Brad Seibel (URI), Heidi Dierssen (UConn - Avery Point)
Pteropod mollusks are a group which is believed to be especially sensitive to climate change because of their highly-soluble aragonitic shells. These animals are prevalent in the rapidly shifting environment of the polar oceans where, owing to the increased solubility of CO2 in cold water, undersaturation of calcium carbonate compounds is first expected to occur. In this system, my research has shown that food availability plays an important role in the long term metabolic rate of pteropod species (Maas et al., 2011 MEPS). This broad scale pattern of seasonal food availability and oxygen consumption dynamically interacts with this species response to acidified conditions. I have shown that thecosome (shelled) pteropods have a reduction in metabolic rate (O2 consumption) when exposed to high CO2 (1000 ppm) only during seasons where food availability is high (Seibel, Maas and Dierssen, 2012 PLOS One). During years of low primary productivity, the metabolic rate of these animals is already depressed, indicating that physiological compensation for hypercapnia requires an energetic investment which can not be sustained during periods of food deprivation.