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We present the results of dynamic modeling of the western Mediterranean that accounts for observed global positioning system (GPS) surface deformation of the Alboran Sea and surrounding Rif and Betic Mountains as the result of the combined effects of relative motion of the Eurasian and Nubian plates, low strength in the Alboran Sea region and sub-lithospheric processes occurring beneath the External Rif domain. Assuming that the lithosphere behaves elastically over the short time period of the GPS observations, an elastic plate model is considered in our study, including an area of weak lithosphere (factor of 10) centered on the Alboran Sea and in which lateral boundary conditions consist of the Nubia-Eurasia oblique convergence. Sub-crustal processes are modeled by application of a horizontal traction on a small area (patch) at the base of the elastic plate. Our modeling studies demonstrate the need for sub-crustal or sub-lithospheric, southwestward-directed forcing to account for observed southwestward motion of the Rif and Betic domains. Based on the location, orientation, and small area of the traction patch, we hypothesize that forcing is associated with delamination and rollback of the subducted African continental lithospheric mantle beneath the External Rif zone, due to the pull of the oceanic part of the Western Mediterranean slab, a dynamic process that may be similar to that where the over-riding plate is driven toward the subduction zone during slab rollback. doi: 10.1130/G30963.1

The Mediterranean Sea became disconnected from the world's oceans and mostly desiccated by evaporation about 5.6 million years ago during the Messinian salinity crisis (1-3). The Atlantic waters found a way through the present Gibraltar Strait and rapidly refilled the Mediterranean 5.33 million years ago in an event known as the Zanclean flood (4). The nature, abruptness and evolution of this flood remain poorly constrained (4-6). Borehole and seismic data show incisions over 250 m deep on both sides of the Gibraltar Strait that have previously been attributed to fluvial erosion during the desiccation (4,7). Here we show the continuity of this 200-km-long channel across the strait and explain its morphology as the result of erosion by the flooding waters, adopting an incision model validated in mountain rivers. This model in turn allows us to estimate the duration of the flood. Although the available data are limited, our findings suggest that the feedback between water flow and incision in the early stages of flooding imply discharges of about [10.sup.8] [m.sup.3] [s.sup.-1] (three orders of magnitude larger than the present Amazon River) and incision rates above 0.4 m per day. Although the flood started at low water discharges that may have lasted for up to several thousand years, our results suggest that 90 per cent of the water was transferred in a short period ranging from a few months to two years. This extremely abrupt flood may have involved peak rates of sea level rise in the Mediterranean of more than ten metres per day., The main evidence for a kilometre-scale sea level drop in the Mediterranean is the excavation of canyons by the rivers flowing to the empty sea during the Messinian stage, up [...]

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 [delta]- and [epsilon]-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. deep anoxic hypersaline lake | element cycling | geosphere--biosphere interaction | Mediterranean Sea | microbial diversity

Strait uplift due to isostasy played a pivotal role in the development and maintenance of a desiccated Mediterranean basin during the Late Miocene Messinian salinity crisis. New threedimensional flexure models for the western Mediterranean suggest that most of the giant evaporite body was deposited before sea-level lowering. Any mechanism that subsequently caused a Mediterranean sea-level lowering by a few hundred meters during several thousand years sufficed to cause isostatic uplift and closure of the gateways, thus choking the Mediterranean to desiccation. Due to this isostatic feedback, multiple desiccation and reflooding phases driven by Milankovitch cycles are unlikely. When the Atlantic connection had been lost and sea level had dropped, a sizeable regional uplift of the Strait of Gibraltar developed that presented a formidable obstacle to reflooding. Rollback and steepening of the Gibraltar slab may have played a key role at the end of the Miocene by dynamically lowering the sill region, thus reinstating the oceanic connection.

Detailed sedimentological analyses of diamicton sequences in two areas of the Pindus Mountains, Greece, indicate multiple episodes of glacier advance and retreat during cold stages of the Middle-Pleistocene. These glacial sequences represent some of the most southerly in Europe and are important archives of regional and global climate change. The Pindus glaciers were relatively small by world standards and would have been highly responsive to changes in air temperature and precipitation. On Mount Tymphi, at least three phases of glacier advance are recorded within deposits assigned to the Skamnellian Stage (MIS 12). Further north on Mount Smolikas, a thick multiple diamicton sequence records evidence for multiple glacier advances during both the Skamnellian Stage and the Vlasian Stage (MIS 6). These records highlight the dynamic nature of glacier behaviour in the Mediterranean mountains during the Middle Pleistocene and provide new evidence for unstable cold stage climates.

Seafloor backscatter data are used to image the product of one of the youngest major mass-wasting events in the northwestern Mediterranean Sea: a 26 [km.sup.3] debris-flow deposit that covers 2000 [km.sup.2] of the Ebro continental slope and base of slope, offshore Spain. Backscatter images provide unprecedented insights on debris-flow dynamics in the deep sea. A pattern of low-backscatter patches represents large sediment blocks that moved while keeping their internal coherence. High-backscatter alignments restricted to topographic lows that represent coarse sediment pathways separate the blocks. The results presented prove the occurrence of large catastrophic sediment failures near heavily populated coastal areas even in continental margins considered to be geodynamically quiet, such as those of the northwestern Mediterranean. Keywords: debris flow, continental slope, seafloor imagery, western Mediterranean.

Nematode assemblage composition, trophic structure and biodiversity were followed over an annual cycle in a Posidonia oceanica bed of the NW Mediterranean to test the response to temporally changing food availability (sediment organic matter, bacterial and microphytobenthic biomass). The sediment-water interface of the seagrass meadow was characterised by high particulate organic matter concentrations. Also, seagrass sediments had high organic matter content, chloropigment concentrations and bacterial biomass. All organic matter components (i.e. carbohydrates, proteins and lipids) changed temporally, with higher concentrations in winter and spring and lower concentrations in summer; however, overall, large amounts of organic compounds were potentially available for (seagrass) benthic consumers throughout the year. Nematode assemblage in the P. oceanica bed maintained a high genus number (88 genera), and atrophic structure tightly coupled with the composition of the potential food sources. In agreement with the relevance of microphytobenthos, epigrowth-feeder nematodes (2A) represented the dominant trophic guild. The biomass of predator nematodes (2B) was significantly correlated with the biomass of other nematodes. Non-selective deposit feeders (1B) displayed a close relationship with the concentration of proteins, carbohydrates and biopolymeric carbon (i.e. labile organic detritus). Conversely to what was expected, epigrowth feeders were not correlated with chloropigment concentrations, but showed a significant relationship with the number of dividing bacteria, possibly suggesting atrophic plasticity of the 2A feeding guild. The coupling between temporal changes in food sources and temporal variability of the nematode trophic structure was highlighted by a CANOCO analysis, which allowed us to identify and associate, at each sampling time, nematode genera and their feeding habits, with specific environmental variables and food indicators. Furthermore, species diversity (H') and evenness (J) calculated on nematodes identified to the genus level displayed evident temporal changes, also reflected by the index of trophic diversity (ITD). Both structural and functional diversity were coupled with high concentration and highly heterogeneous composition of the food sources (including organic detritus, microphytobenthic algae and bacteria) potentially available to nematodes. These data suggest that temporal changes in quantity and quality of food sources do not only influence nematode dynamics and trophic composition, but also influence nematode structural and functional diversity.

The article describes a new species of Lucinidae, Lucinoma kazani, found in the deep-water regions of the Eastern Mediterranean Basin. The bivalve favors methane gas-saturated mud, and has ctenidia symbionts typical for Lucinidae.

The annual depositional flux of carbon (C), nitrogen (N), and phosphorous (P) to the sediments under a northeast Spain Posidonia oceanica meadow was evaluated, and the sources and fate of the material deposited elucidated. The annual deposition of carbon represented 198 g C [m.sup.-2] [yr.sup.-1], 72% of which was derived from the seston and 28% from P. oceanica detritus. The depositional flux was poor in nitrogen (13.4 g N [m.sup.-2] [yr.sup.-1]) and phosphorous (2.01 g P [m.sup.-2] [yr.sup.-1]), although comparable to the nutrient inputs required to support the growth of P. oceanica. Remineralization in the sediment only returned 15.6 g C [m.sup.-2] [yr.sup.-1], yielding a net carbon accumulation of 182 g C [m.sup.-2] [yr.sup.-1]. Our results show that in the Mediterranean littoral P. oceanica meadows are important sites of net organic carbon burial, derived from sedimented sestonic particles and seagrass detritus.

Products of two mud volcanoes from the distal part of the Mediterranean Ridge accretionary complex have been investigated regarding their B, C, and O stable isotope signatures. The mud breccias have been divided into mud matrix, lithified clasts, biogenic deposits, and authigenic cements and crusts related to fluid flow and cementation. Isotope geochemistry is used to evaluate the depth of mobilization of each phase in the subduction zone. B contents and isotope ratios of the mud and mud clasts show a general trend of B enrichment and decreasing [delta][sup.11]B values with increasing consolidation (i.e., depth). However, the majority of the clast and matrix samples relate to moderate depths of mobilization within the wedge (1-2 km below seafloor). The carbonate cements of most of these clasts as well as the authigenic crusts, however, provide evidence for a deep fluid influence, probably associated with the decollement at 5-6 km depth. This interpretation is supported by decollement at 5-6 km depth. This interpretation is supported by [delta][sup.13]C ratios of the crust, which indicate precipitation of C from thermogenic methane, and by the [delta][sup.11]B ratios of pore-water samples of mud-breccia drill cores. Clams (Vesicomya sp.) living adjacent to fluid vents have [delta][sup.11]B and [delta][sup.18]O values corresponding to brines known in the area, which acted as the parent solution for shell precipitation. Such brines are most likely Miocene pore waters trapped at deep levels within the backstop to the accretionary prism, probably prior to desiccation of the Mediterranean in the Messinian (6-5 Ma). Combining all results, deep fluid circulation and expulsion are identified as the main processes triggering mud liquefaction and extrusion, whereas brines contribute only locally. Given the high B contents, mud extrusion has to be considered a major backflux mechanism of B into the hydrosphere. Keywords: boron, stable isotopes, mud volcanism, accretionary complex, Mediterranean Ridge, TIMS.

Flood-generated turbidity currents represent an important process of marine sedimentation. However, no deposit related to this process has yet been described at sea. Turbiditic sequences cored at 2000 m water depth in the Mediterranean show tractive structures and superposition of reverse and normal grading. They are related to floods triggered during the twentieth century. Deposits from flood-generated turbidity currents have a great impact on the interpretation of deep-ocean paleoclimate records obtained near continental margins by linking deep-marine sedimentary records to continental climatic changes through flood frequency and magnitude. Implications of this study should help redefine the reservoir character of oil fields in fine-grained turbidites. Keywords: Mediterranean, flood-related turbidites, hyperpycnal turbidity currents, sedimentary sequence, coarsening-upward unit.

Three extensional phases can be recognized in the northern, Anglona area of the Oligo-Miocene Sardinian Rift during a fifteen million year period which spanned Corsica-Sardinia continental microplate separation and Western Mediterranean back-arc basin opening. In response to this multiphase rifting, a complex facies architecture involving clastic, carbonate and volcanic rocks developed. Integrated onshore facies and structural analysis, dating and offshore seismic data are here used to reconstruct the tectono-stratigraphic history of the Anglona area. Initial late Oligocene extension created a half-graben geometry with syn-rift clastic deposits shed locally from fault-bounded highs, passing laterally to lacustrine marlstones. Calc-alkaline volcanic activity subsequently predominated as volcanic centres developed along one half-graben bounding fault. Voluminous pyroclastic and epiclastic material was supplied to the adjacent half-graben accommodation space and was deposited in marginal to marine conditions. Second-phase mid-Aquitanian-early Burdigalian extensional faulting, recognized from localized clastic syn-rift stratal wedges, truncated and subdivided the half-graben. The syn-rift sediments were sealed by a regionally correlated ignimbrite that in turn was offset by late second-phase faulting. Third-phase extensional fault movement which reactivated the original fault trend then occurred. A perched lake developed in the resultant topography coeval with the progressive marine transgression of lower areas. As sea-level rose during mid-Burdigalian times, reefal carbonates and grainstones developed on fault-block highs whilst calcarenites and marlstones were deposited in hangingwall locations. Initial extension was coeval with the formation of the Sardinian proto-rift and the initiation of the Western Mediterranean basin. Second-phase faulting occurred as the Corsica-Sardinia microplate rotated to its present position during Western Mediterranean back-arc basin spreading. Final extension can be correlated to a second major extension phase along the Oligo-Miocene Sardinian Rift following back-arc basin opening, as extension was transferred towards the fore-arc. In Anglona, the main influence of multiphase tectonism was on rift topography, providing accommodation space and localized uplifted source areas. Varying relative sea-level mainly controlled the broad types of facies belts that developed. Contemporaneous calc-alkaline volcanism played a major role in the supply of basin filling material and in changing the topography locally.

Data regarding the frequency and occurrence of sea storms in the Adriatic Sea and the Western Mediterranean during the last millennium have been extracted from historical written sources. The Adriatic Sea shows two anomalous periods of high storm frequency: the first half of the 1500s and the second half of the 1700s. In the 1500s the storms were more frequent in autumn, while in the late 1700s they occurred at high frequency in winter. In the Western Mediterranean, storms had a higher frequency in the first half of the 1600s, with two lesser periods of high frequency in the 1400s and at the end of the 1700s. Although both records show a maximum frequency of sea storms during the Sp6rer Minimum (1416-1534) of solar activity, sunspot series yield no, or poor, correlation during the other periods of lowest activity, i.e., Oort Minimum (1010-1090), Wolf Minimum (1282-1342), and Maunder Minimum (1645-1715), suggesting that a teleconnection between sea storms and sunspots is improbable or masked in this region. No teleconnection was found either between the El Nino-Southern Oscillation (ENSO) and surges flooding Venice or the Western Mediterranean storms or between Venice surges and the Northern Atlantic Oscillation (NAO).

Marine vertebrate faunas from the latest Cretaceous phosphates of the Palmyrides Chain of Syria are described for the first time. Recent fieldwork in the phosphatic deposits of the Palmyra area (mines of Charquieh and Khneifiss, outcrops of Bardeh, Soukkari and Soukhneh) have yielded a rich and diversified assemblage of marine vertebrates, including more than 50 species of chondrichthyes, osteichthyes, squamates, chelonians, plesiosaurians and crocodilians. Selachians are the most abundant and diverse component of the faunas and are represented by at least 34 species of both sharks and rays. Actinopterygians include representatives of six families, the most common being the enchodontids. Squamates are known by six mosasaurid species and an indeterminate varanoid. Chelonians are represented by at least two bothremydids and two chelonioids. Finally, elasmosaurid plesiosaurs and indeterminate crocodilians are also present in the fossil assemblages. The difference in faunal composition observed between the sites is interpreted as being due to palaeoecological preferences related to the Hamad Uplift palaeostructure. The marine vertebrate faunas of Syria show close affinities with those of the latest Cretaceous phosphatic deposits of North Africa and the Middle East and are typical of the southern Tethyan realm. From a biostratigraphical point of view, the selachians are the only suitable material to provide elements of an answer to the long debated question of the age of the Syrian Senonian phosphates. They suggest an Early Maastrichtian age for most of the phosphates of the Palmyrides Chain.

Multiple layers of sapropels occur widely in the sedimentary record of the Mediterranean Sea and record repetitions of paleoclimatic conditions that favored increased production and preservation of marine organic matter. A combination of hydrogen and carbon isotope analyses of Pleistocene sapropels from the Tyrrhenian Sea reveals new aspects of the factors leading to their deposition. Organic matter (delta)D values that are significantly more negative in sapropels than in adjacent marls indicate a combination of dilution of surface waters by meteoric waters and increased burial of lipid-rich organic matter during periods of sapropel deposition. Organic (delta)(super 13)C values in sapropels that are less negative than those in marls suggest periods of markedly elevated marine biological production. The opposite but concordant excursions of these two isotopic parameters imply that the sapropel layers formed from increased export of marine organic matter from the photic zone to the sea floor during periods of greater fluvial delivery of continental nutrients to the Mediterranean Sea. Furthermore, the isotopic evidence indicates that periods of wetter climate were widespread in southern Europe at the same times as in northern Africa.

Sessile macroepifauna was sampled at six rocky sites between 2 and 90 m depth with a number of different methods involving both underwater photography and collection of specimens. A total of 212 species (or varieties) were identified, belonging to seven higher taxa: poriferans (24 species), cnidarians (32), molluscs (8), serpuloidean polychaetes (33), bryozoans (90), brachiopods (4) and ascidians (21). The combined use of a varied array of sampling methods was effective in obtaining a rich faunal inventory. Deep and offshore sites tended to be richer in species than shallow and inshore sites. In all cases species richness was higher at sites closest to hydrothermal vents on the sea floor. Although there are no comparable inventories of marine sessile epifauna in the Aegean, the high number of species found, with a relatively low sampling effort in a restricted area, indicates that the marine biodiversity of this sea is not as low as traditionally believed.

Results of isozyme electrophoresis were used to explore the genetic relationships between several Mediterranean morphs of Cerithium (Gastropoda: Prosobranchia), for which taxonomy is currently uncertain because of high intraspecific variability and low interspecific differentiation. The large species, classically known as C. vulgatum Bruguiere, 1789 was identified at four sites (two in the French Mediterranean and two in southern Spain). Two different larval types were found in the French sites, but poecilogony could not be demonstrated. Individuals collected from harbours were not genetically distinct from open-sea populations of classic C. vulgatum. However, a population in the Embiez lagoon (French Mediterranean) which morphologically resembles C. vulgatum did display distinct genetic traits, supporting its status as a separate species. Of the small Cerithium species usually known as C. rupestre, two sympatric species (C. 'rupestre' Risso, 1826 and C. lividulum Risso, 1826) were distinguished. Genotype frequencies within the analysed populations revealed much heterozygote deficiency. FsT values (fixation index measuring the effects of population subdivision) suggest a higher genetic differentiation for C. lividulum populations than for C. vulgatum populations. We assume that a high larval dispersal capability (via planktotrophy) allows a high gene flow between populations of C. vulgatum.

Allozyme differentiation is discussed as seen in cuttlefish, Sepia officinalis (Mollusca: Cephalopoda), from the northeast Atlantic and Mediterranean. The area has been proposed as a new phylogeographical area, but more taxa should be studied before such a designation is made. Of the cuttlefish, 11 Iberian samples showed moderate genetic differentiation explainable based on genetic differentiation between Atlantic and Mediterranean samples. Significant clines in allele frequencies were seen for 5 of 6 polymorphic loci.

Hermaphroditism and sexual maturity of the red porgy Pagrus pagrus (Teleostei: Sparidae) are discussed. Gonadal changes were studied using histology in populations 0.5-6.5 years in age. The presence of males seems to come from the sexual change of adult functional females. The species is protogynous. At age 6.5 years some females were still female.

An electron-microscope investigation of a late Quaternary laminated diatomaceous sapropel in the deepest part of the moat of the Napoli mud volcano on the Mediterranean ridge has been linked with recent progress in the understanding of the ecology of mat-forming diatoms to create a model of the formation of organic-carbon-rich sapropels. It is clear that diatoms played a key role in sapropel formation. Evidence of high diatom production has often been interpreted as upwelling-related, but a study of the diatoms involved indicates an alternative explanation, with diatoms growing under conditions of sustained seasonal stratification.

The high-salinity water flowing out of the Mediterranean Sea descends to mid depths in the density-stratified ocean, continues as a narrow jet along the Iberian continental slope, and intermittently detaches large-scale eddies (called 'Meddles'). This process is important because it maintains the relatively high mean salinity of a major water mass (the 'Mediterranean Intermediate Water') in the North Atlantic. Our simplified model of this jet consists of a moving layer with intermediate density [[Rho].sup.2] sandwiched between motionless layers of density [[Rho].sub.1] < [[Rho].sup.2] and [[Rho].sup.3] > [[Rho].sup.2]. The inshore (anticyclonic) portion of the midlevel jet (in the '[[Rho].sup.2]-water') rests on an inclined bottom (the continental slope), whereas the (cyclonic) offshore portion rests on the density interface of the stagnant deep ([[Rho].sup.3]) layer. An inviscid, steady, and finite-amplitude longwave theory is used to show that if the cross-stream topographic slope increases gradually in the downstream direction, then the '[[Rho].sup.2]-jet' is deflected off the bottom slope and onto the upper density interface of the [[Rho].sup.3] layer. The computed magnitude of this separation effect is such as to produce an essentially free jet which is removed from the stabilizing influence of the continental topography. It is therefore conjectured that time-dependent effects (baroclinic instability) will produce further amplification, causing an eddy to detach seaward from the branch of the jet remaining on the slope.

Based on lithostratigraphic comparisons the Menderes Massif has been correlated with the Cycladic Massif, thereby implying that the eastern Mediterranean consists of a narrow pre-Alpine basement belt which is laterally continuous over a long distance and which experienced a similar Alpine orogenic history. Our work indicates that the architecture, the age of basement and the pre-Alpine and Alpine tectonometamorphic history of both massifs differ fundamentally from each other. The Menderes Massif consists of remnants of the Cycladic Massif which overly an exotic unit, the Menderes nappes. Both massifs do not represent lateral continuations which has implications for palaeogeographic reconstructions. Keywords: Eastern Mediterranean, Menderes Massif, Cycladic Massif, tectonics, palaeogeography.

Drilling results from two mud volcanoes on the Mediterranean Ridge accretionary complex as well as extensive geophysical surveys have provided new insights about the geometry of these domes at depth. Mud extrusion is related to buoyancy and plate convergence between Africa and Eurasia that caused back-thrust faulting of accreted strata containing overpressured mud at depth. The domes mainly consist of mud breccia formed of as much as 65% polymictic clasts embedded in a clayey matrix of presumed late Miocene age. Volumetric estimates of extruded mud in a well-studied area around the Olimpi mud-volcano field were balanced against sediment input at the deformation front. The results demonstrate that only a small fraction of rock mass having entered the subduction zone since the Messinian is needed to compensate for the mud expelled in the study area. Most of the sediment ([approximately]95% or more) is either subducted or incorporated into the accretionary prism. The volume of gas expelled with the liquefied, overpressured mud was estimated to range between 1.68 x [10.sup.6] and 2.85 x [10.sup.7] [m.sup.3]/yr.

Dissolved esterase activity is discussed relative to its use as a phytoplankton lysis tracer and as related to evidence of high phytoplankton lysis rates in the northwestern Mediterranean. Information on a test of key assumptions underlying use of the dissolved esterase method is given along with detail of procedures. Importance of summer phytoplankton lysis rates as a loss factor is studied.

In allozyme analysis of tissue samples of 910 European hake, Merluccius merluccius, polymorphism was found at 21 of 34 protein-coding loci. The samples were from six North Atlantic and four Mediterranean locations. A major subdivision was seen from allelic differences related to the two collections. Gene flow from nearby Atlantic to proximal Mediterranean populations was suggested by allele frequencies and relevant oceanographic and geological information. Present management, based on two distinct populations, is justified. The differing and separate northern and southern stocks suggested by the International Council for the Exploration of the Sea (ICES) do not constitute an adequate description.

A study was conducted on patterns in a seagrass meadow in the Gulf of Naples, Mediterranean Sea to investigate contamination, accumulation and seasonal variability of heavy metals such as copper, zinc, lead and cadmium. Results showed that metal levels in seagrass leaves and their associated epibiota are not homogenous and all metal species, except for copper, displayed significant differences in concentration between leaves and epibiota. Moreover, metal levels in leaves are influence by seasonal cycles.

A new study investigates the effect of water temperature on the asexual and sexual phases of the reproductive cycle of the marine sponge Mycale contarenii. Samples were collected between Jun 1994 and May 1996 in the Porto Cesareo Basin of the Mediterranean. The study concludes that water temperature does not promote female gamete differentiation, unlike other temperate region sponges, and also shows that sexual and asexual processes seemingly overlap. Budding appears to be a successful asexual strategy and plays an important part in maintaining the sponge population.

Diving affects the density of the colonial bryozoan Pentapora fascialis, according to a study of two benthic habitats, vertical walls and boulders, in a marine reserve off Spain's northeastern coast. It was unclear how the size of colonies was affected. A trend toward more cryptic positions was also found. The impact of diving was more pronounced on boulders than on walls. Recovery seems to take place slowly and with difficulty for such sublittoral benthic communities after the disturbances associated with diving.

Accelerator-mass-spectrometry radiocarbon dating has been used in five widely spaced cores to identify the date of emplacement of a large-volume turbidite bed in the Balearic Basin of the western Mediterranean. It was possible to produce an estimate of 22,000 calendar years before present for emplacement of the bed, when sea level was at its lowest level during the Last Glacial Maximum. The very large size of the Balearic Abyssal Plain bed indicates that it is an unusual event in the recent history of this margin.

Commercial trawlers were used to collect 349 red mullet specimens from seven locations in Greece and one in France in a study which examined genetic protein variation in striped red mullet and red mullet populations from the Mediterranean Sea. Standard horizontal starch-gel electrophoresis was used to analyze samples of white muscle, eye and liver removed from the mullets. Results revealed the presence of a high degree of genetic polymorphism in both species. In addition, all enzyme loci manifested well-resolved staining patterns consistent with recognized enzyme subunit structure for the two species.

A study was conducted to characterize a biogeochemical framework that simulates the temporal evolution of the main nitrogen stocks and fluxes at the DyFAMed station at the Northwestern Mediterranean Sea. The region supported a strong seasonal cycle and an export of dissolved organic matter. Results indicated that a number of processes need to be considered in biogeochemical models. These include phytoplankton growth limitation by deep mixing, C:Chl ratio dependence and semi-refractory dissolved organic matter accumulation.

Marine research shows that transparent goby fish Aphia minuta fished in the Mediterranean Sea surrounding the Island of Majorca largely comprise of very young fish aged between three and six months. Length-frequency and otolith microstructure analysis indicates that the fish populations contain fish aged up to eight months in age. Male and female fish have similar overall growth performance indices.

Marine research shows that shelf-dwelling fish larva are mainly found in ocean water depths of up to ten meters deep. Some species, such as the fish Gobiidae, are found at depths of over 40 meters deep. Vertical distribution patterns of fish larva may be related in some way to horizontal population trends. Horizontal distribution patterns for around fish twenty species are observed.

There are six species of the Moridae family in the Mediterranean and they dominate the ocean's deep-water western slopes. A new study investigates the diet and feeding habits of Lepidion lepidion at depths between 1000 and 2000 mt. The study shows that the fish is a euryphagic predator and mostly preys on crustaceans. The diversity of the Lepidion's diet varies with water depth. Further details of the study are presented.

Microbiological research has identified a new strain of marine melanogenic bacterium, designated strain MMB-1, which comes from the genus Alteromonas. The organism uses L-tyrosine as a specific monophenolic precursor for melanin synthesis and contains two polyphenol oxidases, including a tyrosinase-like latent enzyme. It respires aerobically and uses sodium in growth processes. It is cytochrome c oxidase negative.

The sponges Tethya citrina and T. aurantium in Stagnone di Marsala lagoon, Mediterranean, are oviparous and gonochoric, and have a single discrete cycle of oocyte production every year. The two species show an overlapping period of oocyte production in the summers. Due to short periods of spermatogenesis, there is a lack of males in both the species. The sponges reproduce via asexual buds in autumn and winter. T. citrina produces less buds and more eggs as compared to T. aurantium.

The high microbial biomass and activity in Mediterranean trenches at depths exceeding 3750 m, are due to the capture of organic matter in the trenches. The availability of food is an important factor for microbial growth in the oxic deep-sea sediments. Phytodetritus input, measured in terms of chloroplastic pigment equivalents (CPE), decreases from a depth of 200 m to deeper regions in the Eastern Mediterranean basin. However, Hellenic Trench and Pliny Trench, present at more than 3750 m depth, show high level of CPE. The high level of food stimulates microbial activity in these trenches.

The cumaceans species dwelling in the upper slopes of western Mediterranean show wide reproductive period, and those inhabiting the lower parts have reproductive peak in summers and narrow recruitment period in the late winter and spring. Diastyloides serrata, Leucon macrorhinus, L. siphonatus and L. affinis found in the upper 500 m of the slope show wider reproductive period. L. longirostris, Makrokylindrus longipes and Cyclaspis logicaudata that live in the lower layers have narrow reproductive period. The reproductive period correlates with the input of phytodetritus from the euphotic zone.

Xenotrichula intermedia populations present in the Mediterranean Sea, the northwestern Atlantic and the Gulf of Mexico are genetically different but morphologically similar. Analysis of 16 morphological features shows that the populations in the Gulf of Mexico differ from the others in having a smaller pharynx. However, the nucleotide sequence of the mitochondrial cytochrome oxidase I gene is different in different populations. This indicates that the different populations are separate sibling species rather than a single species.

The addition of phosphorus (P) to cultures of Synechococcus cells isolated from the Mediterranean Sea decreases the duration of the G1 phase of the cell cycle. This causes the cells to enter and leave the S and G2 phases earlier than normal. The addition of nitrogen fails to affect the cell cycle. A study indicates that the Synechococcus cells are P-limited rather than N-limited during summers. The concentration of P that affects 50% of the bacterial cells is low during June and increases by July.

The slope off the Mediterranean coast of France has a geomorphology that makes the site ideal for studying the distribution of migratory micronekton crustaceans. Adding to the advantage of the place is its changeable wind and current regimes. Two pelagic communities, namely, epipelagic, mesopelagic and infrapelagic oceanic fauna, and neritic benthopelagic fauna, are present in the area. Some bathypelagic species are present at the bottom of the slope.

The spherulous cells in the Mediterranean sponge Crambe crambe produce and store toxic compounds. The distal ectosome exhibits higher toxicity as compared to the basal choanosome. Both the orange and colorless spherulous cells that are present in the same zones are likely to contain the toxic substances. The cell fraction of the sponge containing the spherulous cells is highly toxic, but the cell fraction of choanocytes and archeocytes is almost harmless.

The characteristics of the habitat and the temporal distribution of recruitment among the juvenile fishes of the Mediterranean littoral have been analyzed. The 24 species studied have well-defined habitats with characteristically distinctive substrate types. Sparid species inhabit the shallowest zone and prefer varied bottoms. Labrid species are localized on rocky substrates with high algal cover and recruit during summer while sparids recruit at different times of the year.