Effect of carbonate ion concentration and irradiance on calcification in planktonic foraminifera

• Main Authors: Lombard, F., da Rocha, R. E., Bijma, J., Gattuso, J. -P.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: Earth Science; [SDU]Sciences of the Universe [physics]; Ocean acidification; Planktonic foraminifera
• Online Access: https://hal.science/hal-04113864; https://doi.org/10.5194/bg-7-247-201010.5194/bgd-6-8589-2009

International audience The effect of carbonate ion concentration ([CO 3 2- ]) on calcification rates estimated from shell size and weight was investigated in the planktonic foraminifera Orbulina universa and Globigerinoides sacculifer. Experiments on G. sacculifer were conducted under two irradiance levels (35 and 335 μmol photons m -2 s -1 ). Calcification was ca. 30% lower under low light than under high light, irrespective of the [CO 3 2- ]. Both O. universa and G. sacculifer exhibited reduced final shell weight and calcification rate under low [CO 3 2- ]. For the [CO 3 2- ] expected at the end of the century, the calcification rates of these two species are projected to be 6 to 13% lower than the present conditions, while the final shell weights are reduced by 20 to 27% for O. universa and by 4 to 6% for G. sacculifer. These results indicate that ocean acidification would impact on calcite production by foraminifera and may decrease the calcite flux contribution from these organisms.