Environmental changes related to the 8.2-ka event and other climate fluctuations during the middle Holocene: Evidence from two dystrophic lakes in NE Poland:

Multi-proxy palaeoecological data (pollen, diatom, Cladocera) about the environment during the middle-Holocene from Suchar II and Suchar Wielki, dystrophic lakes, in NE Poland are presented. Fluctuations in the pollen concentration, indicative of changes in pollen productivity and shifts in woodland composition, document the considerable instability of the climate in NE Poland between 9200 and 5750 cal. yr BP. The recognised colder events were dated to ca. 9050–8950, 8700–7800, 7600–7250, 7100–6600 and 6050–5900 cal. yr BP. All these coolings are expressed as decreases in the pollen concentration of thermophilous taxa such as Corylus avellana, Ulmus, Quercus, Tilia cordata t. and Fraxinus exelsior. The most pronounced was the second of these cold climatic anomalies, which lasted about nine centuries and can be equated with the 8.2-ka event. Significant cooling at that time is confirmed by the appearance of cold-water species of cladocerans and diatoms.