Meeting Abstract
Larval metamorphosis of benthic marine invertebrates is often regulated by chemical cues that indicate the best place to settle, metamorphose, and survive to adulthood. These stimuli determine the distribution of many species and impact the structure of marine communities. With substantial decreases in ocean pH levels expected by 2100, it is important to look into the effects of ocean acidification (OA) on the ability of marine organisms to perceive metamorphic cues. In this study we sought to identify the sizes at which individuals of the marine gastropod Crepidula fornicata do or do not release metamorphosis inducing stimuli, and if there are other cues (e.g., biofilms) that induce metamorphosis. We also examined the impact of reduced pH (7.5 versus pH of 8.0) on induction. Competent larvae (4 replicates of 10-12 larvae each) were exposed to potential cues for 3–6 hours to assess the source of metamorphic cues. Sources included C. fornicata adults (2–30 mm shell length), the body of the adult snails without shells, shells with the body removed, and shells sterilized to remove biofilms and symbionts. 20 mm excess KCl and Instant Ocean at 30 ppt served as positive and negative controls, respectively. Individuals ≥ 7 mm in shell length were most effective at inducing metamorphosis. The body of the snail and biofilms on the shell alone both induced metamorphosis, but less effectively than intact adults; sterilized shells did not induce metamorphosis. Reduced pH had no significant effect on the ability of large adults (28.13 ± 2.8 mm) to stimulate metamorphosis. Our results suggest that multiple chemical cues induce metamorphosis, and that OA will have no significant effect on larval perception of cues for metamorphosis in this species.
