Many of the microorganisms found on environmental surfaces are pigmented. Of what possible advantage is the pigment?
So they can absorb different light frequencies to use for energy (from photosynthesis). Light travels in water according to the frequency (wavelength). So different pigmented organisms are able to exist in different environments, possibly reducing competition with other forms.
Pigments have many advantages for the cell. They can absorb light to be used in photosynthesis. Specific pigments absorb light in a specific range - so the more pigments the more light can be absorbed and used for photosynthesis. Pigments also protect the cells from damage by UV radiation. More recently it has been suggested that some pigments inhibit the growth of some microorganisms.
