Meeting Abstract
Human-induced changes in seawater chemistry, including reductions in pH (‘ocean acidification,’ OA), are known to induce both mechanical and physiological costs for many marine organisms, and emerging evidence suggests that reduced pH can also disrupt an organism’s behavior. While such behavioral changes have the potential to influence a variety of species interactions (e.g., avoidance responses of prey to predators), the nature and strength of OA-induced behavioral shifts may also depend on the evolutionary histories of exposure of vulnerable taxa to low pH. Here we investigated impacts of ocean acidification on the antipredator, “crawl out” behavior of two geographically separated populations of intertidal turban snails (Tegula funebralis) as induced by chemical cues from the predatory sea star, Pisaster ochraceus. We found that low seawater pH attenuated the archetypal crawl out responses of snails, but that the behavioral impairment of snails also varied with site of origin. The percentage of time that fleeing snails spent out of the water, in refuge from predation, decreased with declining pH in turban snails sourced from a region exposed to strong upwelling (Bodega Bay, CA), where seawater pH is routinely lower. In contrast, snails that originated from a region of more benign pH conditions (San Diego, CA) maintained a robust response to predator cue regardless of seawater pH. Although OA is expected to pose a major threat to marine species, our work suggests that geographic variation in tolerance to reductions in pH may play an important role in determining population responses to future conditions.
