Meeting Abstract
Dissolution of excess anthropogenic CO2 into the ocean is causing the marine environment to decrease in pH. This ‘ocean acidification’ is predicted to threaten a broad variety of marine organisms, particularly calcifying animals such as the thecosome (i.e., shelled) pteropods. Due to spatial and seasonal variability in carbonate chemistry within the Gulf of Maine, pteropods in this environment may already be exposed to under-saturated, and hence corrosive, waters during certain seasons. To understand the implications of this variability we have explored the physiological response of the local population of thecosome pteropod, Limacina retroversa, to CO2 over the course of a year. Sampling for pteropods was done at four time points and was followed by four 7-14 day laboratory exposures to CO2 (ambient, 800, 1200 ppm). Using an integrated set of metabolic, gene-expression and shell quality studies, we examined whether pteropods vary seasonally in their sensitivity to CO2 exposure on time-scales relevant to acclimation responses. Similar to previous work with this species and others, there were pronounced changes in shell quality that were discernible after less than 3 days of exposure, while changes to metabolic rate were not pronounced. Our previous study of the transcriptomic response of the thecosome species Clio pyramidatato short term CO2 exposure (10 h, 800 ppm) revealed that despite a lack of change in respiration rate, expression of genes associated with biomineralization was affected by CO2 exposure. Directed studies of biomineralization-associated gene families and a differential expression analysis of the transcriptome of L. retroversa, in combination with both metabolic and shell quality metrics, will provide a complete picture of the effect of CO2 on this sentinel species.
