A pressing priority for scientists and managers is to understand how both individual species and whole ecological communities will respond to climate change. Knowing how climate change and related environmental conditions influence key ecological interactions is an important avenue for broadening scientific understanding and predictive ability. In Oregon, coastal ocean conditions, including temperature and carbonate chemistry, are expected to change as climate change advances. Pisaster ochraceus is the prototypical keystone predator, whose strong impact on Oregon intertidal community structure is largely based on a functional response to prey. We studied how temperature, pCO2, food availability, and their interactions, as well as resting metabolic rate, affect growth, calcification, respiration and predation rates in Pisaster ochraceus sea star recruits. We conducted controlled laboratory studies in an ocean acidification mesocosm at Hatfield Marine Science Center in Newport, Oregon.
Results/Conclusions
Fed sea stars grew more and ate larger prey in warmer treatments, but number of prey consumed depended on pCO2 treatment. Calcification (percent body weight calcified) did not depend on temperature or pCO2, but sea stars that were fed ad libitum had lower relative calcification than those that were starved, which is likely because sea stars with food resources were able to add non-calcified biomass more quickly. By showing how changing ocean conditions impact sea star physiology and predatory behavior at a critical, early life stage, this study can help scientists and managers understand the mechanisms by which climate-related changes can affect top predators at early life history stages and thus lead to impacts on communities.