UV-susceptibility of photosynthesis of adult sporophytes of four brown Antarctic macroalgae (Phaeophyceae)

The Antarctic ozone hole is reported to develop annually in Austral spring since the late 1970s and results in increasing irradiances of solar UV-B radiation on the earth’s surface and in the aquatic environment (Farman et al. 1985, Häder et al. 1998). Exposure of organisms to enhanced UV-B radiation results in multiple damage, e.g. dimerisation of DNA molecules, formation of reactive oxygen species, inhibition of photosynthesis and growth (Roleda 2006, Lesser 2006, Rautenberger & Bischof 2006, Mansilla et al. 2006). Due to a lower solar zenith angle over Antarctica, the irradiance of ultraviolet radiation is usually lower in comparison to the tropics. Therefore, Antarctic macroalgae are generally considered to be adapted to these low UV irradiances and may thus exhibit a higher UV-susceptibility than temperate or tropical macroalgae. In this study we aimed to evaluate the susceptibility of photosynthetic efficiency of four abundant field-grown macroalgae from Antarctica, exposed to artificially increased irradiances of UV-radiation.