What role does UV‐B radiation play in freshwater ecosystems?

Increases in incident UV‐B radiation (280–320 nm) have been observed at temperate as well as polar latitudes in recent decades. Although UV‐B radiation makes up only a small portion of the total energy of solar radiation and attenuates rapidly in the water column, the high sensitivity of living organisms to UV‐B radiation makes the observed increases potentially important in aquatic ecosystems. To date, research has focused largely on the primary producers in marine ecosystems in Antarctica where ozone depletion and subsequent increases in UV‐B radiation have been most pronounced. This review addresses the potential role of UV‐B radiation in freshwaters by taking into account some of the information available in marine systems and applying some of the recent advances in our understanding of the ecology of freshwaters. The potential for complex rather than simple responses of freshwater ecosystems to UV‐B radiation is emphasized.