Understanding past climatic and hydrological variability in the Mediterranean from Lake Prespa sediment isotope and geochemical record over the Last Glacial cycle

Here we present stable isotope and geochemical data from Lake Prespa (Macedonia/Albania border) over the Last Glacial cycle (Marine Isotope Stages 5–1) and discuss past lake hydrology and climate (TIC, oxygen and carbon isotopes), as well as responses to climate of terrestrial and aquatic vegetation (TOC, Rock Eval pyrolysis, carbon isotopes, pollen). The Lake Prespa sediments broadly fall into 5 zones based on their sedimentology, geochemistry, palynology and the existing chronology. The Glacial sediments suggest low supply of carbon to the lake, but high summer productivity; intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter, there must have been within sediment reducing conditions and methanogenesis. MIS 5 and 1 sediments suggest much more productivity, higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen-depleted bottom waters. We also calculated lakewater δ18O from siderite (authigenic/Glacial) and calcite (endogenic/Holocene) and show much lower lakewater δ18O values in the Glacial when compared to the Holocene, suggesting the lake was less evaporative in the Glacial, probably as a consequence of cooler summers and longer winter ice cover. In the Holocene the oxygen isotope data suggests general humidity, with just 2 marked arid phases, features observed in other Eastern and Central Mediterranean lakes

West Nile virus transmission. results from the integrated surveillance system in Italy, 2008 to 2015

IIn Italy a national Plan for the surveillance of imported and autochthonous human vector-borne diseases (chikungunya, dengue, Zika virus disease and West Nile virus (WNV) disease) that integrates human and veterinary (animals and vectors) surveillance, is issued and revised annually according with the observed epidemiological changes. Here we describe results of the WNV integrated veterinary and human surveillance systems in Italy from 2008 to 2015. A real time data exchange protocol is in place between the surveillance systems to rapidly identify occurrence of human and animal cases and to define and update the map of affected areas i.e. provinces during the vector activity period from June to October. WNV continues to cause severe illnesses in Italy during every transmission season, albeit cases are sporadic and the epidemiology varies by virus lineage and geographic area. The integration of surveillance activities and a multidisciplinary approach made it possible and have been fundamental in supporting implementation of and/or strengthening preventive measures aimed at reducing the risk of transmission of WNV trough blood, tissues and organ donation and to implementing further measures for vector control

A precisely dated speleothem record of termination III and marine isotope stage 7 from Corchia cave, Italy

National audienc

The last 7 millennia of vegetation and climate changes at Lago di Pergusa (central Sicily, Italy)

International audienceThe aim of this study is to investigate climate changes and human activities under the lens of palynology. Based on a new high-resolution pollen sequence (PG2) from Lago di Pergusa (667 m a.s.l., central Sicily, Italy) covering the last 6700 yr, we propose a reconstruction of climate and landscape changes over the recent past in central Sicily. Compared to former studies from Lago di Pergusa (Sadori and Narcisi, 2001), this work provides a reconstruction of the evolution of vegetation and climate over the last millennia in central Sicily, indeed completing previous results with new pollen data, which is particularly detailed on the last 3000 yr.Joint actions of increasing dryness, climate oscillations, and human impact shaped the landscape of this privileged site. Lago di Pergusa, besides being the main inland lake of Sicily, is very sensitive to climate change and its territory was inhabited and exploited continuously since the Palaeolithic. The lake sediments turned out to be a good observatory for natural phenomena that occurred in the last thousands of years.Results of the pollen-based study are integrated with changes in magnetic susceptibility and a tephra layer characterization. The tephra layer was shown to be related to the Sicanians' event, radiocarbon dated at 3055 ± 75 yr BP (Sadori and Narcisi, 2001).We performed palaeoclimate reconstructions by MAT (Modern Analogues Technique) and WAPLS (Weighted Average Partial Least Square). Palaeoclimate reconstructions based on the core show important climate fluctuations throughout the Holocene. Climate reconstruction points out four phases of cooling and enhanced wetness in the last three millennia (2600–2000, 1650–1100, 850–550, 400–200 cal BP, corresponding to the periods between 650–50 BC, and 300–850, 1100–1400, 1550–1750 AD, respectively). This appears to be the evidence of local responses to global climate oscillations during the recent past

Carta Geologica d’Italia alla scala 1:50.000, Foglio 448 Ercolano

Carta Geologica d’Italia alla scala 1:50.00

Decoupling between the tropics and the mid- to high-latitude North Atlantic region during Marine Isotope Stage 7

Studies of subtropical speleothems, North Atlantic marine cores and Greenland ice cores covering the last glacial cycle suggest that the climates of the high latitude North Atlantic and the Asian monsoon regions were closely coupled. Heinrich Events in the North Atlantic triggered a weakening of the Asian monsoon, whereas abrupt warmings during Dansgaard-Oeschger cycles saw an intensification of the monsoon. It has also been argued that this coupling occurred during glacial terminations, with ice-rafting events during deglaciation leading to suppression of the Asian monsoon. The implication of these patterns is that close coupling between the high latitudes and the tropics in the Northern Hemisphere may be a persistent feature of Late Quaternary climate. We present a replicate speleothem record from Corchia Cave (Italy) which shows that the tropics and high latitudes of the Northern Hemisphere were strongly decoupled during the MIS7d-7c transition, simultaneous with deposition of sapropel S8 in the Mediterranean Sea. Our cave record shows that the strong precession-driven intensification of Asian and African monsoons brought wet conditions in the Mediterranean region, yet at this time the high and middle latitudes of Europe were in the grip of a deep stadial. Unlike the millennial-scale climate swings of the last glacial and the inferred response to ice-rafting events through the last four terminations, the Asian monsoon was apparently unaffected by these high latitude stadial conditions. Furthermore, it seems the exceptionally strong insolation increase at this time had little noticeable effect on ice-sheet dynamics over the northern continents, suggesting that tropical - high latitude coupling maybe either a transient feature or, at the very least, more complicated than previously though

Lateglacial-Holocene abrupt vegetation changes at Lago Trifoglietti in Calabria, Southern Italy: The setting of ecosystems in a refugial zone.

International audienc

A record of glacial-interglacial cycles over the last one million years from Antro del Corchia speleothems

Antro del Corchia (Corchia Cave) is a large cave located in the Alpi Apuane karst of northern Tuscany, Italy. The cave receives most of its recharge from frontal systems crossing southwestern Europe and western Mediterranean, making the site sensitive to changes in ocean and atmospheric conditions in the North Atlantic. Parts of the cave are rich in speleothems. A suite of stalagmites, flowstones and subaqueous mounds has been sampled to investigate regional palaeoclimate. Stable oxygen and carbon isotopes time series produced from these speleothems, anchored in time using U-Th, U-U and U-Pb isotopic dating, preserve evidence for regional rainfall and temperature changes over millennial and glacial-interglacial timescales that can be linked via the marine-core record to North Atlantic palaeoclimate. A single speleothem core, recovered from a subaqueous mound in the cave, preserves the last 11 glacial-interglacial cycles, constituting a rare and seemingly continuous palaeoclimate record spanning the last 960 ka. More detailed palaeoclimate reconstructions are emerging from the faster growing stalagmites from the cave. The entire speleothem stack provides a means for establishing the timing of glacial terminations and inceptions

Holocene hydrological changes in south-western Mediterranean as recorded by lake-level fluctuations at Lago Preola, a coastal lake in southern Sicily, Italy

International audienc

Stratigraphic evidence for a " pluvial phase " between ca. 8200-7100 ka from Renella Cave (Central Italy)

International audienceA stratigraphic and chronological study of the upper level of Renella Cave (Apuan Alps, Central Italy) reveals that two episodes of flowstone accumulation bracket a thick clastic layer deposited between ca 8.2 and 7.1 ka. This layer, which represents a period of enhanced cave flooding, is substantially in phase with an interval of depleted oxygen isotope values previously recorded in a stalagmite from nearby Corchia Cave, interpreted to have resulted from an increase in local precipitation. These data confirm that during this period of time the region experienced relatively wetter conditions, including an increase in high-magnitude events capable of invading the higher passages of Renella Cave. The timing of the clastic phase occurred when the Eastern Mediterranean experienced deposition of sapropel layer S1, which is thought to reflect the stagnation of sea water produced largely by enhanced flood activity along the Nile in response to increased monsoon intensity in northern equatorial Africa. Recent estimates suggest that S1 may have lasted from ca 10.8 to ca 6.1 ka cal BP. Combined evidence from Renella and Corchia Cave indicates that the period corresponding to the wettest phase in the Apuan Alps was much shorter than this, and suggests that there is no straightforward connection between increased advection of water vapour from the Atlantic between 8.2 and 7.1 ka, as recorded in the Corchia and Renella records, and monsoon-driven enhancement of Nile discharge and S1 deposition in the eastern Mediterranean