Solar radiation is a physical force, modulating the earth?s ecosystems. The visible range of the solar spectrum most notably comprises beneficial effects, promoting processes such as photosynthesis. The ultraviolet (UV) portion of the solar spectrum, however, induces various detrimental effects in both terrestrial and aquatic organisms on all systemic levels. I studied the effects of UV-exposure on different UV- and oxidative stress parameters and defence systems against direct and indirect UV-damage in shallow water amphipods. The UV-tolerance was compared in species from two different polar regions (Antarctic King George Island and Arctic Spitsbergen), currently undergoing different degrees of ozone depletion, in relation to a reference species from a temperate North Sea coast, which displays higher natural UV-impact, however, lower ozone depletion compared to the polar areas. I distinguished between dose- and wavelength-dependent effects and also considered the possible influence of nutrition on UV-protective capacities by comparing herbivorous and carnivorous/necrophagous amphipods.