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Highlights • Suprabenthic assemblages from the Blanes Canyon and adjacent slope were analysed. • High-energy hydrodynamic events and topography are drivers of biodiversity. • Suprabenthic assemblages were similar in the canyon and slope at greater depths. • "Canyon effect" on suprabenthic assemblages was suggested at depths 1200 m). At shallowest depths, the canyon sites were characterized by a high contribution of motile omnivores while the slope sites were characterized by a high contribution of detritivores to the total abundance. Highly motile predators on zooplankton were dominant at deepest sites in both environments. Our results suggest that taxonomic and trophic diversity in the northwestern Mediterranean may be influenced by the abrupt topography and its interaction with hydrodynamic conditions (intensification of currents; variable intensity of disturbance/hydrodynamic events; food pulses linked to food availability). These are major drivers which influence the spatial and temporal availability of food sources to the various faunal compartments eventually propagating up the food web. [ABSTRACT FROM AUTHOR]

Marine litter is commonly observed everywhere in the ocean. In this study, we analyzed 17 km of video footage, collected by a Remotely Operated Vehicle (ROV) at depths ranging between 20 and 220 m, during 19 transects performed on the rocky banks of the Straits of Sicily. Recently, the Contracting Parties of the Convention on Biological Diversity (CBD) recognized this site as an Ecologically or Biologically Significant Area (EBSA). The research aim was to quantify the abundance of marine litter and its impact on benthic fauna. Litter density ranged from 0 items/100 m 2 to 14.02 items/100 m 2 with a mean (±standard error) of 2.13 (±0.84) items/100 m 2 . The observed average density was higher (5.2 items/100 m 2 ) at depths >100 m than at shallower depths (<100 m, 0.71 items/100 m 2 ). Lost or abandoned fishing lines contributed to 98.07% of the overall litter density, then representing the dominant source of marine debris. Litter interactions with fauna were frequently observed, with 30% of litter causing “entanglement/coverage” and 15% causing damage to sessile fauna. A total of 16 species showed interaction (entanglement/coverage or damage) with litter items and 12 of these are species of conservation concern according to international directives and agreements (CITES, Berne Convention, Habitat Directive, SPA/BD Protocol, IUCN Red List); we also observed 7 priority habitats of the SPA/BD Protocol. This research will support the implementation of monitoring “Harm” as recommended by the UN Environment/MAP Regional Plan on Marine Litter Management in the Mediterranean, and the Marine Strategy Framework Directive (MSFD). The institution of a SPAMI in the investigated area could represent a good management action for the protection of this hotspot of biodiversity and to achieve a Good Environmental Status (GES) for the marine environment by 2020, under the MSFD. [ABSTRACT FROM AUTHOR]

Beach nourishment is a widely utilized solution to counteract the erosion of shorelines, and there is an active discussion on its possible consequences on coastal marine assemblages. We investigated the impact caused by a small-scale beach nourishment carried out in the Western Adriatic Sea on macrofaunal recruitment and post-settlement events. Artificial substrates were deployed in proximity of nourished and non-manipulated beaches and turbidity and sedimentation rates were measured. Our results indicate that sedimentation rates in the impacted site showed a different temporal change compared to the control sites, suggesting potential modifications due to the beach nourishment. The impact site was characterized by subtle changes in terms of polychaete abundance and community structure when compared to controls, possibly due to beach nourishment, although the role of other factors cannot be ruled out. We conclude that small-scale beach nourishments appear to be an eco-sustainable approach to contrast coastal erosion. [ABSTRACT FROM AUTHOR]

Diatoms have been shown to produce and release a wide range of secondary metabolites that mediate interactions between individuals of different species. Among these compounds, different types of fatty acid derived long-chained polyunsaturated aldehydes (PUAs) have been related to multiple functions such as intra- or interspecific signals and adverse effect on the reproduction of marine organisms. Several studies have reported changes on growth, cell membrane permeability, flow cytometric properties and cell morphology in phytoplankton organisms exposed to PUAs, but little information is available on the effect of these compounds on benthic microalgae. Ostreopsis cf. ovata is a toxic benthic dinoflagellate which causes massive blooms along the Mediterranean coasts typically during the late summer period. In this study the effects of three toxic PUAs known to be produced by several algae (2 E ,4 E -decadienal, 2 E ,4 E -octadienal and 2 E ,4 E -heptadienal) on the growth, cytological features and cell morphology of O. cf. ovata were investigated. Our results show a clear decrease of O . cf. ovata growth with longer-chain molecules than with shorter-chain ones, confirmed also by EC 50 values calculated at 48 h for 2 E ,4 E -decadienal and 2 E ,4 E -octadienal (6.6 ± 1.5, 17.9 ± 2.6 μmol L −1 respectively) and at 72 h for 2 E ,4 E -heptadienal (18.4 ± 0.7 μmol L −1 ). Moreover, morphological analysis highlighted up to 79% of abnormal forms of O. cf. ovata at the highest concentrations of 2 E ,4 E -decadienal tested (9, 18 and 36 μmol L −1 ), a gradual DNA degradation and an increase of lipid droplets with all tested PUAs. Further studies are needed to better clarify the interactions between diatoms and O . cf. ovata , especially on bloom-forming dynamics. [ABSTRACT FROM AUTHOR]

Sponges are important components of marine benthic communities with a worldwide distribution ranging from polar to tropical regions. They play a key role in benthic–pelagic coupling processes through their active suspension feeding, providing a trophic link between the benthos and the overlying water column. Little is known about their broad-scale distribution and feeding ecology. The general tendency is to quantify their trophic impact through small patch estimations. In this work, two of the most abundant sponges in Mediterranean coastal bottoms ( Aplysina aerophoba and Axinella polypoides ) were studied combining remotely operated vehicle (ROV) survey with in situ feeding experiments. Spatial, bathymetrical distribution and population size structure of these species were analysed, together with their trophic ecology, in spring and autumn. We found that A. aerophoba is distributed between 5 and 20 m depth, with maximum densities of 1.6 sponges m − 2 . This species ingested 0.12–0.39 mg of carbon (C) g AFDW − 1 (ash free dry weight) day − 1 in spring and 0.09–0.13 mg C g AFDW − 1 day − 1 in autumn. Conversely, A. polypoides was found between 10 and 70 m depth, with maximum densities of 7.6 sponges m − 2 . This species ingested 0.07–0.17 mg C g AFDW − 1 day − 1 in spring, and 0.18–0.60 mg C g AFDW − 1 day − 1 in autumn. The highest uptake of C concentrated between 5 and 15 m depth for A. aerophoba and between 65 and 70 m depth for A. polypoides . In the 1.14 ha of studied coastal bottom, A. aerophoba ingested 1.87 g C during spring and 0.19 g C during autumn, whereas A. polypoides 13.60 g C and 29.36 g C during spring and autumn, respectively. The present approach allowed a spatially explicit quantification of benthic–pelagic coupling processes produced by two of the most common sponges in a Mediterranean coastal area. This methodology, applied to benthic communities, mirrors similar approaches used in terrestrial forestry studies for C flux estimation. [ABSTRACT FROM AUTHOR]

We have evaluated the environmental and biological processes affecting the stable oxygen and carbon isotope composition of live (Rose Bengal stained) and dead (unstained) tests of different benthic foraminiferal species from the western Mediterranean Sea. Samples were retrieved from comparable water depths but contrasting trophic regimes, comprising the meso- to eutrophic Alboran Sea and the oligo- to mesotrophic Mallorca Channel. The recorded isotope signatures mirror the average microhabitat depth of each species and reflect the specific gradients in pore water δ 13 C of dissolved inorganic carbon (δ 13 C DIC ) and oxygen. Maximum δ 13 C DIC pore water gradients of up to − 2.3‰ were estimated under the influence of meso- to eutrophic conditions in the Alboran Sea. The δ 13 C signal of Uvigerina mediterranea reflects the opportunistic behavior of this species as its δ 13 C is shifted to more negative values at higher organic matter fluxes. Accordingly, the δ 13 C signal of U. mediterranea appears particularly suitable as a proxy for quantitative reconstructions of past trophic conditions. Previously reported ontogenetic increase of stable isotope values is confirmed for buliminid taxa (genera Uvigerina and Globobulimina ), while it is largely absent in rotaliid taxa (genera Cicidides , Cibicidoides , and Melonis ). Particularly strong metabolic fractionation is observed in small specimens of Uvigerina peregrina overprinting the pore-water δ 13 C DIC signal and resulting in steep ontogenetic δ 13 C gradients. The δ 18 O values of epifaunal taxa, which thrive under high dissolved oxygen concentrations, and the shallow to intermediate infaunal Melonis barleeanum , are up to 1.2‰ lower relative to equilibrium calcite. In epifaunal taxa, this depletion can be attributed to enhanced fractionation at high concentrations of metabolically utilizable oxygen. [ABSTRACT FROM AUTHOR]

The distribution of crustaceans in 3 transects (İskenderun, Mersin, and Anamur bays, including depths of 10, 25, 50, 75, 100, and 200 m) located within Turkish coastal borders of the Cilician shelf was studied between 2005 and 2007 to show the association with habitat types, eutrophication level, and depth-dependent environmental parameters in representative months of each season (winter, spring, summer, and autumn). A total of 153 crustacean taxa were found. Of the specimens identified at species level, 93 species were distributed in the Mediterranean Sea and Atlantic Ocean, 12 in the Indian Ocean and the Red Sea, and 4 in the cosmopolitan waters of the oceans. Three crustacean assemblages were distinguished according to the habitat types and eutrophication levels of the study sites: 1) the crustacean community of the eutrophic regions was dominated by decapods and characterized by high biomass, low faunistic characters, and high nutrient concentrations; 2) the assemblage of the bottom, vegetated with a meadow, exhibited well-diversified assemblages mainly composed of amphipod species with high faunistic characters, low biomass, and dissolved oxygen content; and 3) the assemblage of the nonvegetated undisturbed soft bottom was associated with the sedimentary parameters along the bottom depths (10-25 m, 50-100 m, and 150-200 m). [ABSTRACT FROM AUTHOR]

Sedimentation and burial affect a variety of habitats worldwide, especially within coastal marine systems. In the Mediterranean, seagrasses like Cymodocea nodosa are commonly subjected to sedimentation and, although the response of C. nodosa has been documented, few studies have included macrofaunal responses. We used a manipulative field experiment to examine the effects of a single small-scale, pulse burial event on benthic invertebrate macrofauna. Burial did not affect the total abundance, richness, or diversity of higher taxa nor the live abundance or diversity after 5 days. However, live higher taxa richness decreased by day 3. After 5 days, such decrease reversed and partial recovery seemed to occur. Almost 2 months later, three of the buried plots remained with some additional sedimentation, but the other three had lost their sediment. We compared faunal metrics of buried plots between days 5 and 54 and found greater diversity on day 54, providing evidence that macrofaunal recovery apparent 5 days after burial seemed to persist. Although we likely underestimated the effects and can only be conservative with our conclusions, taken together our results suggest small-scale, pulse burial events can have some negative effects on the C. nodosa-associated benthic macrofaunal community, but the community can recover within a few weeks. [ABSTRACT FROM AUTHOR]

Satellite data show a steady increase, in the last decades, of the surface temperature (upper few millimetres of the water surface) of the Mediterranean Sea. Reports of mass mortalities of benthic marine invertebrates increased in the same period. Some local studies interpreted the two phenomena in a cause-effect fashion. However, a basin-wide picture of temperature changes combined with a systematic assessment on invertebrate mass mortalities was still lacking. Both the thermal structure of the water column in the Mediterranean Sea over the period 1945–2011 and all documented invertebrate mass mortality events in the basin are analysed to ascertain if: 1- documented mass mortalities occurred under conditions of positive temperature trends at basin scale, and 2- atypical thermal conditions were registered at the smaller spatial and temporal scale of mass mortality events. The thermal structure of the shallow water column over the last 67 years was reconstructed using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS programme. A review of the mass mortality events of benthic invertebrates at Mediterranean scale was also carried out. The analysis of in situ temperature profiles shows that the Mediterranean Sea changed in a non-homogeneous fashion. The frequency of mass mortalities is increasing. The areas subjected to these events correspond to positive thermal anomalies. Statistically significant temperature trends in the upper layers of the Mediterranean Sea show an increase of up to 0.07°C/yr for a large fraction of the basin. Mass mortalities are consistent with both the temperature increase at basin scale and the thermal changes at local scale, up to 5.2°C. Our research supports the existence of a causal link between positive thermal anomalies and observed invertebrate mass mortalities in the Mediterranean Sea, invoking focused mitigation initiatives in sensitive areas. [ABSTRACT FROM AUTHOR]

The large-scale deep-sea biodiversity distribution of the benthic fauna was explored in the Mediterranean Sea, which can be seen as a miniature model of the oceans of the world. Within the framework of the BIOFUN project (“Biodiversity and Ecosystem Functioning in Contrasting Southern European Deep-sea Environments: from viruses to megafauna”), we investigated the large spatial scale variability (over >1,000 km) of the bathyal macrofauna communities that inhabit the Mediterranean basin, and their relationships with the environmental variables. The macrofauna abundance, biomass, community structure and functional diversity were analysed and the α-diversity and β-diversity were estimated across six selected slope areas at different longitudes and along three main depths. The macrobenthic standing stock and α-diversity were lower in the deep-sea sediments of the eastern Mediterranean basin, compared to the western and central basins. The macrofaunal standing stock and diversity decreased significantly from the upper bathyal to the lower bathyal slope stations. The major changes in the community composition of the higher taxa and in the trophic (functional) structure occurred at different longitudes, rather than at increasing water depth. For the β-diversity, very high dissimilarities emerged at all levels: (i) between basins; (ii) between slopes within the same basin; and (iii) between stations at different depths; this therefore demonstrates the high macrofaunal diversity of the Mediterranean basins at large spatial scales. Overall, the food sources (i.e., quantity and quality) that characterised the west, central and eastern Mediterranean basins, as well as sediment grain size, appear to influence the macrobenthic standing stock and the biodiversity along the different slope areas. [ABSTRACT FROM AUTHOR]

The trophic ecology, energy and reproductive states of the deep-water shrimp Aristaeomorpha foliacea, widely distributed along the slopes of the Mediterranean Sea Basins, were analysed in eight areas spread along ca. 3000km in order to identify patterns in the habitat conditions supporting the species. From W to E the areas were situated between the north side of Eivissa (39°12′N, 1°20′E, in the Balearic Basin) and off Mersin, Turkey (36°15′N, 34°19′E, in the Levantine Sea). Trends identified mainly as a function of longitude from west to east were: (i) higher δ15N, parallel to δ15N shifts in the top 200m of the water column for particulate organic N (Pantoja et al., 2002). The δ15N trend indicates that the deep trophic web, i.e. A. foliacea at 400–600m, reflects the δ15N signal of the photic zone; (ii) a similar significant trend of δ13C, related with exploitation of pelagic versus benthic resources by A. foliacea in each area (i.e. by local variability of terrigenous inputs via submarine canyons). More depleted δ13C was found at mid-longitudes (Tyrrhenian Sea and Sicily Channel) linked to higher consumption of macroplankton prey (Pasiphaea spp., euphausiids and mesopelagic fishes). The feeding intensity (gut fullness, F) and prey diversity (J) of A. foliacea were related, according to generalized linear models, with the temperature and salinity of intermediate waters, variables in turn associated with latitude and longitude. Both F and J were higher in areas with greater shrimp density. The optimal ecological habitat of A. foliacea appears to be located in the Tyrrhenian Sea and the Sicily Channel, where we found the highest F, the greatest trophic diversity and A. foliacea in the best biological condition (i.e. with higher hepato-somatic index, HSI). These are also the areas with the highest densities of A. foliacea. In contrast, in the western Mediterranean Sea (Balearic Basin and the southern Balearic Islands), where A. foliacea has low densities, the shrimp showed generally lower values of trophic indicators and biological condition. [ABSTRACT FROM AUTHOR]

Highlights: [•] We propose a comparative study on the benthic macrofauna sampling. [•] The work was carried out in ten transitional aquatic ecosystems covering a wide salinity range. [•] We describe benthic assemblages sampled by box corer and leaf bags. [•] We use PERMANOVA to analyze communities’ structural characteristics and biotic indices. [•] Results highlight the need to standardize sampling methodologies for benthic macrofauna in these ecosystems. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF) that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean. We combined molecular phylogenetic analyses of soritids and their algal symbionts as well as network analysis of Sorites orbiculus Forskål to compare populations from the Gulf of Elat (northern Red Sea) and from a known hotspot in Shikmona (northern Israel) that consists of a single population of S. orbiculus. Our phylogenetic analyses show that all specimens found in Shikmona are genetically identical to a population of S. orbiculus living on a similar shallow water pebbles habitat in the Gulf of Elat. Our analyses also show that the symbionts found in Shikmona and Elat soritids belong to the Symbiodinium clade F5, which is common in the Red Sea and also present in the Indian Ocean and Caribbean Sea. Our study therefore provides the first genetic and ecological evidences that indicate that modern population of soritids found on the Mediterranean coast of Israel is probably Lessepsian, and is less likely the descendant of a native ancient Mediterranean species. [ABSTRACT FROM AUTHOR]

Abstract: Flow regulation is generally perceived to negatively influence fluvial ecosystems through alterations of natural habitat conditions, particularly in highly variable Mediterranean streams. However, the detection of impact may depend on chosen metrics, requiring a multiple-lines-of-evidence approach for ecologically relevant impact assessment. In this study, we compare the community structure, the trophic function, the microhabitat influence and the body condition of benthic invertebrates between the regulated Bullaque River and unregulated tributaries (Guadiana River basin, central Spain). Invertebrates and physical microhabitats were studied seasonally in 2010. Total abundance, EPT abundance, Rheoindex and LIFE metrics were higher in the regulated river during summer, whereas Shannon diversity was lower. Rheoindex and LIFE were higher in the tributaries during winter. Filterers were very abundant in spring and summer in the tributaries and the regulated stream, respectively. Deposit feeders dominated during summer in the tributaries. Despite these differences, ANOSIM revealed similar community structure and feeding groups characteristics in both fluvial system types. In addition, body condition, measured as fluctuating asymmetry level, indicated that daming created favourable developmental conditions for several invertebrate species in the Bullaque River. This suggests that daming surprisingly buffered from the adverse environmental conditions inflicted by seasonal summer drougths, which occur recurrently in Mediterranean areas. Results also suggest that the application of fluctuating asymmetry could therefore be promising for revealing integral ecological responses to different and often combined forms of anthropogenic and natural disturbance. [Copyright &y& Elsevier]

Cryptobenthic fish communities are a rarely studied and ill-defined component of the marine benthos. Quantitative sampling of seventy-six 1 × 1 m plots at Cape Šilo, Northern Adriatic Sea, yielded 522 cryptobenthic and 67 epibenthic individuals of 27 species. Canonical Correspondence Analysis (CCA) identified variation of 3 out of 17 habitat variables (depth, presence of bedrock, and presence of short thallus algae on boulders) as significantly and strongly correlated with species occurrence. Interpretation of CCA triplots allowed the description of niches of the 13 most abundant species, as well as the tentative identification of three major habitat types structuring the cryptobenthic fish community (inclined bedrock, infralittoral algae, and the deeper infralittoral mixed bottom). The study highlights the largely unstudied ecological relevance of the cryptobenthic fish community as revealed by an unexpected high diversity and the numerical dominance of some species which previously were considered rare. An improved definition of cryptobenthic fishes is provided. [ABSTRACT FROM AUTHOR]

Spatio-temporal variations of soft-bottom zoobenthic communites in Mersin Bay were examined at seven stations between February and October 2009. A total of 337 species were encountered, of which Polychaeta had the highest number of species (136 species), and Mollusca possessed the highest number of individuals (65% of total specimens) and biomass (59% of total biomass). The highest benthos density (max. 9760 ind. m−2) and biomass (max. 133 g m−2) were found at shallow-water stations, whereas the highest diversity index values were calculated at the deepest station. The molluscs Cerithidium diplax, Corbula gibba and Bittium reticulatum dominated the area. Changes of zoobenthic communities were spatial rather than temporal and were strongly correlated with depth and the sediment structures. A total of 40 alien species were found in the area, of which 15 species were possibly transported to the area by ships and the others were Lessepsian migrants. The most domiant alien species in the area were C. diplax, Finella pupoides, Notomastus mossambicus and Amphiodia obtecta. Alien species formed dense populations at shallow water stations, and accounted for 12% of total number of species and 31% of total number of individuals in the area. The community parameters estimated for alien species significantly differed among stations but not among sampling periods. The main factors negatively affecting the number of alien species and individuals were depth, the clay percentage and total organic carbon concentration in sediment. The number of native species and individuals in the area show moderate positive correlations with those of aliens. [ABSTRACT FROM AUTHOR]

Remotely operated vehicle (ROV) video observations were used to document benthic fauna at a hydrocarbon drilling location, at 2 720 m depth, in the poorly studied deep water off northern Egypt. The decapod Chaceon mediterraneus was the most common organism at the site and the only benthic megafaunal invertebrate observed. Three species of fish, Coryphaenoides mediterraneus, Cataetyx laticeps and Bathypterois mediterraneus, were also encountered. These findings confirmed these three species as the deepest-distributed benthic fish in the eastern Mediterranean, and confirmed that the deep Mediterranean, in particular the eastern basin, is one of the world's poorest deep-sea ecosystems in terms of diversity. The behaviour exhibited by the species observed was consistent with their natatory capacity, deduced from their feeding intensity (gut fullness) and diet (mainly suprabenthic prey were consumed), and conservative life strategies adapted to an extremely low energy environment. [ABSTRACT FROM AUTHOR]

A total of 44 molluscan species belonging to 5 classes were identified in 3 transects (including depths of 10, 25, 50, 75, 100 and 200 m) located in Kumkuyu, Limonlu, and Erdemli. Overall, no significant difference in community parameters such as diversity index, evenness index, and species richness was found among transects. The species abundance showed seasonal and depth-wise variations. The highest species richness (6-16 species) was encountered between depths of 10 and 100 m in winter and spring, whereas the molluscan population increased in warm seasons due to the high abundance of Corbula gibba and Nucula nitidosa. Bivalves and gastropods were abundantly found at depths of 10-200 m, 10-25 m, and 75-100 m. Two main molluscan assemblages were determined: the first assemblage occurred in the shallow water (10-50 m) and was characterized by high abundances of C. gibba, Abra alba, and Tellimya ferruginosa, and the second occurred in deep waters (75-200 m) and was characterized by the presence of Falcidens gutturosus, N. nitidosa, and Astarte fusca. Depth, the fine-grain size of sediment, and total organic carbon were the main factors governing the distribution of the mollusks in the area. Among the species, only Conomurex persicus was an alien species. [ABSTRACT FROM AUTHOR]

Abstract: In the Mediterranean Sea, the vermetid Dendropoma petraeum (Monterosato, 1884) forms highly biodiverse reefs that have received increasing attention in recent years although very little is known about the food habit of this species. The main goal of this study was to describe the trophic role of planktonic and benthic food sources for D. petraeum. Specimens from three morphological zones of the reef (inner edge, cuvette and outer edge) at two sites with different wave exposure along the north-western coast of Sicily (Italy; western Mediterranean) were compared for δ13C and δ15N. Isotopic determinations were also carried out on potential food sources identified in epilithon, reef macroalgae and suspended particulate organic matter. δ13C for D. petraeum showed significantly more depleted values in the more exposed conditions (i.e. the site with higher wave exposure and outer edge of the reef), while δ15N did not differ appreciably. These results suggest greater exploitation of benthic sources in the sheltered than in the exposed site and reveal diet shift and trophic flexibility at a small spatial scale for the reef-former D. petraeum. [Copyright &y& Elsevier]

Abstract: Mud volcanoes are cold seeps, in which the escape of gas and fluids associated with mud creates 3-D bottom structures that enhance the spatial heterogeneity and potentially alter the functioning of the benthic ecosystems. We investigated a complex system of mud volcanoes of the Mediterranean Sea characterised by the presence of different structures (i.e., isolated domes, domes surrounded by moats, clustered domes, and ridges) displaying different levels of seepage. We hypothesize that the combined effects of seafloor heterogeneity (i.e., different 3-D structures as revealed by detailed topographic analysis), fluid emissions and trophic characteristics of these systems can influence the structural and functional biodiversity of meiofauna (with special focus on the nematodes). We found that sediments affected by intensive seepage displayed the lowest faunal abundances and number of higher taxa. However, mud volcanoes without emissions, but characterized by a high structural complexity (such as the ridges), were associated with the highest meiofaunal abundances and number of higher taxa. Mud volcanoes hosted also a remarkable abundance of rare taxa specifically associated with these structures (e.g., acarians, cumaceans, tanaids, cladocerans and hydroids) and absent in slope sediments (used as a control). Each mud-volcano area displayed a different nematode species composition. Overall 76 nematode species (from a total of 235) were exclusively associated with mud-volcano structures, whilst 29 were exclusively encountered in slope sediments. We conclude that the presence of mud volcanoes, for their contribution to increase spatial heterogeneity and for the extreme conditions associated with gas emissions, promotes higher levels of beta diversity, thus enhancing the regional (gamma) benthic diversity. These findings provide new insights on the factors controlling meiobenthic biodiversity in mud volcanoes and clues for future action of conservation of the biodiversity specifically associated with these habitats. [Copyright &y& Elsevier]

Sympatric sea urchin species are usually considered to belong to the same grazer guild. Nevertheless, their role in community dynamics may vary due to species-specific morphological traits, feeding preferences and foraging behavior. In the Mediterranean Sea, the two species Paracentrotus lividus and Arbacia lixula co-occur in barren areas. Whereas P. lividus is usually considered responsible for creating a barren ground, the roles of the two sea urchin species in its maintenance are currently unclear. The relative and combined effects of P. lividus and A. lixula on maintaining the benthic community in the barren state were tested experimentally, using orthogonal exclusion of the two species. Results show that exclusion of A. lixula, regardless of the presence of P. lividus, led to a significant decrease in the surface of bare rock and a significant change of the algal assemblages, thus demonstrating the major role of this species in maintaining the barren state. [ABSTRACT FROM AUTHOR]

Abstract: Holocene Madrepora-Lophelia subfossil frames recovered at ca. 690m from deep-water coral grounds south of Malta (Strait of Sicily, Central Mediterranean Sea) were found to entrap shells of cnidarian predatory gastropods such as Babelomurex sentix, “Coralliophila”squamosa (morphotype ruderatus) and architectonicids. This finding documents the capability of deep-water coral reefs to serve as taphonomic traps eventually promoting the preservation of rare components of their original biota. [Copyright &y& Elsevier]

Abstract: Recruitment is a principal controlling factor in population dynamics of marine species. In marine invertebrates with a planktonic larval stage, such as echinoids, recruitment is assured by larval supply, settlement and juvenile survival. Larval supply and juvenile survival are affected by a wide range of factors, including temperature, presence of predators, quality and quantity of food. Echinoid larval settlement is mainly conditioned by the finding of a suitable substrate to metamorphose. The sea urchins Arbacia lixula and Paracentrotus lividus are considered key species of the Mediterranean infralittoral rocky shores. At high densities, the grazing activity of both species can produce and maintain barren grounds, a particular habitat condition characterized by extremely low cover values of erect algae with high presence of naked substrates and encrusting corallinales, poor in biodiversity and ecosystem functions. We tested the role of different settlement substrates on the metamorphosis competent larvae of the two species. Furthermore, from our larval rearing trails we were able to identify strong temperature effects on larval development of the two species. P. lividus and A. lixula larvae have been reared at 18°C but for the second species it was necessary to use higher temperatures (22°C) to perform settlement experiments, as in the 18°C set all larvae died in the first week. Both species larvae have been fed Cricosphaera elongata. Metamorphosis of competent larvae has been induced using different substrates: naked stones, Lithophyllum incrustans, Stypocaulon scoparium, Corallina elongata, turf forming algae and Posidonia oceanica. For each species, two larval batches were used for settlement experiments; for each larval batch two replicates/substrates were set up. No differences in the rate of metamorphosis on any of the tested substrates were observed for P. lividus, while A. lixula showed to prefer naked stones and encrusting coralline algae Considering that A. lixula population growth may trigger barren extension on rocky shores, this may lead to a positive feedback between barren extension and A. lixula population density. Furthermore, our results suggest that the predicted rise in seawater temperature may favor A. lixula larval survival and inhibit P. lividus. Combining information on temperature tolerance with other sources of information for these species in the Mediterranean, it is possible to develop a conceptual model of the interaction between the two species and the alternative state of their habitats. [Copyright &y& Elsevier]

Abstract: Toxicity tests were performed exposing the polychaete Dinophilus gyrociliatus to seawater samples containing the toxic dinoflagellate Ostreopsis cf. ovata. Experiments were carried out twice in mid summer, when O. cf. ovata bloomed, and twice in late summer, when the dinoflagellate density declined. Each time, four treatments were considered: original sample; reference sample, which always contained 200 O. cf. ovata cells ml−1; filtered-seawater sample; artificial seawater (control). All the time, almost all worms survived in the controls and filtered-seawater treatments. In mid summer, the mortality of worms in the treatments containing O. cf. ovata was high and density-dependent. On the other hand, mortality in groups exposed to the original and reference samples collected in late summer was negligible. The high per cell toxicity of O. cf. ovata during mid summer could represent an allelopathic response. The test with D. gyrociliatus appears to be a promising tool for assessing the ecological risk of toxic dinoflagellate blooms. [Copyright &y& Elsevier]

Benthic recovery following cessation of wastewater discharges in shallow soft-bottom environments off Barcelona was assessed by revisiting an old sampling site in 2008 that had been studied when the impacts of such discharges were more acute (1987–88). In 1987–88, sediments were highly polluted by organic matter and inorganic contaminants. Although the amount of silt–clay in the sediments diminished from 95 to 25% during the intervening 20-year period and significant improvements were observed in the content of polychlorinated biphenyls and polycyclic aromatic hydrocarbons, their metal content was still very high. However, the benthic community currently showed a clear increase in complexity and diversity. It changed from an assemblage that was 98%-dominated by the Capitella capitata complex to an assemblage dominated by Mediomastus fragilis, Capitella capitata and Ophryotrocha hartmanni. By 2008, more species were found and there was increased representation from different trophic groups, whereas the abundance and biomass values were clearly reduced by almost two and one order of magnitude, respectively. Mean annual density evolved from 385,261 ind. m–2 with a mean annual biomass of 12.75 g dry wt m–2 in 1987–88 to 8155 ind. m–2 and 0.94 g dry wt m–2 in 2008. Using a regression model that allowed comparability between both sets of data, secondary production of the community was reduced from 207.7 g dry wt m–2 year–1 in 1987–88 to 8.0 g dry wt m–2 year–1 in 2008. The organic input decreased, but the metal concentration present in the sediments may inhibit their full recovery to normal conditions. [ABSTRACT FROM AUTHOR]

Abstract: Eutrophication enhances organic C inputs to the sea bottom, so that the quantity and biochemical composition of sedimentary organic matter are expected to change under different trophic status conditions. In turn, changes in the trophic status are often associated with shifts in the abundance and community structure of the benthos. We investigated the quantity and biochemical composition (protein, carbohydrate, lipid and phytopigment) of sedimentary organic matter together with abundance and community structure of meiofauna in two regions of the Mediterranean Sea characterized by different levels of primary productivity. At each region, five transects were randomly selected along the coastline. At each transect, three stations located at increasing distance from the shore and different water depth were investigated. Uni- and multivariate analyses of variance revealed that the quantity and biochemical composition of sediment organic matter displayed the most relevant differences between stations, suggesting their potential use as descriptor of the benthic trophic state at the small spatial scale (i.e. <2 km). The correlation analyses, corroborated by nMDS dispersion plots and cluster analyses highlighted that the biopolymeric C content of the sediment and the algal fraction of sediment organic matter were inversely related and able to discriminate the trophic status at the scale of region, transect and station. Uni- and multivariate analyses on meiofaunal assemblages revealed that differences at different spatial scales were less evident in terms of abundance and richness of meiofaunal taxa but were more evident in terms of taxonomic composition. Furthermore, these differences were enhanced when the analyses were restricted using the meiofaunal rare taxa (i.e. those taxa representing <1% of the total meiofaunal abundance) as an input. The results of the multivariate multiple regression analyses revealed that the taxonomic composition of meiofaunal assemblages was driven mostly by protein, biopolymeric C and chlorophyll-a concentrations but also by the algal fraction of biopolymeric C. We conclude that, the study of the quantity and biochemical composition of sediment organic matter coupled with an analysis of the rare meiofaunal taxa allows an ecosystem-oriented assessment of the trophic status of marine benthic environments. [Copyright &y& Elsevier]

Abstract: Quantification and comparisons of the structure of subtidal marine communities are essential for answering a suite of basic and applied ecological questions. However, time constraint associated with sampling underwater by scuba diving is a major obstacle to achieve adequate sampling effort. We tested a technique for rapid-assessment of hard substrate epibenthic communities, based on counts of the frequency of different taxa within sampling units (quadrats). This technique was compared to a broadly used technique, based on visual estimation of percent cover of taxa, to determine whether a significant amount of information is lost when using the rapid assessment technique. We applied both techniques in three case studies from the Ligurian Sea, in the NW Mediterranean. Field measurements showed that the same communities can be surveyed twice as fast with the frequency-count compared to the cover-estimation. Structural variables of communities as species richness and diversity yield almost identical values with the two techniques while dominance showed underestimated by frequency-count when compared to the cover-estimation. Multivariate analyses indicated that the two techniques yield similar results, highlighting similar patterns of variation in all three case studies, particularly when data are transformed (square-root or fourth-root transformation). Our findings suggest that applying the frequency-count technique to the assessment of benthic communities is an effective strategy for increasing sampling effort when working underwater at depth. [ABSTRACT FROM AUTHOR]

Cold seep communities in the Mediterranean Sea have only been discovered two decades ago, and their trophic ecology has been the subject of very few studies. We investigated the benthic food web of two deep chemosynthesis-based ecosystems on the Napoli and Amsterdam mud volcanoes (MVs) in the eastern Mediterranean Sea (~2,000 m depth). Seeping methane has been detected at the surface of both MVs during pioneering cruises and has been hypothesised to be assimilated by benthic fauna as observed in other oceans' margins. Given the extreme oligotrophic character of the eastern Mediterranean Sea, we a priori expected that chemosynthetic food sources, especially methane-derived carbon (MDC), played a major trophic role in these deep seep communities relative to what has been observed in other seep systems worldwide. We aimed at unravelling the trophic relationships on Napoli and Amsterdam MVs through the analysis of carbon, nitrogen and sulphur isotopes both in the dominant benthic invertebrates including the small endofauna (300 μm < size < 1 cm) and in the sedimented organic matter. In particular, we assessed the fraction of MDC in the tissue of several heterotrophic and symbiotic species. Low mean δS and δC values (0.4 ± 4.8‰ and −31.6 ± 5.7‰, respectively) obtained for mega- and macrofauna suggested that the investigated benthic food webs are virtually exclusively fuelled by carbon of chemosynthetic origin. A few grazer invertebrates (δS up to 11‰) depart from this trend and could complement their diet with sedimented and decayed phytoplanktonic organic matter. Faunal δC values indicated that the oxidation of sulphur is likely the predominant energetic pathway for biosynthesis on both MVs. Nevertheless, mytilid bivalves and small capitellid, ampharetid and spionid polychaetes were C-depleted (δC < −37‰) in a way indicating they assimilated a significant portion of MDC. For these later heterotrophic species, MDC ranged between 21 and 31% (lower estimates) and 97 and 100% (upper estimates). However, our results highlighted that the origin of assimilated carbon may be complex for some symbiotic species. The vestimentiferan tubeworm Lamellibrachia sp., which exclusively depends on its sulphur-oxidising endosymbionts, showed a ~20‰ inter-individual δC variability on a very small spatial scale (<1 m) at the summit of Napoli MV. This mostly reflects the variable isotopic composition of pore-water-dissolved inorganic carbon (DIC) and evidenced that tubeworms (and subsequently their endosymbionts) uptake DIC derived from multiple methane oxidation processes in varying proportions. The lower and upper MDC estimates for the vestimentum of Napoli's individuals were 11-38 and 21-73%, respectively. Finally, data on trophic ecology of Napoli and Amsterdam MVs clearly corroborate previous geophysical results evidencing the spatial heterogeneity of Mediterranean MV environmental conditions. [ABSTRACT FROM AUTHOR]

In order to assess the diet composition of the wide-eyed flounder Bothus podas, we analysed the stomach contents of 388 specimens collected seasonally on sandy bottoms of the north-western coast of Sicily (central Mediterranean). The benthic communities in the same area were also studied in order to investigate the feeding selectivity of B. podas. The prey items found in the stomach contents analysed were mostly benthic organisms. The diet composition of B. podas was dominated by Gammaridea, Apseudidae and Cumacea that were also the most abundant categories in the benthic community. Active prey, such as benthic and epibenthic crustaceans, were highly selected, whereas molluscs and polychaetes were only occasionally ingested. Significant differences found in prey abundance by site were related to the different benthic compositions in the sites examined rather than to changes in the feeding behaviour of B. podas. Significant differences in diet by seasons were explained by the highest abundance of Caprellidea, Gammaridea and Cumacea in spring and summer. The observed feeding patterns were related to spatial and temporal variation of prey abundance in the benthos. As a result, B. podas can be considered an active opportunistic predator. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper was to test how benthic fauna and biogeochemical properties of sediment will vary in response to similar levels of organic enrichment (induced by fish farming) as a function of bottom-habitat type (i.e., mud versus seagrass/coarse sediments), distance from the enrichment source and depth. Our results showed that samples from silty sediments in the vicinity of fish farms have higher TOC and TON values, higher oxygen consumption, higher PO4 release and lower benthic diversity. In this context muddy sites are more likely to be identified as impacted/critical, than coarse sediment ones. [Copyright &y& Elsevier]

Abstract: This work evaluates four indices that have been used for benthic macroinvertebrate ecological quality classification in the Mediterranean Sea. Our study was based on the data obtained from the participation of Greece and Cyprus in the Mediterranean Geographical Intercalibration group. The indices AMBI, M-AMBI, MEDOCC and BENTIX were applied to the available benthic species data, and the succession of the ecological groups along the graded values of each index was plotted. The level of agreement among methods was calculated, and the performance of each method in estimating ecological quality status was evaluated. AMBI, based on the Atlantic model, and its derivative M-AMBI overestimated the statuses, while MEDOCC showed the best level of agreement with BENTIX. BENTIX gives equal weight to tolerant and opportunistic species groups, which correlates them more closely than the other indices and makes BENTIX the most sensitive in detecting ecological disturbances in the Eastern Mediterranean basin, where tolerant and opportunistic groups seem to play an equally important role in the response of benthic communities to stressors. [Copyright &y& Elsevier]

The aim of this study was to analyse the variability of four different benthic biotic indices (AMBI, BENTIX, H′, M-AMBI) in two marine coastal areas of the North-Western Mediterranean Sea. In each coastal area, 36 replicates were randomly selected according to a hierarchical sampling design, which allowed estimating the variance components of the indices associated with four different spatial scales (ranging from metres to kilometres). All the analyses were performed at two different sampling periods in order to evaluate if the observed trends were consistent over the time. The variance components of the four indices revealed complex trends and different patterns in the two sampling periods. These results highlighted that independently from the employed index, a rigorous and appropriate sampling design taking into account different scales should always be used in order to avoid erroneous classifications and to develop effective monitoring programs. [Copyright &y& Elsevier]

Mar Menor lagoon is one of the largest hypersaline coastal lagoons in the Mediterranean Sea. The lagoon is threatened by environmental degradation due to the urban growth around it, the intensive agriculture in its watershed and the remains of mining activities in the nearby Cartagena-La Uni6n area. The present study aims at estimating the levels of zinc and lead in the water column, sediments and marine flora and fauna of Mar Menor lagoon. The ranges of the total concentrations in the water column were 9.36-28.7 µg/L for Zn, 1.61-12.6 µg/L for Pb and 3.01-29.70 µg/L for Mn. Zinc was mostly found in the dissolved phase (70%) whereas lead and manganese in the suspended phase (63-76%). Highest values were measured at stations closer to streams flowing trough drainage basins including agricultural zone and the mining remains. Concerning sediments, the values were very high especially at the southern part, indicating transport of suspended matter from currents. The metal content in the sediments is higher than the content in particulate matter and there is an increased bioavailability of Zn and Pb. Zinc and lead were measured in the thallus of four marine flora species. Maximum zinc concentration was measured in Cymodosea nodosa (132 µg/g) and maximum lead in Acetabularia acetabulum (93.5 µg/g) in samples from the southern lagoon. From the two benthic fauna species studied, it was observed that heavy metals accumulate mostly in the animal flesh. The highest concentration of Zn and Pd was measured in the flesh of the mollusk Ostrea edullis with values of 1,856 and 51.0 µg/g respectively. These values reveal the effect of heavy metal pollution in the lagoon ecosystem. [ABSTRACT FROM AUTHOR]

The twilight or mesophotic zone is amongst the less explored marine regions. In coastal areas, investigations and manipulative experiments on benthic biodiversity and ecosystem functioning at depths up to[50 m have been recently made possible by the progress of SCUBA techniques. In this study, we tested the effects of the presence of a gorgonian forest characterised by a large and dense population of the gold coral Savalia savaglia (Bertoloni 1819) on the benthic biodiversity (nematode species richness, and meiofauna community structure and richness of taxa), trophic guilds state (molluscs) and ecosystem functioning in the surrounding sediments. The S. savaglia colonies create elevated and complex tertiary structures. Our results indicate that the presence of these colonies was associated with a significantly increased deposition of bioavailable substrates and enhanced biodiversity, when compared with soft bottoms at the same depth but without gold corals. The higher biodiversity and altered trophic conditions resulted in higher rates of ecosystem functioning (e.g., higher benthic biomasses). These results suggest that S. savaglia should be particularly protected not only for its specific rarity, endemism and vulnerability but also because it has a prominent role in sustaining high levels of biodiversity and ecosystem functioning in the surrounding benthos of the twilight zone. [ABSTRACT FROM AUTHOR]

The article presents a survey of the continuous high-resolution time-series of the hyperbenthic community and local environmental conditions in the benthic boundary layer (BBL) of the DYFAMED-BENTHOS station of the deep Northwest Mediterranean Sea. It states that near-bottom sediment-trap mooring was deployed four meters above the bottom and an Aanderaa current meter was used to determine the near-bottom current velocities. The collected organisms were mostly meiobenthic and were dominated by copepods which generally involve that of cylopinid genus Barathricola and the tisbid genus Tisbe. It reveals high temporal variations of the swimmers for both intra- and interannual. It reveals that the variations were the result of the variability in both physical and trophic environmental factors.

Abstract: The distribution of recent shallow-water benthic foraminifera in surface sediment samples from cool-water carbonate environments of the Oran Bight, Alboran Platform and Mallorca Shelf in the Western Mediterranean Sea was studied. Multivariate statistical analyses resulted in the identification of species assemblages, representing different environmental settings. In all three regions the assemblages show a distinct bathymetric zonation that is mainly attributed to the distribution of rhodoliths and related substrates, but also to water turbulence and the availability of food at the sea floor. The live assemblages (Rose Bengal stained individuals) are characterised by rather low diversity and low standing stocks, likely reflecting seasonal population dynamics. In the Oran Bight, elevated standing stocks of “high food”-taxa suggest the impact of anthropogenic eutrophication on the near-coastal benthic ecosystems of this area. The diversity of the dead assemblages is higher than in siliclastic shelf ecosystems of the Mediterranean Sea but lower when compared to carbonate environments of the Levantine Sea. This regional difference is mainly attributed to lower sea surface temperatures and the lack of Lessepsian invaders in the western Mediterranean Sea. In all study areas, a distinct faunal change occurs between approximately 80–90m water depth. This change coincides with the lower distribution limit of living rhodoliths at the shelf of Mallorca, providing coarse-grained substrates that are dominated by attached taxa. Below this depth interval, the fauna shows regional differences depending on the grain-size and related accumulation of organic material. Fine-grained substrates with infaunal niches are restricted to low-energy environments on the deeper shelf southwest off Mallorca. [Copyright &y& Elsevier]

The article presents the study on the size diversity and species diversity patterns of benthic macroinvertebrates in the salt marshes of the Mediterranean. It states that the study aims at determining the response of benthonic macroinvertebrates on the biotic and abiotic factors of size and species diversities. The result highlights the importance of abiotic and biotic interactions on both diversity metrics and the applicability of the macroinvertebrate size-based interaction in the abiotically filtered environments.

The day–night cycle is one of the strongest geophysical cycles modulating species’ behavioral rhythms. However, in deep-water continental margins, where light intensity decreases over depth, interspecific competition may alter behavioral responses to day–night cycles. The burrowing decapod crustacean Nephrops norvegicus is a large-size predator in benthic communities, exerting despotic territorial behavior. In this study, we analysed how the effect of light intensity cycles on decapod behavioral rhythms is reduced as one moves from shelves to slopes. In the Western Mediterranean, the predatory behavior and interspecific competition for substrate use of Nephrops increases moving from the shelf (100–110 m) to the slope (400–430 m). Vector fitting and generalized additive models were used to assess the effect of light intensity and behavioral rhythms of N. norvegicus on the temporal variation of prey decapods co-occurring in trawl tow catches carried out on the shelf and the slope during October 1999 and June 2000. The combination of diel variations in light intensity and N. norvegicus abundance influences the activity rhythms of prey decapods in a depth- and seasonal-dependent manner. Light modulation is stronger on the shelf and weaker on the slope, where Nephrops population size is greater. Although present regression analysis does not necessarily imply a direct cause–effect relationship between rhythms of predators and prey, we suggest that Nephrops alters the temporal patterning in the behavior of its prey on the slope, where light intensity is reduced. This alteration is stronger in endobenthic species than in benthopelagic species; the former rely on bottom substrate for the expression of behavioral rhythms, experiencing stronger interspecific competitions with Nephrops at time of activity. [ABSTRACT FROM AUTHOR]

Growth dynamics and bioactivity variation of the Mediterranean demosponges Agelas oroides and Petrosia ficiformis were investigated over 15 months at Paraggi and Colombara within the Marine Reserve of Portofino Promontory (Mediterranean Sea, Ligurian Sea, Italy). For both species, growth rates varied between individuals and were unaffected by initial sponge size. The two species showed a different trend in growth pattern: A. oroides did not vary significantly between seasons, sites and depths; in contrast, some individuals of P. ficiformis showed a seasonal pattern, shrinking during winter as water temperature decreased and growing during summer when water temperature increased. Differences in growth between the two species may result from different reproductive cycles, food availability, species-specific thermophily and patterns of spatial competition. Moreover, spatial competition probably induced sponges to produce bioactive secondary molecules. Spatial and temporal variation of bioactivity of both species was examined for the first time by studying its effect on human neuroblastoma cells. The bioactivity of A. oroides extracts differed significantly between seasons, sites and depths, whereas the cytotoxicity of P. ficiformis differed significantly between seasons and depths (differences for sites were not determined). These results suggest the possible influence of environmental factors on bioactive metabolite biosynthesis. [ABSTRACT FROM AUTHOR]

The article presents the results of a study which examined the relationships linking continental inputs from the Rhone River in the northwestern Mediterranean Sea to the biodiversity of the coastal benthic ecosystem and fishery production. Using variations in river flow, the structure of macrobenthic assemblages were determined and were estimated by the rarefaction method. Carbon stable isotopes were analysed in Rhone particulate organic matter (POM), marine surface water POM, surface sediments and in prey animals on different trophic levels in the food web.

Late in summer 2003, extensive mass mortality of at least 25 rocky benthic macro-invertebrate species (mainly gorgonians and sponges) was observed in the entire Northwestern (NW) Mediterranean region, affecting several thousand kilometers of coastline. We were able to characterize the mortality event by studying six areas covering the main regions of the NW Mediterranean basin. The degree of impact on each study area was quantified at 49 sites by estimating the proportion of colonies affected in populations of several gorgonian species compared with reference data obtained in years without mortality signs. According to these data, the western areas (Catalan coast and Balearic Islands) were the least affected, while the central areas (Provence coast and Corsica-Sardinia) showed a moderate impact. The northernmost and eastern areas (Gulf of Genoa and Gulf of Naples) displayed the highest impact, with almost 80% of gorgonian colonies affected. The heat wave of 2003 in Europe caused an anomalous warming of seawater, which reached the highest temperatures ever recorded in the studied regions, between 1 and 3 °C above the climatic values (mean and maximum). Because this exceptional warming was observed in the depth ranges most affected by the mortality, it seems likely that the 2003 anomalous temperature played a key role in the observed mortality event. A correlation analysis between temperature conditions and degree of impact seems to support this hypothesis. Under the present climate warming trend, new mass mortality events may occur in the near future, possibly driving a major biodiversity crisis in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Abstract: High resolution benthic foraminiferal analyses of sediment cores collected at different sites in the Eastern Mediterranean Sea revealed that profound changes occurred in deep-sea ventilation over the past 124–119 ka BP. The three cores (SIN97-GC01, BAN89-GC09, BD02-GC01) were selected in order to investigate middle and deep bathyal ecosystems in the Eastern Mediterranean basin. At site SIN97-GC01 (933 m water depth, Urania Basin), the presence of benthic fauna in the sapropel layer, and the gradual increase in benthic foraminiferal abundance from the middle part of the sapropel, suggest that the sea-floor was partially ventilated and that re-oxygenation had increased considerably during the late phase of S5 deposition. Cores BAN89-GC09 (2011 m water depth, Napoli Dome) and BD02-GC01 (2470 m water depth, Ionian Sea) show a different pattern. During sapropel S5, benthic abundance and diversity strongly decrease and microfauna even disappears in some levels, suggesting the establishment and maintenance of stagnant and anoxic conditions at the seafloor until the end of S5 deposition. In the deepest part of the basin, the re-establishment of the benthic foraminiferal community at the top of the S5 layer indicates a relatively slow bottom re-oxygenation. At the southernmost site, the foraminiferal assemblage records a short oxygenation pulse during the deposition of sapropel S5 linked to a short cold spell. The results of this study suggest that the evolution of the dysoxic–anoxic conditions, as well as the re-oxygenation pattern at the end of the stagnant period, were characterised by spatial and temporal variability, possibly controlled by basin physiography. [Copyright &y& Elsevier]

Abstract: The performances of two commonly used non-destructive sampling procedures for rocky benthic assemblages (i.e. photography and visually assessed quadrats) were compared. A damaging human activity, date mussel (Lithophaga lithophaga) harvesting (DMH), was chosen. Directly impacted sites were compared with reference conditions (controls). Both visual quadrats and photography were equally able to detect differences between impacted situations and controls. However, visual quadrats showed high variability among replicates and estimated higher species richness for controls, while photography did so for impacts. Pooling photos in a ‘sum photo quadrat’ showed that differences between the two methods are due to sampling unit size rather than sampling procedure itself. As a small sampling unit is unavoidable with photography, visual quadrats should be preferred in investigating shallow rocky reefs for their larger size; however, longer working time underwater with quadrats does not allow for numerous replicates. Pooling many photos to reach sampling sizes comparable with those of quadrats may be a valid alternative to reconcile image resolution and areal coverage. [Copyright &y& Elsevier]

The article examines the spatial and seasonal distribution of macrobenthic invertebrates in Mediterranean solar saltworks ecosystems. Within ecosystems, results showed that the spatial variability at the regional level was greater than seasonal variability. Spatial variability in the salinity and confinement gradient levels was greater than within-level variability. In both its spatial and seasonal aspects, the abiotic environment was found to be critical in determining the macrobenthic community structure. It was found that biotic factors play a significant role in structuring the macrobenthic fauna.

The ecological quality of 127 stations from six Adriatic coastal lagoons was assessed using a suite of biotic indices: H′, d, 1−λ′, Δ ∗, Δ +, W, AMBI, BOPA and FINE. The analysis indicated the difficulties in deriving and using the existing indices from benthic communities in highly variable environmental conditions in coastal lagoons. Different metrics rendered different results: the use of H′ resulted in the classification of all stations as “Moderate/Poor/Bad”, whereas BOPA classified the majority of the stations as “Good/High”. Using Δ +, most of the stations resulted as “Not anthropogenically impacted”, while the W-statistics gave 82 stations as “Undisturbed” and 45 as “Moderately/Grossly disturbed”. AMBI classified 55 stations as “High/Good” and 72 as “Moderate/Poor/Bad”, whereas those were 32 and 95 with FINE, respectively. The latter, which was developed just for Italian coastal lagoons, was the most conservative among the indices studied. Yet, it showed the highest correlation with the species/abundance matrix. Using indices developed for coastal waters in lagoons can give the distorted indication that the water body is degraded, when it might be just a natural, low diversity, high abundance community, i.e. a lagoonal community. Moreover, the outcome of the use of a certain index has a financial dimension such that lagoons misclassified as being “poor status” will then require expensive remediation measures. For the lagoons studied, there is probably an adequate quality and quantity of benthic data available for making management decisions, but this study highlights the limits of the existing indices for lagoonal ecosystems. The challenge for the next future is to couple long term conservation of the natural environment with the highly productive activities carried out in lagoonal ecosystems. [Copyright &y& Elsevier]

Abstract: The macrofauna of the Bay of Banyuls-sur-Mer, initially sampled in 1967–1968 and revisited in 1994, was re-sampled again in 2003, using the same gear and techniques. Results allowed us to overcome some of the flaws of a previous long-term comparison (i.e. between 1967–1968 and 1994). Our data confirm major changes (increase in species richness and changes in macrofauna composition) already observed between 1967–1968 and 1994. The most important changes observed during that period were the increase of the polychaete Ditrupa arietina within the Spisula subtruncata and Nephtys hombergii communities, and the decrease of the polychaetes Scoloplos armiger and Notomastus latericeus in the S. armiger community. Temporal changes in macrofauna composition followed the same general pattern within both the S. subtruncata and the N. hombergii communities. Macrofauna compositions recorded in 1967–1968 and 1994 differed most and the ones recorded in 2003 were intermediate. Temporal changes in abundances of dominant species within these two communities were clearly opposite between 1967–1968 and 1994 compared to 1994 and 2003. Both S. subtruncata and N. hombergii communities are submitted to re-suspension events induced by storms. Strong re-suspension events in the Bay of Banyuls-sur-Mer were hind-casted from 1965 to 2005 based on meteorological data using two procedures calibrated on a one-year time series of wave measurements. Their frequency negatively correlated with the North Atlantic Oscillation (NAO) annual index. The 1994 survey corresponded to a period characterised by a high NAO index and a low number of strong re-suspension events especially during spring, which is the period of recruitment of D. arietina. These observations are consistent with the occurrence of a bottleneck immediately after recruitment, which may account for instability of the population dynamics of this particular species. Temporal changes in macrofauna composition within the deepest S. armiger and Venus ovata communities were characterised by important differences between 1967–1968 and 1994 and almost identical compositions in 1994 and 2003. [Copyright &y& Elsevier]

1. Understanding whether Marine Protected Areas (MPAs) can be considered as a suitable tool for restoring the structure and function of populations and assemblages is urgently needed to achieve an effective policy of mitigation of human impact in coastal management. However, to date, the role played by MPAs in enhancing ecosystems resilience has been more advocated than unambiguously documented. 2. This study was designed to test whether full protection in marine reserves facilitates recovery of benthos impacted by the date mussel Lithophaga lithophaga fishery, one of the most harmful human activities affecting subtidal rocky habitats in the Mediterranean Sea. 3. The effects of this destructive fishery were reproduced at one fully protected location ( P) and at two unprotected control locations ( Cs) in the SW Mediterranean Sea. At each location, three plots (4 m2) of rocky surface at 4–6 m depth were disturbed experimentally, while another three plots served as reference. In each plot, the species composition and relative cover of the sessile benthic assemblages were sampled photographically on each of five occasions during a period of 20 months. 4. Over and above variation in habitat features among locations, multivariate and univariate analyses revealed significant differences between P-vs.- Cs in patterns of assemblage recovery and showed that, at the fully protected location, recovery was faster than at the unprotected control locations. 5. Our results suggest that MPAs have the potential to change the trajectories of recovery of disturbed assemblages by accelerating the processes of recolonization and call for further investigation to identify the specific mechanisms underlying increased resilience. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the possible effects of discharges from a desalination plant on the macrobenthic community inhabiting the sandy substratum off the coast of Blanes in Spain (NW Mediterranean) using multivariate and univariate analyses. Two controls and one putatively impacted location were selected and visual censuses were carried out 12 times before and 12 times after the plant had begun operating. No significant variations attributable to the brine discharges from the desalination plant were found. The failure to record any impact may be explained by the high natural variability that is a characteristic feature of bottoms of this type and also by the rapid dilution undergone by the hypersaline brine upon leaving the discharge pipe. [Copyright &y& Elsevier]

Macrofaunal communities and specific bulk properties of organically enriched sediments were investigated in the coastal lagoon of Cabras (Sardinia, western Mediterranean) on a grid of twenty-nine sampling stations, in spring 2001. Species composition and community structure indicated poor and heterogeneous macrofaunal communities, characterized by few predominant taxa typical of degraded environments, such as Polydora ciliata, Tubificidae nc and Neanthes succinea, distributed differently in some areas of the lagoon. Sediments were homogeneously muddy, with a mean silt þ clay content of 93%. The analysis of specific grain size intervals within the mud fraction, however, highlighted a marked spatial variability of sediment particle distribution. Simple associations included a positive relationship of both Ficopomatus enigmaticus and Corophium sextonae, patchily distributed along the shores, with sediment sorting (σ), an index of sediment selection due to hydrodynamic energy. By contrast, inner areas, characterized by a major accumulation of finer particles (and organic matter), with a sediment mean size (Φ) up to 8.2 phi, were least populated. The results suggest the existence of an early stage of faunal succession which might be related to an excessive organic content of sediments and the tendency to dystrophic events in the Cabras lagoon. [ABSTRACT FROM AUTHOR]

Microbial and meiofaunal dynamics and their relationships with the biochemical composition of the sedimentary organic matter were investigated in a semi-enclosed marine system (Marsala lagoon, Western Sicily, Mediterranean Sea). Sediment samples were collected on a monthly basis from March 1996 to February 1997 in four stations located along a N­S transect characterized by different hydrodynamic regimes. Total sedimentary organic matter concentration ranged from 5.68± 1.11 to 156.28±12.63 mg g-1 , while the biopolymeric fraction of organic carbon (BPC, measured as sum of the lipids, carbohydrates and proteins) accounted for only a small fraction (∼ 24%) of total organic matter. Total meiofaunal density was extremely low, accounting for, on annual average, 112± 29 ind.=10cm-2 and largely dominated by nematodes (on annual average from 40% to 91% of total meiofaunal density). Benthic microbial density ranged from 0.22±0.02 × 109 to 106.83± 16.77×109 g-1 sediment dry weight (DW). Microbial biomass ranged from 0.01± 0.003 to 7.04±0.14 mg Cg-1 sediment DW and accounted for a significant fraction of BPC at all stations (∼10%). Low chlorophyll-a concentration in the sediments of the Marsala lagoon (on annual average from 2 to 16 μg g-1 sediment DW) suggests that organic detrital and heterotrophic bacteria largely dominate the sedimentary organic matter and do not promote the transfer of carbon towards the higher trophic state. [ABSTRACT FROM AUTHOR]