Insight into shell growth dynamics of Mactromeris polynyma in the St. Lawrence Estuary using sclerochemistry
Résumé
This study explores the potential of geochemical data to accurately date Mactromeris polynyma shells collected in the Lower St. Lawrence Estuary, and to assess the species' utility as an environmental archive. Previous growth studies of M. polynyma from the St. Lawrence ecosystem showed a possible overestimation of annual growth lines using the classic sclerochronology methodology. Our study proposes a new method based on chemochronology, coupling Ba/Ca and Sr/Ca ratio profiles to distinguish between disturbance lines and actual annual growth lines. By aligning the Sr/Ca profiles thanks to the peaks of Ba/Ca, drastic decreases in the Sr/Ca ratio have been highlighted. These drops, which are detectable in all specimens, precisely locate the annual growth lines, making it possible to study variations in the growth rate. Our chemochronology method is a powerful tool for precisely aging M. polynyma, making this innovative method an alternative to sclerochronology techniques for highlighting annual growth lines for species that are difficult to age. Highlights: Chemochronology as a new methodology to age specimens Ba/Ca ratio as a tool to align Sr/Ca ratio profiles Aligned Sr/Ca ratio profiles show common sharp decreases among specimens Sharp Sr/Ca ratio decreases accurately locate annual growth lines M. polynyma has great potential as an environmental archive
Fichier principal
Insight into shell growth dynamics of Mactromeris polynyma in1.pdf (14.6 Mo)
Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)