Porites' coral calcifying fluid chemistry regulation under normal- and low-pH seawater conditions in Palau Archipelago: Impacts on growth properties.

• Published in: Science of The Total Environment
• Main Authors: Canesi, Marine, Douville, Éric, Bordier, Louise, Dapoigny, Arnaud, Coulibaly, Gninwoyo Eric, Montagna, Paolo, Béraud, Éric, Allemand, Denis, Planes, Serge, Furla, Paola, Gilson, Eric, Roberty, Stéphane, Zoccola, Didier, Reynaud, Stéphanie
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2023
• Subjects: Biological carbonate chemistry regulation; Calcifying fluid; Massive Porites corals; Ocean acidification; Palau; Skeletal density; Pollution; Waste Management and Disposal; Environmental Chemistry; Environmental Engineering; Life sciences; Aquatic sciences & oceanology; Physical; chemical; mathematical & earth Sciences; Chemistry; Sciences du vivant; Sciences aquatiques & océanologie; Physique; chimie; mathématiques & sciences de la terre
• Online Access: https://orbi.uliege.be/handle/2268/309187; https://doi.org/10.1016/j.scitotenv.2023.168552

peer reviewed Ongoing ocean acidification is known to be a major threat to tropical coral reefs. To date, only few studies have evaluated the impacts of natural long-term exposure to low-pH seawater on the chemical regulation and growth of reef-building corals. This work investigated the different responses of the massive Porites coral living at normal (pHsw ~ 8.03) and naturally low-pH (pHsw ~ 7.85) seawater conditions at Palau over the last decades. Our results show that both Porites colonies maintained similar carbonate properties (pHcf, [CO32-]cf, DICcf, and Ωcf) within their calcifying fluid since 1972. However, the Porites skeleton of the more acidified conditions revealed a significantly lower density (~ 1.21 ± 0.09 g·cm-3) than the skeleton from the open-ocean site (~ 1.41 ± 0.07 g·cm-3). Overall, both Porites colonies exerted a strong biological control to maintain stable calcifying fluid carbonate chemistry that favored the calcification process, especially under low-pH conditions. However, the decline in skeletal density observed at low pH provides critical insights into Porites vulnerability to future global change.