Mid-Holocene history of a central European lake: Lake Komoany, Czech Republic

摘要

Palaeolimnological reconstruction of the aquatic environment in Lake Komoany, based on sedimentology, geochemistry, and diatom and macrofossil analyses in the littoral part of the basin, reflects the mid-Holocene history of the profile from its origin c.9100 cal. a BP to its final transformation into an alder carr c.4100 cal. a BP. The existence of the littoral zone can be best explained by increased precipitation during the studied interval. A stable diatom community, diatom-inferred total phosphorus (50-80gL(-1)) and pH (similar to 7.6), along with stable concentrations of elements associated with changes in its watershed indicate a long-lasting, balanced aquatic environment with no major shifts attributable to external factors, including climate change. From c.4700 cal. BP, there started a transition to terrestrial conditions, caused by either natural infilling processes or decreased precipitation. Alternation of remarkable dry/wet phases was not detected, in contrast to numerous analogous central European and supraregional records. Potential human impact was revealed through increases of Corylus and Populus pollen in the Neolithic. These anthropogenic changes in the lake surroundings had no detectable influence on the lacustrine environment. The gathered data suggest undramatic, balanced mid-Holocene environmental and climatic settings for this central European locality, in direct contrast to numerous analogous studies from the region emphasizing fluctuations and shifts found in the sediment record.