Meeting Abstract

12.2  Tuesday, Jan. 4  Effects of ocean acidification on swimming performance in larval sand dollars and oysters CHAN, K.Y.K.*; GRŰNBAUM, D.; O’DONNELL, M.J. ; Univ. of Washington; Univ. of Washington; Univ. of Washington kychan@uw.edu

Ocean acidification (OA) is expected to negatively impact calcifying organisms, including the planktonic larval stages of many marine invertebrates. Planktonic larvae play critical roles in the benthic-pelagic life cycle of marine organisms by connecting and sustaining populations. Calcified larvae typically are denser than sea water, and hence rely on swimming to navigate the vertically structured water column. We studied the effects of OA on swimming performances in two calcified larval forms: plutei of the sand dollar, Dendraster excentricus and veligers of the oyster, Crassostrea gigas. Here, we focus on the plutei, which have calcified skeletal rods supporting their bodies and use ciliary bands looped around calcified arm rods for both swimming and feeding. We hypothesized that morphological changes of these calcified structures under OA conditions have functional consequences that would affect larval survivorship. We used non-invasive video tracking techniques to quantify the swimming behaviors of plutei reared under present-day (380 ppm) and elevated pCO2 level predicted for 2100 (1000 ppm). Acidified larvae had narrower larval bodies and smaller stomachs, suggesting reduced feeding success. However, their swimming performance, measured by total and net vertical swimming speeds, was not significantly affected by OA. This suggests morphological adjustments in response to OA may prioritize swimming over feeding, implying deferred negative consequences for later developmental stages.