Author:

Keywords:

Late-glacial Lake Bled, late-glacial lake bled, Chironomids, chironomids, cladocera, Cladocera, Plant Macrofossils, plant macrofossils, stable isotopes, Stable isotopes, pollen, Pollen, north-atlantic region, 2 minor oscillations, younger dryas, gerzensee switzerland, southwestern bulgaria, lacustrine sediment, summer temperatures, holocene transition, genetic diversity, last termination, Science & Technology, Life Sciences & Biomedicine, Marine & Freshwater Biology, Plant macrofossils, NORTH-ATLANTIC REGION, 2 MINOR OSCILLATIONS, YOUNGER DRYAS, GERZENSEE SWITZERLAND, SUMMER TEMPERATURES, HOLOCENE TRANSITION, LAST TERMINATION, PIRIN MOUNTAINS, AGE CALIBRATION, EUROPEAN ALPS, 04 Earth Sciences, 05 Environmental Sciences, 06 Biological Sciences, Marine Biology & Hydrobiology, 31 Biological sciences, 37 Earth sciences, 41 Environmental sciences

Abstract:

This study investigates the palaeoecological record (delta O-18, delta C-13, pollen, plant macrofossils, chironomids and cladocera) at Lake Bled (Slovenia) sedimentary core to better understand the response of terrestrial and aquatic ecosystems to Late-glacial climatic fluctuations. The multi-proxy record suggests that in the Oldest Dryas, the landscape around Lake Bled was rather open, presumably because of the cold and dry climate, with a trend towards wetter conditions, as suggested by an increase in tree pollen as well as chironomid and cladocera faunas typical for well-oxygenated water. Climatic warming at the beginning of the Late-glacial Interstadial at ca. 14,800 cal yr BP is suggested by an increase in the delta O-18 value, the appearance of Betula and Larix pollen and macrofossils, and a warmth-adapted chironomid fauna. With further warming at ca. 13,800 cal yr BP, broad-leaved tree taxa (Quercus, Tilia, Ulmus), Artemisia, and Picea increase, whereas chironomid data (Cricotopus B) suggest lowering of lake levels. After 12,800 cal yr BP (and throughout the Younger Dryas), the climate was colder and drier, as indicated by lower delta O-18 values, decline of trees, increase of microscopic charcoal, xerophytes and littoral chironomids. A warmer climate, together with the spread of broad-leaved tree taxa and a deeper, more productive lake, mark the onset of the Late-glacial/Holocene transition. These results suggest that terrestrial and aquatic ecosystems at Lake Bled were very dynamic and sensitive to Late-glacial climatic fluctuations.