The lacustrine sediment record of Oberwinkler Maar (Eifel, Germany): Chironomid and macro-remain-based inferences of environmental changes during Oxygen Isotope Stage 3

The lacustrine record of Oberwinkler Maar (Eifel, Germany) is the northernmost continuous record documenting the Weichselian Pleniglacial in central Europe - a period characterized by multiple abrupt climate oscillations known as the Dansgaard/Oeschger cycles. Here, the results of a high-resolution study of chironomid remains are presented, with a focus on the earlier part of Oxygen Isotope Stage (OIS) 3 (60-50 kyr BP) covering four stadial/interstadial cycles. During the stadials, the chironomid fauna of the former lake was dominated by many cold-stenothermic chironomid taxa, indicating a cold, oligotrophic lake. The concentrations of chironomid remains were lower during the interstadials, and featured a higher number of warm-indicating taxa. This could have been the result of a higher summer temperature at the study site, but also of bottom-water anoxia, an increase in trophic state or a combination of all these factors. During the stadial intervals, a taxon that is restricted to (sub-)arctic environments is present in our record, suggesting a change in the temperature regime rather than in-lake processes as the driving mechanism for the changes in the chironomid record. Although, consistently, there was a response of the lake ecosystem to climate changes, the amplitude of this response was not constant. This study provides unique and independent evidence of the impact of Dansgaard/Oeschger climate variability on the European continent during the earlier part of OIS-3.