Effects of reduced pH on shell integrity of a common whelk from a natural undersea CO2 vent community off Vulcano Island, Italy.

Hexaplex trunculus is a widespread Mediterranean gastropod mollusc that plays a crucial role in benthic ecosystem dynamics. Individuals occur in shallow, sublittoral habitats near Vulcano Island, Italy, where an undersea CO2 vent provides a gradient of seawater acidification mimicing future predicted levels of ocean acidification. Individuals were collected from three sites with declining pH [ambient ( pH 8.18), medium (pH 8.05) and low (pH 7.49)]. Dissolution of shells was clearly evident at the medium (smoothing of outer shell ) and low (pitting and holes) pH sites. Scanning electron microcroscopy will provide a qualitative comparative assessment of micro-scale impacts of shell dissolutio…