Sand provenance of Le Dune and Torre Guaceto beach (Southern Italy).

The sandy littoral sectors of the Apulia Region (Southern Italy) show a large textural and compositional variability of the beach sands characterizing the different sedimentary dynamics of the Ionian and Adriatic coastal areas. The study areas include two Apulian pocket beaches (Torre Guaceto and Le Dune beach) which are representative of the coastal dynamics of a large sector of the central/northern Mediterranean Sea involving southern Adriatic Sea and northern Ionian Sea. Torre Guaceto beach is a 1 km littoral stretch located on the Adriatic Sea. Beach sediments range between coarse and fine sands and they include siliciclastic minerals and carbonate granules. Le Dune beach is located along the Ionian Seaside and develops for about 800 m. Beach sediments range from very coarse to mediumfine sands and they are mainly made up of bioclast fragments. Both study areas are part of marine protected reserves which includes 15 different habitats of the typical Mediterranean submerged populations and the presence of Posidonia oceanica meadows. Sedimentological, compositional and ecological investigations allowed describing the textural and petrographic characteristics of the beach sands by interpreting their sand provenance. The physical/biological interactions led us to analyse the beach sedimetary dynamics which is fundamental for pocket beach conservation. The sand compositional study highlighted the presence of mixed hybrid sands (terrigenous and bioclastic) and a longshore significant composition variability at Torre Guaceto beach, whereas the carbonate component (bioclasts more than 90% and lithics) represents the main element of Le Dune beach

Sediment provenance of a carbonate bioclastic pocket beach - Le Dune (Ionian Sea, South Italy)

This study focuses on the analysis of a carbonate bioclastic pocket beach located along a coastal sector of the Apulia Ionian Sea, Le Dune beach, South Italy. The beach develops for about 800 m and it is exposed to the south-westerly and southerly seas. Coastal sediments range from very coarse to mediumefine sands and they are mainly composed of bioclasts (more than 90%) which include molluscs, foraminifers, echinoderms, algae branched, bryozoans, spicules of sponges and arthropods. The study area is one part of a marine protected reserve characterised by 15 different habitats of the typical Mediterranean submerged populations and the presence of Posidonia oceanica meadows. The aim of our research is to highlight the correlation between physical and biological processes influencing Le Dune beach dynamics and its sediment provenance by analysing the textural and compositional characteristics of beach sands, which is fundamental for pocket beach conservation. The beach sand analysis, deriving from textural, compositional and bioclast investigations, underlines that one of the main indicators of the beach dynamics is the bioclast component, which provides relevant information about sand provenance and sediment transport. The beach constitutes a semi-close system only nourished by the shells of organisms and by the erosion of headlands and dunes without important sediment interchange with adjacent littoral sectors

Sediment provenance of a carbonate bioclastic pocket beach - Le Dune (Ionian Sea, South Italy)

This study focuses on the analysis of a carbonate bioclastic pocket beach located along a coastal sector of the Apulia Ionian Sea, Le Dune beach, South Italy. The beach develops for about 800 m and it is exposed to the south-westerly and southerly seas. Coastal sediments range from very coarse to mediumefine sands and they are mainly composed of bioclasts (more than 90%) which include molluscs, foraminifers, echinoderms, algae branched, bryozoans, spicules of sponges and arthropods. The study area is one part of a marine protected reserve characterised by 15 different habitats of the typical Mediterranean submerged populations and the presence of Posidonia oceanica meadows. The aim of our research is to highlight the correlation between physical and biological processes influencing Le Dune beach dynamics and its sediment provenance by analysing the textural and compositional characteristics of beach sands, which is fundamental for pocket beach conservation. The beach sand analysis, deriving from textural, compositional and bioclast investigations, underlines that one of the main indicators of the beach dynamics is the bioclast component, which provides relevant information about sand provenance and sediment transport. The beach constitutes a semi-close system only nourished by the shells of organisms and by the erosion of headlands and dunes without important sediment interchange with adjacent littoral sectors

The northern fault of the onshore-offshore Monte Giove relief in the southern Adriatic Sea, Italy: implications for tectonic reactivation in the Apulian Foreland

We provide improved constraints on the timing, geometry and kinematics of the fault that may control the northern submerged morpho-structural relief termed Monte Giove, offshore from the town of Polignano a Mare. We have integrated onshore and offshore data, and interpreted seismic profiles from the ViDEPI project pertaining to the offshore Adriatic Sea of the Murge area, and made field observations north of Polignano a Mare. The fault has been surveyed onshore and mainly offshore along a distance of ~25 km. Generally striking E–W, it dips at high angle to the NNE in the west and to the N in the east. Active since at least the Cretaceous, this was reactivated after the Early Pleistocene with dextral oblique-slip kinematics. It borders the Monte Giove submerged relief/structural high, and continues eastwards in the Adriatic Sea into the Northern Deformation Zone/”Murge basse” graben, that in turn affected the onshore Murge area. Fault reactivation may have been related to a strain field in the outer part of the gentle buckle fold that involved the continental lithosphere of the Apulian Foreland (i.e., the areas of the Murge onshore and the Adriatic Sea offshore) since the Middle Pleistocene, as roll-back of the subducting lithosphere halted. Besides its tectonic reactivation, this fault has important implications as regards local seismic hazard, as well as the morphology influencing the present-day bioherm

A multidisciplinary approach for evaluating Sabellaria bioconstructions: The case study of Torre Mileto (Northen Gargano coast, Adriatic sea)

The S. spinulosa (Leukhart, 1849) worm reef of Torre Mileto is a site of extraordinary beauty, proposed as a Site of Community Importance (SCI) to be protected by law. Recent studies highlight both the ability of this structure to increase the biodiversity of the adjacent sector of coast, and to act as a barrier to defend from coastal erosion as well as a temporary reservoir of sediments, lengthening the cycle of sand in the beach.This work shows the results of image analysis techniques on bioconstruction samples integrated with seasonal and annual monitoring. A multidisciplinary approach involving sedimentological, ecological and biological analysis techniques offers an overall view of the evolutionary state of the environment and provides quantitative data which are necessary for the protection and monitoring of this sit

The sedimentary dynamics of Sabellaria alveolata bioconstructions (Ostia, Tyrrhenian Sea, central Italy)

Sabellaria alveolata (Linnaeus 1767) is a polychaete able to build bioconstructions of different thickness, size and patchiness, in intertidal and subtidal environments. Its biological features have been the object of numerous studies worldwide. The worm reefs are formed by millions of tubes built by sand and shells (whole or in fragments) bonded together with a strong glue produced by the worm itself. Hence, Sabellaria alveolata represents a sedimentological asset for the coastal protection, since it contributes to create natural barriers against storm waves and erosion, and supplies the beach with new sandy deposits. This work shows a multidisciplinary approach to studying a bioconstruction of Sabellaria alveolata along the Latium coast (Ostia, Tyrrhenian Sea, central Italy), proposing image analysis as a novel technique to investigate worm reefs, along with classical sedimentological/ecological tools. The Sabellaria bioconstructions have been analysed at different scales of observation, suggesting the more appropriate strategies to develop a reliable model illustrating the different growth steps of these bioconstructions

Massive bioconstructions built by Neopycnodonte cochlear (Mollusca, Bivalvia) in a mesophotic environment in the central Mediterranean Sea

The present paper provides a multidisciplinary fine-scale description of a Mediterranean mesophotic new habitat dominated by the bivalve Neopycnodonte cochlear (Poli, 1795), building large and thick pinnacles on vertical cliffs at two study areas along the southern Italian coast. The pinnacles, constituted by a multilayered aggregation of living and dead specimens of N. cochlear, were interconnected with each other to form a framework of high structural complexity, never observed before for this species. The bioconstruction, considerably extended, resulted very complex and diversified in the associated community of structuring organisms. This latter included 165 taxa attributable to different ecological groups occurring in different microhabitats of the bioconstruction. Among the secondary structuring taxa there were scleractinians, serpulids and bryozoans, all contributing to the deposition of calcium carbonate, and poriferans, helping to bind shells together or eroding carbonate by boring species. In comparison with coralligenous sensu stricto and the recently described Mediterranean mesophotic coral reef, the Neopycnodonte bioconstruction showed peculiar features, since it lacked the major contribution of encrusting coralline algae and scleractinians as reef builders, respectively