Palaeoclimate Analysis of Sediment Cores from the Fjords and Lakes of the Vestfold Hills

From the abstracts of some of the referenced papers:The relationship between surface sediment diatom assemblages and measured limnological variables in 33 coastal Antarctic lakes was examined by constructing a diatom-water chemistry dataset. Canonical correspondence analysis revealed that salinity and silicate each explain significant amounts of variation in the distribution and abundance of the surface sediment diatom taxa. Salinity has the strongest influence, revealing its value for limnological inference models in this coastal Antarctic region.A comprehensive diatom stratigraphy is used to calculate a palaeosalinity history for an Antarctic lake via an established diatom-salinity transfer function for the Vestfold Hills, Antarctica. A sediment core taken from Ace Lake in 1995 shows three distinct changes in diatom assemblage constituents: initial benthic hyposaline - freshwater taxa are replaced by marine planktonic and sea-ice taxa with these taxa in turn replaced by the benthic hypersaline taxa dominant in the lake today. These changes in assemblage composition enable the lakewater salininty of each stage to be determined, and the Holocene evolution of the lake to be refined. Deglaciation of the Vestfold Hills at the beginning of the Holocene exposed Ace Lake basin; following this, fresh lacustrine diatoms were deposited from ~11 380 to ~8110 corrected 14C yrBP. Relative sea-level rise after this time led to the progressive marine inundation of the lake and the deposition of marine diatom taxa. Marine taxa were dominant in the sediment for more than 6000 years. Isostatic rebound and stabilisation of the sea-level isolated Ace Lake and at ~1480 corrected 14C yrBP saline lacustrine diatoms became the dominant taxa, indicative of the concentration of dissolved salts through evaporation after isolation.

基于部分参考文献的摘要内容：本研究通过构建硅藻（diatom）-水化学数据集，分析了南极沿岸33个湖泊的表层沉积硅藻组合与实测湖沼学变量之间的关联。典范对应分析（Canonical Correspondence Analysis）结果显示，盐度与硅酸盐均可显著解释表层沉积硅藻类群的分布与丰度变异，其中盐度的影响最为显著，证实了其在该南极沿岸区域湖沼学推断模型中的应用价值。
依托南极维斯托尔德丘陵（Vestfold Hills）已建立的硅藻-盐度转换函数，本研究通过完整的硅藻地层序列重建了某南极湖泊的古盐度演化历史。
1995年从艾斯湖（Ace Lake）获取的沉积岩芯显示，硅藻组合组成发生了三次显著变化：初始阶段以底栖低盐-淡水类群为主，随后被海洋浮游类群与海冰类群取代，最终又被现今该湖占优势的底栖高盐类群所替代。组合组成的这些变化可用于确定各阶段的湖水盐度，并完善该湖泊的全新世演化历史。
全新世初期，维斯托尔德丘陵的冰川消融使得艾斯湖盆地裸露出来；此后在校正后的14C年代~11380至~8110 yrBP期间，沉积了淡水湖相硅藻。
此后相对海平面上升导致湖泊逐渐被海水淹没，并沉积了海洋硅藻类群，该类群在沉积物中占据优势的时长超过6000年。
冰后回弹（Isostatic rebound）与海平面稳定使得艾斯湖与海洋隔绝；在校正后的14C年代~1480 yrBP时，咸水湖相硅藻成为优势类群，这表明湖泊隔绝后通过蒸发作用使得溶解盐类不断富集。