Abstrakt
The 8.2 kiloyear event was the most abrupt climatic cooling to occur during the Holocene. Currently there are very few detailed records describing ecosystem responses to the event from Central Europe.
Here, we present multi-proxy evidence from a sediment profile from a small tarn in the Bohemian Forest, Czechia (49°05'N, 13°24'E; 1079 m a.s.l.; 4.2 ha; max. depth 17 m; catchment area 0.65 km2; anoxia near bottom, sediment poor in HC). We identified a series of erosion events correlated with the 8.2 ka cooling.
To reconstruct the lake-catchment response, water invertebrate fauna remains (including chironomids), diatoms, plant macroremains, charcoal, pollen, and bark beetle remains were analyzed. An initial phase of erosional activity likely began with a fire event within the catchment ~8500 cal.
BP, which allowed for the rapid succession replacement of a Pinus-Betula dominated landscape to a Picea dominated system with more pronounced presence of bark beetles. The 8.2 ka event was characterized by sharp increase in both littoral and profundal chironomid taxa, higher diversity in the other macrozoobenthos, and dominance of heavily silicified planktonic diatoms suggesting intensive mixing of the lake water, improvement of oxygen conditions near the bottom, and increased transport of the fossils from the littoral zone to the central part of the lake basin.
We conclude that the climatic deterioration likely had a greater environmental impact in Central Europe than previously assumed.