Geochemical signals in bivalve carbonate hold the potential to record environmental change over timescales from months to centuries; however, not all bivalves provide reliable proxy records, and modern studies are essential to calibrate these relationships prior to use in palaeo-environmental reconstruction. In this study, 19 shells of the estuarine bivalve Arthritica helmsi, from 14 sites in Southeastern Australia, were obtained from museum collections and analysed for trace elemental (Sr/Ca, Mg/Ca, Sr/Li and Ba/Ca) and stable isotopic ratios (¹⁸O/¹⁶O and ¹³C/¹²C). Mean Sr/Ca and Mg/Ca exhibited significant negative correlations to temperature (R² = 0.49, p = 0.001; R² = 0.25, p = 0.02) in agreement with previously published models for trace element partitioning into inorganic aragonite. In addition, the within-shell range of Sr/Ca and Mg/Ca, as measured by laser ablation ICP-MS, correlated to the temperature range (R² = 0.22, p = 0.03; R² = 0.46, p = 0.002, respectively). Sr/Li ratios were also negatively correlated to temperature (R² = 0.34, p = 0.008); however, a significant difference in the model coefficients with previous studies indicates this proxy should be applied with caution. Both oxygen and carbon isotope values exhibited large differences between shells from terrestrial, estuarine and marine waters, suggesting that these stable isotopes hold a potential to record large environmental changes such as sea-level changes or freshening/salinisation in estuarine environments. This study presents the first geochemical study of Arthritica helmsi, highlighting its potential as an environmental tracer.

中文翻译：

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澳大利亚东南部河口短寿命双壳类动物地球化学的环境控制

双壳碳酸盐中的地球化学信号具有记录从几个月到几个世纪的时间范围内环境变化的潜力。然而，并非所有双壳类动物都提供可靠的代理记录，现代研究对于在用于古环境重建之前校准这些关系至关重要。在这项研究中，从博物馆收藏品中获得了澳大利亚东南部14个地点的河口双壳类节肢动物Arthritica helmsi的贝壳，并分析了痕量元素（Sr / Ca，Mg / Ca，Sr / Li和Ba / Ca）和稳定的同位素比率（¹⁸ O / ¹⁶ O和¹³ C / ¹² C）。平均Sr / Ca和Mg / Ca与温度呈显着负相关（R ² = 0.49，p = 0.001；R ² = 0.25，p = 0.02）与先前公布的将痕量元素分配到无机文石中的模型一致。此外，通过激光烧蚀ICP-MS测量的Sr / Ca和Mg / Ca的壳内范围与温度范围相关（R ² = 0.22，p = 0.03; R ² = 0.46，p = 0.002，分别）。Sr / Li比也与温度呈负相关（R ² = 0.34，p= 0.008）；但是，模型系数与以前的研究存在显着差异，因此应谨慎使用此代理。氧气和碳同位素值在陆地，河口和海水中的壳之间都显示出很大的差异，这表明这些稳定的同位素具有记录大型环境变化（如海平面变化或河口环境中的淡化/盐化）的潜力。这项研究是对Arthritica helmsi的首次地球化学研究，强调了其作为环境示踪剂的潜力。