Effects of ocean acidification on larval Atlantic surfclam (Spisula solidissima) from Long Island Sound in Connecticut

The Atlantic surfclam (Spisula solidissima) supports a $29.2-million fishery on the northeastern coast of the United States. Increasing global carbon dioxide (CO2) in the atmosphere has resulted in a decrease in ocean pH, known as ocean acidification (OA), in Atlantic surfclam habitat. The effects of OA on larval Atlantic surfclam were investigated for 28 d by using 3 different levels of partial pressure of CO2 (rho CO2): low (344 uatm), medium (821 mu atm), and high (1243 mu atm). Samples were taken to examine growth, shell height, time to metamorphosis, survival, and lipid concentration. Larvae exposed to a medium rho CO2 level had a hormetic response with significantly greater shell height and growth rates and a higher percentage that metamorphosed by day 28 than larvae exposed to the high- and low-level treatments. No significant difference in survival was observed between treatments. Although no significant difference was found in lipid concentration, Atlantic surfclam did have a similar hormetic response for concentrations of phospholipids, sterols, and triacylglycerols and for the ratio of sterols to phospholipids, indicating that larvae may have a homeoviscous adaptation to OA at medium rho CO2 levels. Our results indicate that larval Atlantic surfclam have some tolerance to slightly elevated rho CO2 concentrations but that, at high rho CO2 levels, they may be susceptible to OA.

Automated summary

The study found that larval Atlantic surfclam exhibited a hormetic response at moderate CO2 concentrations, showing significantly increased shell height and growth rates, as well as a higher metamorphosis rate. Although there was no significant difference in survival rates, Atlantic surfclam showed some tolerance to ocean acidification at moderate CO2 concentrations.