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Α sediment trap mooring has been deployed for one year (10/2007- 9/2008) at 1000 m water depth, in western Black Sea. The maximum coccosphere fluxes, with almost monospecific assemblage of Emiliania huxleyi, have been recorded during May and June. The seasonally controlled coccolithophore patterns are strongly related to those of sea surface temperature and accumulated rainfall in the area, triggering riverine nutrient input. Coccosphere fluxes in North Aegean Sea have been calculated from a sediment trap deployment at 500 m (1/2011-12/2011). E. huxleyi is the dominant species, followed by Syracosphaera pulchra, Rhabdosphaera clavigera as minor assemblage components. Maximum fluxes have been observed in between May-June. A single mooring with two sediment traps (500 and 1700 m) was deployed at the southern margin of the Cretan Sea (1/2001-2/2002) [1]. The results obtained from 500 m depth show that the highest productivity season was recorded from January till late September with the highest flux values observed between late March to late June. During this period the pattern was characterized by three main phases that correlate well with the gradual increase in SST from January till September. Coccosphere sinking assemblages were characterized by high abundances of E. huxleyi, followed by Florisphaera profunda, R. clavigera and Syracosphaera spp. Six moorings have been deployed at different sites along the south–west margin of Crete, providing a total of eight sediment-trap time series (6/2005- 5/2006) [2]. Maximum coccosphere fluxes were recorded in between March to June, featured by dominance of E. huxleyi and subordinate Helicosphaera carteri, Umbilicosphaera spp. and S. pulchra; intermediate fluxes from June to November, with high abundance of the deep photic zone species Algirosphaera robusta, F. profunda, Gladiolithus flabellatus; and low fluxes from November to February, with high flux of A. robusta, S. pulchra and Syracosphaera spp. These three periods correspond to the seasonal changes in sea surface temperature and surface mixed layer depth. Coccolithophore fluxes from the central part of the Ionian Sea have been studied from a sediment trap mooring (9/1999-6/2001) at 500 and 2800 m water depth [3]. Peak coccolithophore export production is observed in May, a secondary peak is observed in September-October. The assemblages is dominated year-round by the cosmopolitan species E. huxleyi, followed by the deep-dwelling F. profunda and by several minor species (Syracosphaera pulchra, R. clavigera, A. robusta, G. flabellatus, Calcidiscus leptoporus, Umbellosphaera tenuis and small Syracosphaera spp.) which are most abundant during the summer period of upper water column stratification. A high seasonal pattern characterizes the coccolithophore assemblages from all the investigated areas of eastern Mediterranean and Black seas. The export production and biogenic carbonate fluxes are strongly dependent on the nutrient influx, the vertical mixing and sea surface temperatures of the water column, in a north-south and east-west transient.

The recent exploration of the Mediterranean Ridge area has resulted in the discovery of some of the most extreme deep-sea environments, characterized by peculiar geochemical and physical condition. Tyro Basin was the first deep sea, hypersaline brinefilled, anoxic depression found. This and subsequent structures were named “hypersaline anoxic basins”, having total dissolved salts as high as 500 g/L and sulphide content upto 20 mM/L. The origin of these structures is morphologically connected to the compressive regime of the Mediterranean Ridge, due to the African plate subducting beneath Eurasia. The brine composition and physical characteristics are mainly due to the dissolution of underlying Messinian evaporites. The brines are characterized by the absence of oxygen, the presence of high concentrations of H2S and CH4, and by an extremely sharp seawater/brine interface, thus with a strong density contrast. This interface is a hotspot for a large variety of mostly redox-controled strong bacterial activity. In the last years, different projects have dealt with with the study of those basins. The work has focussed on the reconstruction of drastic composition changes of the water column, the evaluation of the anoxia trends and of the chemical elements concentration, and more recently, thanks to the technical innovations on seafloor mapping, to a progressively more accurate characterization of the shape and structure of the seabed. In the last three years, the Milan–Bicocca University has been responsible for geophysical data acquisition and analysis in the EU Moccha Project (Multidisciplinary study of continental/ocean climate dynamics using high-resolution records from the eastern Mediterranean), whose cruises (Doppio 2008, Macchiato 2009, Ristretto&Lungo 2010–11) allowed the collection of information (Multibeam Echosounder Simrad EM302) on several target areas at the Mediterranean Ridge. The processing and elaboration of the geophysical data allowed a highly detailed and extended morpho-bathymetric characterization of Urania, Atalante, Discovery, Bannock, Medee, Kryos, and Thetis anoxic basins. The coupling of new geophysical information with the biotechnological results of EU BIODEEP Project (Biotechnologies from the Deep: EU Community 2001–2004), also coordinated by Milan–Bicocca University, will be presented in this work as a first approach to a “Habitat Mapping” definition on the extreme anoxic basin environment, suggesting a methodology for subsequent studies on the same area.

The examined bathyal area, ranging from about 300 to 1100 m water depth, is located along the southern Apulian continental slope. It includes the so-called Cold-Water Coral (CWC) Mound Province of Santa Maria di Leuca and is characterized by three main physiographic domains: from east to west (1) a large mass-transport deposition area where mound-like features occur, (2) a prominent ridge covered by sparse debris deposits where drift sedimentation is documented, and (3) a series of narrow ridges and fault scarps that outline large erosive features (e.g., canyons). The analysis of videos, samples and acoustic facies from ten selected sites shows that both live and dead CWCs (mostly represented by the scleractinian species Madrepora oculata, Lophelia pertusa and Desmophyllum dianthus) occur in all three domains. In particular, video and sample analyses have allowed us to distinguish three main habitat groups (coral-, hardground- and muddominated habitats) which contain diverse subhabitats, generally grading into each other. By combining sample/video data with acoustic facies, we can assert that (a) extensive coral thickets, formed by dead and live colonies of M. oculata and L. pertusa, characterize the upper part of several mound-like structures of the eastern sector and, most probably, the top of elongated ridges from the western sector, (b) small-scale bioconstructions, dominated by the solitary gregarious species D. dianthus, preferentially occur along subvertical and overhanging walls of the western sector, (c) mud-dominated facies are spread on horizontal to gently sloping bottoms of all three sectors. Our study highlights a significant spatial heterogeneity of the bathyal benthic habitats from the southern Apulian slope. This seems to well reflect the complexity of variable geomorphic and/or hydrographic processes acting upon the slope. Moreover, remarkable variations of skeletonized faunal assemblages, observed along several sediment cores (from 30 to 150 cm long), reveal that benthic communities have been locally affected by recurrent short-term changes over time.

A quantitative study by means of multivariate analysis was carried out on molluscs yielded by 8 small cores, up to 40 cm long, recovered in 2010 (CoralFISH EU-FP7 Project) along the Apulian margin off Santa Maria di Leuca (S Italy), 525 to 784 m depth. The mainly silty seafloor of this area is characterized by mound-like and elongated topographic features (50–300 m wide and up to 25 m high) whose upper part is generally olonized by cold-water coral communities. Shells were picked from 31 core levels and then identified – when possible – to species, revealing a diverse fauna including 79 benthic taxa (37 Bivalvia, 3 Scaphopoda, 39 Gastropoda) out of 112 recognized in the area by sorting 24 contextually recovered box-corer samples. The dominant taxon is the small infaunal bivalve Kelliella miliaris; among other relevant elements, Abra ongicallus, Notolimea crassa and Alvania cimicoides are also mud-related, while Heteranomia squamula, Delectopecten vitreus, Asperarca nodulosa and Bathyarca pectunculoides thrive on hard substrates. The multivariate analysis (clustering, MDS) was conducted on a 79 species x 29 samples abundance matrix, defining three groups (A to C); they were analyzed in terms of the dominance and similarity contributions of species and proved to belong to different habitats as regards bottom type and relationships with corals. A and B are quite homogeneous; the former is restricted to coral mound tops and appears to be related to coral branches or rubble, while the latter is found both in inter-mound areas and on the mound upper flanks and links to a frankly muddy seafloor. Conversely, group C is heterogeneous and interpreted as transitional; the MDS dispersion of its levels led to perform a second step analysis on a reduced matrix. This revealed at least three different transitional stages (C2 to C4) between coral rubble and mud habitats. C3, found at or near mound tops just below mud-related faunas, appears closer to group A; C4, mostly epresented at the NE base of mounds, is more similar to B; C2 occurs quite randomly and includes a mixed fauna. The mollusc groups and stages studied herein match quite well with both macrohabitats and thanatofacies recognized in the area by means of bottom samples and submarine video surveys (APLABES Project, HERMES Project).

In this work we present the results from a time series of sediment trap moorings located at 500 m in the pelagic Ionian Sea, focusing in particular on the biogenic calcareous and siliceous component. We quantify the fluxes of coccolithophores and diatoms, identifying a seasonal succession in the assemblage composition, as related to the environmental conditions. Introduction The understanding of present-day biogenic fluxes is of key importance in providing information on how the ecological signal is transferred from the surface waters to the sediment archives, in order to interpret paleofluxes. In the oligotrophic eastern Mediterranean, coccolithophores are known to play a major role as primary producers, while diatoms are subordinate, also due to the significant silica-undersaturation of the basin. Therefore, while there are some previous data on the present-day fluxes of coccolithophores at several locations in the basin [1, 2, 3], there are only a few data on diatom fluxes [4,5] and no detailed information on their specific assemblage composition in the sinking fluxes. We investigated the fluxes of coccolithophores and diatoms along three yearly intervals of a 7-year-long sediment trap deployment above Urania basin (35°13’N, 21°30’E) in the Ionian Sea, aiming at assessing the seasonality and interannual variability of the sinking biogenic fluxes. Methodology Sediment traps are PPS5/2, with 1 m aperture and 24 collection vials. Each mooring was deployed for approximately one year, resulting in a sample resolution of 10 to 15 days. Coccolithophores and diatoms were analyzed on sub-samples (1/800-1/8000 and 1/40 respectively) processed following standard methods [6,7 respectively] and expressed as number per square meter per day. Results and Discussion Preservation of both coccolithophores (coccoliths and coccospheres) and diatoms was very good at all samples. The presence of delicate species (holococcolithophores, Discosphaera tubifera among coccolithophores and weakly silicified taxa among diatoms) indicates that no dissolution occurred during either sedimentation through the water column, or sample storage and processing. Overall, the assemblages recovered at our sediment-trap site are typical of subtropical areas of the world’s oceans. In fact coccolithophore species are those typically found in assemblages from subtropical and temperate settings, dominated by the cosmopolitan Emiliania huxleyi. Diatoms are ~70% tropicalsubtropical species, with a minor contribution from subtropical-temperate and temperate taxa and a very slight contribution from cold-water species. During the first year of observation (1999-2000), the total flux of coccolithophores and diatoms was maximum in late summer-fall, along with the total particle flux, decreased during the whole winter period and increased again in late spring. The combined fluxes of coccolithophores and diatoms allowed to identify three main periods within the annual cycle, characterized by different assemblage composition: a) late summer-fall period, characterized by highest coccolithophore species diversity, consisting of both surface oligotrophic and deep-dwelling taxa and warm water diatom taxa dominated by Nitzschia interruptestriata and Thalassionema bacillare; b) late fall-winter period, characterized by lower coccolithophore diversity, dominated by the cosmopolitan E. huxleyi and the deep-dwelling Florisphaera profunda and by the increase of cooler-water diatom taxa; c) spring period, characterized by highest relative abundance of E. huxleyi and decrease of F. profunda within coccolithophores and by an increase in abundance of major and minor diatom taxa. A similar seasonal pattern was identified in coccolithophore assemblage composition in the following years, although the pattern of total particle and coccolithophore flux was different. In fact maxima occurred either in late spring to summer (2000-2001) or in early spring to late spring (2005-2006). Nonetheless, the main changes in the relative abundance of the different coccolithophore species occurred in the same intervals. Diatom assemblages in these series are still under study. Overall, the variations identified in the coccolithophore and diatom fluxes in the investigated three-year time series testify the seasonal changes in surface water conditions, including the sea surface temperature cycle and the presence of stratification in the upper layers. The seasonal cycle of water column mixing and stratification results in fact in the development of a different production depth within the water column, with the increase of surface oligotrophic species from summer to fall, the prolonged persistence of a deep chlorophyll maximum from summer to late winter and a clear dominance of the most abundant r-selected species during periods of more extended water column mixing

The present work reports the main results obtained from recent seafloor-mapping activities carried out offshore from south-western Albania. The area explored consists of two distinctive physiographic units: the Vlora Gulf (which is bounded to the west by the Karaburun Peninsula) and the upper continental slope offshore from the western side of the Karaburun Peninsula. Along these areas, 500 km 2 of multibeam echo-sounder coverage, about 2500 km of chirp-sonar data, and 200 km 2 of side-scan sonar mosaic (100-500 kHz) were acquired. This new acoustic data set was collected by two different oceanographic expeditions, which were carried out in the framework of the Centro Internazionale di Scienze del Mare (CISM) project (supported by Interreg III Italia-Albania), which focused on studying, through a multidisciplinary approach, the geological setting and the ecosystem conditions of a poorly investigated area of the Adriatic Sea, such as the Vlora Gulf. The investigated area incorporates water depths measurements from 5 m down to 57 m, whereas the offshore margin of the Karaburun Peninsula has been investigated down to 900 m water depth. The acquired high-resolution multibeam bathymetry, combined with the described chirp-sonar echo-types, documents how the recent evolution of the Vlora Gulf is strictly dependent on complex, sedimentary dynamics established in this area. Here, the Vjose River is the dominant source of sediment for the continental shelf. We provided evidences that the (Vjose River) sediment distribution is under the control of a complex, local circulation pattern that is defined by the peculiar regional shape of the gulf which is tectonically controlled. The tectonic control on the present-day, sedimentary processes is also evident offshore from the Karaburun Peninsula, along the upper slope, where important resedimentation processes have been recognized and are related to the recent geodynamic evolution of the margin. © 2011 Coastal Education and Research Foundation.

The "Santa Maria di Leuca" Cold-Water Coral (CWC) province (northern Ionian Sea) was investigated for the first time to detect eventual occurrence of methane anomalies as a possible indication of hydrocarbon seepage stimulating the coral growth. Most coral mounds have developed in correspondence with tectonic scarps and faults, orthogonal to the southern margin and trending NWSE, which could be potential sites of gas escape. A visual and instrumental inspection was performed by using a new deep-sea probe equipped with video-cameras, sonar. CTD, methane sensors, and a water sampler. Eight areas were explored by 10 surveys, depths ranging from 380 to 1100 m, for a total of more than 26 h of continuous video and instrumental recording. Sediments were also sampled by gravity corers and analysed in laboratory.The images allowed to assess distribution, abundance and geometry of the colonies, most of which are developed on morphological highs often characterised by tectonic scarps. All data indicate however the lack of a significant occurrence of methane, both in seawater and sediments. No direct or indirect expressions of gas seepage were recognised on the seabed. Weak methane anomalies were detected only in seawater at the base of some fault-linked scarps, where more reducing conditions and bacterial methanogenesis are possibly enhanced by less water circulation. The faults are not fluid-bearing as previously suggested by high-resolution geophysical signatures. The development of the coral colonies thus cannot be attributed to seeping fluids, but to a favourable physiographic position with exposure to nutrient-rich currents. (C) 2009 Elsevier Ltd. All rights reserved.

Thanatofacies and the skeletonized components of the living facies, from which they originate have been studied from the Santa Maria di Leuca (SML) deep-water coral mound province. Faunal analysis was carried out by means of bottom sampling and underwater video observations, taking into account all benthic taxonomic groups, mostly corals, molluscs, serpulids, bryozoans, ostracods, foraminifers and barnacles, which permitted recognition of six different facies. These thanatofacies are easily distinguishable and appear to be largely corresponding and overlapping with related living facies. Some occur in mound areas, others in the intermound ones. They are as follows: the Framework-building Coral facies (FC), characterised by colonial corals, mostly Madrepora oculata; the Coral Rubble facies (CR), with proximal and distal aspects, characterised by large- to small-sized and densely to loosely packed coral fragments; the Solitary Coral facies (SC), dominated by different species depending on the availability and dimensions of hard exploitable surfaces; the Gryphus and Isidella facies (GI) in relatively coarse-grained bottoms; the Mollusc Mud facies (MM) and the Foraminifer Mud facies (FM) in comparably homogeneous silty bottoms. Facies distribution and spatial variability are discussed, in relation to hydrology and sea-floor topography. Furthermore, the SML facies are compared with living facies from the present-day Mediterranean and Pleistocene sediments of the same area. Data on bioclastic assemblages can serve for comparison with other recent aphotic, non-tropical carbonates. © 2009 Elsevier Ltd. All rights reserved.

A significant example of technological spin-off from the GEOSTAR project is represented by the special-purpose instrumented module, based on the deep-sea ROV MODUS, which was developed in the framework of the EU-sponsored project BIODEEP. The goal to be achieved has been defined as the exploration, through real-time video images, measurements and accurate video-guided sampling, of the deep hypersaline anoxic basins of the eastern Mediterranean Sea at water depths well exceeding 3000 meters. Due to their peculiar characteristics, these basins are one of the most extreme environments on Earth and represent a site of utmost interest for their geochemical and microbial resources. The paper presents the strategies and the main results achieved during the two cruises carried out within the BIODEEP project.

Urania basin in the deep Mediterranean Sea houses a lake that is >100 m deep, devoid of oxygen, 6 times more saline than seawater, and has very high levels of methane and particularly sulfide (up to 16 mM), making it among the most sulfidic water bodies on Earth. Along the depth profile there are 2 chemoclines, a steep one with the overlying oxic seawater, and another between anoxic brines of different density, where gradients of salinity, electron donors and acceptors occur. To identify and differentiate the microbes and processes contributing to the turnover of organic matter and sulfide along the water column, these chemoclines were sampled at a high resolution. Bacterial cell numbers increased up to a hundredfold in the chemoclines as a consequence of elevated nutrient availability, with higher numbers in the upper interface where redox gradient was steeper. Bacterial and archaeal communities, analyzed by DNA fingerprinting, 16S rRNA gene libraries, activity measurements, and cultivation, were highly stratified and metabolically more active along the chemoclines compared with seawater or the uniformly hypersaline brines. Detailed analysis of 16S rRNA gene sequences revealed that in both chemoclines δ- and ε-Proteobacteria, predominantly sulfate reducers and sulfur oxidizers, respectively, were the dominant bacteria. In the deepest layers of the basin MSBL1, putatively responsible for methanogenesis, dominated among archaea. The data suggest that the complex microbial community is adapted to the basin's extreme chemistry, and the elevated biomass is driven largely by sulfur cycling and methanogenesis.

Between 140 and 170 m water depth, more than 100 small-scale domes and peculiar ridges were mapped a few miles offshore of south-eastern Sicily along the Malta plateau (eastern Mediterranean Sea), Swath bathymetric data along with a dense grid of side scan sonar and seismic profiles were acquired in an area extending over 100 km 2 . Gravity cores, water samples and video observations were also collected at selected sites. Mapped domes were found from 50 to 200 m wide and no more than 5 m high occurring on the seafloor, isolated or arranged in clusters. Ridges consisted of large tabular sub-elongated structures, elevated from 5 to 10 m from the surrounding seafloor, and had flat tops on which numerous close-set, small cones occurred, appearing in video observation as carbonate buildings strongly colonized by gorgonians. Characteristic acoustic signatures (i.e. blank areas and/or turbidity zones and enhanced reflections in seismic records), measured gas anomalies in seawater samples and detected plumes on echosounder profiles suggest that both the domes and ridges are influenced by active seeps. In addition, their spatial distribution reflected patterns of tectonic lineaments produced by the late Miocene to present-day geo-dynamic evolution of the Malta plateau, which is also an important hydrocarbon province. Results from gravity cores suggest that mud extrusion seems to be the main process responsible for the origin of the domes, which are formed by gray mud with only a few centimeters of biogenic sand at the top, indicating that recent bioclastic material is not a major contributor to mound building. However, at present, active degassing appears to be the main process that controls the morphological and sedimentological expression of both the domes and ridges. Therefore, a quiescent or intermittent active stage for mud extrusion is considered.

Organic-rich sedimentary units called sapropels have formed repeatedly in the eastern Mediterranean Sea, in response to variations of solar radiation. Sapropel formation is due to a change either in the flux of organic matter to the sea floor from productivity changes or in preservation by bottom-water oxygen levels. However, the relative importance of surface-ocean productivity versus deep-water preservation for the formation of these organic-rich shale beds is still being debated, and conflicting interpretations are often invoked. Here we analyse at high resolution the differences in the composition of the most recent sapropel, S1, in a suite of cores covering the entire eastern Mediterranean basin. We demonstrate that during the 4,000 years of sapropel formation, surface-water salinity was reduced and the deep eastern Mediterranean Sea, below 1,800 m depth, was devoid of oxygen. This resulted in the preferential basin-wide preservation of sapropel S1 with different characteristics above and below 1,800 m depth as a result of different redox conditions. We conclude that climate-induced stratification of the ocean may therefore contribute to enhanced preservation of organic matter in sapropels and potentially also in black shales. © 2008 Macmillan Publishers Limited.

Coastline migration significantly affects the evolution of marine and continental environments. Tracing sea-level changes that have occurred in the past can be achieved using evidence from marine benthic associations of fossil molluscs. This paper outlines a strategy for documenting recent molluscan benthic assemblages in order to detect abrupt or gradual variations in their depositional succession that could reflect changes in the land-sea relationship. Characteristics of molluscan fossil assemblages are reviewed and an example of such an analysis is offered from research conducted in Iskenderun Bay in the northeastern Mediterranean Sea. © 2007 Springer.

he relative and absolute abundances and accumulation rates of forarninifera and calcareous nannofossils were quantified in a box core containing sapropel S I from the Florence Rise area (SE of Cyprus; 2302 m water depth). The main objective of this study was to reconstruct in detail variations in paleoecological conditions of water masses during the deposition of this sapropel. In particular, we qualitatively evaluated the importance of carbonate dissolution on planktonic assemblages to better interpret the abundance profiles obtained from the two investigated taxa. Selective carbonate corrosion in the core is shown by (1) the decrease in shell mass weight of selected species of planktonic foraminifera, (2) the decrease in accumulation rate of dissolution-susceptible holococcoliths and coccolith species, and (3) the absence of pteropods. However, the presence of other relatively dissolution-susceptible coccolith species throughout all of the S I interval suggests moderate dissolution. Florisphaera profunda shows a marked increase in paleofluxes within the sapropel coupled with a decrease in the accumulation rate of the upper-middle photic zone coccoliths, suggesting an ecological depth-separation of the water column, probably characterised by higher nutrient availability at depth and nutrient-depleted surface waters between similar to 10 and 6.5 kyr BR In the same interval Turborotalita quinqueloba and Globigerina bulloides, two formaniniferal species frequently occurring during periods of high fertility, increase in relative abundance. The maximum increase in relative abundance of Globigerinoides ruber (var. alba and rosea) marks the climatic optimum phase and the maximum stratification in surface water that occurred at the beginning of sapropel S1 deposition when the bottom waters were anoxic. An important change in foraminiferal assemblages occurs at similar to 8 kyr BP and corresponds with a negative shift in CaCO3, Ba and C-org contents. This short interval marks the establishment of relatively less anoxic conditions in the bottom water, introducing the last phase of sapropel formation. After similar to 6.5 kyr BP, a progressive re-establishment of normal oceanographic conditions occurred before the real end of the sapropel S1. This transition is well recorded by the reoccurrence and major accumulation rate of the mixing indicator foraminiferal species Globorotalia inflata and by the gradual decrease in abundance of F profunda. (c) 2005 Elsevier B.V. All rights reserved.

Detailed study of the temporal and spatial patterns of planktonic foraminiferal assemblages was performed on seven eastern Mediterranean deep-sea cores to evaluate differences and similarities in their stratigraphic records during the Eemian sapropel S5 interval. Changes in the succession of planktonic assemblages are very similar in all investigated sapropel S5 sequences. Analyses carried out on the 63 and 150 mu m size fractions indicate that during this time interval, size does not significantly affect the stratigraphic patterns. Benthic assemblages were studied at three sites, where their succession of changes was concordant but locally different. In this framework, comparison of S5 sapropels layers from different areas of the eastern Mediterranean suggests that the onset of the dark colour does not occur in the same stratigraphic position at a regional scale, whereas the absence/drastic reduction of benthic foraminifera within sapropel intervals appears to be a "time equivalent" event and corresponds to the last local occurrence of Globorotalia inflata. (c) 2005 Elsevier B.V. All rights reserved.

Cool to periglacial conditions, accompanied by a sea-level drop, are thought to result in an unchanged composition and ecological meaning of the rhodalgal carbonates, which occur frequently in the present-day, current-swept areas of the Mediterranean upper shelf. Form, internal structure and species composition of rhodoliths are believed to reflect the environmental conditions present in their biotope. To test these hypotheses, the relationship between rhodolith facies and sea-level rise was investigated in four cores recovered at the Pontian Islands (Tyrrhenian Sea) shelf break. The core basal intervals have been AMS radiocarbon dated, providing uncalibrated ages ranging from 10 040 +/- 50 years BP to 10 380 +/- 50 years BP. All four cores show a transition from basal rhodolith-rich, biodetritic, muddy-gravelly sand to rhodolith-barren, silty sand or sandy mud, along a deepening-upward succession. A facies of coral line-coated fragments of bryozoan colonies has been identified above the rhodolith facies as the deepest coralline growth form in all cores, before the final burial. Molluscan associations and rhodolith abundance, morphology and composition are ecologically compatible with the embedding sediment and testify the transition from the late Pleistocene circalittoral coastal detritic or shelf-edge detritic assemblages at the base of cores, up to the present-day bathyal muds. In the late Pleistocene and Holocene, as at present, the Pantine shelf was characterized by a low sedimentary input under moderate current action, fostering deep coralline growth.

Summary Viral and prokaryote abundance were investigated in a deep-hypersaline anoxic basin of the Eastern Mediterranean Sea (DHAB Atalante basin at c. 3000 m depth). This system was compared with two nearby deep-sea sites characterized by oxic conditions. Viral abundance and virus to prokaryote abundance ratio in hypersaline anoxic sediments displayed values close to those reported in oxic sites. The analysis of vertical profiles of viral abundance in the Atalante basin revealed the lack of significant changes with depth in the sediment, suggesting that benthic viruses in these anoxic and hypersaline conditions are preserved or resistant to decay. The anoxic basin displayed also very high concentrations of labile organic components (proteins and lipids) and extracellular DNA. These findings suggest that the DHAB sediments represent a reservoir for long-term preservation of benthic viruses and nucleic acids.

Deep hypersaline anoxic basins in the Mediterranean Sea are a legacy of dissolution of ancient subterranean salt deposits from the Miocene period. Our study revealed that these hypersaline basins are not biogeochemical dead ends, but support in situ sulfate reduction, methanogenesis, and heterotrophic activity. A wide diversity of prokaryotes was observed, including a new, abundant, deeply branching order within the Euryarchaeota . Furthermore, we demonstrated the presence of a unique, metabolically active microbial community in the Discovery basin, which is one of the most extreme terrestrial saline environments known, as it is almost saturated with MgCl 2 (5 M).

The fluxes and budget of organic matter from the oligotrophic surface waters of the eastern Mediterranean to the deep waters are poorly known, and little information is available on past and present macrobenthic activity on the sea floor. Evidence of macrobenthic activity can be direct, through recovery of living organisms or their autochthonous skeletal remains, or indirect, through bioturbation and trace fossils. The evidence of biological activity in deep eastern Mediterranean sediments has been evaluated and compared through 210Pb profiles from box-cores and study of dredge samples from sites on Medina Rise (1374 m water depth), the Messina Abyssal Plain (4135 m) and several sites along the Mediterranean Ridge, SW and S of Crete (1783 to 3655 m). All these sites are remote from the continental shelves, so the biological benthic activity is expected to depend primarily on primary production from surface waters. The results show that present-day macrobenthos and trace fossils are generally scarce, especially at depths > 2500 m. This observation is supported by surface sediment 210Pb excess distributions that show a surface mixed layer (SML) 2500 m. The historical layer of some box-cores and the Pleistocene hardgrounds collected in the Cleft area (Mediterranean Ridge) do, however, record a macrobenthic activity that is apparently more intense than at present, which may be related to higher primary production of the Pleistocene glacial intervals. In contrast with most areas of the present-day deep eastern Mediterranean which depend on surface primary production based on photosynthesis, a relatively dense and diversified macrobenthic community based on chemosynthesis has been recognised at depths > 1100 m on the Napoli Dome mud volcano in the Olimpi area, and on the Kazan and other mud volcanoes in the Anaximander Mountains. En el Mediterráneo oriental los flujos de materia orgánica desde las aguas superficiales oligotróficas hasta las aguas profundas son poco conocidos y en general hay poca información sobre la actividad del macrobentos en el fondo del mar. La evidencia de la actividad macrobentónica puede ser directa, a través de los organismos vivos o de los restos de esqueletos autóctonos, o inidrecta, a través d ela bioturbación y fósiles. La evidencia de la actividad biológica en los sedimentos profundos del mediterráneo Oriental se ha evaluado y comparado por medio de los perfiles del 210Pb provenientes de muestreos con box-corer y dragas tomados en varios puntos del dorsal mediterráneo, al SO y S de Creta (entre 1783 y 3655 m). Se espera que la actividad biológica de estos fondos alejados de la plataforma continental dependa principalmente de la producción primaria de las aguas superficiales. Los resultados muestran que el macrobentos actual y los fósiles son generalmente escasos, especialmente en fondos superiores a los 2500 m. Estas observaciones se basan en la distribución del exceso de 210Pb que se ha encontrado en la capa superficial de mezcla del sedimento, inferior a 6 cm de grosor, en los cores de aguas inferiores a 2500 m; y de solo 2-3 cm a mayor profundida. Estos valores son mucho más bajos que la media de la capa supqerfical de mezcla de unos 10 cm en los sedimentos marinos de otras zonas. Es probable que la producción primaria actual en el Mediterráneo oriental no pueda soportar ninguna actividad macrobentónica estructurada a más de 2500 m. la capa histórica en algunos box-corer de los fondos duros del Pleistoceno muestreados en el áreade Cleft registran, sin embargo, una catividad macrobentónica aparentemente más inyensa que la actual, y que podría relacionarse con una producción primaria alta durante los intervalos interglaciales del Pleistoceno. Contrariamente a lo encontrado en la mayoría de las áreas actuales en el mediterráneo oriental profundo, el cual depende de la producción primaria superficial basada en la fotosíntesis, en le volcán fangoso de Napoli Dome en el área de Olimpi, en el Kazan y otros volcanes fangosos de las montañas Anaximader, se ha encontrado una comunidad macrobentónica relativamente densa y diversificada basada en procesos quimiosintéticos.

Several geochemical and micropaleontological proxies were studied in a well developed sapropel S5 from a core collected south of Crete to investigate the causes and the mechanisms of its deposition, to reconstruct the paleoenvironmental and paleoceanographical conditions at time of its formation and to detect the roles played by productivity and anoxia. The geochemical proxies are also used to unravel the sediment provenance and therefore to help tracing water circulation patterns and freshwater sources. The multiproxy approach reveals that the sapropel layer has high internal variability and five different depositional phases can be identified, four within the visible sapropel layer. An increase in temperature and the development of a Deep Chlorophyll Maximum characterise the onset of the sapropel (phase 1), with enhanced productivity being favoured by local riverine input, not clearly ascribable to Nile river freshwater discharge, and by the shoaling of the pycnocline/nutricline. Surface water stratification and productivity develop, together with strong seafloor dysoxia/anoxia. Phase 2 is characterised by lower stratification, slightly lower temperature and/or higher seasonal contrast, and still high productivity. Phase 3 records high productivity, high temperature and high stratification, probably more sustained by the Nile input. A sudden partial re-oxygenation takes place at the end of this phase, changing the main features of the sapropel. In the fourth phase, productivity starts to decrease, water stratification seems to be partially broken down and sediment oxygenation increases. A transitional phase (phase 5) occurs between the end of the visible sapropel and the normal pelagic post-sapropel sedimentation, where productivity is still high and oxygenation improves compared to the visible sapropel layer. The massive occurrence of Polysphaeridium zoharyi, cyst of a red tide forming dinoflagellate, also characterises this phase. The geochemical proxies indicate that pre-sapropel and post-sapropel sediments are quite different from each other, and the provenance shifts from a more mixed to a more markedly southern origin of sediments.

The distribution of coccolithophorid assemblages is analyzed from water samples collected in the photic zone of the middle Ionian Sea during a cruise of R/V Urania in November-December 1997. Coccolithophorids are an important phytoplankton group in the oligotrophic eastern Mediterranean, and their coccoliths make an important contribution to the sediments of this area, being also widely used for paleoclimatic and paleoceanographic reconstructions. Nevertheless, studies on extant coccolithophorids ecology and distribution in the eastern Mediterranean are limited and mostly related to surface waters: this study, even if restricted to a single period of the year, provides the first detailed analysis of species distribution throughout the photic zone, with relation to the main local physicochemical parameters. During the investigated period, the area is characterized by the presence of a surface mixed layer, reaching a depth of 25 to 90 m. Below this layer, a marked thermo- and halocline is developed. Coccolithophorids are the dominant phytoplankton group in the investigated samples and reach concentrations up to 2 x 10(4) coccospheres per liter of seawater. The species assemblage is that typical of the subtropical latitude, with a general high species diversity and a well-defined depth distribution. It is in fact possible to recognize an upper photic zone assemblage, dominated by E. huxleyi and characterized by higher concentration and species diversity and a lower photic zone where typically deep-living species (i.e., F. profunda, G. flabellatus) are present. These two zones are separated by a transition layer, where species of both zones are represented and new ones appear. Such vertical distribution appears to be strictly related to the local hydrology, with the zone boundaries rising and falling as a function of the location of the isotherms. In particular the first significant occurrence of F. profunda from surface to the deep photic zone corresponds with the start of the thermocline. Comparison of present plankton data with the surface sediment record, although displaying a consistent pattern of species assemblage, shows some differences in the presence and relative abundance of some species (G. oceanica): this can be related to seasonal as well as interannual variations in the pattern and intensity of surface circulation in the investigated area.

In 1968 hot brines from which gypsum had precipitated were discovered in the Red Sea, in a divergent plate boundary setting with hydrothermal activity1. We now report the discovery of cold brines in an entirely different geodynamic situation, a convergent plate boundary in the eastern Mediterranean, where the heatflow is very low2 and no hydrothermal activity occurs. Decimetric pure gypsum crystals precipitate from the cold brines, which occupy the bottom of a rimmed anoxic basin near the southern edge of the Mediterranean Ridge, close to the Sirte Abyssal Plain. Nucleation of the crystals does not occur at the surface, but from the deep brines, because the salinity of the water is normal down to the depth of -3,000 m. We propose the name 'Bacino Bannock' for this basin, after the Consiglio Nazionale delle Ricerche R/V Bannock from which the bottom-water brines were surveyed and sampled. © 1985 Nature Publishing Group.

Relationships between autochthonous and allochthonous species in different death assemblages of shelf environment, both recent and fossil, are discussed on the grounds of their relative abundances. The percentages, plotted against the sedimentary features (grain size distribution primarily) of the biotopes, exhibit significant variations which seem to be useful in the reconstruction of some physical characters of the paleoenvironments, like depth, wave motion and bottom currents. -English summary

Background: Extracellular dissolved DNA has been demonstrated to be present in many terrestrial and aquatic environments, actively secreted, or released by decaying cells. Free DNA has the genetic potential to be acquired by living competent cells by horizontal gene transfer mediated by natural transformation. The aim of this work is to study the persistence of extracellular DNA and its biological transforming activity in extreme environments like the deep hypersaline anoxic lakes of the Mediterranean Sea. The brine lakes are separated from the upper seawater by a steep chemocline inhabited by stratified prokaryotic networks, where cells sinking through the depth profile encounter increasing salinity values and osmotic stress. Results: Seven strains belonging to different taxonomic groups isolated from the seawater-brine interface of four hypersaline lakes were grown at medium salinity and then incubated in the brines. The osmotic stress induced the death of all the inoculated cells in variable time periods, between 2 hours and 144 days, depending on the type of brine rather than the taxonomic group of the strains, i.e. Bacillaceae or gamma-proteobacteria. The Discovery lake confirmed to be the most aggressive environment toward living cells. In all the brines and in deep seawater dissolved plasmid DNA was substantially preserved for a period of 32 days in axenic conditions. L'Atalante and Bannock brines induced a decrease of the supercoiled form up to 70 and 40% respectively; in the other brines only minor changes in plasmid conformation were observed. Plasmid DNA after incubation in the brines maintained the capacity to transform naturally competent cells of Acinetobacter baylii strain BD413. Conclusion: Free dissolved DNA is likely to be released by the lysis of cells induced by osmotic stress in the deep hypersaline anoxic lakes. Naked DNA was demonstrated to be preserved and biologically active in these extreme environments, and hence could constitute a genetic reservoir of traits acquirable by horizontal gene transfer.