From ctenophores to scyphozoans: parasitic spillover of a burrowing sea anemone.

Most host-parasite associations are explained by phylogenetically conservative capabilities for host utilization, and therefore parasite switches between distantly related hosts are rare. Here we report the first evidence of a parasitic spillover of the burrowing sea anemone Edwardsiella carnea from the invasive ctenophore Mnemiopsis leidyi to two scyphozoan hosts: the native Mediterranean barrel jellyfish Rhizostoma pulmo and the invasive Indo-Pacific nomad jellyfish Rhopilema nomadica, collected from the Eastern Mediterranean Sea. Edwardsiella carnea planulae found in these jellyfish were identified using molecular analyses of the mitochondrial 16S and nuclear 18S rRNA genes. Overall, 93 planulae were found on tentacles, oral arms, and inside of the gastrovascular canals of the scyphomedusae, whereas no infection was observed in co-occurring ctenophores. DNA metabarcoding approach indicated seasonal presence of Edwardsiella sp. in the Eastern Mediterranean mesozooplankton, coinciding with jellyfish blooms in the region. Our findings suggest a non-specific parasitic relationship between Edwardsiella carnea and various gelatinous hosts based on shared functionality rather than evolutionary history, potentially driven by shifts in host availability due to jellyfish blooms. This spillover raises questions about the ecological impacts of parasitism on native and invasive scyphozoan hosts and the potential role of Edwardsiella in controlling their populations.

Age and environment are the main drivers shaping the wild common sole (Solea solea) microbiota.

Microbiota plays an essential role in fish growth and health and may be influenced by the changing environmental conditions. Here, we explored the microbiota of wild common sole, one of the most important fishery resources in the Mediterranean Sea, collected from different areas in the North Adriatic Sea. Our results show that the sole microbiota differs from that of the surrounding environment and among the different body sites (gill, skin and gut). Gut microbiota composition showed to be strongly related to fish age, rather than maturity, sex or sampling site. Age-related shifts in gut microbial communities were identified, with increased abundances of Bacteroidia and Desulfobacteria, unveiling potential microbial proxies for age estimation crucial for fisheries management. Our results expand the limited knowledge of the wild common sole microbiota, also in the light of the potential usefulness of the fish microbiota as a tool for future stock identification and connectivity studies.

Functional ecological traits in young and adult thalli of canopy-forming brown macroalga Gongolaria barbata (Phaeophyta) from a transitional water system.

Background: Gongolaria barbata is a canopy-forming brown macroalga that thrives in the intertidal and subtidal habitats of the warm-temperate Mediterranean Sea, which is particularly exposed to environmental changes due to its peculiar geographical location and exposure to both global and local stressors. Testing whether this species is featured by specific functional, eco-physiological and biochemical traits allowing an efficient use of habitat resources and adaptation to environmental stress, and whether this potential might change with population growth, is essential for predicting the performance of the algae under different environmental abiotic variables (e.g., temperature, nutrient availability, light) and biotic interactions (such as grazing). Methods: Young (juveniles) and adult thalli of G. barbata were sampled in the winter season from the Venice Lagoon, Italy, featured by high environmental changes (temperature, salinity) and analyzed for thallus dry matter content (TDMC), photosynthetic activity, photosynthetic pigment and protein content, and antioxidant capacity to assess if thallus age may be considered a significant driver in determining the ecological responses of this species to environmental changes. Results: Our results showed that TDMC was higher in adults than juveniles. At the functional level, rapid light curves indicated an elevated photosynthetic efficiency in juveniles compared to adults highlighted by the higher quantum yield of PSII electron transport, electron transport rate, and Rubisco content observed in juveniles. On the contrary, adults exhibited a higher non-photochemical quenching and total pigment concentration. No difference in maximum PSII photochemical efficiency and D1 protein content between the two thalli groups was found. Along with better photosynthesis, juveniles also displayed a higher amount of total polyphenols, flavonoids, and tannins, and a stronger antioxidant capacity compared to adults. Conclusions: Our findings revealed significant differences in the eco-physiological characteristics of G. barbata at different growth stages. It was observed that young thalli, allocate more energy to photosynthesis and chemical defenses by increasing the production of antioxidant compounds, such as polyphenols, flavonoids, and tannins. With growth, thalli likely adopt a more conservative strategy, reducing photosynthesis and promoting structural biomass accumulation to mitigate the potential risks associated with prolonged exposure to environmental stressors, such as the wavy way. Although our study focused on a single phase of G. barbata life cycle under winter settings, it offers preliminary insights into this species eco-physiological traits and auto-ecology. Future research could explore the potential implications of these findings, evaluating the species' resilience to environmental changes at the population level.

Active mussel biomonitoring for the health status assessment of the Western Mediterranean Sea.

The Western Mediterranean coast is under the influence of anthropogenic pressures, including land use, increasing amounts of dangerous waste and habitat destruction. In 2021, the French RINBIO network (http://www.ifremer.fr/envlit/) originally dedicated to assess chemical contamination in the region, focused on biological effects produced by contaminants and the interaction with natural variability in mussels using an active caging strategy. Cell and tissue level biomarkers were applied for 17 sampling sites divided in three sub-regions categorized by different environmental conditions. Results provide critical information for ecosystem health assessment using mussels as sentinel species in the Western Mediterranean Sea. The influence of natural and confounding factors (trophic condition, reproductive cycle, caging strategy), on biological responses to mild chemical contamination, was discussed and discriminated for health status assessment. Results provide valuable data available as reference values for the assessment of biomarkers and histopathological alterations for large-scale active biomonitoring campaigns in the Western Mediterranean Sea.

Biological activities of derived pigments and polyphenols from the newly recorded alga Phyllymenia gibbesii.

The newly recorded Phyllymenia gibesii in the Mediterranean Sea at Alexandria coast of Egypt is regarded as a significant source of bioactive substances and is applied as an antioxidant, anti-inflammatory, and antimicrobial agent. According to the HPLC chromatograms, the acetone extract of P. gibesii comprised ten photosynthetic pigments (chlorophyll-a, chlorophyll-d, α-carotene, ß-carotene, phycocyanin, allophycocyanin, antheraxanthin, ß-cryptoxanthin, lutein, and violaxanthin). Total carotenoids were the dominant class in the pigments' profile, achieving a concentration of 257 g/g dry weight. The P. gibbesii extract had a total content of phenols (146.67 mg/g) and a total content of flavonoids (104.40 mg/g). The capacity of all the investigated biological activities augmented with the concentration of the algal extract. The maximal DPPH scavenging capacity was 81.44%, with an inhibitory concentration (IC50) of 9.88 µg/mL. Additionally, the highest ABTS scavenging capacity was 89.62%, recording an IC50 of 21.77 µg/mL. The hemolytic activity of P. gibbesii attained a maximum capacity of 49.88% with an IC50 of 100.25 µg/mL. Data also showed the maximum anti-inflammatory effectiveness at 81.25%, with an IC50 of 99.75 µg/mL. Furthermore, the extract exhibited antimicrobial capacity against all reference strains, particularly at high concentrations (0.1 mg/mL), with the greatest effect on C. albicans and E. coli.

Genetic drift, historic migration, and limited gene flow contributing to the subpopulation divergence in wild sea beet (Beta vulgaris ssp. maritima (L.) Arcang).

Cultivated beet (Beta vulgaris L. ssp. vulgaris) originated from sea beet (B. vulgaris ssp. maritima (L.) Arcang), a wild beet species widely distributed along the coasts of the Mediterranean Sea and Atlantic Ocean, as well as northern Africa. Understanding the evolution of sea beet will facilitate its efficient use in sugarbeet improvement. We used SNPs (single nucleotide polymorphisms) covering the whole genome to analyze 599 sea beet accessions collected from the north Atlantic Ocean and Mediterranean Sea coasts. All B. maritima accessions can be grouped into eight clusters with each corresponding to a specific geographic region. Clusters 2, 3 and 4 with accessions mainly collected from Mediterranean coasts are genetically close to each other as well as to Cluster 6 that contained mainly cultivated beet. Other clusters were relatively distinct from cultivated beets with Clusters 1 and 5 containing accessions from north Atlantic Ocean coasts, Clusters 7 and Cluster 8 mainly have accessions from northern Egypt and southern Europe, and northwest Morocco, respectively. Distribution of B. maritima subpopulations aligns well with the direction of marine currents that was considered a main dynamic force in spreading B. maritima during evolution. Estimation of genetic diversity indices supported the formation of B. maritima subpopulations due to local genetic drift, historic migration, and limited gene flow. Our results indicated that B. maritima originated from southern Europe and then spread to other regions through marine currents to form subpopulations. This research provides vital information for conserving, collecting, and utilizing wild sea beet to sustain sugarbeet improvement.

Soundscape analysis can be an effective tool in assessing seagrass restoration early success.

Restoration of vulnerable marine habitats is becoming increasingly popular to cope with widespread habitat loss and the resulting decline in biodiversity and ecosystem services. Lately, restoration strategies have been employed to enhance the recovery of degraded meadows of the Mediterranean endemic seagrass Posidonia oceanica. Typically, habitat restoration success is evaluated by the persistence of foundation species after transplantation (e.g., plant survival and growth) on the short and long-term, although successful plant responses do not necessarily reflect the recovery of ecosystem biodiversity and functions. Recently, soundscape (the spatial, temporal and frequency attribute of ambient sound and types of sound sources characterizing it) has been related to different habitat conditions and community structures. Thus, a successful restoration action should lead to acoustic restoration and soundscape ecology could represent an important component of restoration monitoring, leading to assess successful habitat and community restoration. Here, we evaluated acoustic community and metrics in a P. oceanica restored meadow and tested whether the plant transplant effectiveness after one year was accompanied by a restored soundscape. With this goal, acoustic recordings from degraded, transplanted and reference meadows were collected in Sardinia (Italy) using passive acoustic monitoring devices. Soundscape at each meadow type was examined using both spectral analysis and classification of fish calls based on a catalogue of fish sounds from the Mediterranean Sea. Seven different fish sounds were recorded: most of them were present in the reference and transplanted meadows and were associated to Sciaena umbra and Scorpaena spp. Sound Pressure Level (SPL, in dB re: 1 µPa-rms) and Acoustic Complexity Index (ACI) were influenced by the meadow type. Particularly higher values were associated to the transplanted meadow. SPL and ACI calculated in the 200-2000 Hz frequency band were also related to high abundance of fish sounds (chorus). These results showed that meadow restoration may lead to the recovery of soundscape and the associated community, suggesting that short term acoustic monitoring can provide complementary information to evaluate seagrass restoration success.

Marine fungal community composition and diversity across a polluted site in the south Mediterranean coast: the Monastir Bay, Tunisia.

Marine fungi communities play a crucial role in the recycling of nutrients, restoration of biological systems, and the overall functioning of ecosystems. While aquatic fungal communities do react to pollution, there is a significant lack of information regarding the changes in the fungal community's structure, caused by marine pollution. In this study, we aim to address this gap in knowledge by investigating the range and makeup of fungal species present in marine environments in a polluted bay in Tunisia, spanning a biodiversity hotspot (Monastir Bay). Sequence analysis of the internal transcribed spacer region from culturable mycobiome and physicochemical parameters were investigated at seven sites in the bay. A total of 32 fungal taxa were identified at the genus and/or species levels and were assigned to four major groups (Aspergillacae 37.5%, Dothiomyceta 21.87%, Sordariamyceta 28.12%, and Yeasts 12.5%) with a remarkable predominance of Aspergillus genus. Assessment of the Shannon-Wiener diversity index and the Simpson dominance index revealed that the highest species diversity index (0.84) was recorded at the Kheniss site. Our results suggest the existence of diverse fungal communities, can be considered a useful community model for further ecological and evolutionary study of fungi in the bay.

Shark shuffle: segregated co-occurrence of multiple dusky and sandbar lineages at a human-altered habitat in the eastern Mediterranean Sea.

Requiem sharks (genus Carcharhinus) have previously been reported to form large aggregations around marine infrastructures in the eastern Mediterranean Sea. While this behaviour may offer fitness advantages at the individual level, the implications of extended residency at human-altered habitats for population persistence have yet to be assessed. In this work, we investigated the phylogeographic and demographic composition of sharks near a coal-fired power and desalination station in Israel. Our aim was to infer habitat use and the mechanisms underlying the aggregation behaviour, and to highlight potential conservation impacts. We sampled, measured, and released 70 individuals between 2016 and 2022 to assess genetic variability within the cytochrome C oxidase I (COI) region and to analyse the aggregation's structure based on the sharks' size and sex distribution. In addition, we performed meristic counts on a reference specimen collected dead at another power station in Israel to supplement species identification using the abovementioned techniques. Our findings indicate size-based sex segregation of adult female dusky and male sandbar sharks (Carcharhinus obscurus and Carcharhinus plumbeus, respectively), with each species comprising two COI haplotypes. In the dusky shark, one haplotype corresponded to an Indo-Pacific lineage, and the other matched an Atlantic lineage. In the sandbar shark, we observed a haplotype previously sampled in the Mediterranean Sea, the Red Sea, the Northwest Indian Ocean, and South Africa, and another haplotype that was unique to our study site and genetically closer to the former than to sequences sampled in other ocean basins. This study provides the first indication of sympatric aggregation amongst phylogeographically distinct dusky and sandbar shark lineages, suggesting that human-altered habitats in the eastern Mediterranean Sea may influence the distribution of these species. Based on the observed segregation pattern, we conclude that the site does not function as a nursery, parturition, or mating area, and discuss other plausible explanations that warrant further research. Finally, we highlight important directions for future research and the implications of our findings for management and conservation.

Zooplankton responses to simulated marine heatwave in the Mediterranean Sea using in situ mesocosms.

Globally, marine heatwave frequency, intensity, and duration are on the rise, posing a significant threat to plankton communities, the foundational elements of the marine food web. This study investigates the ecological and physiological responses of a temperate plankton community in the Thau lagoon, north-western Mediterranean, to a simulated +3°C ten-day heatwave followed by a ten-day post-heatwave period in in-situ mesocosms. Our analyses encompassed zooplankton grazing, production, community composition in water and sediment traps, as well as oxidative stress and anti-oxidant biomarkers. The results revealed increased abundances of harpacticoid copepods and polychaete larvae during the simulated heatwave and post-heatwave event. Sediment trap data indicated elevated mortality, particularly dominated by polychaete larvae during the post-heatwave period. Oxidative stress biomarker (lipid peroxidation LPX) levels in the plankton community correlated with temperature, signaling cellular damage during the heatwave. LPX increased and proteins decreased with increasing salinity during the experiment. Offspring production peaked during the post-heatwave phase. Notably, the calanoid copepod Acartia clausi exhibited a preference for ciliates as its primary prey, constituting 20% of the overall available prey. Our findings suggest a potential shift in coastal zooplankton communities during future marine heatwaves, transitioning from calanoid mesozooplankton dominance to a system featuring meroplankton and/or harpacticoid copepods. Although species preying on microzooplankton may gain advantages in such conditions, the study underscores the damaging impact of heatwaves on organismal lipids, with potential consequences for reproduction, growth, and survival within marine ecosystems.

Distribution and functional perspective analysis of epiphytic and endophytic bacterial communities associated with marine seaweeds, Alexandria shores, Egypt.

There is an enormous diversity of life forms present in the extremely intricate marine environment. The growth and development of seaweeds in this particular environment are controlled by the bacteria that settle on their surfaces and generate a diverse range of inorganic and organic chemicals. The purpose of this work was to identify epiphytic and endophytic bacterial populations associated with ten common marine macroalgae from various areas along the Mediterranean Sea coast in Alexandria. This was done to target their distribution and possible functional aspects. Examine the effects of the algal habitat on the counting and phenotypic characterization of bacteria, which involves grouping bacteria based on characteristics such as shape, colour, mucoid nature, type of Gram stain, and their ability to generate spores. Furthermore, studying the physiological traits of the isolates under exploration provides insight into the optimum environmental circumstances for bacteria associated with the formation of algae. The majority of the bacterial isolates exhibited a wide range of enzyme activities, with cellulase, alginase, and caseinase being the most prevalent, according to the data. Nevertheless, 26% of the isolates displayed amylolytic activity, while certain isolates from Miami, Eastern Harbor, and Montaza lacked catalase activity. Geographical variations with the addition of algal extract may impact on the enumeration of the bacterial population, and this might have a relationship with host phylogeny. The most significant observation was that endophytic bacteria associated with green algae increased in all sites, while those associated with red algae increased in Abu Qir and Miami sites and decreased in Eastern Harbor. At the species level, the addition of algal extract led to a ninefold increase in the estimated number of epiphytic bacteria for Cladophora pellucida in Montaza. Notably, after adding algal extract, the number of presented endophytic bacteria associated with Codium sp. increased in Abu Qir while decreasing with the same species in Montaza. In addition to having the most different varieties of algae, Abu Qir has the most different bacterial isolates.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) distribution, origins, and risk evaluation in the Egyptian Mediterranean coast sediments.

A study was conducted on 31 surface sediments located in different sectors of the Egyptian Mediterranean coast. The sediments were analyzed for their pollution levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The sediments were collected from various depths in harbors, coastal lakes, bays, and lagoons, covering the southeastern Mediterranean of the Nile Delta region. The study aimed at determining the distribution, origin, and potential ecological impact of OCP and PCB pollutants. The researchers used the SRM method of GC-MS/MS to measure the concentration of 18 PCBs and 16 OCPs residues. The study found that the total concentration of OCPs in the samples ranged from 3.091 to 20.512 ng/g, with a mean of 8.749 ± 3.677 ng/g. The total concentration of PCB residues ranged from 2.926 to 20.77 ng/g, with a mean of 5.68 ± 3.282 ng/g. The concentration of DDTs exceeded the effect range low (ERL) (1.00) and threshold effect level (TEL) (1.19) in several stations, but it was still below the effect range median (ERM) (7.00) and the probable effect level (PEL) (4.77). This indicates a low ecological risk. The principal component analysis (PCA) was also conducted to determine the sources of all pollutants in the sediment. The PCA showed significant correlations between the concentrations of Gama-HCH and Beta-HCH (0.741), suggesting similar sources. PRACTITIONER POINTS: OCPs and PCBs residues were analyzed in the sediment of the southeastern Mediterranean. The concentration, existence, and causes of OCPs and PCBs were investigated. OCPs and PCBs ecological risk and ecotoxicological calculation were investigated in detail. Cluster analysis, PCA, and correlation coefficient were also investigated.

Assessing benthic macroinvertebrate communities' spatial heterogeneity in Mediterranean transitional waters through eDNA metabarcoding.

Transitional waters are important habitats both for biodiversity and ecological functions, providing valuable natural resources and relevant ecosystem services. However, they are highly susceptible to climate changes and anthropogenic pressures responsible for biodiversity losses and require specific biomonitoring programs. Benthic macroinvertebrates are suitable as ecological indicators of transitional waters, being affected by biological, chemical, and physical conditions of the ecosystems about their life cycles and space-use behaviour. The advent of high-throughput sequencing technologies has allowed biodiversity investigations, at the molecular level, in multiple ecosystems and for different ecological guilds. Benthic macroinvertebrate communities' composition has been investigated, at the molecular level, mainly through DNA extracted from sediments in marine and riverine ecosystems. In this work, benthic macroinvertebrate communities are explored through eDNA metabarcoding from water samples in a Mediterranean transitional water ecosystem. This research highlighted the validity of eDNA metabarcoding as an efficient tool for the assessment of benthic macroinvertebrate community structure in transitional waters, unveiling the spatial heterogeneity of benthic macroinvertebrate communities correlated to the measured environmental gradients. The results suggest that peculiar features of transitional water ecosystems, such as shallow waters and limited currents, facilitate the assessment of benthic macroinvertebrate communities through environmental DNA analysis from surface water samples, opening for more rapid and accurate monitoring programs for these valuable ecosystems.

Epiphytic microbiome associated with intertidal seaweeds in the Mediterranean Sea: comparative analysis of bacterial communities across seaweed phyla.

The complex interactions between epiphytic bacteria and marine macroalgae are still poorly understood, with limited knowledge about their community structure, interactions, and functions. This study focuses on comparing epiphytic prokaryotes community structure between three seaweed phyla; Chlorophyta, Rhodophyta, and Heterokontophyta in an easternmost rocky intertidal site of the Mediterranean Sea. By taking a snapshot approach and simultaneously collecting seaweed samples from the same habitat, we minimize environmental variations that could affect epiphytic bacterial assembly, thereby emphasizing host specificity. Through 16S rRNA gene amplicon sequencing, we identified that the microbial community composition was more similar within the same seaweed phylum host compared to seaweed host from other phyla. Furthermore, exclusive Amplicon Sequence Variants (ASVs) were identified for each algal phyla despite sharing higher taxonomic classifications across the other phyla. Analysis of niche breadth indices uncovers distinctive affinities and potential specialization among seaweed host phyla, with 39% of all ASVs identified as phylum specialists and 13% as generalists. Using taxonomy function prediction, we observed that the taxonomic variability does not significantly impact functional redundancy, suggesting resilience to disturbance. The study concludes that epiphytic bacteria composition is connected to host taxonomy, possibly influenced by shared morphological and chemical traits among genetically related hosts, implying a potential coevolutionary relationship between specific bacteria and their host seaweeds.

Mesophotic zone as buffer for biodiversity protection: A promising opportunity to enhance MPA effectiveness.

Coastal areas conservation strategies often left deeper habitats, such as mesophotic ones, unprotected and exposed to anthropogenic activities. In this context, an approach for including the mesophotic zone inside protection plans is proposed, considering 27 Italian Marine Protected Areas (MPAs) as a model. MPAs were classified considering their bathymetries, exposure to marine heat waves (MHWs), mass mortality events (MMEs) and, using a local ecological knowledge (LEK) approach, the estimated resilience of certain sessile species after MMEs. Only 8 MPAs contained considerable mesophotic areas, with stronger MHWs mainly occurring in shallower MPAs, and MMEs mostly affecting coralligenous assemblages. Even with only a 10% response rate, the LEK approach provided useful information on the resilience of certain species, allowing us to suggest that the presence of nearby mesophotic areas can help shallower habitats facing climate change, thus making the "deep refugia" hypothesis, usually related to tropical habitats, applicable also for the Mediterranean Sea.

Sandy bottoms have limited species richness but substantially contribute to the regional coastal fish ß-diversity: A case study of the Central Mediterranean Sea.

Global marine biodiversity loss impairs entire ecosystems and their stability. Robust biodiversity estimates are key to inform policies and management strategies, and need to consider the contribution of diverse habitats, including those for which estimates of biodiversity are scattered or totally absent. This study assessed the fish diversity associated with three main coastal habitats (rocky bottoms, Posidonia oceanica meadows, sandy bottoms), and their role in shaping the overall coastal fish diversity, also in relation to potential environmental and anthropogenic drivers affecting patterns of fish diversity in coastal areas. Using underwater visual census, we sampled 62 sites distributed on the three habitats, for a total of 496 replicates. We assessed the contribution of each habitat to ß-diversity, divided into Local Contribution to ß-diversity (LCBD), a comparative indicator of the contributions to ß-diversity of each habitat, and Species Contribution to ß-diversity (SCBD), which measures the relative importance of each species in affecting ß-diversity. Finally, we modelled species diversity in relation to potential environmental and anthropogenic drivers. Overall, 72 species were recorded, with the highest species richness observed on rocky bottoms (56 species, 16 unique to this habitat), followed by P. oceanica (38 species, 0 unique) and sandy bottoms (32 species, 14 unique). Sandy bottom assemblages had a significantly higher contribution to LCBD than P. oceanica meadows and rocky bottoms, and two of the five species with the highest contribution to SCBD are exclusively associated with sandy bottoms. Finally, sea surface temperature, sea surface salinity, and habitat were highlighted as significant predictors of species richness. Our findings, aside from highlighting the environmental drivers of coastal fish diversity in the Mediterranean Sea, unravel the potential key role of sandy bottoms in contributing to overall coastal fish diversity and can inform conservation planning.

Artificial light at night alters the locomotor behavior of the Mediterranean sea urchin Paracentrotus lividus.

Artificial light at night (ALAN) is a recognized source of anthropogenic disturbance, although its effects on biological systems have not been fully explored. Within marine ecosystems, coastal areas are the most impacted by ALAN. Here, we focused on the Mediterranean sea urchin Paracentrotus lividus, which has a crucial role in shaping benthic ecosystems. Our objective was to investigate if ALAN affects the nocturnal locomotor behavior of P. lividus. A semi-controlled field study was conducted along a rocky shore near a promenade lit at night. Results suggested a potential impact of ALAN on the locomotor behavior of sea urchins. Individuals of P. lividus tended to move away from the light sources while its directions in dark conditions were uniform. Their locomotor performance, in presence of ALAN, was characterized by shorter latency time, lower sinuosity and higher mean speed at increasing light intensity, with potential cascading effect at the ecosystem level.

Macro-and micro-plastics detected in razorbill Alca torda in the western Mediterranean Sea.

The Mediterranean Sea is a hotspot for plastic pollution and, consequently, an area at high risk of plastic exposure for oceanic seabirds. In this work we retrieved plastic items from different tissues/organs of razorbills Alca torda. This is a piscivorous species of the Alcidae family usually thriving along the North Atlantic coasts. In the winter 2022-2023, some individuals were observed in the Mediterranean area up to the Italian tyrrhenian coasts. Among the five carcasses examined, three contained plastic debris, mainly in the digestive system, in the form of fragments and fibers. The latter were also found in the pectoral muscles and, in one individual, in the liver. Polyethylene was the most represented polymer (55.2 %), followed by polypropylene (24.1 %) and cellulose (10.4 %). Previous reports hypothesized that North Atlantic razorbills are less exposed to plastic pollution because of their feeding strategy. Our results contradict this hypothesis, highlighting their susceptibility to plastic contamination.

Minerals and trace element compositions of some seaweeds from the Marchica lagoon, North-East Mediterranean coast of Morocco.

The objective of the present study was to evaluate the mineral and heavy metals composition of different seaweeds growing in Marchica lagoon. To this end, green seaweeds, red seaweeds, and brown seaweeds were collected from three different stations in the Marchica lagoon. The highest concentration of Ca was measured in Centroceras clavulatum (17.12 ± 0.60), K in Caulerpa prolifera (15.17 ± 0.20), Na in Gracilaria dura (4.16 ± 0.03) and Hypnea musciformis (4.09 ± 0.03), Mg in Ulva rigida (2.80 ± 0.06), and the highest concentration of P was registered in Ulva intestinalis (3658 ± 14). Centroceras clavulatum and Gracilaria dura had the highest Al, Fe, and Sr levels. Cystoseira compressa had the highest As (53.8 mg/kg) and Rb (43 mg/kg). These findings suggest that seaweeds collected from Marchica lagoon could be used as potential sources of minerals and trace elements in seaweed-based products for human and animal nutrition alike.

Terrain, oceanographic, and biological factors underlying the development of Mediterranean coastal animal forests.

Marine Animal Forests (MAFs) form three-dimensional seascapes and provide substrate and shelter for a variety of species. We investigated the fine-scale distribution pattern of three habitat-forming species of the coastal Mediterranean MAFs: Eunicella cavolini, E. singularis and Paramuricea clavata, and assessed the influence of terrain, oceanographic, and biological factors on their distribution and the formation of MAFs in the central-northern Tyrrhenian Sea. Species presence and abundance were obtained through seafloor HD imagery and were combined with terrain and oceanographic parameters extracted from remote sensing data using distance-based linear modeling (DistLM) and generalized additive model (GAM). The three studied species occurred in all the study areas, with marked differences in their abundance and distribution across the different sites and habitat type, in relation to seafloor characteristics. Specifically, positive relationships emerged between the density of colonies and terrain parameters indicative of high seafloor complexity, such as slope and roughness, as well as the number species structuring MAFs. A clear niche separation for the three species was observed: E. cavolini and P. clavata were reported on coralligenous reefs, and in areas where the seafloor complexity may enhance hydrodynamics and transport of organic matter, while E. singularis was observed on red algal mats at shallower depths. A better understanding of the ecology of these gorgonians, as well as of the drivers determining MAFs formation, represent the first step toward the conservation of these threatened habitats which are currently poorly protected by management and conservation plans.