Changes and Crises in the Mediterranean Sea: Current problems

As a contribution to the World Environment Day 2017, the Accademia Nazionale dei Lincei promoted the meeting “Changes and Crises in the Mediterranean Sea” devoted to the effects of climate change and human impact on the Mediterranean ecosystems and biodiversity. Here is presented a selection of papers given at the meeting held in Rome, on October 17, 2017. Studies deal with structural changes in the marine communities, the impact of thermal stress, acidification, pollution and fishing activities on benthic communities, and on deep-sea biodiversity and ecosystems. Understanding human impact on the Mediterranean Sea is the first step to manage and protect marine environments in a sustainable way

Towards a map of the Upper Pleistocene loess of the Po Plain Loess Basin (Northern Italy)

Upper Pleistocene (MIS 4-2) loess sequences occur in most of continental Europe and in Northern Italy along the Po Plain Loess Basin. Loess is distributed along the flanks of the Po Plain and was deposited on glacial deposits, fluvial terraces, uplifted isolated hills, karst plateaus, slopes and basins of secondary valleys. Loess bodies are generally tiny and affected by pedogenesis, being locally slightly reworked by slope processes and bioturbation. Notwithstanding, loess in the Po Plain is an important archive of paleoenviron-mental record and its mapping provides new insights in paleoenvironmental and palaeoseismic reconstructions of Northern Ital

QUATERNARY STRATIGRAPHY AND SOIL DEVELOPMENT AT THE SOUTHERN BORDER OF THE CENTRAL ALPS (ITALY): THE BAGAGGERA SEQUENCE

A complcx sequence exposed in clay Pit, near Bagaggera, is described in some details. Palaeomagnetic stratigraphy and archaeologic fillds indicate that the sediments of the Bagaggera basin accumulated at least from Farly Pleistocene up to Late Pleistocene. The sedimentary development, reconstructed on the ground of sedimentary, petrographic and mineralogical evidences, has been determined by climatic variations and tectonic activity. Five glacial Stages are recorded in the sedimentary sequence, the oldest one dating back to Early Pleistocene, and only the' last two are directly connected with the front of the Alpine glaciers. Five different paleosols are interlayered in the basin fill; they indicate that, during Interglacial periods of Middle and part of Early Pleistocene, soil forming processes were not very different from those which operated in Postglacial times. On the contrary the oldest paleosol, dating back to Early Pleistocene or Late Pliocene, is due to stronger weathering and probably developed in a different pedoclimatic environment. Further the stratigraphic and genetic meaning of some soil features, very frequent in Lombard paleosols, is discussed.  &nbsp

PRELIMINARY PALEOMAGNETIC INVESTIGATIONS ON PLEISTOCENE SEQUENCES IN LOMBARDY NORTHERN ITALY

Paleomagnetic measurements have been carried out in continental sediments of Northern ltaly. The loess deposits of Copreno, the loess and paleosols of Cascina Lina and Barlassina, and the la­custrine sediments of Pontida all belong to the Brunhes Normal Polarity Epoch, in agreement with their previous chronostratigraphic classification. The lower lacustrine sediments of Bagaggera, previously attributed to the antepenultimate glaciation, belong to the Matuyama Reversed Polarity Epoch, whilee the overlying sandy-loamy sequence belongs to the Brunhes. At Leffe the entire sequence up to the top of the lacustrine sediments belongs to the Matuyama Epoch, being in such way older than previously admit­ted. These paleomagnetic results prove that the "ferretto" is a complex of paleosols of different age, ranging from Lower to Middle Pleistocene

PRELIMINARY PALEOMAGNETIC INVESTIGATIONS ON PLEISTOCENE SEQUENCES IN LOMBARDY NORTHERN ITALY

Paleomagnetic measurements have been carried out in continental sediments of Northern ltaly. The loess deposits of Copreno, the loess and paleosols of Cascina Lina and Barlassina, and the la­custrine sediments of Pontida all belong to the Brunhes Normal Polarity Epoch, in agreement with their previous chronostratigraphic classification. The lower lacustrine sediments of Bagaggera, previously attributed to the antepenultimate glaciation, belong to the Matuyama Reversed Polarity Epoch, whilee the overlying sandy-loamy sequence belongs to the Brunhes. At Leffe the entire sequence up to the top of the lacustrine sediments belongs to the Matuyama Epoch, being in such way older than previously admit­ted. These paleomagnetic results prove that the "ferretto" is a complex of paleosols of different age, ranging from Lower to Middle Pleistocene

A model of the glacial retreat of upper Rennick Glacier, Victoria Land, Antarctica

AbstractThe morphology of the Lichen Hills in the upper section of Rennick Glacier, Victoria Land, Antarctica, is summarised as follows: (a) a top surface on the volcanic rocks with scattered erratic blocks; (b) an exhumed Kukri Peneplain, sculptured with roches moutonnees with striae and crescentic gouges on which lie moraines and patches of drift of mainly volcanic rocks; (c) a granitic bedrock eroded by glaciers into sharp peaks and cirques on top of which there is a glacial drift attributable to ancient blue-ice areas higher than those observed at present and which may be correlated with the Terra Nova drift (Late Wisconsin); (d) various Holocene ice-cored moraines that are pushed to the lee side of the nunataks arid are often banded in strips of different lithology. The bands of the Holocene moraines are related to the rock complexes that became exposed from the ice during the lowering of the surface of the glacier Analysis of the lithology and pattern of the supraglacial debris, as well as of the blue-ice areas, allows us to construct a depositional model for the moraines, and to relate the glacial drift to blue-ice areas existing since the Last Glacial Maximum (LGM).The proposed model shows the different stages of recession of upper Rennick Glacier that are also valid for similar situations observed in northern Victoria Land. A surface lowering of upper Rennick Glacier of several hundred metres shows that significant changes have occurred at the Pacific edge of the East Antarctic ice sheet since the LGM

Last Lateglacial glacier advance in the Gran Paradiso Group reveals relatively drier climatic conditions established in the Western Alps since at least the Younger Dryas

The Late Pleistocene to Holocene transition in the Northern Hemisphere was characterized by abrupt millennial-scale climatic changes testified in the Alpine Chain by proxy records derived from glacial landforms and deposits. A detailed reconstruction of the paleo-glaciers during the deposition of the pre- Little Ice Age (LIA) moraines and newly obtained 10Be exposure ages provide information on the timing of a glacier advance in the Gran Paradiso Group (Western Alps, Italy) related to the regional Egesen stadial as a response to the climatic deterioration at around 12.9e11.7 ka (corresponding to the Younger Dryas in northern Europe and to the Greenland stadial 1 in the INTIMATE event stratigraphy). The study area represents a key site to define the behaviour of the Egesen paleo-glaciers, since they are located in a significant climatic area between the moister Maritime Alps and the Northern Alps. The ELA reconstructions and the comparison with other Alpine sectors provide evidence that current relatively drier conditions in the area postdate the LGM and were already present during the Egesen stadial. Our results support a strong positive YD Arctic Oscillation index, which led to drier conditions in southern Europe and caused negative winter precipitation anomalies