Environmental and climatic variability during the Middle Würmian in the northern Alps

阿尔卑斯地区的末次冰期被称为乌尔米亚冰期，其特征是北方半球强烈的气候变化，如海因里希事件和Dansgaard-Oeschger（D-O）旋回。后者在格陵兰冰芯的同位素变化中得到了很好的证明，并在那里命名为格陵兰间冰柱和冰柱。然而，在格陵兰冰盖之外，D-O循环的规模及其对环境的影响却没有得到充分的研究。这是特别真实的阿尔卑斯山地区，他们主要是从不连续的洞穴沉积物同位素记录报告。在阿尔卑斯山最后一次盛冰期开始之前，人们对短期气候变化对阿尔卑斯山环境的影响知之甚少。这一时期的沉积物序列保存不足是主要原因。在这里，ALPWÜRM项目启动，其中气候，植被，动物群和环境条件的变化在中乌尔缅应检查。对德国东南部内阿尔卑斯地区Nesseltalgraben一个27米长的沉积物剖面进行的初步调查，发现了意想不到的大量化石遗迹。这些数据提供了对距今至少27,000年至43,000年（未校准的14 C年代）的环境条件的详细了解，这对北方阿尔卑斯山来说是前所未有的。本项目应改进现有的沉积学、地球化学和花粉分析，以便以高分辨率重建沉积条件和植被变化。将对沉积物中特别保存的介形虫和苔藓组合进行彻底调查。对介形虫瓣膜和苔藓遗骸的氧同位素分析将结合起来，并将提供有关阿尔卑斯地区中乌尔阶期间温度变化的更多信息。将采用多种测年方法，包括放射性碳测年、发光测年和磁性地层学，以尽可能准确地提供年龄模型。在项目过程中收集的气候和环境记录最终将与阿尔卑斯山地区内外其他档案的重建进行比较和联系，以实现对中乌尔米亚气候和环境的一致重建。该项目将大大有助于解决阿尔卑斯山在最后一次冰川高峰期之前极端气候波动的强度及其对区域生物多样性的影响问题。

The last glacial period, which is called Würmian glaciation in the Alpine region, was characterized in the northern hemisphere by strong climate variations such as Heinrich events and Dansgaard-Oeschger (D-O) cycles. The latter are well documented by isotopic variations in Greenland ice cores and named Greenland interstadials and stadials there. Outside of the Greenland ice sheet, the magnitude of the D-O cycles and their impact on the environment, however, are inadequately studied. This is especially true for the Alpine area, where they are mainly reported from discontinuous speleothem isotope records. Very little is known about the impact of short-term climate variability on the Alpine environment right before the start of the last glacial maximum in the Alps. The scarce preservation of sediment sequences from this period is the main cause for it. Here the project ALPWÜRM kicks in, in which the changes of climate, vegetation, fauna and environmental conditions during the middle Würmian shall be examined. Preliminary investigations on a 27 m long sediment profile at the inner-Alpine locality Nesseltalgraben in southeast Germany delivered an unexpected abundance of fossil remains. These provide detailed insights into the environmental conditions of the period from at least about 27,000 to 43,000 years before present (uncalibrated 14C dates), which is so far unprecedented for the Northern Alps. Already existing sedimentological, geochemical and pollen analyses shall be refined in the project in order to reconstruct sedimentary deposition conditions and vegetational changes in high resolution. Ostracod and moss assemblages, which are exceptionally preserved in the sediment, will be thoroughly investigated. Oxygen isotope analyses on ostracod valves and moss remains will be combined and will provide additional information on the temperature variations during the Mid-Würmian in the Alpine realm. A multiple dating approach will be applied, including radiocarbon dating, luminescence dating and magnetostratigraphy to provide an age model as exactly as possible. The climate and environmental records collected in the course of the project will ultimately be compared and linked with reconstructions from other archives inside and outside the Alpine realm, in order to reach a consistent climate and environmental reconstruction for the middle Würmian. The project will significantly contribute to the question of how strong the extreme climatic fluctuations in the Alps were before the last glacial maximum and which impact they had on the regional biodiversity.