Seasonal Upwelling Conditions Modulate the Calcification Response of a Tropical Scleractinian Coral

Natural processes such as upwelling of deeper-water masses change the physical-chemical conditions of the water column creating localized ocean acidification events that can have an impact on the natural communities. This study was performed in a coral reef system of an archetypical bay within the Tayrona National Natural Park (PNNT) (Colombia), and aimed to quantify net calcification rates of a foundational coral species within a temporal context (6 months) taking into account the dynamics of seasonal upwelling that influence the study area. Net calcification rates of coral fragments were obtained in situ by the alkalinity anomaly technique in short-term incubations (similar to 2.5 h). We found a significant effect of the upwelling on net calcification rates (Gnet) (p < 0.05) with an 42% increase in CaCO3 accretion compared to non-upwelling season. We found an increase in total alkalinity (A(T)) and dissolved inorganic carbon (DIC) with decreased aragonite saturation (Omega(ara)) for the upwelling months, indicating an influence of the Subtropical Under Water mass (SAW) in the PNNT coral community. Significant negative correlations between net calcification with temperature and Omega(ara), which indicates a positive response of M. auretenra with the upwelling conditions, thus, acting as enhancer of resilience for coral calcification.

Automated summary

This study was conducted in a coral reef system in Tayrona National Natural Park in Colombia, aiming to quantify the net calcification rates of a foundational coral species in a temporal context of 6 months, taking into account the influence of seasonal upwelling. The results showed a significant increase in CaCO3 accretion during the upwelling season, indicating a positive response of the coral calcification to the upwelling conditions.