Meeting Abstract
The earth’s oceans are becoming more acidic due to absorption of atmospheric CO2. Ocean acidification (OA) decreases the concentration of carbonate ions in seawater, and may impose increased energy costs on organisms that deposit calcium carbonate shells and skeletons. Larval stages of these organisms are especially vulnerable to combined stresses of OA, low salinity, and nutrition, which may have a common energetic basis. Our study species, the caenogastropod Crepidula fornicata, is widely distributed in temperate near-shore environments including estuaries where pH and salinity vary greatly. We investigated how acidification and low salinity affect larval growth, induction of metamorphosis, and juvenile growth. Larvae and juveniles were cultured at 4 combinations of salinity (20 or 30 ppt) and pH (7.6 or 7.9). At high salinity, larvae grew at similar rates at pH 7.6 and 7.9. However, larvae grew more slowly at low salinity, and the effect of salinity dilution on larval growth was magnified by lower pH. Few of the larvae in the combined low pH/low salinity treatment became competent for metamorphosis, but larvae in other treatments metamorphosed at high frequency in response to elevated [K+] by 15 days after hatching. In contrast to larvae, juveniles grew at similar rates at pH 7.6 and 7.9 within low as well as high salinity treatments. Juveniles generally grew faster at high salinity regardless of pH. However, juveniles that had been reared at low salinity as larvae grew faster at low salinity as juveniles during the first 4 days after metamorphosis, suggesting a carryover effect of larval acclimation to low salinity. (Supported by NSF 1416690.)
