Ultradian rhythms in shell composition of photosymbiotic and non-photosymbiotic mollusks

• Published in: Biogeosciences
• Main Authors: de Winter, Niels, Killam, Daniel, Fröhlich, Lukas, de Nooijer, Lennart, Boer, Wim, Schöne, Bernd, Thébault, Julien, Reichart, Gert-Jan
• Other Authors: Vrije Universiteit Amsterdam Amsterdam (VU), San Francisco Estuary Institute, Richmond, CA, USA, University of Mainz, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Royal Netherlands Institute for Sea Research (NIOZ), University of Mainz, Mainz, Germany, 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 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)-Centre National de la Recherche Scientifique (CNRS), This research has been supported by the European Commission, Horizon 2020 Framework Programme (UNBIAS (grant nos. H2020-MSCA-IF-2018, 843011)); the Fonds Wetenschappelijk Onderzoek (grant no. 12ZB220N); the Aard-en Levenswetenschappen, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (grant no. 024.002.001); the Deutsche Forschungsgemeinschaft (grant nos. SCHO/793/21 and SCHO 793/23); and the Agence Nationale de la Recherche (grant no. ANR-18-CE92-0036-01)., ANR-18-CE92-0036,HIPPO,Pecten maximus, archive multi-proxy haute-résolution de la production primaire en rade de Brest(2018), European Project: 844909
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: ARAGONITIC BIVALVE SHELLS; RESOLUTION TRACE-ELEMENT; TRIDACNA-GIGAS BIVALVES; GIANT CLAM; ARCTICA-ISLANDICA; GROWTH-RATESICP-MS; STABLE-ISOTOPES; CLIMATE VARIABILITY; CERASTODERMA-EDULE; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Arctica islandica
• Online Access: https://hal.univ-brest.fr/hal-04186979; https://hal.univ-brest.fr/hal-04186979/document; https://hal.univ-brest.fr/hal-04186979/file/bg-20-3027-2023.pdf; https://doi.org/10.5194/bg-20-3027-2023

The chemical composition of mollusk shells is a useful tool in (paleo)climatology since it captures inter- and intra-annual variability in environmental conditions. Trace element and stable isotope analysis with improved sampling resolution now allows in situ determination of the composition of mollusk shell volumes precipitated at daily to sub-daily time intervals. Here, we discuss hourly resolved Mg / Ca, Mn / Ca, Sr / Ca, and Ba / Ca profiles measured by laser ablation inductively coupled plasma – mass spectrometry (ICP-MS) through shells of the photosymbiotic giant clams (Tridacna maxima, T. squamosa, and T. squamosina) and the non-photosymbiotic scallop Pecten maximus. Precise sclerochronological age models and spectral analysis allowed us to extract daily and tidal rhythms in the trace element composition of these shells. We find weak but statistically significant expressions of these periods and conclude that this cyclicity explains less than 10 % of the sub-annual variance in trace element profiles. Tidal and diurnal rhythms explain variability of, at most, 0.2 mmol mol−1 (∼ 10 % of mean value) in Mg / Ca and Sr / Ca, while ultradian Mn / Ca and Ba / Ca cyclicity has a median amplitude of less than 2 µmol mol−1 mol mol−1 (∼ 40 % and 80 % of the mean of Mn / Ca and Ba / Ca, respectively). Daily periodicity in Sr / Ca and Ba / Ca is stronger in Tridacna than in Pecten, with Pecten showing stronger tidal periodicity. One T. squamosa specimen which grew under a sunshade exhibits among the strongest diurnal cyclicity. Daily cycles in the trace element composition of giant clams are therefore unlikely to be driven by variations in direct insolation but rather reflect an inherent biological rhythmic process affecting element incorporation. Finally, the large amount of short-term trace element variability unexplained by tidal and daily rhythms highlights the dominance of aperiodic processes in mollusk physiology and/or environmental conditions over shell composition at the sub-daily scale. Future studies should ...