Pollen and diatom analysis on varved sediments in Lake Jues (Harz Mountains, Germany)

Studies combining sedimentological and biological evidence to reconstruct Holocene climate beyond the major changes, and especially seasonality, are rare in Europe, and are nearly completely absent in Germany. The present study tries to reconstruct changes of seasonality from evidence of annual algal successions within the framework of well-established pollen zonation and 14C-AMS dates from terrestrial plants. Laminated Holocene sediments in Lake Jues (10°20.70' E, 51°39.30' N, 241 m a.s.l.), located at the SW margin of the Harz Mountains, central Germany, were studied for sediment characteristics, pollen, diatoms and coccal green algae. An age model is based on 21 calibrated AMS radiocarbon dates from terrestrial plants. The sedimentary record covers the entire Holocene period. Trophic status and circulation/stagnation patterns of the lake were inferred from algal assemblages, the subannual structure of varves and the physico-chemical properties of the sediment. […]

在欧洲，结合沉积学证据与生物证据以重建全新世气候，尤其是在重大气候变化之外的季节性变化的研究相对罕见，而在德国则几乎完全缺失。本研究旨在从已建立的孢粉带区和陆地植物14C-AMS测年框架内，依据年度藻类演替的证据来重建季节性变化的变迁。位于德国中部哈茨山脉西南边缘的约斯湖（东经10°20.70'，北纬51°39.30'，海拔241米）的层状全新世沉积物被研究以确定沉积特性、孢粉、硅藻和甲藻绿藻。基于陆地植物的21个校准AMS radiocarbon测年数据构建了年龄模型。沉积记录覆盖了整个全新世时期。通过藻类群集、亚年度纹层结构以及沉积物的物理化学性质，推断出湖泊的营养状态和循环/停滞模式。