A study of the effects of near UV radiation on the pigmentation of the blue-green alga Gloeocapsa alpicola.

The UV survival characteristics of a wild-type and a UV resistant strain of Gloeocapsa alpicola were compared. Except for a higher carotenoid content the resistant strain was similar to the wild-type. However, on exposure to UV radiation the level of carotenoids in the wild-type fell sharply whereas no such decrease occurred in the resistant strain. Growth of cells in diphenylamine and under red and blue light reduced the survival rate. This phenomenon is linked with a reduced carotenoid level in the cell, indicating that they perform an important protective function.