title: Populations of Pacific oysters Crassostrea gigas respond variably to elevated CO2 and predation by Morula marginalba.
abstract: Ocean acidification is anticipated to decrease calcification and increase dissolution of shelled molluscs. Molluscs with thinner and weaker shells may be more susceptible to predation, but not all studies have measured negative responses of molluscs to elevated pCO2. Recent studies measuring the response of molluscs have found greater variability at the population level than first expected. Here we investigate the impact of acidification on the predatory whelk Morula marginalba and genetically distinct subpopulations of the Pacific oyster Crassostrea gigas. Whelks and eight family lines of C. gigas were separately exposed to ambient (385 ppm) and elevated (1000 ppm) pCO2 for 6 weeks. Following this period, individuals of M. marginalba were transferred into tanks with oysters at ambient and elevated pCO2 for 17 days. The increase in shell height of the oysters was on average 63% less at elevated compared to ambient pCO2. There were differences in shell compression strength, thickness, and mass among family lines of C. gigas, with sometimes an interaction between pCO2 and family line. Against expectations, this study found increased shell strength in the prey and reduced shell strength in the predator at elevated compared to ambient pCO2. After 10 days, the whelks consumed significantly more oysters regardless of whether C. gigas had been exposed to ambient or elevated CO2, but this was not dependent on the family line and the effect was not significant after 17 days. Our study found an increase in predation after exposure of the predator to predicted near-future levels of estuarine pCO2.
authors: School of Science and Health, University of Western Sydney, Hawkesbury 2753 NSW, Australia;
authors: John M
authors: JM
authors: Wright
authors: School of Science and Health, University of Western Sydney, Hawkesbury 2753 NSW, Australia;
authors: Laura M
authors: LM
authors: Parker
authors: Port Stephens Fisheries Institute, Department of Primary Industries, Taylors Beach 2316, NSW, Australia; and.
authors: Wayne A
authors: WA
authors: O'Connor
authors: School of Science and Health, University of Western Sydney, Hawkesbury 2753 NSW, Australia;
authors: Mark
authors: M
authors: Williams
authors: CSIRO Food Futures Flagship & CSIRO Marine and Atmospheric Research, Hobart 7001 TAS, Australia.
authors: Peter
authors: P
authors: Kube
authors: School of Science and Health, University of Western Sydney, Hawkesbury 2753 NSW, Australia; pm.ross@uws.edu.au.
authors: Pauline M
authors: PM
authors: Ross
mesh_terms: D060105:Animal Shells / Q000737:chemistry / Q000187:drug effects; D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology*; D049896:Crassostrea / Q000187:drug effects*; D009028:Morula / Q000187:drug effects*; D011235:Predatory Behavior / Q000187:drug effects*
chemical_list: D002245:Carbon Dioxide