Year: 2023
Type: article
Abstract: . 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 analyses with improved sampling resolution now enable the use of mollusk shells for paleoenvironmental reconstructions at a daily to sub-daily resolution. Here, we discuss hourly resolved Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca profiles measured by laser ablation ICP-MS through shells of photosymbiotic giant clams (Tridacna maxima, Tridacna squamosa and Tridacna 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 significant expression of these periodicities but 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 (~10 % of mean value) in Mg/Ca and Sr/Ca, while Mn/Ca and Ba/Ca cyclicity has a median amplitude of less than 2 µmol/mol (~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 some of the strongest diurnal cyclicity. Daily cycles in trace element composition of giant clams are therefore unlikely to be driven by variations in direct insolation itself but reflect an inherent biological rhythmic process affecting element incorporation. Finally, the large amount of trace element variability unexplained by periodic variability highlights the dominance of aperiodic processes in mollusk physiology and/or environmental conditions on shell composition at the sub-daily scale. Future studies should aim to investigate whether part of this aperiodic variability in shell chemistry reliably records weather patterns or circulation changes in the paleoenvironment.
Source: Biogeosciences
Institutions: Vrije Universiteit Brussel, Vrije Universiteit Amsterdam, San Francisco Estuary Institute, Johannes Gutenberg University Mainz, Royal Netherlands Institute for Sea Research, Centre National de la Recherche Scientifique, Ifremer, Laboratoire des Sciences de l'Environnement Marin, Institut de Recherche pour le Développement, Utrecht University
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: gold
Estimated APC paid: $1,628
Funders: European Commission, Deutsche Forschungsgemeinschaft, Agence Nationale de la Recherche, Universiteit Utrecht, Fonds Wetenschappelijk Onderzoek, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Netherlands Earth System Science Centre, Aard- en Levenswetenschappen, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Horizon 2020 Framework Programme, H2020 Marie Skłodowska-Curie Actions
Awards: Bivalve shell-based, high-resolution multi-proxy reconstruction of marine primary production – Pecten maximus, Bay of Brest, G1311090270, G2084081293, G2189472788, G2535273770, G285994706, G3144226917, G3255201259, G3345895242, G434337789, G4521373248, G4656594441, G4689608210, Improving the accuracy of techniques for high-resolution seasonal-scale climate reconstructions from bivalve shells, G4937468798, G5237714278, G5719220881, G623109121, G6329715174, G6509606559, G7358480839, G8156542052, UNravelling BIvAlve Shell chemistry: Advanced Techniques for Accurate Reconstructions of Sub-annual Climate, G8512683158, G8650820596
OpenAlex ID: W4385370100