ABSTRACT
Ultraviolet B radiation (UV-B) radiation directly alters the structure of deoxyribonucleic acid (DNA) and indirectly damages nucleic acids. There is variability in the responses to UV-B radiation between different species or isolates of individual species, and even within the life cycle of a single species. Since the water column does not screen UV radiation for marine organisms inhabiting shallow seas, the impacts of UV radiation on these ecosystems have been extensively studied, primarily focusing on the population growth rates, carbon assimilation, and nitrogen metabolism of microalgae. Photoinhibition has been observed in macroalgae that were exposed to UV-B and subsequently recovered under dim light. Dynamic photoinhibition is a protective mechanism that is caused by an active down-regulation of photosynthesis and has often been described in the genus Ulva. Adaptations, such as increased protection via carotenoids, have been shown to increase in Ulva spp. under exposure to UV-B.
