Search Results (98)

This study provides the first comprehensive characterization of benthic macrofaunal communities in the Loukkos estuary, highlighting their spatial and seasonal variability and the environmental factors shaping their structure. A total of 47 species were identified across 12 site–season combinations, dominated by molluscs (47%), polychaetes (23%), and crustaceans (21%). Species richness varied considerably along the estuarine gradient, ranging from fewer than five species in the upstream sector to up to 30 species downstream. Overall, higher diversity was observed in the downstream areas and during the dry season. Macrofaunal density also exhibited substantial variability, ranging from 95 ind.m⁻² to 14,852 ind.m⁻², with a mean density of 2535 ± 4058 ind.m⁻². Multivariate analyses identified four distinct benthic assemblages structured primarily by spatial factors (ANOSIM R = 0.86, p = 0.002), with negligible seasonal effect (R = −0.03, p = 0.6). Assemblages ranged from marine-influenced communities at the estuary mouth dominated by Cerastoderma edule, through rich and diverse seagrass-associated communities in the lower estuary dominated by Bittium reticulatum, and moderately enriched mid-estuary communities characterized by Scrobicularia plana and Hediste diversicolor, to species-poor upstream communities dominated by the tolerant species H. diversicolor. Canonical analysis showed that salinity and vegetation explain nearly 40% of the variation in benthic assemblages, highlighting the key role of Zostera seagrass beds as structuring habitats. Moreover, upstream anthropogenic pressures alter environmental conditions, reducing benthic diversity and favoring tolerant species. Full article

Seagrass meadows play a critical role in biogeochemical cycling, especially in nitrogen and sulphur processes, driven by their associated microbiome. This study provides a novel functional analysis of microbial communities in seagrass (Zostera marina) rhizosphere and endosphere, comparing seedlings and mature plants. While nitrogen-fixing bacteria are more abundant in seedlings, mature plants exhibit greater microbial diversity and stability. Sediment samples show higher microbial diversity than roots, suggesting distinct niche environments in seagrass roots. Key microbial taxa (sulphur-oxidizing and nitrogen-cycling bacteria) were observed across developmental stages, with rapid establishment in seedlings aiding survival in sulphide-rich, anoxic sediments. Chromatiales, which oxidize sulphur, are hypothesized to support juvenile plant growth by mitigating sulphide toxicity, a key stressor in early development. Additionally, sulfate-reducing bacteria (SRB), though potentially harmful due to H₂S production, may also aid in nitrogen fixation by producing ammonium. The study underscores the dynamic relationship between seagrass and its microbiome, especially the differences in microbial community structure and function between juvenile and mature plants. The study emphasizes the need for a deeper understanding of microbial roles within the seagrass holobiont to aid with Blue Carbon stores and to improve restoration success, particularly for juvenile plants struggling to establish effective microbiomes. Full article

This review provides current knowledge of the potential benefits of native Mediterranean seagrasses for human health, specifically focusing on their anti-inflammatory and antioxidant properties. The four main species examined—Posidonia oceanica, Cymodocea nodosa, Zostera marina, and Zostera noltii—are integral components of marine ecosystems, providing essential habitats and supporting biodiversity. Recent studies highlight their rich bioactive compounds that show significant therapeutic potential against oxidative stress and chronic inflammation, which are prevalent in various health disorders. This overview synthesizes the current literature, emphasizing the mechanisms through which these seagrasses exert their beneficial effects. Furthermore, it addresses the environmental implications of the excessive use and abuse of conventional anti-inflammatory drugs, advocating for a shift towards natural alternatives derived from marine resources. By exploring the bioactivity of these Mediterranean seagrasses, research here collected underscores the importance of integrating marine plants into health and wellness strategies, thereby promoting both human health and ecosystem sustainability. This exploration not only enriches the understanding of their applications on human health but also stimulates further research in this promising field, paving the way for innovative approaches to combat chronic diseases and support environmental conservation. Full article

Seagrass ecosystems support complex biological interactions that shape marine community structure and ecosystem functioning. Thanks to their structural complexity, they support heterogeneous communities and interact with associated benthic invertebrates and fish populations, establishing complex relationships that influence the performance and fitness of the involved organisms. This study, through a systematic review, investigated the existing potential biotic interactions between seagrasses and epibionts–epiphytes on a global scale. We created a complex search string and ran it in the online databases Scopus and Web of Science, yielding a total of 62 final outcomes spanning from 1984 to 2024. Our results revealed both positive and negative effects of different biotic interactions among these habitat formers and their associated symbionts. The review showed that the most studied interactions referred to Posidonia oceanica (Delile, 1813) L. and Zostera marina (Linnaeus, 1753), which provide refuge and habitat to different epiphytes and epibionts. The reviewed studies highlighted the importance of epiphytes, their potential role in seagrass growth, nutrient dynamics, and their implications for light absorption, while epibionts enhance canopy structure and can protect seagrasses from predation, but potential drawbacks remain poorly understood. Understanding and preserving these intricate biotic interactions is critical to ensuring the long-term functionality and resilience of seagrass ecosystems in a continuously changing environment. Full article

The Neotropical genus Nudopeza (Micropezidae, Taeniapterinae) is described for a group of 41 species, including Nudopeza tapanti sp. nov. (type species) and Nudopeza pronigra (Hennig) n. comb. for Grallipeza pronigra Hennig 1934, Nudopeza arcuata (Hennig) n. comb. for Grallipeza arcuata Hennig 1934, and the following 38 additional new species: N. cegex sp. nov, N. cura sp. nov, N. duplitheca sp. nov, N. gilli sp. nov., N. glypha sp. nov., N. gracei sp. nov., N. hansoni sp. nov., N. horologia sp. nov., N. laselva sp. nov., N. mephitis sp. nov., N. mexicana sp. nov., N. micromephitis sp. nov., N. nigrivertex sp. nov., N. nigriscutellum sp. nov., N. nudarcuata sp. nov., N. penai sp. nov., N. palenque sp. nov., N. paramephitis sp. nov., N. peruviensis sp. nov., N. quadrivitta sp. nov., N. ruficincta sp. nov., N. rutilans sp. nov, N. sirena sp. nov., N. sumaco sp. nov., N. trinidadensis sp. nov., N. uniseta sp. nov., N. variterga sp. nov., N. venezuelensis sp. nov., N. verpa sp. nov., N. versivitta sp. nov., N. viriola sp. nov., N. viva sp. nov., N. yungasensis sp. nov., N. zarza sp. nov., N. zostera sp. nov., N. zumera sp. nov., N. zygoma sp. nov., and N. zytha sp. nov. Full article

Seagrass is a key primary producer in coastal ecosystems; however, most studies on seagrass-benthos interactions have focused on subtidal zones. Some species such as Zostera japonica grow in intertidal flats; however, their ecological functions remain unclear. Understanding whether intertidal seagrass beds contribute to benthic abundance and diversity can provide insights that facilitate tidal flat conservation. The present study clarifies the role of intertidal Z. japonica as a food source for benthos. Field surveys were conducted in an intertidal flat in Matsushima Bay, Japan. Five benthic species (Batillaria cumingii, Umbonium costatum, Phacosoma japonicum, Nereididae, and Paguroidea) were identified. Carbon and nitrogen stable isotope ratios (δ¹³C, δ¹⁵N) and fatty acid compositions of sediment organic matter, seawater, and target benthos were analyzed to determine food sources. The results showed that B. cumingii actively consumed Z. japonica-derived organic matter present in both seagrass and sandy sediments. Z. japonica also influenced bacterial community structure, providing a favorable habitat for Nereididae. Filter feeders (U. costatum and P. japonicum) exhibited minimal reliance on Z. japonica-derived organic matter. The findings suggest that, similar to subtidal seagrass ecosystems, intertidal seagrass meadows support benthic communities by supplying organic matter and enhancing bacterial production. Full article

Zostera marina meadows play a key role in the Baltic Sea ecosystem. They are characterized by high primary production and provide feeding and reproduction grounds for organisms. These characteristics vary due to year-round environmental changes and may be due to the characteristics of the meadows themselves. Organisms inhabiting seagrass meadows are involved in the transformation of substances from terrestrial runoff, and, through bioturbation and bioirrigation, affect biogeochemical processes in the sediments. This study aimed to determine the structure of benthic communities inhabiting Z. marina meadows and their bioturbation (BP_C) and bioirrigation (IP_C) potential as affected by seagrass density and seasonal changes. This study shows a positive correlation between the density of Z. marina and the structure of macrozoobenthos, as well as the bioturbation and bioirrigation potential of the studied communities. The autumn season stimulated the density of macrofauna and recorded the highest values of their potential activities indices. The presence of Z. marina positively affects macrozoobenthic communities and their functioning regardless of seagrass density, indicating that seagrass meadows inhabited by macrofauna are key biotopes that can support biogeochemical processes in the coastal zone more effectively than bare sand. Full article

Using fishes as indicators of estuarine degradation is informative in long-term monitoring programs. Beach seine hauls were used in four estuaries that differed in their trophic and tidal status. The study found that inner, middle, and outer estuarine nearshore fish communities differed significantly at from all estuaries, for all sampling times. To reduce the effects of within-estuary variability, between-estuary differences were examined separately for inner, middle, and outer estuarine areas. These analyses revealed differences in north-south and trophic status in communities between estuaries. The north-south differences were characterized by more benthic fishes, such as mummichogs and fourspine stickleback in the microtidal northern estuaries and proportionally more pelagic fishes, such as Atlantic silversides and river herring in the mesotidal estuaries. In both multivariate and univariate analyses, mummichogs were also featured as being most abundant in the more eutrophic estuaries. The distance-based redundancy analysis showed that bare sediment coverage was the strongest correlate of the north-south differences, while the Ulva to Zostera plant gradient was more influential in predicting eutrophication impacts on communities in the inner and middle estuary. Full article

In the Caleri lagoon, a coastal lagoon in the Po River Delta, Northern Adriatic, the transplant of the dwarf eelgrass Zostera noltei was used as a nature-based solution to attempt the ecological restoration of a previously depleted lagoon area. A total of 135 15-cm-diameter sods were transplanted, with the donor site at the Venice lagoon. Using unmanned aerial vehicles (UAVs), eelgrass transplants were mapped and monitored with great precision. After two years, the area covered by eelgrass increased from the initial 2.5 m² to 60 m². Changes in the community structure and on the frequency of biological traits of macrobenthos occurred at the transplant site, with a higher frequency of epifaunal predators and herbivores, and of organisms with longer life spans and larger body sizes. Sensitive and indifferent taxa were always higher in the transplant site than in the bare bottom control site, where opportunistic taxa continued to dominate. Ecological quality status measured through M-AMBI and HBFI indices showed a clear improvement in the transplant site. The rapid changes in benthos demonstrate that even relatively small-scale transplantation of dwarf eelgrass can restore faunal communities very rapidly. Full article

The search for bioactive natural compounds, traditionally focused on terrestrial environments, has increasingly expanded to the seas and oceans, opening new frontiers for exploration. Among the diverse organisms inhabiting these ecosystems, marine phanerogams have emerged as a promising source of health-promoting bioactive compounds. This review highlights the distinctive chemical diversity of seagrasses including species such as Posidonia oceanica, Zostera marina, and Cymodocea nodosa, among others, and focusses on the growing interest in natural therapies as alternatives to conventional pharmaceuticals. Compounds such as polysaccharides or secondary metabolites such as polyphenol and flavonoids produced by marine plants exhibit a broad range of beneficial properties, including anti-inflammatory, antibacterial, antioxidant, and antidiabetic qualities. This review describes how these compounds can mitigate inflammation, promote skin health, and combat oxidative stress. Moreover, certain marine extracts have demonstrated potential to inhibit cancer cell growth and improve metabolic disorders like obesity and diabetes. The manuscript also discusses the potential of marine plant extracts in the development of novel therapeutic agents to address various illnesses, including infections, chronic diseases, and metabolic disorders. It emphasizes the need for further research to fully elucidate the mechanisms underlying the activity of these bioactive compounds and their potential therapeutic applications. In summary, this study highlights marine plants as a valuable reservoir for identifying organic molecules, paving the way for innovative advancements in medical and healthcare interventions. Full article

Low-salinity conditions are generally used in land-based cultivation to promote the germination and growth of Zostera marina L. and to improve the restoration effect of seagrass beds. Different salinity conditions lead to morphological and physiological differences. To investigate the impacts of salinity and osmotic pressure on the germination and early development of Zostera marina seeds, this study utilized seawater with different salinity conditions and PEG-6000 solutions to simulate various non-ionic osmotic pressures and examine the germination, cotyledon growth, and leaf differentiation over 28 days, as well as determine the biochemical traits on days 1, 3, 5, and 7. The results show that the cumulative germination rate in LS-0 was 91.6%, but it was not significantly affected by the PEG solutions. The different salinities (5, 10, and 15) had no significant effect on the germination rate, which ranged from 76.4% to 78.8%: low salinity and low osmotic pressure stimulated the germination by accelerating the water uptake through increased osmotic pressure differences. The leaf differentiation was regulated by the osmotic pressure and salinity. In LS-10, the most used condition, the leaf differentiation rate was 35.2%, while PEG-10 displayed 6.4%. The total soluble sugar and soluble protein in the seeds decreased. Antioxidant enzyme activities were activated under low-salinity conditions, which supported germination within a tolerable oxidative stress range. Full article

Seagrass meadows, including those formed by Zostera noltei, play a crucial role in marine ecosystem health by providing habitat stability and coastal protection. In the Romanian Black Sea, Z. noltei meadows are critically endangered due to pressures from eutrophication, habitat loss, and climate change. This study presents a comprehensive baseline assessment of Z. noltei meadows near Mangalia, Romania, utilizing in situ field methods and UAV mapping conducted in the spring and summer of 2023. Seven meadow sites (Z1–Z7) were identified, with notable variability in density, shoot counts, and coverage across sites. Site Z1 exhibited the highest density (1223 shoots/m⁻²) and Z5 and Z7 the longest leaves (an average of 60 cm), reflecting possible environmental influences. Statistical analyses revealed significant inter-site differences in shoot density and leaf length, with density emerging as a primary differentiator. Ex situ analyses of epiphyte load indicated a median, balanced epiphyte load. This baseline dataset supported the selection of Z1 as a reference donor site for seagrass relocation activities along the Romanian coast in 2023. By providing critical insights into Z. noltei structure and health, this study supports future conservation efforts and evidence-based management of these vulnerable coastal habitats. Full article

Remote sensing is heavily relied upon where eelgrass maps are needed for tracking trends, project siting and permitting, water quality assessments, and restoration planning. However, there is only a moderate degree of confidence in the accuracy of maps derived from remote sensing, thus risking inadequate resource protection. In this study, semi-synchronous drone, side-scan sonar, airplane, and satellite missions were conducted at five Massachusetts eelgrass meadows to assess each method’s edge-detection capability and mapping accuracy. To ground-truth the remote sensing surveys, SCUBA divers surveyed the meadow along transects perpendicular to shore to locate the last shoot (i.e., meadow’s edge) and sampled quadrat locations along the transect for percent cover, canopy height, and meadow patchiness. In addition, drop frame underwater camera surveys were conducted to assess the accuracy of each remote sensing survey. Eelgrass meadow delineations derived from each remote sensing method were compared to ground-truthing data to address the following study objectives: (1) determine if and how much eelgrass was missed during manual photointerpretation of the imagery from each remote sensing method, (2) assess map accuracy, as well as the effects of eelgrass percent cover, canopy height, and meadow patchiness on method performance, and (3) make management recommendations regarding the use of remote sensing data for eelgrass mapping. Results showed that all remote sensing methods were associated with the underestimation of eelgrass. At the shallow edge, mean edge detection error was lowest for drone imagery (11.2 m) and increased with decreasing image resolution, up to 38.5 m for satellite imagery. At the deep edge, mean edge detection error varied by survey method but ranged from 72 to 106 m. Maximum edge detection errors across all sites and depths for each survey method were 112.4 m, 121.4 m, 121.7 m, and 106.7 m for drone, sonar, airplane, and satellite data, respectively. The overall accuracy of eelgrass delineations across the survey methods ranged from 76–89% and corresponded with image resolution, where drones performed best, followed by sonar, airplanes, and satellites; however, there was a high degree of site variability. Accuracy at the shallow edge was greater than at the deep edge across all survey types except for satellite, where accuracy was the same at both depths. Accuracy was influenced by eelgrass percent cover, canopy height, and meadow patchiness. Low eelgrass density (i.e., 1–10% cover), patchy eelgrass (i.e., shoots or patches spaced > 5 m) and shorter canopy height (i.e., <22 cm) were associated with reduced accuracy across all methods; however, drones performed best across all scenarios. Management recommendations include applying regulatory buffers to eelgrass maps derived from remote sensing in order to protect meadow edge areas from human disturbances, the prioritization of using SCUBA and high-resolution platforms like drones and sonar for eelgrass mapping, and for existing mapping programs to allocate more resources to ground-truthing along meadow edges. Full article

Background/Objectives: Biogenic volatile organic compounds (BVOCs), extensively studied in terrestrial plants with global emissions around 1 PgC yr⁻¹, are also produced by marine organisms. However, benthic species, especially seagrasses, are understudied despite their global distribution (177,000–600,000 km²). This study aims to examine BVOC emissions from key Mediterranean seagrass species (Cymodocea nodosa, Posidonia oceanica, Zostera noltei, and Zostera marina) in marine and coastal lagoon environments. Methods: BVOCs were collected using headspace solid-phase microextraction (HS-SPME) using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibers and analyzed by gas chromatography–mass spectrometry (GC-MS). Results: An important chemical diversity was found with a total of 92 volatile compounds (61 for Z. noltei, 59 for C. nodosa, 55 for P. oceanica, and 51 for Z. marina), from different biosynthetic pathways (e.g., terpenoids, benzenoids, and fatty acid derivatives) and with several types of chemical functions (e.g., alkanes, esters, aldehydes, and ketones) or heteroatoms (e.g., sulfur). No differences in chemical richness or diversity of compounds were observed between species. The four species shared 29 compounds enabling us to establish a specific chemical footprint for Mediterranean marine plants, including compounds like benzaldehyde, benzeneacetaldehyde, 8-heptadecene, heneicosane, heptadecane, nonadecane, octadecane, pentadecane, tetradecane, and tridecanal. PLS-DA and Heatmap show that the four species presented significantly different chemical profiles. The major compounds per species in relative abundance were isopropyl myristate for C. nodosa (25.6%), DMS for P. oceanica (39.3%), pentadecane for Z. marina (42.9%), and heptadecane for Z. noltei (46%). Conclusions: These results highlight the potential of BVOCs’ emission from seagrass ecosystems and reveal species-specific chemical markers. Full article

There is increasing interest in the role that seagrasses play in storing carbon in the context of climate mitigation, but many knowledge gaps in the factors controlling this storage exist. Here, we provide a small case study that examines the role of infaunal biodiversity in influencing seagrass and the carbon stored in its sediments. A total of 25 species of invertebrate were recorded in an intertidal Zostera marina meadow, where these species were dominated by polychaete worms with no bivalves present. We find organic carbon storage (within the top 20 cm) measured by AFDW to be highly variable within a small area of seagrass meadow ranging from 2961 gC.m⁻² to 11,620 gC.m⁻² with an average (±sd) of 6460² ± 3274 gC.m⁻². Our analysis indicates that infaunal communities are significantly and negatively correlated with this sediment organic carbon. However, this effect is not as influential as hypothesised, and the relatively small sample size of the present study limits its ability to provide strong causality. Other factors, such as algal abundance, curiously had a potentially stronger influence on the carbon in the upper sediments. The increasing richness of infauna is likely reducing the build-up of organic carbon, reducing its ecosystem service role. We believe this to likely be the result of bioturbation by specific species such as Arenicola marina and Ampharete acutifrons. A change in sediment organic carbon suggests that these species could be key drivers of bioturbator-initiated redox-driven organic matter turnovers, influencing the microbial processes and remobilizing sediment compounds. Bioturbators should be considered as a limitation to C_org storage when managing seagrass C_org stocks; however, bioturbation is a natural process that can be moderated when an ecosystem is less influenced by anthropogenic change. The present study only provides small-scale correlative evidence with a range of surprising results; confirming these results within temperate seagrasses requires examining this process at large spatial scales or with targeted experiments. Full article