Comparison of Mediterranean Pteropod Shell Biometrics and Ultrastructure from Historical (1910 and 1921) and Present Day (2012) Samples Provides Baseline for Monitoring Effects of Global Change

• Published in: PLOS ONE
• Main Authors: Howes, Ella, Eagle, Robert A., Gattuso, Jean-Pierre, Bijma, Jelle
• 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), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Sciences Los Angeles (AOS), University of California Los Angeles (UCLA), University of California-University of California, Institut du Développement Durable et des Relations Internationales (IDDRI), Institut d'Études Politiques IEP - Paris, European Project: 265103,EC:FP7:ENV,FP7-ENV-2010,MEDSEA(2011)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: OCEAN ACIDIFICATION; ANTHROPOGENIC CO2; TEMPERATURES; ARAGONITE; DYNAMICS; IMPACTS; CARBON; ACL; envir; geo; Ula; ice core; Ocean acidification
• Online Access: https://doi.org/10.1371/journal.pone.0167891; https://hal.sorbonne-universite.fr/hal-01466190/file/journal.pone.0167891.pdf; https://hal.sorbonne-universite.fr/hal-01466190

International audience Anthropogenic carbon perturbation has caused decreases in seawater pH and increases in global temperatures since the start of the 20 th century. The subsequent lowering of the saturation state of CaCO 3 may make the secretion of skeletons more problematic for marine cal-cifiers. As organisms that precipitate thin aragonite shells, thecosome pteropods have been identified as being particularly vulnerable to climate change effects. Coupled with their global distribution, this makes them ideal for use as sentinel organisms. Recent studies have highlighted shell dissolution as a potential indicator of ocean acidification; however, this metric is not applicable for monitoring pH changes in supersaturated basins. In this study, the novel approach of high resolution computed tomography (CT) scanning was used to produce quantitative 3-dimensional renderings pteropod shells to assess the potential of using this method to monitor small changes in shell biometrics that may be driven by climate change drivers. An ontogenetic analysis of the shells of Cavolinia inflexa and Styliola subula collected from the Mediterranean was used to identify suitable monitoring metrics. Modern samples were then compared to historical samples of the same species, collected during the Mediterranean leg of the Thor (1910) and Dana (1921) cruises to assess whether any empirical differences could be detected. Shell densities were calculated and scanning electron microscopy was used to compare the aragonite crystal morphology. pH for the collection years was hind-cast using temperature and salinity time series with atmospheric CO 2 concentrations from ice core data. Historical samples of S. subula were thicker than S. sub-ula shells of the same size from 2012 and C. inflexa shells collected in 1910 were significantly denser than those from 2012. These results provide a baseline for future work to develop monitoring techniques for climate change in the oceans using the novel approach of high-resolution CT scanning.