Reports of increasing rates of ozone depletion and predictions of the resulting increased levels of ultraviolet-B radiation at the earth's surface have been documented. Plant scientists have investigated the effects of increasing UV-B radiation on crop plants, but the responses in native plants in natural ecosystems are largely unknown. Meaningful studies of the effects of increasing UV-B radiation on native plants should include the stresses associated with their natural environments. Although coastal salt marshes are highly productive, the very low plant diversity together with high salt concentrations create habitats which are not very resilient to disturbances. The data for crop plants indicate wide variation in plant responses, suggesting possible selective effects that could be very damaging to the delicate balances present in natural communities. The purpose of this study id to examine the interactive effects of increasing UV-B radiation and salt stress in holophytic plants of coastal salt marshes. Specific objectives include investigations of whether increasing UV-B radiation results in selective effects on species composition and whether these plants, which are normally exposed to high light intensities, develop protective mechanisms against higher levels of UV-B radiation.
