STREBLE, Laurie; University of North Carolina, Chapel Hill: Ultraviolet Radiation and Marine Invertebrate Larvae

Research has shown that some invertebrate larvae are damaged by exposure to natural sunlight. To date, however, few taxa have been tested and it is unknown how general the effects are. Survival of larvae is very critical to the survival of a species because it determines the size of the adult population, thus it is important that we learn how the survival of individuals in this stage can be extended to adulthood. In this study, I examined the effects of sunlight on larvae from several invertebrate groups in the Puget Sound, Washington. I isolated the PAR, UVA, and UVB portions of the light spectrum and exposed larvae to these treatments to determine mortality and sublethal effects. To examine whether laboratory results modeled natural effects, I also tested sand dollar larvae at different depths in the field. Several species of brachyuran crab larvae, rhizocephalan barnacle larvae, ascidian larvae, brachiopod larvae, nudibranch larvae, tubeworm larvae, and sand dollar larvae had dramatically different sensitivities to sunlight. Sand dollar larvae also showed significant sublethal effects (determined by measurements of arm lengths). Sand dollar larvae in the field showed significant light damage to a depth of nearly 1 meter. The effects of sunlight on invertebrate larvae from different taxa were highly variable. Invertebrate species in different taxa vary in their vulnerability to sunlight damage and may have different protective mechanisms. Therefore it is unlikely that there is one model organism that will predict the effects of light on the larvae of other unstudied species.