In this study, organic geochemical analyses of two sediment cores (BL16 and LV63–23) recovered from the western Bering Sea were carried out to examine the sea-ice variability and its relationship to phytoplankton community evolution over the past century. Bulk stable organic carbon isotopic composition (δ¹³C_TOC) showed pronounced depletion on the northern shelf since the late 1970s, indicating greater terrigenous organic matter (OM) under warming during recent decades. Variation in sedimentary OM in the southward core was closely associated with marine primary productivity and regional deposition processes. Arctic sea-ice proxy IP₂₅ throughout the two cores with different temporal profile patterns demonstrated sea-ice presence with the spatio-temporal variability across the study area over the past century. The phytoplankton marker-IP₂₅ index (PIP₂₅), a proxy for estimating semi-quantitatively sea-ice concentrations, reflected a decreased sea-ice cover with more distinct interannual fluctuations between 0.7 and 0.2 (especially in core BL16) after the late 1970s, coinciding with the recent warming scenario. Increased concentrations of phytoplankton biomarkers (brassicasterol and dinosterol) and their ratios as well as the PIP₂₅ record in core BL16 indicated a synchronous variability of reduced sea-ice cover with the enhancement of phytoplankton productivity since the late 1970s. These results suggested a coupled interaction of the sea-ice condition and planktonic ecosystem in the north Bering shelf. Our results also revealed recent (since the 2000s) spatial heterogeneity in sea-ice coverage between the northern and southern parts of the Bering Sea.

在这项研究中，对从白令海西部回收的两个沉积物岩心（BL16和LV63-23）进行了有机地球化学分析，以检查过去一个世纪中海冰的变化及其与浮游植物群落演化的关系。散装稳定有机碳同位素组合物（δ ¹³ C ^ _TOC）显示从70年代晚期北部货架上显着的损耗，指示在近数十年来在温热更大陆源有机物（OM）。南芯沉积物OM的变化与海洋初级生产力和区域沉积过程密切相关。北极海冰代理IP ₂₅在过去两个世纪中，整个研究区域的两个核心的整个区域都以不同的时间剖面模式显示出海冰的存在，并且时空变化。浮游植物标志物IP ₂₅指数（PIP ₂₅）是半定量海冰浓度的替代指标，反映了1970年代后期海冰覆盖率下降，且年际波动在0.7至0.2之间（尤其是BL16核心）更为明显。 ，与最近的变暖情况相吻合。浮游植物生物标记物（巴西卡斯汀和恐龙固醇）浓度增加及其比例以及PIP ₂₅BL16核心的记录表明，自1970年代后期以来，海冰覆盖减少与浮游植物生产力的提高同步变化。这些结果表明，北白令陆架的海冰条件与浮游生态系统存在相互作用。我们的结果还揭示了自2000年代以来白令海北部和南部之间海冰覆盖范围的空间异质性。