Palynomorph- and chironomid-based analyses of Eemian, Weichselian, and Holocene ecosystem- and climate dynamics in the Baltic Sea region

该项目的主要目标是确定和量化波罗的海地区从Eemian到全新世的生态系统和气候动态。这一目标将通过在IODP第347次考察期间从波罗的海取回的五个地点产生千年至百年规模的孢粉记录来实现。应分析花粉和孢子，以评估陆地生态系统和气候变化。将通过对花粉组合应用最近生活亲属法和现代类似物技术，生成陆地区域的定量降水和温度数据。对于海洋沉积物，甲藻孢囊和其他海洋代用品应在与陆地孢粉形相同的样品中进行分析，以定性评估海洋领域同时期的温度和盐度变化。其中一个主要的工作假设是，基于植被的定量气候重建方法将在较长的温暖间隔期间提供精确的结果，特别是对于中/晚Eemian和中/晚全新世，但植物迁移滞后将阻碍较短温暖间隔的重建（例如，Weichselian interstadials）和早期间冰期。由于要分析的地点沿着从波罗的海北方到南部的路线，如果对所有剖面都采用一致的年龄模型，就有可能查明迁移效应。此外，摇蚊幼虫遗骸将用于湖泊沉积物样品中，以获得与植被无关的气候数据。对于海洋领域，除了甲藻孢囊，代理分析的合作者将允许定性和可能也定量的温度reconstructions.The波罗的海地区是一个特别有趣的地区，这种分析，由于其中间位置之间的高纬度和中欧和南欧，以及不同植被带（南方冷温带森林和北方封闭的北方森林）之间的过渡。钻探地点所在盆地的高沉积速率保证了高时间分辨率和良好的孢粉形态保存。在目前正在进行的IODP-第347次陆上考察之前和期间进行的试点研究表明，不同地点的细粒沉积物中的孢粉保存情况非常好，湖泊沉积物中含有水生昆虫幼虫的遗骸。该研究结果将有助于更详细地了解北方的环境和气候动力学，并有助于了解北方半球过去13万年来的气候遥相关。

The main goal of this project is the identification and quantification of ecosystem and climate dynamics in the Baltic Sea region from the Eemian to the Holocene. This goal shall be achieved via the generation of millennial- to centennial-scale palynomorph records from five sites retrieved from the Baltic Sea during IODP Expedition 347. Pollen and spores shall be analysed to assess terrestrial ecosystem and climate change. Quantitative precipitation and temperature data for the terrestrial realm will be generated via the application of the nearest-living-relative method and the modern analogues technique to the pollen assemblages. For marine sediments, dinoflagellate cysts and additional marine proxies shall be analyzed in the same samples as the terrestrial palynomorphs, to qualitatively assess coeval temperature and salinity changes in the marine realm. One of the main working hypotheses is that vegetation-based methods for quantitative climate reconstructions will deliver precise results during longer warm intervals, particularly for the Middle/Late Eemian and Middle/Late Holocene, but that plant migration lags will hamper reconstructions for shorter warm intervals (e.g., Weichselian interstadials) and early interglacial phases. Since the sites to be analysed are positioned along a route from the Northern to the Southern Baltic Sea, it should be possible to identify migration effects if consistent age models can be applied to all profiles. Furthermore, chironomid larvae remains shall be used in samples from lacustrine sediments to gain vegetation-independent climate data. For the marine realm, in addition to dinoflagellate cysts, proxies analyzed by collaborators will allow qualitative and probably also quantitative temperature reconstructions.The Baltic Sea region is a particular interesting area for such analyses due to its intermediate position between the high latitudes and Central and Southern Europe, and also at the transition between different vegetation zones (cool temperate forest in the South and closed boreal forest in the North). High sedimentation rates in the basins where the sites have been drilled guarantee high temporal resolution and good palynomorph preservation. Pilot studies preceding and during the currently ongoing IODP-Expedition-347 onshore party indicate that palynomorph preservation is very good in fine-graded sediments from the different site, and that lacustrine sediments contain remains of aquatic insect larvae. The results of the proposed study will significantly contribute to a more detailed view on environment and climate dynamics of Northern Europe and to the understanding of climate teleconnections in the Northern Hemisphere during the past 130 000 years.