Phytoplankton dynamics in coastal ecosystems is increasingly altered by land-based human activities. Yet, this global vision conceals major disparities, among sites and through time. As conventional monitoring time series are quite sparse and relatively short, biological records of environmental variability appear as relevant tools to gain insights into phytoplankton dynamics over larger temporal and spatial scales. Here, we present results of an interdisciplinary project dealing with chemical information archived in shells of Pecten maximus (Bivalvia; Pectinidae), known to form daily growth striae on its shell surface. Several individuals were collected in the Bay of Brest (France) in 2011 and 2012, and analyzed for the molybdenum and lithium concentrations in their soft tissues and the element-to-calcium ratios (Mo : Ca and Li : Ca) in their calcitic striae. All shells revealed high synchrony and reproducibility in their Mo : Ca and Li : Ca profiles, characterized with a major peak at the end of May and in mid-June 2011, respectively. Detailed analysis of physical, chemical, and biological variables measured in seawater during an extensive 9-month environmental survey enabled a meticulous description of phytoplankton dynamics in 2011 and its impact on shell geochemistry. Main findings strongly suggest that (1) the timing of Mo : Ca peaks reflects the occurrence of silicon limitation and diatom aggregation periods, (2) the height of these peaks relates to the amplitude of the first spring diatom bloom, and (3) Li : Ca serves as a proxy for the temporal dynamics of diatom biovolume and of biogenic silica recycling at the sediment–water interface.

中文翻译：

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扇贝壳作为温带沿海生态系统中浮游植物相关生态过程的地球化学档案

沿海生态系统中的浮游植物动态日益受到陆上人类活动的影响。然而，这种全球视野掩盖了地点之间和时间上的重大差异。由于传统的监测时间序列非常稀疏且相对较短，环境变化的生物记录似乎是深入了解更大时间和空间尺度上的浮游植物动态的相关工具。在这里，我们展示了一个跨学科项目的结果，该项目处理了保存在Pecten maximus壳中的化学信息（双壳纲；果胶科），已知在其壳表面形成日常生长的条纹。2011 年和 2012 年在布雷斯特湾（法国）收集了几个人，并分析了他们软组织中的钼和锂浓度以及他们的方解石纹中的元素与钙的比率（Mo：Ca 和 Li：Ca） . 所有贝壳在其 Mo : Ca 和 Li : Ca 剖面中都显示出高度的同步性和再现性，其特征分别是 5 月底和 2011 年 6 月中旬的一个主要峰值。在为期 9 个月的广泛环境调查期间，对海水中测量的物理、化学和生物变量进行了详细分析，从而能够细致地描述 2011 年的浮游植物动态及其对贝壳地球化学的影响。主要研究结果强烈表明 (1) Mo 的时机：