Meeting Abstract
Today’s ocean surface is subject to increasing atmospheric carbon dioxide concentration, which lowers ocean pH and carbonate ion concentrations. The effects of ocean acidification (OA) on economically and ecologically important species such as shelled mollusks are of growing concern. We investigated effects of OA on suspension feeding in recently metamorphosed juveniles of the gastropod Crepidula fornicata. Brooding adults were collected from southern Puget Sound, WA. They soon released larvae that were then reared under a controlled atmosphere that maintained pH at 7.6 or 8.0. Upon metamorphosis, juveniles were also reared at pH 7.6 or 8.0, so that treatment groups represented 4 combinations of larval and juvenile pH experience. Juveniles were fed daily with Isochrysis galbana. Clearance rates were measured by flow cytometry during the first 3 h following introduction of fresh food and seawater. Among juveniles reared at pH 8.0 and tested 36 h after metamorphosis, individuals derived from pH 7.6 larval cultures fed at lower rates than those derived from pH 8.0 larval cultures. 2-4 d after metamorphosis, juveniles with equivalent larval pH experience fed at lower rates at pH 7.6 than at 8.0. However, clearance rates did not differ for older juveniles that were reared as larvae on a benchtop in ambient seawater at pH 7.8-8.0 and, upon metamorphosis, reared for 20 d as juveniles at pH 7.6 or 8.0. The differences in clearance rates observed in young juveniles were most pronounced in the first hour after feeding, which may suggest a reduced response to food under OA conditions. This may be an important consequence of OA for suspension feeders that exploit temporally and spatially variable food resources.
