Temperature-Dependent Ultraviolet Responses in Zooplankton: Implications of Climate Change

Climate warming and stratospheric ozone depletion increase temperature and ultraviolet (UV) in mid- to high-latitude ecosystems; however, little is known about the interactive effects of temperature and UV on organisms. We exposed Daphnia catawba, Leptodiaptomus minutus, and Asplanchna girodi to UV-B at four different temperatures: 10, 15, 20, and 25°C. Elevated temperatures increased UV tolerance in D. catawba and L. minutus, species that depend heavily on photoenzymatic repair (PER), but decreased UV tolerance in A. girodi, a species that has less PER. Also, body size in Daphnia decreased with increasing UV dose. These results demonstrate that climate change can alter responses to UV through temperature-mediated effects in aquatic ecosystems, and these effects can be species-specific and dependent on PER ability.