Eastern Tyrrhenian Sea Research Articles

Glavonošci kao plijen glavate želve, Caretta caretta (Reptilia: Cheloniidae), iz istočnog Tirenskog mora

This study presents the results of the examination of cephalopod remains extracted from the digestive tract of 40 loggerhead turtles, Caretta caretta, stranded along the Campanian coasts (Southern Italy, eastern Tyrrhenian Sea). We retrieved the remains of 23 cephalopods from 16 turtles (frequency of occurrence = 40%). They belonged to Sepia officinalis (19 specimens) and Octopus vulgaris (2 specimens), both of them benthic neritic species, and Histioteuthis reversa (2 specimens), an oceanic species. Accordingly, loggerheads appear to feed both on the bottom, seemingly in shallow waters, and in the open seawater column; both on muscular items (S. officinalis and O. vulgaris) and ammoniacal ones (H. reversa). This is the first record of H. reversa as a prey of the loggerhead turtle.

Natural vs. anthropogenic metals for reconstructing the source-to-sink pathway (Naples Bay, eastern Tyrrhenian Sea)

The grain size, nutrients, and metals contents of sediments are important tracers for reconstructing the origin of the contaminants and the pathway of the sediments from the source to the sink. This is particularly important in areas with high geological variability and a high demographic pressure. The origin and distribution of contaminants and nutrients allow us to identify the source-to-sink pathway of the sediments. In particular, the Sarno River is one of the main contributing sources of anthropogenic contaminants due to the outflow from the large surrounding large industrial area. Geochemical and physical parameters of sediments were analyzed along a transect from the coastline to a water depth of 112 m, with the objective of exploring the spatial variability of sediment contamination in the continental shelf of Naples Bay. The latter is characterized by a complex geological area and is subject to river inflow from a highly industrialized area. The data have been analyzed using principal component analysis (PCA), hierarchical correlation analysis (CA), and analysis of variance (ANOVA). To distinguish between a natural and anthropogenic origin of contaminants and to construct the source-to-sink pathway, the relationship between geochemical and physical data and their distribution was examined, and the results were compared with published data collected onshore. Four distinct sectors with different associations of metals, grain size, and total organic carbon have been recognized: I) offshore Vesuvius volcano, the occurrence of coarse-grained sediments, associated with As, Fe, Mn, and low TOC values, suggests a natural origin of the contaminant due to the volcanic nature of the substrate; II) offshore the Sarno River, the presence of Cr, Cd, Cu, Pb and Zn, associated with the high TOC content, suggests an anthropogenic origin for the contaminants; III) offshore Sorrento Peninsula, the presence of As, Fe, Mn, and some gravel made up of pumice and bioclasts indicate a predominance of contaminants of natural origin; and IV) finally, the distal part is not subjected to a primary terrestrial input. Metals contamination of anthropogenic origin and the organic matter in sediments decreased rapidly with distance from the coast highlighting the main deposition area close to the river discharge.

Morphological and functional alterations in hemocytes of Mytilus galloprovincialis exposed in high-impact anthropogenic sites

The work aimed to study the induction of morphological alterations in M. galloprovincialis in the field and its suitability to be integrated into a sensitive, simple, and cost-effective cell-based multimarker approach for the detection of the stress status induced by pollution in coastal marine environments in view of ecotoxicological biomonitoring and assessment application. Cellular morphometric alterations was paralleled by the analysis of standardized biomarkers such as lysosomal membrane destabilization, and genotoxocity biomarkers such as micronuclei and binuclated cells frequencies were investigated. The study was carried out by means of a transplanting experiment in the field, using caged organisms from an initial population exposed in the field in two multi-impacted coastal sites of the central Mediterranean area, Bagnoli in the eastern Tyrrhenian Sea and Augusta-Melilli-Priolo in the western Ionian Sea. Capo Miseno (NA) for the Tyrrhenian area and Brucoli (ME) for the Ionian area were chosen as control sites.Hemocyte enlargement and filopodial elongation increased frequencies were observed in organisms exposed to the impacted sites. These morphometric alterations showed strong agreement with the lysosomal membrane destabilization and biomarkers of genotoxicity, suggesting their usefulness in detecting the pollutant-induced stress syndrome related to genotoxic damage.

Commercial sharks under scrutiny: Baseline genetic distinctiveness supports structured populations of small-spotted catsharks in the Mediterranean Sea

The present study, based on microsatellite markers, describes a population genetic analysis of the small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758), representing one of the most abundant and commonly caught cartilaginous fishes in the Mediterranean Sea and adjacent areas. The analyses were performed to unravel the genetic features (variability, connectivity, sex-biased dispersal) of their relative geographic populations, both at the small (around the coast of Sardinia, Western Mediterranean Sea) and at a larger spatial scale (pan-Mediterranean level and between the Atlantic Ocean and the Mediterranean Sea). Individual clustering, multivariate and variance analyses rejected the hypothesis of genetic homogeneity, with significant genetic differences mainly within the Mediterranean between the Western and Eastern basins, as well as between the Mediterranean and the NE Atlantic Ocean. In detail, our results seem to confirm that the Strait of Gibraltar could not represent a complete barrier to the exchange of individuals of small-spotted catshark between the Atlantic Ocean and the Mediterranean Sea. In the latter area, a complex genetic structuring for S. canicula was found. Apart from differences among the Western, Eastern and Adriatic sites, within the Western basin the small-spotted catsharks around Sardinian waters are strongly differentiated from all others (both from the eastern Tyrrhenian Sea and southernmost part of the Algerian basin) and are demographically stable. Several possible mechanisms, both biological and abiotic (e.g., migratory behavior, waterfronts, and oceanographic discontinuities), are discussed here to explain their peculiar characteristics. Overall, the genetic data presented, both at the local and regional level, could represent a baseline information, useful for the temporal monitoring of populations, and to assess the effects of present or future fishing/management/conservation measures.

The Holocene Evolution of the Volturno Coastal Plain (Northern Campania, Southern Italy): Implications for the Understanding of Subsidence Patterns

In the Mediterranean area, several alluvial coastal plains, developed after the Holocene transgression, are affected by subsidence. The Volturno alluvial-coastal plain, along the eastern Tyrrhenian Sea (southern Italy) is characterized by subsidence rates determined through InSAR data analysis and ranging between 0 and <−20 mm/year in an area of about 750 kmq across the Volturno River. Inside this area, the pattern of subsidence shows sites with apparently anomalous localized subsidence. To understand the driving mechanisms of this process, a lithostratigraphic reconstruction was provided focusing on the spatial distribution of the horizons considered weak by a geotechnical point of view; then, the subsidence map was overlain spatially with geological data in a Geographic Information System (GIS) environment. The spatial analysis highlighted the major ground deformation occurring within the outer boundary of the incised paleo-valley, corresponding to the Holocene alluvial/transitional filling that overlies a compaction-free Pleistocene basement. Inside this general trend, differential compaction was detected corresponding to the thick occurrence of clay and peat deposits, suggesting that the subsidence rate registered in the plain are due in part to the consolidation of primary settlements of soft and compressible soils that characterize the subsoil of these areas, and in large part to the secondary consolidation settlements.

Seafloor morphology changes in the inner-shelf area of the Pozzuoli Bay, Eastern Tyrrhenian Sea

Seafloor morphology changes in the inner-shelf area of the Pozzuoli Bay, Eastern Tyrrhenian Sea

Integrated early warning systems in marine bivalves reveal detrimental alterations of coastal habitats

Several biological levels are considered as signals of environmental perturbations so that integrative biological responses have been proposed in environmental monitoring activities. We evaluated the use of markers in Mytilus galloprovincialis at two different levels (protein nitration and S-nitrosylation, and geometric morphometrics) to investigate the sea coastal environmental status. We studied adductor muscle, digestive gland and valves of mussels collected from 3 sampling sites (2 disturbed + 1 control) in eastern Tyrrhenian Sea, and 2 (1 + 1) in western Ionian Sea. Molecular and morphometric markers showed significant variations in relation to environmental conditions, but the most interesting result was evidenced by the analysis of covariation between both protein post-translational modifications and geometric morphometric descriptors. The main interesting finding regards the relationship between protein nitration values (an irreversible molecular marker) of both adductor muscle and digestive gland, and geometric morphometric descriptors (that are Procrustes’ distances) of valve shapes. Molecular and morphometric markers revealed useful warning systems in detecting environmental changes, even if causes and mechanisms altering both cellular metabolism and shape morphology are still unclear. Our findings suggested that pollutants affected the normal cellular metabolic pathways altering the correct functionality at higher biological levels and producing developmental detrimental noise visible on the shell.

Late Pleistocene–Holocene climatic and volcanic events in the bathyal area of the Eastern Tyrrhenian Sea and the stratigraphic signature of the 39 ka Campanian Ignimbrite eruption

Abstract A multidisciplinary study, based on integration of eco-biostratigraphy and tephrostratigraphy, was applied to the sedimentary record of core CET2, recovered in a bathyal area of the Eastern Tyrrhenian Sea, along the Campania Continental Margin. An event stratigraphy of the Late Pleistocene–Holocene succession was obtained, also through the integration of the results coming from the study of the nearby CET1 core. A very detailed integrated stratigraphic framework was reconstructed for the last 40-ka time span, basing on the planktonic foraminifera eco-biozones and correlations of tephra layers. In the time interval older than 40 ka, the relationship between climatic events and tephra layers were highlighted. Some reworked intervals were identified at different stratigraphic levels; the thickest among these was identified just below the Campanian Ignimbrite tephra and interpreted as a debris flow. This deposit is here considered as the stratigraphic signature of the volcano-tectonic event of the Campanian Ignimbrite eruption. Other mass-transport deposits were identified below tephra layers related to very energetic eruptions, thus suggesting a possible link between the huge volcanic explosive eruptions of the Campania Volcanic Zone, coeval fault activity and the occurrence of mass-transport events in the study area.

Shell fluctuating asymmetry in the sea-dwelling benthic bivalve Mytilus galloprovincialis (Lamarck, 1819) as morphological markers to detect environmental chemical contamination.

Investigations on asymmetries showed that deviations from perfect bilateral symmetry are interpreted as environmental changes inducing developmental instability. Since morphological abnormalities increase with pollution, deformations may be considered indicators of the organism exposition to pollution. Therefore, the onset of asymmetry in otherwise normally symmetrical traits has been used as a measure of some stresses as well. In this context, we studied how marine pollution affects the valve morphological alterations in the mussel Mytilus galloprovincialis. We used 180 specimens (30 per site) from the aquaculture area of Goro (River Po delta, northern Adriatic Sea), translocated, and released within 50 × 50 × 50 cm cages in five sites: two disturbed and one undisturbed near Naples (eastern Tyrrhenian Sea), and one disturbed and one undisturbed near Siracusa (western Ionian Sea). Disturbed sites were stressed by heavy industrialization and heavy tankers traffic of crude and refined oil, and were defined basing on sediment contamination. In particular, by the cone-beam computed tomography we obtained 3D virtual valve surfaces to be analyzed by the geometric morphometric techniques. Specifically, we focused the levels of the shell shape fluctuating asymmetry in relation to the degrees of marine pollution in different sites of the Tyrrhenian Sea. The Mahalanobis distances (interpreted as proxy of the individual shape asymmetry deviation from the mean asymmetry) significantly regressed with the sediment contamination gradient. Indeed, although the left-right differences were normally distributed in each studied site, the individual asymmetry scores (IAS) significantly varied amongst the investigated sites. IAS showed higher values in disturbed areas than those of undisturbed ones in both Tyrrhenian and Ionian Sea. Our results are consistent with past studies on molluscans and other taxa, demonstrating some detrimental effects of chemicals on organisms, although the investigated morphological marker did not discriminate the real disturbance source. Our findings indicate that the mussels act as a prognostic tool for sea pollution levels driving detrimental effects on benthic community.

High-resolution morpho-bathymetry of the Gulf of Naples, Eastern Tyrrhenian Sea

ABSTRACTWe present a high-resolution bathymetric map of the Gulf of Naples (Italy), which is surrounded by the two main volcanic complexes of Mt. Somma-Vesuvius and Phlegrean Fields. The morphology is obtained from swath bathymetric in a Digital Terrain Model with a 5 m grid cell size. Bathymetric data display the main seafloor morphologies with a resolution never obtained before. These morphologies include the Ammontatura and Dohrn Canyons, the Penta Palummo, Nisida, Miseno and Banco della Montagna banks, and the bathymetric features of the submerged sector of the Somma-Vesuvius volcano. Overall, a prevailing volcanic nature characterizes the seafloor morphologies located in the northern sector, while the southern one is dominated by sedimentary features. The Final Map could be useful for the evaluation of the volcano-related hazards in the area.

Multidisciplinary tephrochronological correlation of marker events in the eastern Tyrrhenian Sea between 48 and 105 ka

The basal portion (2.92–5.08m from core top) of the CET1 core located in a bathyal area of the eastern Tyrrhenian Sea is the subject of a multidisciplinary investigation, encompassing tephrostratigraphy, quantitative analyses of planktonic foraminifera and calcareous nannofossil assemblages, and δ18O measurements, supported by a 40Ar/39Ar age determination. Calcareous nannofossil assemblages allowed the attribution of the analyzed sediments to the biozone MMN21a, and the succession spans from more than 48 to ca. 105ka, although there are at least two stratigraphic gaps and minor resedimentation episodes. A paleoclimatic reconstruction obtained via δ18O and planktonic foraminifera data identifies several of the major climatic events that occurred in the investigated time span.A total of 13 visible tephra layers and cryptotephras are recognized and correlated with their volcanic sources (Campanian Volcanic Zone and Pantelleria volcano) and, when possible, with well-known and dated events or with widespread marker tephras.Using a combination of biostratigraphic, oxygen isotope, and tephrostratigraphic correlations, we develop a chronostratigraphy for the main climatic events and tephra layers in the core and pinpoint tephra markers for the climatic events comprised between GS 22 and GI 24 in the eastern Tyrrhenian Sea.

Seafloor mapping using high-resolution multibeam backscatter: The Palinuro Seamount (Eastern Tyrrhenian Sea)

ABSTRACTWe present a seafloor map of the summit of Palinuro Seamount, an E–W elongated volcanic ridge located in the Eastern Tyrrhenian Sea. The seafloor was mapped using multibeam backscatter and seafloor samples collected between 80 and 1000 m below the sea level. The high-resolution imaging of the Palinuro seafloor was obtained by merging a Digital Terrain Model with a 2.5 m-sized grid and a backscatter mosaic with 2.5 m pixel. The resulting 1:20,000 scale map includes six main facies recognized based on their backscatter properties. These six facies reflect different lithologies. The Palinuro seafloor map represents a useful tool for morphological and geological studies of the Palinuro volcanic ridge.

A multidisciplinary approach for reconstructing the stratigraphic framework of the last 40 ka in a bathyal area of the eastern Tyrrhenian Sea

A detailed integrated stratigraphic framework for the last 40ka in the eastern Tyrrhenian Sea (central Mediterranean) was obtained through quantitative analyses of planktonic foraminifera assemblages, tephrostratigraphical studies and δ18O measurements on the basinal CET1 cored succession.Relative abundance fluctuations in the planktonic foraminifera assemblages allowed the identification of nine known eco-biozones and several bioevents recognized in the Tyrrhenian area and that are useful for correlations between Mediterranean marine records. Compositional changes in the planktonic foraminifera assemblages together with variations in the oxygen isotope record allowed us to detect the major climatic global fluctuations and some of the minor events that occurred during the investigated time interval.A total of 12 visible tephra layers and cryptotephras have been recognized and correlated with their volcanic sources and/or with known explosive events of Campanian and Sicilian–Aeolian volcanoes.A stratigraphic relationship between foraminiferal and climatic events and tephra layers has been highlighted. For the first time ecostratigraphic and tephrostratigraphic methods were combined to obtain a detailed integrated stratigraphy for the last 40ka in the Tyrrhenian area. The achieved stratigraphic framework provides a useful stratigraphic reference record for the investigated area.

Multi-proxy analysis in defining sedimentary processes in very recent prodelta deposits: the Northern Phlegraean offshore example (Eastern Tyrrhenian Margin)

A multi-proxy analysis of Volturno River prodelta deposits in the outer shelf of Northern Phlegraean margin (Eastern Tyrrhenian Sea) has been carried out to reconstruct the sedimentary processes acting during recent times. The late Holocene sediments were characterized through Subbottom Chirp profiles coupled with sedimentological and petrophysical data. The chronostratigraphic framework was achieved by means of colorimetric parameter a* correlations with nearby dated marine sediment. A time interpretation of about 2,300 years BP is estimated for the sedimentary record collected in the cores. Seismic stratigraphic analysis shows late Holocene outer shelf deposits, characterized by fluid escape features and small-offset faults. However, the undisturbed sedimentation and the preservation of an internal geometry at decimetre scale, as detected by the sedimentological and petrophysical analysis, indicates a slow sliding without sediment reworking for this sedimentological body. So far a possible recent (<2,300 years BP) shear dominated downward displacement of high water content sediments, triggered by the occurrence of seismic activity, is inferred. Based on the depth-age conversion of the detected lithological features, a regular climatically driven change in the sediment supply of the prodelta depositional environment is suggested. The detection of spectrophotometry correlations of Holocene shelf margin sediments, several km apart, goes beyond the previous work and confirms even for continental shelf area the potential value of spectrophotometer data in high-resolution stratigraphic correlations.

Combined palaeomagnetic secular variation and petrophysical records to time-constrain geological and hazardous events: An example from the eastern Tyrrhenian Sea over the last 120 ka

Long-term change of Earth's magnetic field (palaeomagnetic secular variation, PSV) during much of the last approximately 120ka was recorded in cored sediment from the slope margin of the eastern Tyrrhenian Sea. The PSV record has been correlated to master curves of global palaeomagnetic field intensity and PSV records for western Europe. Tephrochronology and radiometric dating (14C and 40Ar/39Ar) have also been used to constrain the age of the PSV record. The combination of the new data with prior PSV and petrophysical data from the area provides a chronological framework for geological events such as large-scale submarine slumps, stratigraphic gaps and short-term changes in deposition rate on the continental margin. These latter changes are linked to the combined action of relative sea-level oscillations, climate events, and consequent variations in land exposure through time. Moreover, new data concerning the thickness and dispersal of Campanian Plain pyroclastic deposits in the marine setting enable volcanic-hazard evaluation. Finally, a pyroclastic deposit (tephra X-6) found offshore in the Southern Campanian marine environment was 40Ar/39Ar dated for the first time at 108.9±1.8kaBP.

Seasonal Variability of the Tyrrhenian Sea Surface Geostrophic Circulation as Assessed by Altimeter Data

AbstractNew insights into the structure and variability of the Tyrrhenian Sea's surface circulation are obtained through the analysis of a very long series of altimetric observations (1993–2010). In late winter and part of spring, a consistent mean flow is individuated in the eastern Tyrrhenian Sea, formed by a stream of Atlantic water that meanders around four anticyclonic structures located along the Italian coast, which have smaller cyclonic companions offshore. The signatures of these vortices are also found in images of chlorophyll and sea surface temperature, as well as in modeling results, both from a high-resolution operational model of the Tyrrhenian Sea's circulation and from a dedicated numerical simulation. Analysis of the energy exchange between eddies and mean flow, together with numerical evidence, suggests that this winter–spring circulation pattern may result from basin-scale instability of the Atlantic stream. In summer, the dynamic is dominated by a well-known dipole located to the east of the Bonifacio Strait. However, in the eastern part of the basin, an anticyclonic cell is also found, probably driven by the negative wind stress curl present in summer in this region. The cell encompasses two anticyclonic vortices located in the areas of the Vavilov and Marsili Seamounts. A multichannel singular spectral analysis of the altimetric time series reveals that, besides the expected, dominant seasonal mode, a significant low-frequency mode of variability is also present. This mode has a period of about six years and is mostly localized in the western part of the basin.

Volcanism and faulting of the Campania margin (Eastern Tyrrhenian Sea, Italy): a three-dimensional visualization of a new volcanic field off Campi Flegrei

By means of information technology, 3D digital geologic models are increasingly the best methods of constraining interpretations of geology at depth. Visualization in three dimensions has allowed us to develop solutions that explain the stratigraphic and structural complexity of the Campania margin of the Eastern Tyrrhenian Sea, especially the lateral relationships among volcanoes and underlying normal faults. Using seismic and sequence stratigraphy and structural geology approaches in a dedicated GIS environment, we interpreted a seismic grid and investigated a subsurface volcanic field in Gaeta Bay (off Campi Flegrei) located within the Campania margin. The Gaeta Bay basin fill is characterized by several volcanic units that were analyzed using 2D structure contour maps and isochron maps. These volcanoes are comparable in size to the edifices of Campi Flegrei, Vesuvius, and the submerged volcanoes of the Bay of Naples. Their age spans from the Lower Pleistocene for the isolated V0 volcano sited in Central Gaeta Bay to 0.4–0.1 Ma for the volcanic field of southern Gaeta Bay. The study of the interplay between volcanic units and faults allowed us to distinguish (1) the oldest fault buried by the Lower Pleistocene V0 volcano in Central Gaeta Bay; (2) a normal fault swarm NE–SW that in the Middle Pleistocene gave rise to a half-graben filled by the V1–V5 volcanic field in southern Gaeta Bay; and (3) post-0.4 Ma normal faults that downthrow the V1 and V3 volcanoes. We correlated the >1,500-m-thick Late Quaternary volcanoes of southern Gaeta Bay to the buried lava volcanoes interlayered with volcanoclastic deposits drilled at Campi Flegrei geothermal wells.

Very high-resolution seismic stratigraphy of Pleistocene eustatic minima markers as a tool to reconstruct the tectonic evolution of the northern Latium shelf (Tyrrhenian Sea, Italy)

This paper analyzes depth variations of seismically detected lowstand features (i.e., paleo–shelf break and lowstand submerged depositional terraces [LSDTs]), in order to define vertical movements along a continental margin. Narrowly spaced, high-resolution two-dimensional reflection seismic data were used, collected along a segment of the continental shelf of Latium (eastern Tyrrhenian Sea, Italy). Seismostratigraphic analysis allowed us to identify the six most-recent fourth-order depositional sequences formed in the past ∼500 k.y. They have a different degree of preservation in the outer and middle shelf, with almost no continuation in the inner shelf. Some wedge-shaped bodies interpreted as LSDTs can be identified in these units. The depth of paleo–shelf break and LSDTs of marine isotope stage 12 (ca. 435 ka) was measured, and gradually varies along the margin between ∼220 m and ∼131 m below current sea level. Differential subsidence rates have been estimated for the area, varying from 0 to −0.21 mm/a. The spatial variations agree with studies of uplifted coastal terraces on land, controlled by localized volcanic activity along the Latium section of the Tyrrhenian coast. The comparison of deformation onshore and offshore has proven to be a promising approach for understanding the evolution of uplifting continental margins.

Integrated stratigraphy for the Late Quaternary in the eastern Tyrrhenian Sea

A high-resolution integrated stratigraphy is presented for the Late Quaternary in the southern-eastern Tyrrhenian Sea. It is based on calcareous plankton taxa (planktonic foraminifera and nannoplankton) distribution, δ18OGlobigerinoidesruber record, tephrostratigraphy and radiometric dating methods (210Pb and 137Cs, AMS 14C) for a composite sediment core (from the top to the bottom, C90-1m, C90 and C836) from the continental shelf of the Salerno Gulf. High sedimentation rates from ca 1 cm/100 y for the early Holocene, to 3.45 cm/100 y for the middle Holocene to 8.78 cm/100 y from late Holocene and to 20 cm/100 y for the last 600 AD, make this area an ideal marine archive of secular paleoclimate changes. Quantitative distributional trend in planktonic foraminifera identify seven known (1F–7F) eco-biozones, and several auxiliary bioevents of high potential for Mediterranean biostratigraphic correlation. Recognised were: the acme distribution of Neogloboquadrina pachyderma r.c. between 10.800 ± 0.400 ka BP and 5.500 ± 0.347 ka BP, a strong increase in abundance of Globorotalia truncatulinoides r.c. and l.c. at 5.500 ± 0.347 ka BP and at 4.571 ± 0.96 ka BP, respectively, an acme interval of Globigerinoides quadrilobatus (between 3.702 ± 0.048 ka BP and 2.70 ± 0.048 ka BP) and the acme/paracme intervals of T. quinqueloba (acme between 3.350 ± 0.054 ka BP and 1.492 ± 0.016 ka BP; paracme between 1.492 ± 0.016 ka BP and 0.657 ± 0.025 ka BP; acme beginning 0.657 ± 0.025 ka BP).These results, integrated with trends of selected calcareous nannofossil species (Florisphaera profunda, Brarudosphaera bigelowii, Gephyrocapsa oceanica and Emiliania huxleyi) and δ18OG.ruber signature, are consistent with the most important pre-Holocene and early Holocene paleoclimatic and paleoceanographic phases i.e., the Bölling–Allerod, the Younger Dryas and the time interval of Sapropel S1 deposition in the eastern Mediterranean Sea. These features revealed the high potential of this shallow water environment for high-resolution stratigraphy and correlation for the western Mediterranean.In addition, the chemical characterization of seven tephra layers supplied further data about the age and the dispersal area of some well-known Campi Flegrei explosive events, inferring the possible occurrence of explosive activity at Vesuvius around the middle of the 6th century, and contributing to refine the tephrostratigraphic framework for the last 15 ka in the south-eastern Tyrrhenian Sea.

Maerl-bed mapping and carbonate quantification on submerged terraces offshore the Cilento peninsula (Tyrrhenian Sea, Italy)

On the continental shelf off the Cilento peninsula (eastern Tyrrhenian Sea) the occurrence of more than 13 km2 of maerl beds was documented through acoustic surveys. Swath bathymetric data along with a dense grid of chirp-sonar profiles were acquired over more than 180 km2. The maerl facies was characterized on the basis of the components analysis of 32 grab samples collected at selected sites. Mapped maerl-beds are predominant on submerged terraces located at variable water depth (wd) between 42 and 52 m. This preferred distribution on submerged terraces is probably associated with relatively vigorous bottom currents generated by local circulation that hinders the deposition of terrigenous sediments. Calcareous red algae result to be the most important producers of carbonates from 40 down to 60 m wd. We calculated the coralline carbonate accumulation from the percentage cover of coralline algae (thin section mapping) × 1 cm-thick layer of sediment × measured coralline density. The total coralline cover (living plus dead) in the Cilento area is 13.96 km2, with a total 316800 tons of algal carbonate in the surface 1 cm layer, that correspond to 20430 g m-2. Living maerl is recorded at a depth of 47 m, with a live coralline cover of about 40% over a minimum area of about 1.2 km2. This live maerl has a thickness of about 1 cm and is composed mainly of unattached branches of Lithothamnion corallioides (P.L.Crouan & H.M.Crouan) P.L.Crouan & H.M.Crouan, 1867. The molluscan association of the maerl bed is dominated by characteristic species of the Coastal Detritic Biocoenosis. The production of carbonate by living coralline algae has been calculated as weight of live corallines in 1 cm-thick layer × 100 y-1 × total area-1 and corresponds to 90.8 g m-2 y-1.