Effects of Temperature and pH on Larval and Juvenile Development in the Marine Gastropod, Crepidula fornicata

Rising atmospheric CO2 levels are associated with warming and acidification in coastal marine ecosystems, with impacts that are especially acute for marine calcifiers. We have investigated the interactive effects of pH and temperature on larval growth, time to metamorphic competence, and juvenile growth in the marine gastropod Crepidula fornicata. Larval growth rates and acquisition of competence for metamorphosis were measured in 4 replicate cultures in each of 4 treatment groups, representing all combinations of pH 7.6 and 8.0, at either 20° or 24°C. Higher pH and higher temperature additively increased larval growth, and larvae became competent for metamorphosis sooner at higher temperature and at higher pH, but there was no significant interaction of pH and temperature on larval growth rates or on frequencies of metamorphosis . After metamorphosis, juveniles from each larval condition were individually cultured at either pH 7.6 or 8.0. Temperature was not controlled during juvenile growth; all individuals were exposed to the same ambient laboratory temperatures of 21°-23°C. Juveniles grew at similar rates in both pH conditions. However, juveniles reared at 24° as larvae grew more slowly than their siblings that had been reared at 20° C as larvae, during the first 7 days of post-metamorphic growth. This difference was no longer apparent by 11 days after metamorphosis for juveniles derived from most larval conditions. However, slower growth persisted in juveniles that had been reared as larvae at 24° and pH 7.6, and kept at pH 7.6 after metamorphosis. This result is consistent with related studies that show persistent effects of larval pH experience that emerge under some juvenile growth conditions