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Combining palaeoecology and palaeogenetics - quaternary environmental change in the S Carpathian and S Apennine Mountains

Final Activity Report Summary - CARPENVCHANGE (Combining palaeoecology and palaeogenetics - Quaternary environmental change in the S Carpathian and S Apennine Mountains)

This research aimed at the multi-proxi palaeoenvironmental analysis of Late Glacial and Holocene lake sediments located deep in the continental interior of Europe, in the Retezat Mts, South Carpathians, Romania. Due to their remoteness, sediments from these glacial lakes have not been studied before, even though they are excellent archives of past climate variability. This project obtained sediment cores from 2 lakes (Taul dintre Brazi, Lake Gales), one of them had water depth over 19 m. Radiocarbon dating of these cores revealed an approximate age of 15-16 ka cal BP for their formation, that in turn places the final retreat of the mountain ice cup to OI Stage Ie, in agreement with recent glacial morphological and isotope studies (Reuther et al. 2007). In 2008, high resolution analysis of the Late Glacial (LG) layers of the lowest altitude lake, Taul dintre Brazi (1740 m a.s.l.) has started using various biological (pollen, plant macrofossil, chironomid, cladocera, diatom) and chemical (major and trace elements, oxygen isotopes) proxies. The LG layers have been analysed for pollen and chironomids at 100 years resolution and quantitative climate reconstruction revealed high amplitude summer temperature changes between interstadial (Bolling/Allerod) and stadial (Younger Dryas) phases, on the order of 2-3 oC.

A prominent feature of this site was the early LG occurrence of European Common Spruce (Picea abies). Needle leaves an stomata confirmed its occurrence around the lake as early as 14,800 cal yr BP along with Larch (Larix decidua), Scotch Pine (Pinus sylvestris), Stone Pine (Pinus cembra) and Dwarf Pine (Pinus mugo). The early occurrence of Picea abies suggested its local dominance at lower elevation during the full glacial, furthermore the species richness of the LG interstadial forest in comparison with other SE European high-mountain sites suggested milder LG climate in comparison with the Alps (same latitude).

The early Holocene layers of Taul dintre Brazi abounded in Picea abies pollen, and an intact cone was also recovered. Using the recent technical achievements in the field of ancient DNA (aDNA) research, the pollen and intact seeds of Picea abies were analysed for short chloroplast DNA misrosatellite regions and successful DNA amplifications provided us a basis to compare the recent and fossil genetic structure of the Picea abies populations. The genetic investigations are in progress and the main question expected to be answered concerns the origin of the recent Picea abies populations: did they inherit their genetic diversity from the glacial populations or immigration from the north and/or south has eradicated the ancient traits.