Our main hypothesis is that many marine species, which some laboratory studies suggest are sensitive to AO, actually have the capacity to acclimatise and potentially adapt to future conditions. This hypothesis is supported by the fact that several populations of reef-building corals thrive at CO₂ emission sites in Ambitle where pH conditions are similar to those in future climate scenarios, suggesting that they are capable of acclimatisation or even adaptation in this extreme environment.

During this first campaign on N/O Alis (CARIOCA), we visited the CO₂ vents at Ambitle, where the corals are subjected to both higher temperatures and acidification. At this site, the seawater around the reef is acidified and the fluids emitted are hot (up to 90°C). Unfortunately, the effect of this warm seawater does not propagate but is immediately dissipated around the vents, ruling out any possibility of studying the coupled effect of acidification and warming. We carried out precise measurements of the main environmental parameters and the chemical parameters of seawater (temperature, salinity, dissolved oxygen, pH, total alkalinity, DIC, nutrient salts, metals); collected samples of corals inside and outside the resurgences and on a pH and temperature gradient for bacteriological and genetic analyses; evaluated the physiological responses of corals living near the vents and in a control site, with normal water conditions, but also transplanted corals between the two sites.