Saint-Pierre and Miquelon (SPM) is a small archipelago where instrumental measures based on water column velocity and temperature profiles compiled comprehensive evidence for strong near-diurnal (25.8h) current and bottom temperature oscillations (up to 11.5 °C) which is possibly the largest ever observed - at any frequency - on a stratified mid-latitude continental shelf. The main objective of our study was to identify if Placopecten magellanicus can record on its shell these high frequency environmental variations. To this end, we have tried to identify proxies for water temperature and food availability through development of a new ultra-high resolution LA-ICPMS analyses method capable of resolving shell surface elemental composition with a 10 μm resolution. This method was applied on two shell fragments, both representing the third year of growth and 2015 annual growth period, respectively coming from two environmentally contrasted sites, more (30 m depth) or less (10 m depth) affected by high frequency thermal oscillations. Our results strongly suggest a relationship between phytoplankton biomass and barium incorporation into P. magellanicus shells at both sites. Even if P. magellanicus might present a physiological control of magnesium incorporation, the shape of the two Mg/Ca profiles seems to illustrate that temperature also exerts a control on magnesium incorporation in P. magellanicus shells from SPM. While U/Ca and Mg/Ca profiles show a strong positive correlation for 30 m site shell, suggesting that uranium incorporation in P. magellanicus shell is at least partially temperature dependent. The absence of such correlation for 10 m site shell suggests differences in uranium environmental availability or in P. magellanicus biomineralization between these two sites. The resolution of this new analytical method raises questions about such data interpretation related to P. magellanicus growth dynamics and physiology or individual scale based environmental measurements.

中文翻译：

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双壳贝壳的痕量元素组成是否记录了超高频环境变化？

圣皮埃尔和密克隆群岛（SPM）是一个小型群岛，在该群岛上，基于水柱速度和温度曲线的仪器测量汇总了强烈的近日（25.8h）电流和底部温度振荡（最高11.5°C）的综合证据在分层的中纬度大陆架上观测到的任何频率的最大地震。我们研究的主要目的是确定麦哲伦能否在其壳上记录这些高频环境变化。为此，我们试图通过开发一种新的超高分辨率LA-ICPMS分析方法来确定水温和食物供应量的替代方法，该方法能够解析10μm分辨率的壳表面元素组成。该方法应用于两个壳碎片，这两个指标分别代表增长的第三年和2015年的增长期，分别来自两个环境相反的地点，受高频热振荡的影响更大（30 m深度）或更少（10 m深度）。我们的结果有力地表明了浮游植物生物量与钡掺入两个地点麦哲伦壳中的关系。即使麦哲伦球菌可能对镁的掺入具有生理控制作用，两个Mg / Ca曲线的形状似乎也说明了温度也可以控制SPM对麦哲伦球壳中镁的掺入。虽然U / Ca和Mg / Ca剖面显示30 m站点壳具有很强的正相关性，这表明在麦哲伦壳中掺入铀至少部分取决于温度。对于10 m站点壳，这种相关性的缺失表明这两个站点之间铀环境可用性或麦哲伦体育生物矿化的差异。这种新的分析方法的分辨率提出了与麦哲伦球菌生长动力学和生理学或基于个体尺度的环境测量有关的这种数据解释的问题。