Insights into coastal phytoplankton variations from 1979 to 2018 derived from Ba/Ca records in scallop shells (Chlamys islandica) from a fishing ground in the northern Gulf of St. Lawrence. (November 2022)

• Record Type: Journal Article
• Authors: Poitevin, Pierre; Roy, Virginie; Galbraith, Peter S.; Chaillou, Gwenaëlle
• Is Part Of: Marine environmental research. Volume 181(2022)
• Publication Date: 2022-11
• Subjects: Barium -- Chlamys islandica -- Fisheries -- Gulf of St. Lawrence -- Phytoplankton -- Sclerochronology; Marine pollution -- Environmental aspects -- Periodicals; Marine ecology -- Periodicals; Mer -- Pollution -- Aspect de l'environnement -- Périodiques; Écologie marine -- Périodiques; Electronic journals; 577.705
• DOI: 10.1016/j.marenvres.2022.105734
• Languages: English
• ISSNs: 0141-1136

Abstract

Abstract: Bivalve growth is affected by phytoplankton quality and availability, but long-term, coastal environmental time series related to these parameters are often lacking. Therefore, it is crucial to develop methods to accurately quantify trends in phytoplankton dynamics over time. This would be especially important for the fished scallop beds in the northern Gulf of St. Lawrence, where landings sharply declined since the early-2000s. Over the past decade, many studies have highlighted the potential of Ba/Ca ratios in bivalve shells as an environmental proxy for phytoplankton dynamics. This study presents records of Ba/Ca ratios in 31 young Chlamys islandica shells sampled in the Mingan Archipelago from 1979 to 2018. The Ba/Ca master chronology showed a decreasing trend since 2002, which could reflect changes in local phytoplankton bloom taxonomic composition, and coincides with the aforementioned decline in scallop landings. Investigations of environmental controls on barium incorporation into the shells highlight the importance of bottom, nutrient-rich waters to support diatom production or export in this fishing area. The use of such high-resolution seasonal records extracted from bio-archives may identify essential environmental mechanisms that will then assist with the development of an ecosystem-based fishery management strategy. Highlights: High inter-reproducibility of Ba/Ca profiles between individuals. Original reconstruction of a seasonally-resolved Ba/Ca chronology over 40 years. Ba/Ca-derived phytoplankton phenology changes may have affected scallop stock. Cold and nutrient-rich water in the study area could support high diatom production. In fisheries, bio-archives may help to identify underlying environmental mechanisms.