Highlights
• Ocean acidification research requires further understanding on the interactions with other stressors.
• We examined the combined effects of pCO2 and arm autotomisation on Asterias rubens.
• Neither stressor affected mortality, growth, arm regeneration, righting time or arm calcium content.
• Lipid content in the pyloric caeca increased in response to elevated pCO2.
• A. rubens appears unaffected by short-term exposure to pCO2 levels predicted for 2100.
Abstract
The impacts of ocean acidification remain less well-studied in starfish compared to other echinoderm groups. This study examined the combined effects of elevated pCO2 and arm regeneration on the performance of the intertidal predatory starfish Asterias rubens, as both are predicted to come at a cost to the individual. A two-way factorial experiment (~400 μatm vs ~1000 μatm; autotomised vs non-automised individuals) was used to examine growth rates, lipid content (pyloric caeca and gonads), and calcium content (body wall) in both intact and regenerating arms, as well as subsequent effects on rate of arm regeneration, righting time (behaviour) and mortality over 120 days. Autotomised individuals tended to show lower (not significant), survival and growth. Elevated pCO2 had no effect on mortality, body growth, arm regeneration, righting time or arm calcium content. Lipid content was higher in the pyloric caeca, but not in the gonads, in response to elevated pCO2 irrespective of autotomisation. The results of the study suggest that adult A. rubens remain unaffected by increased pCO2 and/or arm autotomy for 120 days, although longer term experiments are necessary as the results indicated that survival, growth and calcification may be impaired with longer-term exposure to elevated pCO2.
McCarthy I. D., Whiteley N. M., Fernandez W. S., Ragagnin M. N., Cornwell T. O., Suckling C. C. & Turra A., in press. Elevated pCO2 does not impair performance in autotomised individuals of the intertidal predatory starfish Asterias rubens (Linnaeus, 1758). Marine Environmental Research. Article (subscription required).
