We reconstructed the paleoceanographic evolution of the Japan Sea over the Pleistocene using benthic foraminiferal and organic geochemical records from sediment cores recovered at IODP Site U1426, which was drilled at a water depth of 900 m on the Oki Ridge in the southern Japan Sea. The dominant benthic foraminiferal biofacies and the assemblage composition, total organic and inorganic carbon, coarse fraction percentages indicate a notable reduction in primary productivity between 2150 and 1700 ka, due to the restricted supply of nutrients from the northern Pacific Ocean through the northern connecting strait. The inflow of the Tsushima Warm Current via the southern strait began after 1700 ka and marked a major change in the productivity regime of the Japan Sea, as shown by the increased abundance of calcareous foraminifera and enhanced CaCO₃ (%). A marked shift in productivity occurred during the Middle Pleistocene Transition, as indicated by the dominance of low-oxygen tolerant species, and a higher influx of total organic carbon (%). The onset of more extreme glaciation at ~490–470 ka coincident with the Mid-Brunhes Event was linked to marked changes in foraminiferal assemblage composition, reflecting major changes in sea-level, oxygen availability at the seafloor, and carbonate compensation depth during intense glacial-interglacial cycles. Productivity changes were also modulated by 23 kyr variability, related to precessional insolation forcing at low latitudes, and superimposed on the 41 and 100 kyr variability, linked to high-latitude climate fluctuations.

我们使用IODP站点U1426回收的沉积岩心底栖有孔虫和有机地球化学记录重建了更新世日本海的古海洋演化，该沉积物是在日本南部海的冲绳山脊900 m的水深处钻出的。底栖有孔虫的主要生物相和组合组成（总有机碳和无机碳）的粗略百分率表明，由于从北太平洋到北部连接海峡的养分供应有限，初级生产力在2150至1700 ka之间显着下降。对马暖流从南部海峡开始流入，始于1700 ka之后，标志着日本海生产力的一个重大变化，这表现为钙质有孔虫数量的增加和CaCO的增加₃（％）。生产力的明显变化发生在中更新世过渡期，这表现为低氧耐受性物种的优势以及总有机碳（％）的大量涌入。在约490-470 ka发生中冰期较早事件时，出现了更极端的冰川，这与有孔虫的组成明显变化有关，反映了强烈冰川期海平面的重大变化，海底氧气的可利用性以及碳酸盐补偿深度。 -冰期循环。生产力的变化还受到与低纬度进动强迫相关的23 kyr变异性的影响，并叠加在41 kyr和100 kyr变异性上，与高纬度气候波动有关。