No description available.

Tephrochronologies for three marine core sequences from the Adriatic Sea have been constructed. Two of the sequences, PRAD 1-2 and RF93-77, are located in the central Adriatic and the third, SA03-03, lies in the southern Adriatic. Isotopic and biostratigraphic records are available for all three sequences, features of which have been used as isochronous markers in the region. This project aimed to establish whether tephra layers provide (a) secure, independent isochronous tie-lines and (b) a robust methodology for testing correlations based on other methods. A total of 54 tephra layers have been identified within these sequences, of which only 8 are visible layers, the remainder being classified as cryptotephras. Geochemical characterisation of the ash layers has been undertaken using electron microprobe analysis and laser-ablation trace element methods. Geochemical correlation to the detailed tephra record from Lago Grande di Monticchio was performed using chemical element biplots and discriminant function analysis. Bayesian-based age models were generated for the three Adriatic records using available chronological information that are independent of assumptions of synchroneity between proxy marker events. These models allowed comparisons with tephra and palaeoenvironmental data from Lago Grande di Monticchio and other Mediterranean sites. The results support some assumptions of synchronous regional changes, but not others. The key outcomes are (a) the recognition of additional (non-visible) distal ash layers that enhance the potential for correlating marine and terrestrial records in the central Mediterranean; (b) volcanic ash records preserved in Lago Grande di Monticchio and in some localities proximal to volcanic sources appear to be incomplete; and (c) isotopic records in Adriatic sediment sequences reflect regional forcing factors more than local conditions.

No description available.

A numerical study aimed at investigating the conditions under which different flow regimes appear near coastal capes is presented. The impacts of the regimes are also quantified in terms of integral quantities like mixing, current transport and form drag. Idealized and realistic numerical simulations are run both in barotropically and baroclinically-driven systems. The realistic cases model the Western Adriatic Current (WAC) in the Adriatic Sea. In both cases, the turbulent state of the flow is controlled in first approximation by the Burger number, Bu. When a steady barotropic and geostrophic current impinges on a triangular idealized cape, vertical movements are strong for Bu < 0.1 and pronounced lee waves can be found downstream of the obstacle. For 0.1 less than or equal to Bu < 1, fluid parcels flow more around the obstacle than over it. Flow separation occurs and small tip eddies start to shed. For Bu greater than or equal to 1, tip eddies merge to form larger eddies in the lee of the cape. Flow regimes are also strongly dependent on the obstacle slope alpha when Bu greater than or equal to 1. Flow regime diagrams in the Bu-alpha space are determined. A baroclinic current as the WAC becomes unstable in absence of wind as it separates from the coast for the presence of capes along its path. Downwelling favorable winds narrow and thicken the coastal buoyant current, raising Bu above a critical value and suppressing baroclinic instabilities. Upwelling favorable winds enhance instabilities via the opposite mechanism. With downwelling winds waters mix but remain relatively fresh (S less than or equal to 38), while most of the freshwater signal is lost with upwelling winds. The along-shore transport increases with downwelling winds while it decreases and can even reverse with upwelling winds. The form drag calculated across the obstacles in the different simulations is at least twice the magnitude of skin friction. In barotropic conditions it increases with increasing Bu and decreasing alpha and an empirical parametrization in the Bu-alpha space is put forth. Across the Gargano Promontory, more symmetric pressure fields are observed with downwelling winds; the form drag decreases as a result. The opposite is registered with upwelling winds.

Bottlenose dolphins of the Kvarnerić (NE Adriatic Sea) live in an area of increasing human impact, through tourism and small-scale fisheries. This thesis aimed to assess the status of the local population and to inform managers on factors affecting their distribution and abundance, using data from 1995-2003. Habitat modelling indicated a significant negative impact of proximity to the main ‘marine highway’ and to marine petrol stations. Evidence was found that dolphins may recently have reached a tolerance limit to the number of boats using the area and that they remember crowded areas from one year to the next. Dolphin presence was positively related to particular depths and trawling areas. Apparent adult survival rate was estimated to be significantly lower than for any other bottlenose dolphin population and first year calf survival was also low. A decreasing trend in fecundity rate was found. The population showed a considerable rate of non-random temporary emigration from the study area. The estimated size of the population was small and similar to two other European bottlenose dolphin populations (Moray Firth in Scotland and Shannon Estuary in Ireland). A significant decrease in abundance of about 39% from 1995 was estimated. PVA confirmed the importance of female adult survival to population viability and indicated that the current rate of human-induced mortality is unsustainable. Local extinction risk within three generations was estimated to be high (35%). Applying the IUCN Red List Criteria, the Kvarnerić population should be listed as Endangered under Criterion C and E. This study gives an important insight into the ecology of Adriatic bottlenose dolphins and indicates the need for a regionally and locally synergistic approach to conserve this population.

No description available.

Thèse--Université de Grenoble. / "Bibliographie": p. 155-156.

L'objectif de la recherche est l'étude, d’un point de vue typologique, épigraphique, fonctionnel et commercial, des amphores adriatiques découvertes à Rome dans le secteur du Nuovo Mercato Testaccio. Entre 2005 et 2010, ce secteur, tout proche du Mont des Tessons et du port fluvial, a fait l’objet d’une fouille archéologique .L’état plus antique qu’on a fouillé est caractérisé par un espace ouvert, divisé en enclos, des pièces couvertes et des voies de service. A l’intérieur des enclos sont jetés des remblais constitués principalement par des tessons. La particularité réside dans le matériau utilisé pour organiser l’espace et pour la construction: il s’agit d’amphores (729 ca.). Les conteneurs des alignements sont essentiellement produits sur la côte Adriatique de l’Italie (74%): il s’agit surtout d’amphores à vin du début de l’Empire, Dressel 6A. Leur abondance dans les alignements est peut-être imputable au caractère de décharge organisée du site. En effet, en utilisant les données sur les remblais, on peut reconnaître des différences avec les alignements dans les pourcentages d’amphores adriatiques (9-12% du nombre total de fragments). On suppose que les amphores adriatiques ont été choisies pour bâtir les alignements car il s’agit de conteneurs solides, dont on connaissait déjà la firmitas par les sources anciennes. La déchèterie semble commencer à l’époque de Tibère et être oblitérée au IIe s. Les conteneurs adriatiques du Nuovo Mercato représentent le premier lot de cette importance trouvé à Rome en contexte stratigraphique, l’essentiel des découvertes remontant à la fin du XIXe s. (contextes identifiés par H. Dressel et représentés dans CIL XV,2). / The focus of this research is the study of the Adriatic amphorae found at the Nuovo Mercato Testaccio (Roma), with special regard to the morphological features, epigraphic apparatus and commercial aspects and to the reuse of the containers. In proximity to the Monte dei Cocci and to the Tiber harbour (Emporium), the area was excavated between 2005 and 2010. The oldest level of occupation identified is characterised by alignments of transport containers almost complete, associated with fillings of pottery fragments and building materials. The alignments constituted often the true and proper walls, probably realised in multiple orders of piled-up amphorae. The life of this landfill appears to have begun in the Tiberian age, while its definitive obliteration has been dated to the 2nd century. The material conserved in the alignements documented (ca. 729 amphorae) is higly homogenous, composed of 74% of Adriatic containers, above all the early imperial wine amphorae so-called Dressel 6A. The abundance of Dressel 6A in the alignments is due to the organisation of landfill, in virtue of the robustness of these containers, already known by the ancient sources.The fillings reveal in fact any number of discrepancies versus the alignments: the Adriatic amphorae in these levels are between 9% and 12%. Anyway, the Adriatic containers unearthed at the Nuovo Mercato Testaccio represent the most important discovery of this kind of amphorae in Rome, after the finds of the 2nd half of the XIX century at the Castro Pretorio, edited by H. Dressel in CIL XV, 2.

The Lagrangian dynamics of two-dimensional incompressible fluid flows is considered, with emphasis on transport processes in atmospheric and oceanic flows. The dynamical-systems-based approach is adopted; the Lagrangian motion in such systems is studied with the aid of Kolmogorov-Arnold-Moser (KAM) theory, and results relating to stable and unstable manifolds and lobe dynamics. Some nontrivial extensions of well-known results are discussed, and some extensions of the theory are developed. In problems for which the flow field consists of a steady background on which a time-dependent perturbation is superimposed, it is shown that transport barriers arise naturally and play a critical role in transport processes. Theoretical results are applied to the study of transport in measured and simulated oceanographic and atmospheric flows. Two particular problems are considered. First, we study the Lagrangian dynamics of the zonal jet at the perimeter of the Antarctic Stratospheric Polar Vortex during late winter/early spring within which lies the "ozone hole". In this system, a robust transport barrier is found near the core of a zonal jet under typical conditions, which is responsible for trapping of the ozone-depleted air within the ozone hole. The existence of such a barrier is predicted theoretically and tested numerically with use of a dynamically-motivated analytically-prescribed model. The second, oceanographic, application considered is the study of the surface transport in the Adriatic Sea. The surface flow in the Adriatic is characterized by a robust threegyre background circulation pattern. Motivated by this observation, the Lagrangian dynamics of a perturbed three-gyre system is studied, with emphasis on intergyre transport and the role of transport barriers. It is shown that a qualitative change in transport properties, accompanied by a qualitative change in the structure of stable and unstable manifolds occurs in the perturbed three-gyre system when the perturbation strength exceeds a certain threshold. This behavior is predicted theoretically, simulated numerically with use of an analytically prescribed model, and shown to be consistent with a fully observationally-based model.

Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation. Acoustic systems like high-frequency multibeam sonar are efficient tools in monitoring the environmental evolution around artificial reefs, whereas water turbidity can limit visual dive and ROV inspections. A high-frequency multibeam echo sounder offers the potential of detecting fine-scale distribution of reef units, providing an unprecedented level of resolution, coverage, and spatial definition. How do artificial reefs change over time in relation to the coastal processes? How accurately does multibeam technology map different typologies of artificial modules of known size and shape? How do artificial reefs affect fish school behavior? What are the limitations of multibeam technology for investigating fish school distribution as well as spatial and temporal changes? This study addresses the above questions and presents results of a new approach for artificial reef seafloor mapping over time, based upon an integrated analysis of multibeam swath bathymetry data and geoscientific information (backscatter data analysis, SCUBA observations, physical oceanographic data, and previous findings on the geology and sedimentation processes, integrated with unpublished data) from Senigallia artificial reef, northwestern Adriatic Sea (Italy) and St. Petersburg Beach Reef, west-central Florida continental shelf. A new approach for observation of fish aggregations associated with Senigallia reef based on the analysis of multibeam backscatter data in the water column is also explored. The settlement of the reefs and any terrain change are investigated over time providing a useful description of the local hydrodynamics and geological processes. All the artificial structures (made up by water-based concrete for Senigallia reef and mainly steel for St. Petersburg Beach reef) are identified and those showing substantial horizontal and/or vertical movements are analyzed in detail. Most artificial modules of Senigallia reef are not intact and scour signatures are well depicted around them, indicating reversals of the local current. This is due to both the wind pattern and to the quite close arrangement of the reef units that tend to deflect the bottom flow. As regards to the St. Petersburg Beach reef, all the man-made steel units are still in their upright position. Only a large barge shows a gradual collapse of its south side, and presents well-developed scouring at its east-northeast side, indicating dominant bottom flow from west-southwest to east-northeast. While an overall seafloor depth shallowing of about 0.30 m from down-current deposits was observed for Senigallia reef, an overall deepening of about 0.08 m due to scour was observed at the St. Petersburg Beach reef. Based on the backscatter data interpretation, surficial sediments are coarser in the vicinities of both artificial reefs than corresponding surrounding sediments. Scouring reveals this coarser layer underneath the prevalent mud sediment at Senigallia reef, and the predominant silt sediment at St. Petersburg Beach reef. In the ten years of Senigalia reef study, large-scale variations between clay and silt appear to be directly linked to large flood events that have occurred just prior to the change. As regards the water column investigation, acoustic backscatter from fish aggregations gives detailed information on their morphology and spatial distribution. In addition, relative fish biomass estimates can be extrapolated. Results suggest that most of the fish aggregations are generally associated with the artificial modules showing a tendency for mid- and bottom-water depth distribution than for the surface waters. This study contributes to understanding the changes in artificial reefs over time in relation to coastal processes. Moreover, the preliminary results concerning the water column backscatter data represents progress in fisheries acoustics research as a result of three-dimensional acoustics. They demonstrate the benefits of multibeam sonar as a tool to investigate and quantify size distribution and geometry of fish aggregations associated with shallow marine habitats.