Sequence of seasonally to annually laminated diatomaceous sediment from sediment core DTCI2010 retrieved on the continental shelf off Adélie Land, covering the 1970-2010 CE period

Diatoms account for a large proportion of primary productivity in Antarctic coastal and continental shelf zones. Diatoms, which have been used for a long time to infer past sea surface conditions in the Southern Ocean, have recently been associated with diatom-specific biomarkers (highly branched isoprenoids, HBI). Our study is one of the few sedimentary research projects on diatom ecology and associated biomarkers in the Antarctic seasonal sea ice zone. To date, the Adélie Land region has received little attention, despite evidence for the presence of high accumulation of laminated sediment, allowing for finer climate reconstructions and sedimentary process studies. Here we provide a sequence of seasonally to annually laminated diatomaceous sediment from a 72.5 cm interface core retrieved on the continental shelf off Adélie Land, covering the 1970-2010 CE period. Investigations through statistical analyses of diatom communities, diatom-specific biomarkers and major element abundances document the relationships between these proxies at an unprecedented resolution. Additionally, comparison of sedimentary records to meteorological data monitored by automatic weather station and satellite derived sea ice concentrations help to refine the relationships between our proxies and environmental conditions over the last decades. Our results suggest a coupled interaction of the atmospheric and sea surface variability on sea ice seasonality, which acts as the proximal forcing of siliceous productivity at that scale.

硅藻（diatoms）在南极沿岸及大陆架海域的初级生产力中占据极高比例。长期以来，硅藻被广泛用于反演南大洋的古海面环境状况，近年来其与硅藻特异性生物标志物（diatom-specific biomarkers，即高分支类异戊二烯（highly branched isoprenoids，HBI））的关联得到了明确揭示。本研究是南极季节性海冰区内少数针对硅藻生态及其关联生物标志物的沉积学研究项目之一。迄今为止，尽管已有证据表明阿德利地（Adélie Land）海域发育大量纹层沉积，可支撑更高分辨率的气候重建与沉积过程研究，但该区域尚未得到足够的研究关注。本次研究提供了一枚采自阿德利地外大陆架、长度72.5 cm的界面岩芯中的沉积序列，该序列为季节-年纹层状硅藻沉积，时间覆盖公元1970年至2010年。通过对硅藻群落、硅藻特异性生物标志物及常量元素含量开展统计学分析，本研究以前所未有的分辨率揭示了上述代用指标之间的相互关联。此外，本研究将沉积记录与自动气象站（automatic weather station）监测的气象数据及卫星反演海冰浓度数据进行对比，进一步厘清了近几十年来本研究使用的代用指标与区域环境状况之间的关联机制。研究结果表明，大气与海面变率对海冰季节循环存在耦合调控作用，这是该尺度下硅质生产力的近端驱动因素。