UKOA Benthic consortium study of the metabolic response of marine polychaetes around CO2 vents at Ischia.

To assess the potential for metabolic acclimatization and adaptation that allows colonization of elevated pCO2 areas, a series of in situ transplant and mutual transplant experiments using a group of phylogenetically related polychaetes (tolerant vs. sensitive spp.) living in and around the shallow-water CO2 vents system off Ischia were performed. Post-transplant, metabolic rates and responses of the polychaetes we characterized, allowing us to infer the potential for metabolic adaptation in tolerant versus sensitive species (experiment 1), as well as between populations of tolerant species found both inside and outside the vent areas (experiment 2). Metabolic rates were selected as indicators of physiological acclimatization/ adaptation as they are key to a species' ability to preserve positive life-history traits (i.e. its Darwinian fitness), and ultimately its distribution and abundance patterns locally and globally. We show that the marine polychaete Platynereis dumerilii is able to physiologically adapt to chronically elevated levels of pCO2. However, such adaptation was not ubiquitous among all tolerant species found in the CO2 vents, even when their ecologies are similar. We also show that physiological plasticity to chronically elevated pCO2 as shown by Amphiglena mediterranea can be a viable strategy for the successful colonization of elevated pCO2 environments.