Abstract The species abundances and assemblage of fossil diatoms are used as micropaleontological proxy to reconstruct the northwestern South China Sea continental margin paleo-environment over the last glacial - interglacial cycle and Holocene. Analysis of fossil diatom assemblages in piston core 111PC show a flora over the most recent ~160 kyr. BP dominated by tropical-subtropical planktonic and coastal species, assigned to six local diatom assemblage zones similar to foraminifera-based marine oxygen-isotope stages (MIS 6-1). Diatom abundance and species fluctuations in the core profile study area respond to the glacial – interglacial climate gyration and climate instability. Diatom abundance was higher in the late-Wurm, compared to mid-Wurm glacial and postglacial (Holocene) stages and even lower during the Riss and early-Wurm glacial stages. Change tendency of diatom abundance is significantly different from stations to the southwest but comparable to northeast South China Sea. In MIS 5, relative abundance of tropical diatom taxa decreases upward in response to climate shifts from interglacial to last glacial interval. Diatom species distribution with higher relative abundance of coastal taxa responded to climate-fluctuation during the MIS 4 and MIS 3 transition while biased by local deposition character.

中文翻译：

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自倒数第二次冰期以来海洋硅藻对南海西北海域海洋学和气候变化的响应

摘要 以硅藻化石的物种丰度和组合作为微观古生物学代理，重建了末次冰-间冰期和全新世南海西北部大陆边缘古环境。对活塞核心 111PC 中的化石硅藻组合的分析显示，在最近的 ~160 kyr 上有一个菌群。BP 以热带-亚热带浮游生物和沿海物种为主，被分配到六个类似于基于有孔虫的海洋氧同位素阶段 (MIS 6-1) 的局部硅藻组合区。核心剖面研究区硅藻丰度和物种波动对冰期-间冰期气候回转和气候不稳定性的响应。与中亚龙冰期和后冰期（全新世）相比，亚龙晚期的硅藻丰度更高，而在亚龙冰期和早期亚龙冰期，硅藻丰度更低。硅藻丰度变化趋势从站点到西南有显着差异，但与南海东北部相当。在 MIS 5 中，热带硅藻类群的相对丰度随着从间冰期到末冰期间隔的气候变化而上升。具有较高沿海分类群相对丰度的硅藻物种分布对 MIS 4 和 MIS 3 过渡期间的气候波动有反应，但受局部沉积特征的影响。