Figure 2. Downcore variations of total diatom concentration in core MD02-2529@en

The modern eastern equatorial Pacific (EEP) is a major natural source for atmospheric carbon dioxide and is thought to be connected to high-latitude ocean dynamics by oceanic teleconnections on glacial-interglacial timescales. A wealth of sedimentary records aiming at reconstructing last Quaternary changes in primary productivity and nutrient utilization have been devoted to understanding those linkages between the EEP and other distant oceanic areas. Most of these records are, however, clustered in the pelagic EEP cold tongue, with comparatively little attention devoted to coastal areas. Here we present downcore measurements of the composition and concentration of the diatom assemblage together with opal (biogenic silica) concentration at site MD02-2529 recovered in the coastal Panama Basin. Piston core MD02-2529, collected in an area affected by a multitude of processes, provides evidence for strong variations in diatom production at the millennial timescale during the last glacial cycle. The maxima in total diatom concentration occurred during the early marine isotopic stage (MIS) 4 as well as during the MIS 4/3 transition and MIS 3. Rapid changes in diatom concentrations during the MIS 3 mimics Bond cycles as independently recorded by the SSS estimation derived from planktonic foraminifera from the same core. Such patterns indicate a clear linkage between diatom production in the coastal EEP and rapid climate changes in the high-latitude North Atlantic. In parallel, the long-term succession of the diatom community from coastal diatoms, predominantly thriving during MIS 5 and 4, towards pelagic diatoms, dominant during MIS 3 and 2, points to a long-term change in the surface hydrology. During Heinrich Events, diatoms strongly reduced their production, probably due to enhanced stratification in the upper water column. After the last glacial maximum, diatom production and valve preservation strongly decreased in response to the advection of nutrient (H2SiO4)-depleted, warmer water masses. Our high-resolution record highlights how regional climatic processes can modulate rapid changes in siliceous primary production as triggered by wind-induced local upwelling, indicating that millennial climatic variability can overtake other prominent hydrological processes such as those related to silicic acid leakage.现代东赤道太平洋（EEP）是大气二氧化碳的主要自然排放源，且被认为在冰期-间冰期尺度上通过海洋遥相关与高纬度海洋动力过程相联系。为理解东赤道太平洋与其他远海区域间的此类关联，大量旨在重建晚第四纪初级生产力与营养盐利用变化的沉积记录研究已被开展。然而，此类记录大多集中于东赤道太平洋远洋冷舌区域，对沿岸区域的关注相对匮乏。本文报道了采自巴拿马沿岸盆地的MD02-2529站位的岩芯剖面测量结果，内容涵盖硅藻组合的组成、浓度以及蛋白石（生物硅，biogenic silica）浓度。 活塞岩芯MD02-2529采集于受多重过程影响的区域，其记录显示末次冰期旋回内千年尺度上硅藻生产力存在显著波动。总硅藻浓度峰值出现于海洋同位素阶段（MIS）4早期、MIS 4/3转换期以及MIS 3阶段。MIS 3阶段内硅藻浓度的快速变化，与基于同一岩芯浮游有孔虫获得的海表盐度（Sea Surface Salinity, SSS）估算结果所独立记录的邦德旋回（Bond cycles）特征一致。此类模式表明，沿岸东赤道太平洋的硅藻生产力与北大西洋高纬度地区的快速气候变化存在明确关联。 与此同时，硅藻群落从主要繁盛于MIS 5和MIS 4的沿岸硅藻，向MIS 3和MIS 2占优势的远洋硅藻的长期演替，反映了表层水文环境的长期变化。海因里希事件（Heinrich Events）期间，硅藻生产力大幅下降，这可能源于上层水柱层化作用的增强。末次冰盛期后，受贫硅酸（H₂SiO₄）营养盐的暖水团平流影响，硅藻生产力与壳体保存质量均显著降低。本研究的高分辨率记录揭示了区域气候过程如何调控由风致局部上升流触发的硅质初级生产力快速变化，表明千年尺度气候变率可以掩盖其他重要的水文过程——例如与硅酸泄漏相关的过程。