Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Moore, B., Comeau, S., Bekaert, M., Cossais, A., Purdy, A., Larcombe, E., Puerzer, F., Mcculloch, Malcolm, Cornwall, C
• Other Authors: Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), The University of Western Australia (UWA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: acclimation; conceptacles; coralline algae; multi-generational; ocean acidification; pH variability; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Ocean acidification
• Online Access: https://hal.science/hal-03847680; https://hal.science/hal-03847680/document; https://hal.science/hal-03847680/file/Moore_et_al_2021_Preprint.pdf; https://doi.org/10.1098/rspb.2021.0130

International audience The future of coral reef ecosystems is under threat because vital reef-accreting species such as coralline algae are highly susceptible to ocean acidification. Although ocean acidification is known to reduce coralline algal growth rates, its direct effects on the development of coralline algal reproductive structures (conceptacles) is largely unknown. Furthermore, the long-term, multigenerational response of coralline algae to ocean acidification is extremely understudied. Here, we investigate how mean pH, pH variability and the pH regime experienced in their natural habitat affect coralline algal conceptacle abundance and size across six generations of exposure. We show that second generation coralline algae exposed to ocean acidification treatments had conceptacle abundances 60% lower than those kept in present day conditions, suggesting that conceptacle development is initially highly sensitive to ocean acidification. However, this negative effect of ocean acidification on conceptacle abundance disappears after three generations of exposure. Moreover, we show that this transgenerational acclimation of conceptacle development is not facilitated by a tradeoff with reduced investment in growth, as higher conceptacle abundances are associated with crusts with faster growth rates. These results indicate that the potential reproductive output of coralline algae may be sustained under future ocean acidification.