . </Li> <Li> Particles in water can scatter light . The Colorado River is often muddy red because of suspended reddish silt in the water . Some mountain lakes and streams with finely ground rock, such as glacial flour, are turquoise . Light scattering by suspended matter is required in order that the blue light produced by water's absorption can return to the surface and be observed . Such scattering can also shift the spectrum of the emerging photons toward the green, a color often seen when water laden with suspended particles is observed . </Li> </Ul> <Li> Particles and solutes can absorb light, as in tea or coffee . Green algae in rivers and streams often lend a blue - green color . The Red Sea has occasional blooms of red Trichodesmium erythraeum algae . </Li>

What is the true color of the ocean