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首页> 外文期刊>Journal of Paleolimnology >Climate changes during the last glacial termination inferred from diatom-based temperatures and pollen in a sediment core from Längsee (Austria)
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Climate changes during the last glacial termination inferred from diatom-based temperatures and pollen in a sediment core from Längsee (Austria)

机译：末次冰川终结期间的气候变化是由来自硅省（奥地利）的沉积物中的硅藻基温度和花粉推断的

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摘要

A sediment core section from Längsee, a small meromictic lake in the southern Alpine lowland (Carinthia, Austria) close to the Würmian ice margin, was investigated by means of diatoms and pollen. The main aims of the study were to reconstruct water temperature as a signal of climate change during the last glacial termination, compare the aquatic and terrestrial response to the changing climate, and place our findings into a climatic frame on the northern hemispheric scale. A calibration data set (ALPS06) of 116 lakes was constructed using data from newly studied lakes and from two previously published data sets and we established a transfer function for predicting summer epilimnetic water temperatures (SEWT). A locally weighted weighted average regression and calibration model (Rjack2 = 0.89; RSMEP = 1.82°C) was applied to the fossil diatom assemblages in order to reconstruct SEWT. Three major sections were distinguished in the time window of approximately 19–13 cal ka BP, which fitted well with the oxygen isotope curve and the isotope-event stratigraphy from the Greenland ice-core GRIP. The first section was a warming period (SEWT range from 11.6 to 18.0°C; average 15.8°C = ca. 6°C below present) called the Längsee oscillation, which probably correlates with the warmer sub-section (GS-2b) of the Greenland Stadial 2. The subsequent section represents a climate cooling, called the Längsee cold period (SEWT range between 10.6 and 15.9°C; average 12.9°C), which probably corresponds with the sub-section GS-2a of the Greenland Stadial 2, the Heinrich 1 cold event of the North Atlantic, and partially the Gschnitz Stadial in the Alps. The Längsee cold period shows a tri-partition: Two colder phases are separated by a warmer inter-phase. The passive ordination of the core sample scores along maximum water depth indicated that the Längsee cold period was drier than the Längsee oscillation. Strong short-term fluctuations during the Längsee oscillation and the Längsee cold period indicate climate instability. The third section represented climate warming during the Längsee late glacial interstadial (=Greenland Interstadial 1, GI-1) with an average SEWT of 17.5°C. From the minor climatic fluctuations during this interstadial, mainly indicated by pollen, the fluctuation most likely related to the Gerzensee oscillation showed a SEWT decline. During the early immigration and expansion period of shrubs and trees, aquatic and terrestrial records showed distinct discrepancies that might have arose because of time lags in response and differences in sensitivity. Keywords Alpine lakes - Diatoms - Temperature transfer function - Pollen - Deglaciation
机译：利用硅藻和花粉研究了阿尔卑斯山南部低地（奥地利克恩顿州）附近的一个小型致寒湖Längsee的沉积物核心部分，该岩心靠近Würmian冰缘。这项研究的主要目的是重建水温，作为最后一次冰川终结期间气候变化的信号，比较水生和陆地对不断变化的气候的反应，并将我们的发现放入北半球的气候框架中。使用来自新研究的湖泊和两个先前发布的数据集的数据构建了116个湖泊的校准数据集（ALPS06），我们建立了预测夏季表层水温（SEWT）的传递函数。将局部加权加权平均回归和校准模型（R jack 2 = 0.89； RSMEP = 1.82°C）应用于化石硅藻组合物中，以重建SEWT。在大约19–13 cal ka BP的时间窗口中，可以区分出三个主要部分，它们与氧同位素曲线和格陵兰冰芯GRIP的同位素事件地层非常吻合。第一部分是暖化期（SEWT范围为11.6至18.0°C；平均温度为15.8°C =大约低于现在的6°C），称为朗格振荡，这可能与温度较高的子部分（GS-2b）相关格陵兰大区2。随后的部分代表气候降温，称为朗格西冷期（SEWT范围在10.6至15.9°C之间；平均12.9°C），可能与格陵兰大区2的GS-2a小节相对应。 ，北大西洋的Heinrich 1寒冷事件，以及阿尔卑斯山的部分Gschnitz Stadial。朗格西斯的冷期分为三个部分：两个较冷的阶段被较热的中间阶段分隔开。沿最大水深对岩心样品分数进行的被动排序表明，朗格西冷期比朗格西振荡更干燥。 Längsee振荡和Längsee寒冷时期的强烈短期波动表明气候不稳定。第三部分代表了Längsee晚冰川期（GI-1格陵兰岛际期）期间的气候变暖，平均SEWT为17.5°C。从主要由花粉表明的这一间期的微小气候波动来看，最有可能与Gerzensee振荡有关的波动表明SEWT下降。在灌木和树木的早期迁徙和扩张时期，水生和陆地记录显示出明显的差异，这可能是由于响应时间滞后和敏感性差异而引起的。关键词高山湖泊-硅藻-温度传递函数-花粉-冰川消融

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