Solar damage to the solitary ascidian, Corella inflata

The ascidian Corella inflata (Chordata, Ascidiacea) is common in many areas of Puget Sound, Washington, USA. However, it occurs only in habitats where it is protected from direct sunlight. Previous experiments with artificial lights showed that UV irradiation kills all life stages of this animal. Th e effects of natural sunlight exposure (measuring survival of adults, juven iles, larvae, and embryos) were compared. We partitioned the light spectrum to separate the effects of UVB, UVA, and visible light (PAR). Natural sunl ight severely damaged C. inflata. Adults and juveniles died after 2-5 d. Ex posed embryos failed to develop normally and larvae did not settle. As expe cted, UVB had significant effects, but pronounced effects were also seen wh en the animals were exposed to longer wavelengths alone (UVA and PAR). Thus , the distribution of C. inflata may be determined largely by exposure to l ight. Understanding the basic ecology of this species requires consideratio n of its vulnerability to sunlight damage and the effects of UVB, UVA, and PAR.