Massive perturbation in terrestrial ecosystems of the Eastern Mediterranean region associated with the 8.2 kyr B.P. climatic event

Abstract

International audienc

The Impact of Rapid Climate Change on Prehistoric Societies during the Holocene in the Eastern Mediterranean

“…Although this suggests a direct southern European atmospheric response to changes in North Atlantic thermohaline circulation, here we must note the occurrence of exactly that scenario referred to above, i.e. that at Tenaghi Philippon the effects of the Hudson Bay outflow and of RCC may be compounded (Rohling and Pälike 2005;Pross et al 2009). …”

“…The sites at Steregoiu and Preluca Tiganului are located at a considerable distance (~700km) from the North Atlantic, but equally distant (~700km) from both the Aegean coast and the Black Sea. Strictly speaking, just as for the 8.2 ka calBP cold signal at Tenaghi Philippon (Pross et al 2009), the cause of the 10.2 ka calBP event in Romania remains to be established, although it has been suggested it was caused by perturbation of the North Atlantic circulation (Feurdean et al 2008). According to the pollen-based temperature reconstructions, whereas a significant drop in (average) at both sites during RCC intervals a significant drop in (average) winter temperatures in the order of 4°C has been estimated for both sites during RCC intervals, summer temperatures during RCC intervals appear to have been comparable to those currently prevailing.…”

“…Further terrestrial evidence for the expected massive ecological impact of the movement of extremely cold RCC air in the Northeastern Aegean during RCC periods is provided by pollen data from Tenaghi Philippon, North Greece (Pross et al 2009). Here, during the 8.2 ka calBP RCC event a significant reduction in tree-pollen is observed that is representative of a decline in winter temperatures of more than 4°C.…”

A Late Glacial to Holocene record of environmental change from Lake Dojran (Macedonia, Greece)

“…Terrestrial plant material in general is regarded to provide most reliable ages, as it is not or only marginally affected by the incorporation of aquatic carbon. However, in the record from Tenaghi Philippon pollen grains and peat indicated a significant reservoir effect (Pross et al, 2009). Bulk organic carbon and carbonate shell samples are more influenced by reservoir effects and have to be regarded more critically, particularly because reservoir effects can vary over time.…”

Model sensitivity to North Atlantic freshwater forcing at 8.2 ka

“…Several quantitative estimates of drying exist from proxies in high northern latitudes; these include an ∼8 % reduction in accumulation in central Greenland ice cores and an ∼17 % reduction in rainfall inferred from pollen north of the Mediterranean, although again the standard errors of these reconstructions are nearly as large as the anomalies themselves (Feurdean et al, 2008;Pross et al, 2009;Hammer et al., 1997; Rasmussen et al, 2007). The model simulations generally match the magnitude of drying in central Greenland, but typically do not match either the direction or magnitude of change in southeastern Europe.…”