Bingham, B. L. Western Washington University,
Reitzel, A. L. Illinois Wesleyan University,
Reyns, N. B. State University of New York at Stony Brook,

The ascidian Corella inflata is a common fouling organism in the Puget Sound and the San Juan Archipelago, Washington, USA. Despite its abundance, particularly on floating docks, it is conspicuously absent from areas that receive direct sunlight. We hypothesized that UV irradiation damages exposed individuals and creates the observed distribution. To test this, we exposed C. inflata adults, juveniles, larvae, and embryos to UV irradiation. In laboratory tests and under natural sunlight in the field, UV significantly shortened adult life span. Juveniles died after only 2-3 days in the light. Several hours of exposure were sufficient to decreased larval settlement and metamorphosis. Abnormalities appeared in developing embryos after only 30 minutes of exposure. By selectively filtering natural sunlight, we demonstrated that UV-B wavelengths were most damaging to C. inflata. However, UV-A and visible light also produced significant negative effects. We conclude that C. inflata is sensitive to UV light in all phases of its life history with younger stages being most vulnerable to damage. We suggest that unique life history traits (i.e., time of spawning, brooding behavior, length of larval life) limit exposure and allow C. inflata to persist in its preferred dock habitat despite its UV vulnerability.
Day: Wednesday, Feb. 3
Time: 12:15 - 12:30pm
Location: Sweeney Center
Code: CS65WE1215S