The effects of ultraviolet-B radiation on freshwater ecosystems of the Arctic: Influence from stratospheric ozone depletion and climate change

Depletion of stratospheric ozone, the principal atmospheric attenuator of ultraviolet-B (UVB) radiation, by man-made chemicals has raised scientific and public concern regarding the biological effects of increased UVB radiation on Earth. There is an increased awareness that existing levels of solar UV radiation have an important influence on biological and chemical processes in aquatic ecosystems. For aquatic organisms, numerous studies have shown direct detrimental effects of UVB radiation at each trophic level. Fortunately, many aquatic organisms also possess a range of photoprotective mechanisms against UV radiation toxicity. In addition to its direct impact, harmful effects of UVB radiation at a single-trophic level can cascade through the food web and indirectly affect organisms from other trophic levels. Because UV radiation photochemically reacts with humic substances and other photosensitive agents in the water, increases in solar UVB can also indirectly affect aquatic organisms through the produc...