Algae and aquatic macrophytes responses to cope to ultraviolet radiation – a Review

UV radiation became an important issue since the awareness of the ozone hole in Antarctida and its relationship between the human activity, the depletion of the protecting layer, and the effects of ultraviolet radiation in the biological relevant wavebands on algae and on organisms in general. All aquatic organisms are depended on algae and aquatic plants (submerged or near shallow line) for food, shelter, also as oxygen supplement and CO2 sequestration by photosynthetic procedure. So, a disturbance in this trophic layer creates a global unbalancing. Harmful effects of UV, especially UV-B were intensibly studied under laboratory and field studies, and reported in scientific reports from a large team of scientists. UV- induced repair mechanisms allowing the survival of certain species under UV irradiation is also largely documented in algae species, and in phytoplankton of the entire aquatic systems (freshwater, marine and brackiswater). This study provides an overview of the available literature on the ultraviolet-B (UV-B – λ=280-315 nm) and UV-A radiation (λ=315- 400 nm) concerning the strategies of protection developed by aquatic photoauthotrophs (micro and macroalgae, and aquatic macrophytes, like seagrasses and liverworts) to fit under these wavebands of radiation. It includes studies on prokariotic cyanobacteria, haptophytes, diatoms, dinoflagellates, red algae, brown algae and chlorophytes from freshwater (ponds, lakes) to marine littoral and Open Ocean. It also reports available studies concerning marine and freshwater plants exposed to UV irradiation.