Skeletal remains of marine bivalves, Tridacna spp., can provide multi-proxy records of environmental variables. Sr/Ca ratio, which has been widely used in corals as a paleo-temperature proxy, has also been explored in Tridacna spp. shells in recent decades, but some controversies remain, especially regarding the different Sr/Ca-SST relationships across Tridacnidae species. In this study, ten specimens of three different species (Tridacna gigas, Tridacna squamosa and Tridacna derasa) were collected from the northern South China Sea and the monthly resolution Sr/Ca and δ¹⁸O ratios were investigated. Almost all high-resolution Sr/Ca profiles, determined by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), show pronounced annual cycles and are significantly correlated with paired δ¹⁸O value. However, Sr/Ca ratios of T. gigas are positively correlated with paired δ¹⁸O values, suggesting a negative correlation between T. gigas Sr/Ca and in-situ SST, while Sr/Ca ratios of T. derasa and T. squamosa are negatively correlated with paired δ¹⁸O, suggesting a positive correlation between SST and Sr/Ca in T. derasa and T. squamosa. These interspecies differences highlight the necessity of species identification before using Tridacnidae Sr/Ca ratios in paleoclimate reconstructions. Although the Sr/Ca-δ¹⁸O relationship has obvious interspecies differences, the clear annual cycles in all these specimens indicate that the Sr/Ca ratios of Tridacna spp. may have the potential to be used in reconstructing the past climate seasonality, ENSO variability and so on.

海洋双壳类动物的骨骼遗骸Tridacna spp. 可以提供环境变量的多代理记录。Sr/Ca 比率已在珊瑚中广泛用作古温度代理，也已在Tridacna spp 中进行了探索。近几十年来的壳，但仍然存在一些争议，特别是关于 Tridacnidae 物种之间不同的 Sr/Ca-SST 关系。本研究从南海北部采集了三种不同物种（长砗磲、鳞砗磲和砗磲）的10个标本，月分辨率为Sr/Ca和δ ¹⁸研究了 O 比。几乎所有由 ICP-OES（电感耦合等离子体发射光谱仪）确定的高分辨率 Sr/Ca 分布图都显示出明显的年循环，并且与配对的 δ ¹⁸ O 值显着相关。然而，T. gigas 的Sr/Ca 比率与成对的 δ ¹⁸ O 值正相关，表明T. gigas Sr/Ca 与原位 SST之间呈负相关，而T. derasa和T.squamosa 的Sr/Ca 比率与成对的 δ ¹⁸ O呈负相关，表明T. derasa和T. squamosa 的SST 和 Sr/Ca 之间呈正相关. 这些种间差异突出了在古气候重建中使用鲟科 Sr/Ca 比率之前进行物种鉴定的必要性。尽管 Sr/Ca-δ ¹⁸ O 关系存在明显的种间差异，但所有这些标本中清晰的年循环表明Tridacna spp.的 Sr/Ca 比率。可能有潜力用于重建过去的气候季节性、ENSO 变率等。