The researchers from Saudi Arabia found that the pigment cells of giant clams absorb dangerous UV light and prispuskaya it at longer wavelengths — so the symbiotic algae can use for photosynthesis. Thus bivalve protect themselves and their symbionts from ultraviolet radiation and increase the intensity of useful light. The light of the interaction between pigment cells and the chlorophyll of algae explain the clams of various colors, from bright blue to dark brown write the researchers in Frontiers in Marine Science.
Iridotomy — pigment cells in which alternating layers of protein plates of guanine crystals and cytoplasm. Due to the different refractive indices of these layers pigments interfere the light waves, and can reflect light from the UV to far red. The result is a vivid variety of colors idiocity add Shine to the skin of the fish, chameleons, tree frogs and shellfish. In addition, animals can quickly change the ultrastructure of these cells to scatter or absorb light of a particular wavelength. Function in amazing pigments very different: they can prevent the diffusion of gases to protect it from overheating, to be part of the visual system, to assist intraspecific communication or serve as a disguise.
Giant clams of the genus Tridacna — attached the only animals in which there is iridotomy. In the tissues of these shellfish live in symbiotic unicellular algae, which through photosynthesis feed the animals. Pigment cells in bivalves are on the edges of the mantle, they scatter light deep into the tissue and increases the effectiveness of photosynthesis of the symbionts. There is a hypothesis that iridotomy serve as sun shield, reflecting the inhibition of photosynthesis by ultraviolet light.