CO2-Driven Ocean Acidification Disrupts the Filter Feeding Behavior in Chilean Gastropod and Bivalve Species from Different Geographic Localities

Abstract

We present experimental data obtained with newly hatched veliger larvae of the gastropod Concholepas concholepas and juveniles of the mussel Perumytilus purpuratus exposed to three pCO2 levels. Egg capsules of C. concholepas were collected from three geographic locations in northern (Antofagasta), central (Las Cruces), and southern Chile (Calfuco), and then incubated throughout their entire intra-capsular life cycle at three nominal pCO2 levels, ~400, 700, and 1,000 ppm. Similarly, P. purpuratus were collected from both Las Cruces and Calfuco and exposed to the same pCO2 levels during 6 weeks. Hatched gastropod larvae and mussel juvenile were fed with the haptophyte Isochrysis galbana. Clearance and ingestion rates were estimated for newly hatched larvae, and for juvenile mussel these rates were measured at two observation times (3 and 6 weeks). Our results clearly showed a significant negative effect of elevated pCO2 on the clearance and ingestion for both C. concholepas larvae and P. purpuratus juveniles, which dropped between 15 up to 70 % under high pCO2 conditions. The present study has also shown large variations in the sensitivities of C. concholepas larvae from different local populations (i.e. Antofagasta, Las Cruces, and Calfuco). The influence of both corrosive upwelling waters and the influence of freshwater discharges from Maipo River may explain the minor negative effect of high pCO2 conditions in hatched larvae from Las Cruces’ egg capsules, which would suggest that they are inherently more tolerant to ocean acidification (OA) than organisms that live on regions with a lower pCO2 variability. The present study suggests the need for site-specific studies and reveals the important effect of low pH conditions on feeding activity. Furthermore, this study supports the notion that feeding is a key physiological process susceptible to the effects of OA in marine invertebrates.