Massive dome-shaped coral are the predominant choice for paleoclimate studies due to their consistent and reliable growth. When growing close to sea level, they become limited in their vertical growth and form so-called ‘microatolls’. Microatolls have not yet been extensively explored for paleoclimate reconstruction. Here, we investigate how reliable modern microatolls are against empirical sea-surface temperature using Sr/Ca, δO, Li/Mg and SrU paleothermometry methods on samples from the Society Islands, French Polynesia. Our results show Sr/Ca ratios have the lowest Standard Error of the Inverse Prediction (SEIP) at 0.415 °C ( = 41) with a calibration of Sr/Ca (mmol mol) = −0.082 ± 0.006 SST (°C) + 11.256 ± 0.170 and with high reproducibility across multiple corals. The reproducibility of δO was less good, with SEIP increasing to 0.829 °C ( = 41). Considering methods directly from the literature, Li/Mg ratio empirically corrected for Sr/Ca had the best balance between bias and precision where no local calibration could be available. This study independently evaluates and confirms the suitability of microatolls from well-flushed environments for paleoclimate studies. Fossil dome-shaped grow anywhere between near-surface and roughly 20 m depths which inherently incorporates uncertainty into any sea surface temperature reconstruction. This uncertainty is significantly reduced for microatolls due to their well-constrained bathymetry. The study represents a fundamental step in paleoclimate research targeting consistently near the water-air interface bringing reliability and, especially when combined with their ability to reconstruct past sea-level changes, microatolls have the potential to be central for future paleoenvironmental studies.

中文翻译：

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用于古测温法的滨珊瑚微环礁评估：法属波利尼西亚的校准

巨大的圆顶形珊瑚因其持续可靠的生长而成为古气候研究的主要选择。当生长接近海平面时，它们的垂直生长受到限制并形成所谓的“微环礁”。尚未对微环礁进行广泛探索以进行古气候重建。在这里，我们使用 Sr/Ca、δ18O、Li/Mg 和 SrU 古测温方法对法属波利尼西亚社会群岛的样本进行研究，研究现代微环礁对经验海面温度的可靠性。我们的结果显示，Sr/Ca 比率在 0.415 °C (= 41) 时具有最低的逆向预测 (SEIP) 标准误差，校准为 Sr/Ca (mmol mol) = −0.082 ± 0.006 SST (°C) + 11.256 ± 0.170，并且在多种珊瑚中具有高重现性。 δ18O 的重现性较差，SEIP 增加至 0.829 °C (= 41)。考虑直接来自文献的方法，在无法进行局部校准的情况下，根据经验校正 Sr/Ca 的 Li/Mg 比率在偏差和精度之间具有最佳平衡。这项研究独立评估并确认了来自冲洗良好的环境的微环礁对于古气候研究的适用性。圆顶状化石生长在近地表和大约 20 m 深度之间的任何地方，这本质上将不确定性纳入任何海面温度重建中。由于微环礁的测深条件良好，这种不确定性显着降低。这项研究代表了古气候研究的一个基本步骤，目标始终靠近水-空气界面，带来可靠性，特别是当与重建过去海平面变化的能力相结合时，微环礁有可能成为未来古环境研究的中心。