UV-radiation has long been known to be damaging to life; indeed this quality is being employed increasingly for the disinfection of water and for the mutation of microorganisms for laboratory experiments . UV-B affects plants and animals by modifying both their biological and chemical environment. Damage may occur in a number of ways, including the direct destruction of the genetic material DNA, deactivation of enzymes, disruption of membranes and other cell structures and the generation of highly reactive chemical agents known as "free radicals".

Although biological repair mechanisms exist, mutations may remain as errors in the repair processes. In addition, the repair mechanisms themselves may be deactivated by high UV doses. The interaction of all these processes can lead to a variety of adverse effects on plants and animals. Many effects are sub-lethal, may interact with other factors and may, therefore, be very difficult to attribute to UV-enhancement specifically.

Effects on plants in the sea, in freshwater and on land are of fundamental importance because of their position at the base of all other food chains. By nature, plants have evolved to maximize the surface area they expose to sunlight, but consequently their exposure to damaging UV-radiation is also increased. Elevated UV exposure can cause temporary or irreversible damage to photosynthetic apparatus (including the bleaching of the pigments which trap the sun's energy), to processes of cell division and growth regulation, and to the composition and replication of genetic material. Consequences include a reduction in growth yield, changes in levels and effects of plant hormones and alteration of periods of dormancy, flowering, etc.