The geochemistry of calcifying marine organisms is an excellent proxy for reconstructing paleoceanographic history, but studies of hypercalcified demosponges (sclerosponges) are considerably fewer than those of corals, foraminifers, and bivalves. For this study, we first generated near-annual resolved stable carbon and oxygen isotope (δ¹³C and δ¹⁸O) and element/Ca ratios (Sr/Ca, Ba/Ca, Pb/Ca, U/Ca) time series for 1880–2015 from sclerosponge samples (Acanthochaetetes wellsi) collected at Miyako Island and Okinawa Island in the Ryukyu Islands of southwestern Japan. The δ¹³C records exhibited a typical variation of anthropogenically derived Suess effects, demonstrating that the rates of decrease of –0.0043‰/year before 1960 and – 0.024‰/year after 1960 in the northwestern subtropical Pacific were respectively similar to and about 1.4 times higher than those of the Caribbean Sea in the tropical Atlantic. Spectral analysis of the δ¹⁸O time series revealed significant periodicity of approximately 2, 3, 6.5, 7–10, and 20–30 year/cycle, indicating that sea surface conditions in the southern Ryukyu Islands had been dominated by interannual and decadal variations in temperature and seawater δ¹⁸O since the late nineteenth century. The Sr/Ca and U/Ca ratios for the species A. wellsi (high-Mg calcite) might not be a robust proxy for seawater temperatures, unlike Astrosclera willeyana and Ceratoporella nicholsoni sclerosponges (aragonite). An evident increasing Pb/Ca trend after 1950 found in the samples is probably attributable to Pb emissions from industrial activities and atmospheric aerosols in eastern Asian countries. The Ba/Ca variations differ greatly among sampling sites, which might be attributable to the respective local environments. This evidence demonstrates that more high-resolution age determinations and geochemical profilings enable delineation of secular variations in ocean environments on annual and interannual timescales. Results of our study suggest that if sclerosponges living in deeper ocean environments are collected, spatial and vertical oceanographic variations for the last several centuries will be reconstructed along with coral proxy records.

钙化海洋生物的地球化学是重建古海洋学历史的绝佳代表，但对高钙化海绵（硬海绵）的研究远少于珊瑚、有孔虫和双壳类动物的研究。在本研究中，我们首先生成了近年解析的稳定碳和氧同位素（δ ¹³ C 和 δ ¹⁸ O）和元素/Ca 比率（Sr/Ca、Ba/Ca、Pb/Ca、U/Ca）时间序列，用于1880-2015 年来自日本西南部琉球群岛宫古岛和冲绳岛收集的硬海绵样品（Acanthochaetetes wellsi）。δ ¹³C记录表现出典型的人为Suess效应变异，表明西北亚热带太平洋1960年前–0.0043‰/年和1960年后–0.024‰/年的下降率分别接近并高出约1.4倍位于热带大西洋的加勒比海。δ ¹⁸ O 时间序列的光谱分析揭示了大约 2、3、6.5、7-10 和 20-30 年/周期的显着周期性，表明琉球群岛南部的海面条件以年际和年代际变化为主自 19 世纪后期以来，温度和海水中的 δ ¹⁸ O。A. wellsi物种的 Sr/Ca 和 U/Ca 比率（高镁方解石）可能不是海水温度的可靠代表，不像Astrosclera willeyana和Ceratoporella nicholsoni硬海绵（文石）。样品中发现的 1950 年后明显增加的 Pb/Ca 趋势可能归因于东亚国家工业活动和大气气溶胶的 Pb 排放。Ba/Ca 变化在采样点之间差异很大，这可能归因于各自的当地环境。这一证据表明，更高分辨率的年龄测定和地球化学剖面图能够在年和年际时间尺度上描绘海洋环境的长期变化。我们的研究结果表明，如果收集生活在更深海洋环境中的硬海绵，过去几个世纪的空间和垂直海洋变化将与珊瑚代理记录一起重建。