Meeting Abstract
Ocean acidification (OA) resulting from elevated CO2 is posing a worldwide threat to marine organisms, in part by interfering with the production of shells and other calcified structures. It is increasingly important to identify characteristics of organisms that make them susceptible or resilient to pH change. Species from taxa including gastropods, crustaceans, polychaetes, and fishes spend part of their early development inside encapsulating structures. Such structures are of special interest with regard to OA because (1) they could help to buffer against low pH as they have been shown to do for other environmental risks, and (2) embryos that develop inside such structures may have been selected to withstand the pH decline resulting from their own respiratory CO2 production. We tested the effect of elevated CO2 on hatchling shell size, inorganic and organic content, and development rate in 14 gastropod species with different types of encapsulating structures. We found mostly moderate differences in response to low (600 ppm), medium (1050 ppm), and high (1500 ppm) CO2 concentrations across all species taken as a whole. In a few cases we found a decline in shell length, though without a corresponding decline in inorganic content, suggesting that while calcification was generally resilient to elevated CO2, the morphology of certain shells might have been affected. Development rate decreased in several species and overall among all species, indicating that developmental processes were sensitive to elevated CO2. Species with string-type egg masses appeared particularly sensitive. Our results suggest that encapsulated embryos tend to be resilient to low pH and other effects of CO2, and that designs of some encapsulating structures may contribute to this resilience more than others. Such effects could have implications for future differences between species persistence in the face of increasing OA.
