Meeting Abstract
The limpets Patella caerulea, P. rustica and the whelk Hexaplex trunculus are widespread in the Mediterranean and play important roles in benthic ecosystem dynamics. Individuals of all three species are abundant in the shallow subtidal near Vulcano Island, Italy, where an undersea CO2 vent provides a gradient of seawater acidification simulating 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)]. Scanning electron microscopy was employed to provide a qualitative comparative assessment of prospective microscale impacts on shells. Dissolution of the shell was evident at the medium pH (smoothing of outer shell) and low pH (pitting and holes) collection sites. X−ray diffraction (XRD) provided a quantitative comparative assessment of carbonate composition of shells in individuals collected from the three pH sites. The calcium to magnesium ratio, as well as the aragonite to calcite ratio of the shells varied with pH collection site. To further assess the impacts of seawater pH on shell microstructure, electron backscatter diffraction (EBSD) was conducted. The present study indicates that near-future ocean acidification may be expected to cause alterations in shell mineral composition and shell integrity that render individuals more susceptible to infection and predation. Supported by funds from Abercrombie and Kent Philanthropy and an Endowed Professorship to JBM.
