Search Results (202)

Posidonia oceanica (L.) Delile is a seagrass endemic to the Mediterranean Sea and a significant contributor to human well-being through a variety of ecosystem functions, such as carbon cycling. Despite its ecological significance, most methods for estimating leaf biomass in this species are either destructive or expensive. In this study, 2500 individual leaves from 351 shoots of Posidonia oceanica were collected, across 16 sites in the Ligurian Sea, over two time periods (2016–2018 and 2024–2025), and analyzed for total leaf area and dry weight. An allometric equation following a power-law structure was derived using linear mixed-effects models and it was later validated via 10-fold cross-validation. Although some variations in the intercept term were observed, the allometric scaling structure remained consistent across space and time, providing the first robust species-specific allometric tool to estimate P. oceanica biomass, forming the basis of a proposed non-destructive protocol for meadow-scale biomass estimation. Full article

Seagrasses are vital ecosystem engineers and habitat architects in coastal environments, with Posidonia oceanica in the Mediterranean playing a crucial role as an indicator of ecological health. As an endemic and vulnerable species, P. oceanica meadows are highly susceptible to environmental degradation, underscoring the importance of non-destructive monitoring techniques. Traditional SCUBA-based surveys are accurate but resource-intensive and difficult to scale, especially for estimating shoot density and leaf length. This study applies a conservative acoustic-based approach to assess Posidonia oceanica biometrics, habitat characteristics, and ecological status along the Turkish Levant coast. The method offers a non-destructive alternative to SCUBA surveys and addresses a regional knowledge gap in Mediterranean seagrass monitoring. Acoustic data collected during winter and summer 2019 along the Turkish Levant coast were analyzed to estimate seagrass biometrics and derive ecological indicators, with validation via SCUBA observations. Results show that acoustic methods can reliably estimate shoot density, leaf area index, and canopy height. They provide broad-scale coverage and efficiency, though further refinement is required to improve calibration across depths and substrates. While acoustic methods provide broad, non-invasive coverage, they are affected by spatial and temporal variability that SCUBA surveys capture more reliably. Calibration of the POSIBIOM (vers 1.1) algorithm was based on specimens collected at 15 m depth on rocky substrates. While this provided consistent regression relationships, it may limit accuracy when extrapolated to habitats such as sand, mud, or matte. This study represents the first high-resolution, spatiotemporal mapping of P. oceanica meadows and benthic habitats along a significant portion of the Turkish Levant coast using acoustics alone. Overall, the study highlights the potential of acoustics as a scalable, non-invasive tool for seagrass monitoring. This approach contributes to ecosystem-based management and conservation strategies in the Mediterranean. Future work will focus on refining models to address bottom type- and depth-dependent acoustic responses and improve biometric accuracy. Full article

Evaluating the bathymetric distribution of phytobenthic communities is essential for understanding the factors affecting habitat heterogeneity along a depth gradient. In the present study, we investigated the composition and vertical zonation patterns of phytobenthic communities across different bottom types (rocky and sedimentary) along the Turkish Aegean coasts. Dominant habitat types were identified in 175 depths and classified into 18 categories (Posidonia oceanica, Cymodocea nodosa, Halophila stipulacea, Halopteris spp., Stypopodium schimperi, Ericaria crinita, coralligenous, coralligenous/Mesophyllum spp., Jania spp./Halopteris spp., Ulva spp., rocky, rocky-turf, sandy, sandy-Caulerpa taxifolia var. distichophylla, sandy-Gongolaria montagnei var. compressa, silt, muddy, slime). Among the study sites, P. oceanica meadows (41%) were the dominant habitat in 70 depths, followed by sandy (30%), and rocky bottoms (11%). Total coverage of P. oceanica meadows was recorded as 28%, 80%, 76%, and 56% at 5 m, 10 m, 15 m, and 20 m depths, respectively. Seagrass meadows have started to be replaced by sandy bottoms at 30 m (52%) and 40 m (72%). Considering the bathymetrical divergence in phytobenthic community composition and abundance particularly in urban sites, reflected the influence of intense anthropogenic stressors. Here, non-destructive and cost-effective visual sampling technique based on in situ observations of phytobenthic community assemblages, proved to be an effective approach for the assessment of subtidal habitats. Full article

The present research provides the first quantitative comparison of the hidden fish assemblages in Posidonia meadows and neighboring non-Posidonia habitats. The data and samples were collected at sixty sampling points at three locations on the south side of Brač Island in the eastern Adriatic Sea from October 2023 to June 2025. The gradient of a significant increase in fish abundance and average fish species richness in cuboids and the increase in the frequency of occurrence of fish species were observed from habitats inside Posidonia meadows, over the Posidonia meadow edge, to the habitats outside Posidonia meadows. The primary influence on the abundance was the rarity of species from the family Gobiidae within Posidonia habitats. The markedly different species composition between the Posidonia and non-Posidonia habitats was driven by the high species richness of the family Labridae in the Posidonia habitat compared to the high species richness of the family Gobiidae in the non-Posidonia habitats. The Posidonia meadow edge showed overlap with the two other habitat types, sharing a number of species. The sampling protocol developed in this study is suitable for the quantitative assessment of fishes inhabiting hidden Posidonia microhabitats and provides a methodological basis for future research. The current knowledge of fish in Mediterranean Posidonia meadows, as well as the conservation consequences of still limited knowledge, are discussed. Full article

Mediterranean meadows of Posidonia oceanica are chronically exposed to complex mixtures of environmental contaminants, including metals and trace elements derived from coastal urbanization, maritime traffic, and industrial activities. This study aimed to assess metal-related toxicity in P. oceanica by integrating multi-element burden analysis with a panel of oxidative stress biomarkers. Concentrations of a wide suite of elements were quantified in samples of internal (juvenile), intermediate, and external (adult) leaves, reflecting the ontogenetic structure of the plant. Oxidative responses were evaluated using five biomarkers [i.e., hydrogen peroxide (H₂O₂), lipid peroxidation (TBARS), superoxide dismutase (SOD), glutathione S-transferase (GST), and catalase (CAT)] measured on each leaf compartment. Biomarker data were standardized and integrated into a merged Stress Index summarizing overall physiological toxicity. Associations between individual elements, the sum of all measured elements (ΣallElements), the Stress Index, and single biomarkers were explored using Pearson correlation analysis. Juvenile leaves exhibited the highest Stress Index values, elevated H₂O₂ and TBARS, and marked activation of SOD and GST, indicating early oxidative toxicity. Intermediate leaves showed a trend toward increased CAT activity, not reaching statistical significance, along with minimal damage, suggesting effective detoxification, whereas adult leaves accumulated higher levels of Fe, Ni, and Pb, but displayed moderate stress responses. Overall, leaf-class structure strongly modulated both exposure and toxicological response. The integration of ΣAllElements with multi-biomarker indices provides a robust framework for diagnosing metal-related toxicity in P. oceanica under realistic multi-element exposure scenarios. Full article

Posidonia oceanica meadows are among the most valuable coastal ecosystems in the Mediterranean Sea, providing key ecological functions and socio-economic benefits. Despite conservation efforts, these meadows declined markedly throughout the late 20th century due to cumulative human pressures, although their condition has stabilised more recently under protection, and natural recolonization has even begun in some areas. In this context, active restoration through transplantation has expanded considerably, particularly in response to recent policy initiatives, and is now contributing to the recovery of these ecosystems. However, long-term monitoring to assess active restoration success remains scarce. This study revisits one of the earliest P. oceanica transplantation interventions, initiated in 1996 in front of the tourist harbour of Rapallo (NW Mediterranean), and evaluates its status after nearly 30 years. Surveys conducted in 2019 and 2024 confirmed the persistence of the transplanted meadow. The restored area increased from approximately 20 m² at establishment to 26.9 m² in 2024, and shoot density reached values comparable to well-developed natural meadows in the region. The observed long-term structural stability highlights the need to assess restoration outcomes over decadal timescales. This case study also suggests that fine-scale site conditions, including hydrodynamic shelter and adequate light availability, can strongly influence long-term restoration success. Full article

The accumulation of dead leaves from the Mediterranean seagrass Posidonia oceanica on beaches is a natural process that results in the formation of banquettes and, in some areas, spherical debris known as aegagropiles. These structures provide essential ecosystem functions, particularly coastal protection against erosion. Despite their ecological importance, accumulated Posidonia oceanica biomass is often perceived as undesirable waste by stakeholders such as beach managers, local authorities, and tourists, leading to its systematic removal. This review summarises the chemical characteristics of this marine biomass and assesses its environmental and socioeconomic impact. Additionally, some different valorisation pathways for this biomass waste are examined, including animal feeding, bioactive compound extraction, development of biochar, biofertilisers, and compost, production of biosorbents, biocomposites and building materials, and also energy generation. The findings highlight the significant potential of P. oceanica residues within circular economy strategies and underscore the need for improved management practices that recognise their ecological value. Full article

Marine Protected Areas (MPAs) are essential for preserving marine biodiversity; yet they face challenges from various human pressures, including vessel activities. This study examines the extent, spatial distribution, and temporal variability of vessel activity within the Southwest Marine Protected Area (MT101), a Natura 2000 site off the Maltese Islands, with the aim of identifying where and to what degree different vessel categories overlap with protected marine habitats. Using Automatic Identification System (AIS) data spanning 2017–2022, a cumulative, normalised vessel density approach was applied to five vessel types: passenger, fishing, cargo, tanker, and tug and towing vessel, and spatially integrated with the distribution of four Annex I habitat types, including sandbanks, Posidonia oceanica meadows, reefs, and sea caves. The analysis reveals distinct spatial and temporal hotspots of vessel presence, with passenger and fishing vessels showing consistently high overlap with ecologically sensitive habitats, particularly within bay areas and along sections of the MPA boundary, while cargo, tanker, and tug activities are more concentrated offshore. While direct ecological impacts were not quantified and vessel density serves as a proxy for potential pressure, the results highlight areas where vessel-related pressures are likely to be most pronounced and where management intervention is most urgently required. By linking long-term vessel activity patterns with habitat distribution, this study delivers a spatially explicit and transferable framework for assessing cumulative maritime pressures, providing an evidence base to support targeted, habitat-specific management measures, improved enforcement, and marine spatial planning within MPAs. Full article

The preservation of littoral zones faces escalating challenges from global thermal forcing and anthropogenic pressure, particularly in vulnerable basins like the Mediterranean. This research proposes an expanded Coastal Vulnerability Index to assess 253 km of beaches across the Valencian Community (Spain), integrating sediment durability parameters for the first time. Methodologically, an arithmetic mean of ten physical, biotic, and sedimentological indicators was employed, including a novel Sediment Quality Classification Index (SQCI) derived from accelerated particle wear tests as a key resilience indicator. Results reveal that 40.9% of the coastline exhibits high or very high risk, reaching critical levels in the province of Valencia due to key driving factors such as a 91.8% proportion of fine sediments and the severe degradation of its dune systems. Conversely, the presence of Posidonia oceanica meadows in Alicante acts as a key resilience factor. It is possible to conclude that the mechanical quality of sediment is a determinant for the longevity of protection measures, highlighting the necessity of transitioning from rigid infrastructures towards ecosystem-based adaptation to enhance regional resilience. Full article

Native macroalgal proliferations are emerging as an additional pathway of ecosystem disruption in the Mediterranean Sea, alongside classic invasions by non-indigenous species. Here, we report an unprecedented, large-scale proliferation of the native red alga Dudresnaya verticillata at the Tremiti Islands Marine Protected Area (southern Adriatic Sea), where the species formed extensive filamentous mats across shallow rocks, seagrass meadows, rhodolith and corallith beds, and incoherent bottoms. Underwater surveys documented the widespread occurrence of D. verticillata across the archipelago, and a quantitative photographic analysis was carried out at a representative site characterized by multiple habitat types across the observed depth range of proliferation (10–25 m). Stratified photographic transects were used to estimate percent cover, quantify substrate associations, and evaluate co-occurring benthic components. Taxonomic identification was supported by ad hoc sampling and morphological characters. Overall, D. verticillata covered a mean of 48.7 ± 19.3% of the investigated area, with total cover differing significantly with depth. The highest mean cover occurred at 10–15 m on infralittoral rocky bottoms (60.8 ± 17.4%; 0–90%), intermediate values were recorded at 20–25 m on biogenic/incoherent substrates (49.0 ± 21.3%; 0–100%), and the lowest cover was observed at 15–20 m within a Posidonia oceanica meadow (38.7 ± 15.0%; 0–81%). Degradation forms were detected at all depths, but their relative contribution increased at 20–25 m. These results document a sustained native proliferation with elevated spatial dominance, characterized by rapid expansion and high local cover, highlighting the need to incorporate native “outbreak” dynamics into monitoring and management initiatives in the Mediterranean Sea. Full article

For the first time in the bay of Annaba (Southern Mediterranean), we studied the spatiotemporal distribution of potentially toxic benthic dinoflagellates: Ostreopsis cf. ovata, Prorocentrum lima, Coolia monotis, and Amphidinium carterae, hosted by the dominant macrophytes Posidonia oceanica, Padina pavonica, Codium fragile, and Halopteris scoparia. Sampling of these macrophytes was conducted weekly during spring and summer as well as bi-weekly in autumn and winter, from October 2022 to November 2023, at contrasting sites within Annaba Bay. The measured environmental parameters included temperature, pH, dissolved oxygen, salinity, ammonium, nitrate, nitrite, dissolved organic nitrogen, dissolved inorganic nitrogen, phosphate, dissolved organic phosphorus, silicate, and chlorophyll a. A proliferation of O. cf. ovata was recorded in July 2023, coinciding with a marked increase in temperature, with a maximum abundance exceeding 40 × 10³ cells g⁻¹ of fresh weight (FW) on H. scoparia and C. fragile. The maximum abundance of P. lima reached 8700 cells g⁻¹ FW on H. scoparia during July and August 2023. Coolia monotis exhibited a peak of 2800 cells g⁻¹ FW on H. scoparia. The abundance of A. carterae increased with temperature, reaching a maximum of 980 cells g⁻¹ FW on P. pavonica. The distribution of epiphytic dinoflagellates varied according to the macrophyte substrate. Overall, statistical analyses indicate that benthic dinoflagellate community structure is shaped by the combined effects of temperature, nutrient availability, and ecological niche differentiation, with temperature emerging as the dominant driver. This suggests that climate-driven increases in Mediterranean Sea surface temperatures are likely to extend the seasonal window of harmful benthic algal blooms, thereby enhancing ecological disturbances and potential risks to human health. This study provides the first assessment of BHAB dynamics along the Eastern Algerian coast, highlighting the role of ongoing regional warming in shaping future bloom patterns. Full article

Skin inflammation is characterized by oxidative stress, excessive keratinocyte activation, and the overproduction of pro-inflammatory cytokines. In a previous study, we demonstrated that the hydroalcoholic extract from Posidonia oceanica leaves (POE) mitigates psoriasis-like skin inflammation in a mouse model. In the present study, we investigated the cellular mechanisms underlying these effects in human HaCaT keratinocytes. Non-cytotoxic lipopolysaccharide (LPS) stimulation reproduced key inflammatory features, including impaired cell proliferation, increased production of ROS and NO, and the upregulation of IL-1β, IL-6, TNF-α and CXCL8/IL-8. Co-treatment with POE significantly attenuated these alterations by restoring cell proliferation, suppressing oxidative stress, particularly NOS2/NO, and normalizing both cytokine expression and release. POE alone did not affect cell viability or inflammatory markers, confirming its favorable safety profile. However, POE alone induced a mild pro-apoptotic response, which may contribute to overcoming the apoptosis resistance typically observed in psoriatic keratinocytes. Overall, these findings demonstrate that POE exerts antioxidant and anti-inflammatory effects in activated keratinocytes and support its potential as a marine-derived candidate for complementary strategies in the management of psoriasis-associated inflammatory skin disorders. Full article

Posidonia oceanica (L.) Delile, an endemic seagrass of the Mediterranean Sea, has been increasingly recognized not only for its ecological significance but also for its potential as a source of bioactive compounds in human health. Over the past decade, scientific studies have identified diverse constituents of P. oceanica, including polyphenols, peptides, and polysaccharides, which exhibit antioxidant, anti-inflammatory, cytotoxic, and metabolic regulatory activities. Evidence from in vitro and in vivo models demonstrates its ability to influence key cellular processes such as apoptosis, autophagy, and enzyme inhibition, suggesting therapeutic promise in cancer, skin aging, inflammatory conditions, and metabolic disorders like type 2 diabetes. Recent advances in delivery technologies, such as nanoparticles, micelles, and liposomes, have improved the stability and bioavailability of P. oceanica extracts, enhancing their potential application in pharmaceuticals and cosmeceuticals. Additionally, its antimicrobial and antibiofilm properties suggest applications in food preservation and infection control. By bridging traditional uses with modern scientific validation, P. oceanica exemplifies the emerging potential of marine phytotherapy. As interest grows in nature-derived therapeutics, further research is essential to translate these preclinical findings into clinical applications while ensuring sustainable management and the conservation of this valuable marine resource. Full article

Bio-epoxy composites were fabricated by casting a resin–hardener–filler mixture into 3D-printed molds, using different sea-originated secondary raw materials: mussel shell powder (MSP) (63–83 μm) and Posidonia oceanica short fibers (POF) (1–2 mm). Monofiller composites were prepared with 5 or 10 wt.% MSP, or 5 or 10 wt.% POF. Hybrid formulations were also produced, containing both MSP and POF in two combinations, where the total amount of filler again summed up at 10 wt.%. A subset of the samples was conditioned by immersion in a 35 ‰ NaCl solution reproducing seawater composition until saturation was reached. Characterization was carried out on unconditioned and conditioned samples by Shore D hardness and Charpy impact tests while performing three-point flexural loading only on unconditioned ones. Fracture morphology was also investigated. Adding MSP slightly enhanced resin hardness, whereas impact absorption exhibited, to a variable extent, a two-phase behavior, reproducing crack initiation and propagation. The MSP6-POF4 hybrid configuration provided the greatest improvement in absorbed energy (25–30% higher), which was retained after conditioning. The introduction of fillers, first separately, then in combination, resulted in a reduction in flexural strength to a similar extent for all unconditioned configurations. Finally, composite panels containing 10 wt.% MSP, 10 wt.% POF, and a 6MSP–4POF hybrid formulation, intended for prospective boat deck applications, were fabricated and compared with neat bio-epoxy, showing satisfactory consolidation. Density and post-molding dimensional shrinkage were measured on the panels. Full article

Plastic pollution, particularly in marine environments, has become a major global concern; therefore, monitoring and controlling these contaminants is essential to safeguard ecosystem integrity and human health. This study evaluates the ability of Posidonia oceanica spheroids to incorporate and retain plastic debris, with a particular focus on microplastics (MPs). A total of 1300 spheroids were collected along the Latium coast (Central Italy); among these, 454 (34.9%) contained plastic debris, with an average of 3.1 items per spheroid. Overall, 1415 plastic items were extracted and identified. Based on size classification, 48.7% were microplastics, 29.6% mesoplastics, and 21.9% macroplastics. Plastic items mainly consisted of filaments (40.9 ± 12.6%) and fibers (21.5 ± 5.2%). Eleven different colors were recorded, with white (28.8 ± 9.1%), transparent (13.4 ± 6.0%), and black (11.1 ± 6.8%) being the most frequent. A strong correlation was observed between the number of plastic items contained in the spheroids and proximity to wastewater treatment plants, which are known sources of synthetic fibers. Fourier transform infrared spectroscopy (FTIR) identified a total of 15 polymer materials, with nylon (18.2 ± 11.0%) and polyethylene terephthalate (PET; 17.3 ± 7.2%) being the most abundant. Structural alterations observed in FTIR spectra, together with carbonyl index values, indicate that most MPs are of secondary origin, resulting from prolonged environmental degradation. These results demonstrate that P. oceanica spheroids effectively promote plastic trapping and highlight their potential as a simple and cost-effective monitoring tool for marine plastic pollution. Full article