Photosynthetic acclimation to solar UV radiation of marine red algae from the warm-temperate coast of southern Spain:: A review

A review is presented of the physiological mechanisms developed by benthic macroalgae to cope with deleterious wavelengths, particularly UV radiation. Photoinhibition of photosynthesis, is a photoprotective mechanism in various species studied in southern Spain. Incubations in outdoor systems and transplantation experiments under natural radiation allowed to led to understanding of some the photoprotective strategies used by red algae. Under conditions of enhanced UV-B radiation, algae in shallow sites show marked photoinhibition and rapid recovery of photosynthesis (dynamic photoinhibition), whereas algae from deeper locations can suffer photodamage (chronic photoinhibition). The expression of this photoprotective strategy by intertidal species represents an efficient physiological adaptation to tolerate deleterious irradiance, when low tides coincide with the onset of solar radiation. Subtidal species can be also exposed to high doses of UV radiation. This is particularly evident in clear, Mediterranean waters, where light (including UV-B) can reach to 10 m depth. The implications of photoacclimation processes for macroalgal ecology in warm-temperate littorals and the possible consequences for outdoor cultivation are outlined in terms of environmental UV variability.