Artificial light at night at environmental intensities disrupts daily rhythm of the oyster Crassostrea gigas

• Published in: Marine Pollution Bulletin
• Main Authors: BOTTE, Audrey, PAYTON, Laura, TRAN, Damien
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: ALAN; biological rhythm; circadian clock; Crassostrea gigas; behavior; Sciences de l'environnement
• Online Access: https://oskar-bordeaux.fr/handle/20.500.12278/188669; https://hdl.handle.net/20.500.12278/188669; https://doi.org/10.1016/j.marpolbul.2023.114850

Artificial Light At Night (ALAN) masks the natural light cycles and thus can disturb the synchronization of organisms' biological rhythms with their environment. Although coastlines are highly exposed to this growing threat, studies concerning the impacts of ALAN on coastal organisms remain scarce. In this study, we investigated the ALAN exposure effects at environmentally realistic intensities (0.1, 1, 10, 25 lx) on the oyster Crassostrea gigas, a sessile bivalve subject to light pollution on shores. We focused on the effects on oyster's daily rhythm at behavioral and molecular levels. Our results showed that ALAN disrupts the oyster's daily rhythm by increasing valve activity and annihilating day / night differences of expression of circadian clock and clock-associated genes. ALAN effects occur starting from 0.1 lx, in the range of artificial skyglow illuminances. We concluded that realistic ALAN exposure affects oysters' biological rhythm, which could lead to severe physiological and ecological consequences. Impact de la pollution lumineuse chez les organismes vivant dans les environnements côtiers