ABSTRACT

Sclerochronological data from archaeological shell middens provides crucial information about past environments and subsistence practices of coastal human populations. These studies rely on a strong knowledge of species-specific growth patterns, as it is the main driver of the quantity and quality of information recorded in biogenic carbonates. The limpet Patella vulgata is highly represented in eastern Atlantic shell middens. In this study, the micro-increment formation of its shell was investigated through in situ marking experiments, using calcein fluorochrome (150 mg.L⁻¹) coupled with cohort study and local SST recording. Calcein-stained growth structures confirmed the efficacy of the fluorochrome, and our results shows a disturbed tidal increment formation, with on average more than one increment per day, but less than one increment per tide. Growth is not mainly influenced by environmental factors, but could be forced by competition among limpets and endogenous factor (age and sex), resulting in a highly heterogenous population in terms of growth rates. Growth interruption could not be detected solely by micro-increment observation, causing a major issue for cross-calibration with recorded temperatures, sclerochronological estimation of growth and isotopic profiles. For palaeo-environmental application, we recommend to consider that there is no general population pattern, even at a micro-habitat scale.

摘要

来自考古贝壳的硬化年代学数据提供了有关沿海人口过去环境和生存实践的重要信息。这些研究依赖于对特定物种生长模式的深入了解，因为它是生物碳酸盐中记录的信息数量和质量的主要驱动因素。帽贝 Patella vulgata 在东大西洋贝壳中占有很高的比例。在这项研究中，通过原位标记实验研究了其壳的微增量形成，使用钙黄绿素荧光染料（150 mg.L ^-1) 加上队列研究和当地 SST 记录。钙黄绿素染色的生长结构证实了荧光染料的功效，我们的结果显示了受干扰的潮汐增量形成，平均每天增加一个以上，但每次潮汐少于一个增量。生长主要不受环境因素的影响，但可能受到帽贝之间的竞争和内生因素（年龄和性别）的影响，从而导致人口在增长率方面高度异质化。仅通过微增量观察无法检测到生长中断，这导致了与记录的温度、生长的硬化年代估计和同位素分布进行交叉校准的主要问题。对于古环境应用，我们建议考虑没有一般的种群模式，即使在微生境尺度上也是如此。