Palaeogeographical reconstructions of Lake Maliq (Korça Basin, Albania) between 14,000 BP and 2000 BP

International audienceSince the early 1990s, excavations of a protohistoric lakeside settlement in the Korça basin carried out by a French–Albanian archaeological team have induced geomorphological and palynological studies about the sedimentary records of Lake Maliq. These studies allow us to distinguish a series of centennial-scale high and low lake level events between 4200 and 4000 cal BP (2899–2637 BC/2843–2416 BC) and 2600 cal BP (822–671 BC), probably due to large-scale climate changes (in the Mediterranean basin). In addition, the sediment sequence also gives evidence of a millennial-scale trend of lake level rise. It appears to be an interplay between lake level rises and falls against tectonic subsidence of the basin allowing accommodation space for sediment deposition. The variations of the lake's level and the lake's surface area influenced the development and the abandonment of the nearby lakeside settlements (like the tell of Sovjan). In order to prepare an archaeological survey around the now dried up lake, we made a 3D model of the Holocene deposit from the lake including these lake level results, geomorphological mapping, excavation data, numerous core logs, AMS 14 C dating and SRTM DEM data. The GIS model allowed us to propose four palaeogeographical reconstructions of the extension of Lake Maliq: around 14,000 BP, during the Mesolithic (around 9000 BP – 8781–8542 BC), the Early/Middle Bronze Age transition (around 3800 BP – 2310–2042 BC) and the Iron Age (2600 BP – 822–671 BC). A map of the thickness of the sediments above potential archaeological layers is also proposed

LES VARIATIONS DE L'EXTENSION DU LAC MALIQ (BASSIN DE KORÇË, ALBANIE) EN RELATION AVEC L'OCCUPATION HUMAINE ENTRE 14000 BP ET 2000 BP

International audienceDepuis le début des années 1990, les fouilles archéologiques menées dans le bassin de Korçë, notamment sur le tell de Sovjan, occupé du Néolithique ancien (7990 cal BP, soit 7060 - 6899 av. J.-C.) jusqu’à l’Âge du fer (2600 cal BP, soit 822 - 671 av. J.-C.), ont confirmé l’implantation de populations sédentaires, pratiquant l’agriculture et l’élevage depuis le Néolithique ancien (LAFE 2005 ; LERA 1990 ; LERA et al. 1996 ; TOUCHAIS et al., 2005). Il s’agit de la civilisation dite « culture de Podgorie » (KOBAS 2005 ; KORKUTI 1995 ; PRENDI 1990). La partie nord du bassin de Korçë a été occupée par le lac Maliq, jusqu’à ce qu’il soit asséché par drainage à la fin des années 1950. À cette époque, l’extension du lac variait de 40 km2 à la fin de l’été à 80 km2 (FOUACHE et al. 2001). Du Néolithique ancien à l’Âge du fer, et surtout à la période du Bronze moyen (autour de 3800 cal BP, 2310 - 2042 av. J.-C.), de nombreuses implantations humaines occupaient les rives du lac (fig. 1) comme sur le site de Maliq, le seul site « palaffitique » étudié dans le bassin (PRENDI, 1966) ou Sovjan, un site de rive (TOUCHAIS et alii, 2005).Afin de reconstituer plus précisément la densité de ces sites et d’aboutir à un modèle d’implantation humaine autour du lac Maliq, la Mission franco-albanaise a entrepris des prospections archéologiques systématiques. En préliminaire à ces prospections, des reconstitutions paléogéographiques de l’extension du lac Maliq ont été proposées pour quatre périodes clefs : autour de 14000 BP, le Mésolithique (autour de 9000 cal BP, soit 8781 - 8542 av. J.-C.), le Bronze moyen (autour de 3800 cal BP, soit 2310 - 2042 av. J.-C.) et l’Âge du fer (2600 cal BP, soit 822 - 671 av. J.-C.). Ces reconstitutions ont été réalisées à partir d’un Système d’Information Géographique (SIG) associé à un Modèle Numérique de Terrain (MNT) en trois dimension, incluant des données topographiques, géologiques, paléoenvironnementales et archéologiques.Ces reconstitutions permettent également de discuter de l’influence possible des variations climatiques holocènes sur les fluctuations du niveau du lac Maliq

Pollen−inferred Late−Glacial and Holocene climate in southern Balkans (Lake Maliq)

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Lateglacial and Holocene climate oscillations in the South−western Alps : An attempt at quantitative reconstruction

International audienceThe high topographic complexity of the Alpine region is at the origin of important climate differences which characterise the different areas of the Alps. These differences might have had a strong influence on vegetation and on migrations of human populations in the past. Based on an improved data base containing about 3000 modern pollen samples, the standard “Modern Analogue Technique” has been applied to five pollen sequences from the subalpine belt of the South-western Italian Alps (Laghi dell'Orgials, 2240 m, Lago delle Fate, 2130 m, Torbiera del Biecai, 1920 m, Rifugio Mondovì, 1760 m, Pian Marchisio, 1624 m) to provide quantitative climate estimates for the Lateglacial and Holocene periods. Consistent climate trends are reconstructed for the different sequences. Sites recorded in detail the climate variations when they were located at the limit of two ecotones. Sites above the tree line recorded lower temperature values and less important variations. Climate was cold and dry during the Oldest and Younger Dryas and close to present-day values during the Bølling/Allerød interstadial. At the beginning of the Holocene, climate changed to warmer and moister conditions; a high number of climate fluctuations are recorded at several sites. A climate optimum is recorded in the Atlantic period, which caused a development of fir above its present-day altitudinal distribution. Climatic differences recorded at the various sites are discussed taking into account the limits of the method

Lateglacial and Holocene climate oscillations in the South−western Alps : An attempt at quantitative reconstruction

International audienceThe high topographic complexity of the Alpine region is at the origin of important climate differences which characterise the different areas of the Alps. These differences might have had a strong influence on vegetation and on migrations of human populations in the past. Based on an improved data base containing about 3000 modern pollen samples, the standard “Modern Analogue Technique” has been applied to five pollen sequences from the subalpine belt of the South-western Italian Alps (Laghi dell'Orgials, 2240 m, Lago delle Fate, 2130 m, Torbiera del Biecai, 1920 m, Rifugio Mondovì, 1760 m, Pian Marchisio, 1624 m) to provide quantitative climate estimates for the Lateglacial and Holocene periods. Consistent climate trends are reconstructed for the different sequences. Sites recorded in detail the climate variations when they were located at the limit of two ecotones. Sites above the tree line recorded lower temperature values and less important variations. Climate was cold and dry during the Oldest and Younger Dryas and close to present-day values during the Bølling/Allerød interstadial. At the beginning of the Holocene, climate changed to warmer and moister conditions; a high number of climate fluctuations are recorded at several sites. A climate optimum is recorded in the Atlantic period, which caused a development of fir above its present-day altitudinal distribution. Climatic differences recorded at the various sites are discussed taking into account the limits of the method

Palynomorphs from the Lateglacial and Holocene of the Mt-Athos Basin, Aegean Sea

To unravel the climatic and environmental dynamics in the borderlands of the Aegean Sea during the early and middle Holocene, and notably for the interval of sapropel S1 (S1) formation, we have analysed terrestrial palynomorphs from a marine core in the northern Aegean Sea. The qualitative results were complemented by quantitative pollen-based climate reconstructions. A land-sea correlation was established based on pollen data and sediment lightness measurements from the same core, and previously published benthic foraminifer data from a nearby core. The borderlands of the Aegean Sea underwent a transition from an open vegetation to oak-dominated woodlands between ~10.4 and ~9.5 ka cal BP. A coeval increase in winter precipitation suggests that moisture availability was the main factor controlling Holocene reforestation. The ~50% higher winter precipitation during S1 formation relative to "pre-sapropelic" conditions suggests a strong contribution from the borderlands of the Aegean Sea to the freshwater surplus during S1 formation. The humid and mild winter conditions during S1 formation were repeatedly punctuated by short-term climatic events that caused a partial deforestation and a reorganisation within the broad-leaved arboreal vegetation. In the marine realm, these events are documented by improved benthic oxygenation. The strongest event represents the regional expression of the 8.2 ka cold event and led to an interruption in S1 formation. Except for the interval of S1 formation, the pollen-derived winter temperatures correlate with the smoothed GISP2 K+ series. They support the previously published, marine-based concept that the intensity of the Siberian High strongly controlled the winter climate in the Aegean region. During S1 formation in the Aegean Sea, however, climate conditions in the borderlands were more strongly affected by the monsoonally influenced climate system of the lower latitudes

Ostracod-based isotope record from Lake Ohrid (Balkan Peninsula) over the last 140 ka

International audienceThe stable isotope composition of benthic ostracods from a deep-lake sediment core (JO2004-1) recovered from Lake Ohrid (Albania-Macedonia) was studied to investigate regional responses to climate change at the interface between the north-central European and Mediterranean climate systems. Ostracod valves are present only during interglacial intervals, during the Marine Isotope Stage (MIS) 5 and 1. The ostracod oxygen isotope values (delta O-18) quantitatively reflect changes in the oxygen isotope signal of the lake water (delta O-18(L)). The interpretation of this record however, is far from straight forward. delta O-18(L) variations throughout MIS 5/6 transition (TII), MIS 5 and MIS 1 appear to be controlled by site specific hydrological processes as shown by modern isotope hydrology. The delta O-18(L) trends at TII. MIS 5 and MIS 1 match the timing and the main structural feature of the major regional climate records (Corchia cave delta O-18, Iberian margin Sea Surface Temperature) suggesting that the Ohrid delta O-18(L) responded to global-scale climate changes, although it seems certain that the lake experienced a significant degree of evaporation and varying moisture availability. The carbon isotope signal (delta C-13) seems to respond more accurately to climate changes in agreement with other JO2004-1 proxies. delta C-13 of the ostracod calcite is directly linked to the delta C-13 of the dissolved inorganic carbon (DIC) in the lake, which in this case is controlled by the isotopic composition of the DIC in the incoming water and by the internal processes of the lake. High delta C-13 during cold periods and low values during warm periods reflect changing vegetation cover and soil activity. These results suggest that Lake Ohrid has the potential to capture a long record of regional environment related-temperature trends during interglacial periods, particularly given the exceptional thickness of the lake sediment covering probably the entire Quaternary. (C) 2010 Elsevier Ltd. All rights reserved

JAK Inhibitors Suppress Innate Epigenetic Reprogramming: a Promise for Patients with Sjögren’s Syndrome

International audiencePathogenesis of primary Sjögren's syndrome (SjS) remains obscure. However, recent data demonstrate the implication of epigenetic alterations in the DNA methylation/hydroxymethylation process in SjS mostly affecting genes regulated by two innate cytokines, interferon α (IFNα) and IFNγ as well as the oxidative stress pathways. The Janus kinase (JAK) signal transducer and activator of transcription (STAT) pathway is known to be activated by IFN and reactive oxygen species (ROS). This prompts us to test the potential implication of JAK/STAT signaling on DNA methylation/hydroxymethylation alterations in SjS. For this purpose, the human salivary gland (HSG) cell line was used and cells were treated with both types of IFNs and H2O2 to mimic activated salivary gland epithelial cells (SGEC) as observed in SjS patients. Afterwards, the global DNA level of methylcytosine and hydroxymethylcytosine, the expression of the DNA methylating enzymes (DNMTs) and ten-eleven translocation (TETs) methyl cytosine dioxygenase that controls DNA hydroxymethylation, both at transcriptional and at protein level, as well as STAT phosphorylation and ROS status were determined. Our results showed that expression of TET3 and in turn global DNA hydroxymethylation is controlled through the induction of STAT3 mediated by IFNα, IFNγ, and H2O2. On the other hand, treatment with JAK inhibitors (AG490 and ruxolitinib) reverses this process, suggesting a novel treatment pathway for patients with autoimmune diseases and Sjögren's syndrome