We analyzed the biogenic silica (BSi) content and produced a diatom-based summer sea-surface temperature (SST) reconstruction for sediment core GC4 from the Holsteinsborg Dyb, West Greenland. Our aim was to reconstruct marine productivity and climatic fluctuations during the last millennium. Increased BSi content and diatom abundance suggest relatively high marine productively during the interval of AD 1000–1400, corresponding in time to the Medieval Warm Period (MWP). The summer SST reconstruction indicates relatively warm conditions during AD 900–1100, followed by cooling after AD 1100. An extended cooling period during AD 1400–1900 is characterized by prolonged low in reconstructed SST and high sea-ice concentration. The BSi values fluctuated during this period, suggesting varying marine productivity during the Little Ice Age (LIA). There is no significant correlation between the BSi content and SST during the last millennium, suggesting that the summer SST has little influence on marine productively in the Holsteinsborg Dyb. A good correspondence between the BSi content and the element Ti counts in core GC4 suggests that silicate-rich meltwater from the Greenland ice sheet was likely responsible for changes in marine productively in the Holsteinsborg Dyb.

我们分析了生物二氧化硅（BSi）的含量，并对西格陵兰州Holsteinsborg Dyb的沉积物核心GC4进行了基于硅藻的夏季海面温度（SST）重建。我们的目标是重建上个千年的海洋生产力和气候波动。BSi含量的增加和硅藻的丰度表明，在公元1000-1400年间，海洋生产力相对较高，这与中世纪温暖期（MWP）的时间相对应。夏季SST重建表明，在AD 900–1100期间温度相对较高，随后在AD 1100之后降温。AD1400–1900期间的降温期延长，其特征在于重建的SST持续时间较长且海冰浓度较高。BSi值在此期间波动，表明在小冰期（LIA）期间海洋生产力有所变化。在最近一个千年中，BSi含量与海温之间没有显着相关性，这表明夏季海温对荷斯坦堡地区的海洋生产影响不大。BSi含量与GC4核心中Ti元素含量之间的良好对应关系表明，格陵兰冰原中富含硅酸盐的熔体水可能是荷斯坦堡Dyb海洋生产力变化的原因。