|B.A. Seibel, A.E. Maas, H. Dierseen, |
Energetic plasticity underlies a variable response to ocean acidification in the pteropod, Limacina helicina antarctica, PLoS One, 2012
Anthropogenic carbon dioxide (CO2) diffuses into the ocean causing a reduction in pH. This “ocean acidification” may have a deleterious impact on energetic processes, including calcification, growth and metabolism, in marine organisms. However, an organism's nutritional state and feeding history also influence these physiological parameters. Low regional phytoplankton concentrations, for example, have been implicated in reduced population abundance, delayed spawning, metabolic suppression and local extinctionin Antarctic pteropods, a group widely believed to be susceptible to ocean acidification due to its fragile shell made of aragonite, a highly soluble form of calcium carbonate. Here we show that elevated carbon dioxide (hypercapnia) can suppress metabolism in L. helicina (forma antarctica) by ~20%. However, we further demonstrate metabolic plasticity in response to regional phytoplankton concentration and that the response to CO2 is dependent on the baseline level of metabolism. Thus, pteropod populations may be compromised by climate change, both directly via CO2-induced metabolic suppression, and indirectly via quantitative and qualitative changes to the phytoplankton community . Without the context provided by our long-term observations (four seasons) and a multi-faceted laboratory analysis of the parameters affecting energetics, the complex response of polar pteropods to ocean acidification may be masked or misinterpreted.