Spatio-temporal composition of aquatic birds communityin Juluapan Lagoon, Colima, Mexican Central Pacific / Composición espacio-temporal de las aves acuáticas en la laguna Juluapan, Colima, en el Pacífico Central Mexicano

Abstract Introduction: Aquatic birds (AB) are usually associated with wetlands, which provide refuge, food, and/or nesting sites for resident and migratory species. Despite their ecological importance, there is little knowledge on AB in some tropical environments, such as those found on the Colima coast. Objective: To investigate the spatial and temporal composition of the AB community in Juluapan Lagoon, Colima, Central Mexican Pacific. Methods: Monthly counts were conducted between June 2017 and May 2018 during low-tide conditions to record habitat use by AB. Species richness and bird counts were obtained to compare sampling areas; mean richness and number of individuals were compared between seasons. Results: We detected 53 species and 5 750 individuals. The highest species richness and relative abundance values were obtained in winter at the lagoon area farthest from the connection with the marine system, where anthropogenic activity is lower. Diversity was greater in zones 2 and 3 in spring, summer, and fall. Muddy flats were the most used environment, and the most frequent activity was resting. Nesting activity was only recorded in the middle of the lagoon at the mangrove during spring. "Shorebirds" and "waders" were the most dominant groups in the bird community of the Juluapan lagoon. Conclusions: This coastal wetland is a site of great biological importance for aquatic birds; thus, conservation measures should be implemented, and there should be a continuous study of the effects of anthropogenic pressure.

Resumen Introducción: Las aves acuáticas (AA) son usualmente relacionadas a los humedales debido a que éstos funcionan como sitios de refugio, alimentación y anidación de diferentes especies residentes y migratorias. Sin embargo, el conocimiento sobre las aves acuáticas en algunos humedales es nulo. Objetivo: Investigar la composición espacio-temporal de la comunidad de AA en la laguna Juluapan, Colima, en el Pacífico Central Mexicano. Métodos: Entre junio de 2017 y mayo de 2018 se llevaron a cabo conteos mensuales en condiciones de marea baja para registrar el uso de hábitat de las AA. Se obtuvieron valores de riqueza de especies y número de individuos para realizar comparaciones entre zonas de muestreo, así como el promedio del número de especies y número de individuos para comparaciones entre temporadas. Resultados: Se registraron un total de 53 especies y 5 750 individuos. Los valores de riqueza de especies y densidad de individuos fueron más altos durante invierno, en la zona más alejada al ambiente marino, donde la actividad antropogénica es menor. La diversidad tuvo valores más altos en la zona 2 y 3, durante primavera, verano y otoño. El ambiente más explotado por las aves fueron las planicies lodosas; y el descanso fue la actividad más frecuente. Asimismo, la actividad de anidación sólo se registró en el manglar de la zona media durante primavera. Las "aves playeras" y "aves zancudas" fueron los grupos más predominantes en la comunidad de aves de la laguna Juluapan. Conclusiones: Este humedal costero es un sitio de gran importancia biológica para aves acuáticas, por lo que resulta necesario la implementación de medidas de conservación, así como el estudio de los efectos por la presión antropogénica.

COVID-19 induced lockdown reduced metal concentration in the surface water and bottom sediment of Asia's largest lagoon.

COVID-19 (hereafter COVID) induced lockdown provided a unique opportunity to evaluate the effects of human activities on coastal ecosystems. This study quantified the seasonal variations in concentrations of nine metals (Al, Cr, Cd, Co, Cu, Fe, Mn, Ni, and Pb) in surface water and sediment samples of the largest brackish water lagoon in Asia (i.e., Chilika Lagoon), comparing pre-and post-COVID scenarios. The COVID lockdown resulted in a wide variation in metals concentrations, with surface water showing 1 to 8.6-fold reduction in metals such as Al, Cr, Cu, Fe, Mn, and Pb, while sediment displayed a more modest reduction of 1 to 1.3-fold. Metals like Cd, Co and Ni were below detection limit in post-COVID water samples with a slight decrease (1-fold) in the sediments. COVID lockdown did not show any significant correlation with metal concentrations in water or sediment. This study provides baseline data for metal contamination in the surface water and sediment of the Chilika Lagoon.

Survival strategies of microalgae in response to fluctuating brine environments in Saroma-ko Lagoon sea ice, Hokkaido, Japan.

This study investigated the changes in sea ice temperature, microalgae species distribution, shape changes, and photosynthetic activity observed in the first-year ice that forms in winter in Saroma-ko Lagoon, Hokkaido, Japan. Temperatures at the bottom of the ice remained constant at -1.7°C, near the freezing point, while they varied between -6 and -1°C with diel fluctuations at the surface layer. Carefully collected algal samples showed high photosynthetic quantum yield and acclimation to the light intensities of individual ice layers; this indicates that the algal photosynthetic activity responds to dynamic changes in the ice environment, such as variations in temperature, salinity, and brine space. The algal communities consisted of more than 95% diatoms. Smaller algal cells were distributed in the upper layer of the sea ice compared to the lower layers. Chaetoceros sp., the dominant small-cell species, was evenly distributed throughout the layers. In contrast, Detonula confervacea, the dominant large-cell species, was unevenly distributed in the lower layer, with smaller colony size and cell volume in the upper layer. The shape differences observed in this species were thought to be a response to the changing environment within the first-year sea ice.

Relationship between water quality and phytoplankton distribution of aquaculture areas in a tropical lagoon.

Aquaculture activities can affect water quality and phytoplankton composition. Our study estimated phytoplankton density and composition relating to aquaculture-impacted environmental factors. We analyzed water quality and phytoplankton at 35 sites in a tropical brackish lagoon, including inside aquaculture ponds (integrated farming of fish, shrimp, and crab), at wastewater discharge points, within 300 m of these points, and farther out in the lagoon. Measurements were taken after aquaculture activities started in March and again in July. In both periods, total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a), and turbidity decreased from the aquaculture ponds to the farther lagoon areas. Principal component analysis showed that nutrients, turbidity, and Chl-a were critical factors in aquaculture ponds, while salinity, temperature, pH, dissolved oxygen (DO), and water depth influenced water quality outside the ponds. Phytoplankton density was higher in July than in March due to aquaculture characteristics. Redundancy analysis indicated that phytoplankton, typical of inorganic, turbid, shallow lakes, was present throughout, whereas marine phytoplankton characterized the open water area (OWA). Marine phytoplankton caused a higher Shannon-Wiener index in July compared to March for OWA. Phytoplankton in aquaculture ponds was dominated by Oscillatoria spp., while Thalassiosira spp. dominated outside the ponds. We also identified indicator genera for two connected lagoons. Although constant water exchange prevented identifying specific indicator phytoplankton groups for aquaculture, this revealed the impact of wastewater from aquaculture ponds on the natural environment in the lagoons. Research on phytoplankton communities is necessary for the sustainable development of aquaculture and environmental management in coastal lagoons.

Paleoenvironmental characterization and historical trends of polycyclic aromatic hydrocarbons (PAHs) of Nutrias Lagoon, Uruguay.

Concentrations of polycyclic aromatic hydrocarbons were assessed in a sediment core retrieved from Nutrias Lagoon, located within the Rocha Lagoon Protected Area along the SE Uruguayan coast. Using a210Pb chronology, we reconstructed the historical accumulation of polycyclic aromatic hydrocarbons over the past 123 years (1895-2018). This study, the first of its kind in Uruguay, fills a research gap in understanding historical PAH accumulation and source changes. Our examination of dating, geochemical, and sedimentological data unveiled four main events, with minor instances in 1956 ± 5 and 1964 ± 4, and more significant occurrences in 1914 ± 9 and 1997 ± 2. Additionally, two prominent trend shifts were identified, one predating 1900 and the other in 1986 ± 2. Before 1900, a dry spell was apparent, supported by all proxies, alongside a notable surge in heavy polycyclic aromatic hydrocarbons, likely attributed to fires during this arid period. Post-1986 ± 2, a rise in sedimentation rates in the lagoon was observed, possibly due to increased rainfall. Also, the eutrophication of the lagoon over the years can be observed. Furthermore, a recent increase in polycyclic aromatic hydrocarbons influx at the core's surface was linked to the construction of a nearby lagoon bridge and associated roadwork. Our findings suggest that atmospheric deposition constitutes the primary source of polycyclic aromatic hydrocarbons in the lagoon, offering insights into its recent environmental history and basin dynamics. This study establishes a critical baseline for future research in the region and facilitates the development of effective and sustainable environmental management strategies.

Seasonal dynamics of bacterial communities in a highly polluted coastal lagoon: Dominance of sulfur bacteria in response to elevated H2S levels.

This study aims to evaluate the effects of different environmental gradients and seasonality on the bacterial communities of an impacted coastal lagoon. While the community compositions were homogenous in surface waters with the dominance of Candidatus Pelagibacter, diversity showed high vertical variation due to salinity and dissolved oxygen gradients. Anoxic conditions occurred at deeper parts of the lagoon, particularly at 14 m and 18 m, where nutrient enrichment and high H2S concentration were detected resulting in a shift of bacterial community to anoxic species. Sulfurimonas, Sulfurovum, and Desulfobacula were dominant genera at 14 m and 18 m where the H2S concentration was high. The community composition of the sediment did not change over seasons, dominated by Syntrophus species. The insights gained from this study may contribute to understanding how dissolved oxygen, H2S concentrations and salinity drive bacterial community structure in euxinic ecosystems especially the dominance of anoxic bacteria.

Future Shorelines: A Living Shoreline Site Selection and Design Decision Support Tool that Incorporates Future Conditions Induced by Sea Level Rise.

Most living shoreline site selection and design decision support tools are based upon existing environmental conditions. We developed a web-based, geospatial tool called Future Shorelines that integrates high-resolution landscape elevation data and a matrix of locally derived NOAA Interagency Sea Level Rise Scenarios to characterize future conditions of submergence and shoreline translation induced by sea level rise. Once the practitioner selects a location of interest, sea level rise scenario (e.g., high), and target year (e.g., 2050), the tool will generate plan view and cross-sectional informational graphics specific to their choices. This information can then be paired with other menu options, like parcel ownership, to facilitate the planning and construction of nature-based shoreline stabilization solutions that (1) are located where opportunities for horizontal migration are optimized, (2) remain accessible for monitoring and maintenance, and (3) perform as intended over the design life of the installation. The tool's menu options and the user interface were informed by project partner input solicited during numerous workshops convened over the duration of the 2-year project. This coproduction created a product that was familiar to the end user and therefore increased the likelihood that it would be utilized by them during the planning and design of living shoreline projects. Although developed for use in the Indian River Lagoon, located along the east-central Florida coast, it can be seamlessly replicated for application in other coastal regions of the USA where the requisite data are available.

Hydrodynamics- and remote sensing-based model for estimating the effects of cohesive sediment transport on lagoon siltation in Southwestern Taiwan.

This study investigates localized siltation in the Cigu Lagoon, Southwestern Taiwan, using an integrated approach of hydrodynamic modeling and remote sensing. In regions where in situ data is scarce, remote sensing provides critical complementary data inputs for our sediment model. We employed a multilayered mud sediment model, incorporating initial suspended sediment concentration (SSC) data derived from Landsat imagery, to identify the morphological changes taking place in the lagoon. Over the past few decades, sandbar migration and sedimentation have led to a significant shrinkage of the Cigu Lagoon, which is now at risk of disappearing if a full understanding of the underlying factors is not reached. The loss of the lagoon would have severe implications for the local ecosystem and habitat, as well as for the fishermen who rely on the lagoon for their livelihoods. Our results showed that sedimentation in the Cigu Lagoon is a compounded consequence of the action of the tidal cycle and of waves. Throughout the simulation period, the SSC in the Cigu Lagoon ranged from 1 g m -3 to 50 g m -3. The annual siltation rate of the lagoon due to cohesive sediment transport was 0.82 cm. The simulation results showed that the siltation mainly occurred during the winter, with the dominant factor being the frequent strong waves at this time of year. This study suggests that a management plan for the Cigu Lagoon must be devised and implemented, and that remote sensing and hydrodynamic modeling are valuable tools in communicating about the complex processes involved in a sedimentary system and informing relevant decision-making at the stage of management.

Proximity to inlet channel drives spatial variation in sediment carbon across a lagoonal seagrass meadow.

Seagrass meadows can be sinks for organic carbon, but estimates of global organic carbon stocks are complicated by substantial spatial variability in organic carbon burial observed within meadows. To improve estimates of organic carbon burial in seagrass meadows, it is necessary to understand the causes of the spatial heterogeneity. This study investigated relationships between spatial patterns in sediment organic carbon storage and accretion rates, hydrodynamics, and proximity to sources of organic carbon in a current-dominated Zostera marina Linnaeus meadow in Menemsha Pond, Massachusetts, USA. Sediment and velocity measurements were conducted at six stations along a 150-m transect across the meadow oriented perpendicular to the pond's unvegetated inlet channel. The meadow's edge near the channel had higher organic carbon than the channel as well as the highest organic carbon within the meadow. With increasing distance from the meadow's edge, all of the following decreased: sediment organic and total carbon, sediment accretion rates, peak tidal velocity, sediment trap mass deposition rate, and the relative contribution of non-seagrass sources to sediment organic carbon. Lower tidal velocities farther from the inlet channel reduced sediment resuspension, consistent with lower sediment trap mass deposition, which should enhance organic carbon content and organic carbon accretion rates. However, the opposite trend of decreasing organic carbon content (>50 % across the transect) and decreasing accretion rates with distance from channel was observed. This suggested that the local hydrodynamic intensity was not controlling organic carbon accretion, which was instead constrained by supply limitation and controlled by the lagoon-scale flow circulation.

Contaminant Exposure and Liver and Kidney Lesions in North American River Otters in the Indian River Lagoon, Florida.

The harmful algal bloom (HAB) liver toxin microcystin (MC) and trace element biomagnification were previously detected in organisms in the Indian River Lagoon (IRL), Florida. Since there are no routine screening programs for these contaminants, liver tissue from North American river otters (Lontra canadensis), an important sentinel species in the IRL, was screened for MC via enzyme-linked immunoassay (ELISA), followed by confirmatory analyses via liquid-chromatography/mass spectrometry methods (LC-MS/MS). Liver and kidney samples were evaluated for trace element (As, Cd, Co, Cu, Fe, Hg, Mn, Mo, Pb, Se, Tl, and Zn) bioaccumulation via inductively coupled plasma mass spectrometry (ICP-MS). Histopathologic evaluation of the liver and kidney was conducted to assess possible correlation with toxic insults. Forty-three river otters were evaluated (2016-2022). Microcystin was not detected in any river otter sample (n = 37). Of those tested for trace element bioaccumulation (n = 22), no sample measured above provided reference ranges or estimated toxic thresholds for this species. There were no statistically significant patterns observed based on season, year, or age class, but sex had a small influence on trace element levels in the kidney. One individual had a kidney Cu level (52 µg/g dry weight) higher than any previously reported for this species. Trace elements were detected at presumed background levels providing baselines for future monitoring. For otters with available histopathologic evaluation (n = 28), anomalies indicative of contaminant exposure (non-specific inflammation, necrosis, and/or lipidosis) were present in the liver and kidney of 18% and 4% of individuals, respectively. However, since these lesions were not linked to abnormal trace element bioaccumulation or MC exposure, other causes (e.g., infectious disease) should be considered.

Green Synthesis of Metal Nanoparticles with Borojó (Borojoa patinoi) Extracts and Their Application in As Removal in Water Matrix.

The predominant aim of the current research was to generate a proposal for the removal of arsenic, a highly toxic pollutant, encountered within the Papallacta Lagoon in Ecuador. The average concentrations of As yielded ranges between 18 to 652 µg/L, through the use of metallic nanoparticles. Sampling was performed in the lagoon with their respective geographic locations and "in situ" parameters. Nanoparticles of Mn3O4 NPs, Fe3O4 NPs, and CuO NPs were synthesized at a 0.5 M concentration, using the precipitation method, and borojó (Borojoa patinoi) extract was added as an anti-caking agent as well as antioxidant. The nanoparticles were characterized by visible spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. After arsenic removal treatment using nanoparticles, a randomized experimental design of different concentrations (5 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, and 150 mg/L) was applied at laboratory level. The average diameter of Fe3O4NPs ranged from 9 nm to 36 nm, Mn3O4 NPs were 15-20 nm, and CuO NPs ranged from 25 nm to 30 nm. Arsenic removal percentages using Fe3O4 NPs with a concentration of 150 mg/L was 87%; with Mn3O4 NPs, the removal was 70% and CuO NPs of about 63.5%. Finally, these nanoparticles could be used in a water treatment plant for the Papallacta Lagoon.

Fate and transport of ten plant protection products of emerging concern in a coastal lagoon: Application and evaluation of a multimedia level III fugacity model.

Multimedia fugacity models are effective tools for studying the environmental behaviour and occurrence of contaminants of emerging concern (CECs) and assessing associated risks, especially when experimental data is limited. These models describe processes controlling chemical partitioning, transport, and reactions in environmental media using mathematical statements based on the concept of fugacity. To aid in identifying and prioritizing CECs for future local monitoring, we present here the application of a level III multimedia fugacity model assuming non-equilibrium between compartments and steady-state conditions. This model estimated predicted environmental concentrations (PECs), persistence, distribution, and transport of ten plant protection products (PPPs) in the Venice Lagoon, a complex coastal environment under high anthropogenic pressure. The model was evaluated through uncertainty and sensitivity analysis using the Monte Carlo approach and by comparing PECs with PPP concentrations measured during four sampling campaigns. Results showed good agreement with field data, with the highest concentrations in water and sediments estimated for glyphosate, followed by imidacloprid, metaflumizone, and triallate. The model indicated accumulation of all investigated PPPs in sediments. For most chemicals, advection outflow and degradation in the water column were the main removal mechanisms, while volatilization was significant only for oxadiazon and triallate. Sensitivity and uncertainty analysis revealed that degradation rates, organic carbon/water partitioning coefficients (KOC), and parameters describing air-water interactions had the strongest influence on the model's results, followed by inputs accounting for sediment sinking and resuspension. The lack of data on PPP degradation in brackish waters accounted for most of the uncertainty in model results. This work shows how a relatively simple multimedia model can offer new insights into the environmental behaviour of PPPs in a complex transitional waterbody such as the Venice lagoon, providing useful data for the identification of the CECs to be prioritised in future local monitoring efforts.

Bivalve shell growth from molecular to sclerochronological scale: Environment and intrinsic factors control increment deposition.

Biomineralisation of bivalve shells raises questions at the level of genes to the final calcified product. For the first time, gene expression has been studied in association with growth increment deposition in the mussel Mytilus galloprovincialis. A short-term experiment highlighted that biomineralisation genes exhibit a rhythm of expression consistent with the observed tidal increment formation. Long-term mark-recapture experiments were conducted in three Mediterranean environments and revealed that the mussel shells harbour complex incrementation regimes, consisting of daily, tidal and a mixed periodicity of ∼1.7 growth increment.d-1 formed. The latter is likely related to the local tidal regime, although the mussels were continuously submerged and exposed to a small tidal range. The pattern of growth increments shifted from mixed to daily in Mediterranean lagoon, and to tidal at sea, probably linked to biological clocks. Based on our results and the literature, a hypothetical model for mussel shell increment formation in various habitats is proposed.

Investigating pollution input to coastal groundwater-dependent ecosystems in dry Mediterranean agricultural regions.

The insufficient taking into account of groundwater as a basis for implementing protection measures for coastal wetlands can be related to the damage they are increasingly exposed to. The aim of this study is to demonstrate the pertinence of combining hydrogeological tools with assessment of pollutant fluxes and stable isotopes of O, H and N, as well as groundwater time-tracers to identify past and present pollution sources resulting from human activities and threatening shallow groundwater-dependent ecosystems. A survey combining physico-chemical parameters, major ions, environmental isotopes (18O, 2H, 15N and 3H), with emerging organic contaminants including pesticides and trace elements, associated with a land use analysis, was carried out in southern Italy, including groundwater, surface water and lagoon water samples. Results show pollution of the shallow groundwater and the connected lagoon from both agricultural and domestic sources. The N-isotopes highlight nitrate sources as coming from the soil and associated with the use of manure-type fertilizers related to the historical agricultural context of the area involving high-productivity olive groves. Analysis of EOCs has revealed the presence of 8 pesticides, half of which have been banned for two decades and two considered as pollutant legacies (atrazine and simazine), as well as 15 molecules, including pharmaceuticals and stimulants, identified in areas with human regular presence, including rapidly degradable compounds (caffeine and ibuprofen). Results show that agricultural pollution in the area is associated with the legacy of intensive olive growing in the past, highlighting the storage capacity of the aquifer, while domestic pollution is sporadic and associated with regular human presence without efficient modern sanitation systems. Moreover, results demonstrate the urgent need to consider groundwater as a vector of pollution to coastal ecosystems and the impact of pollutant legacies in planning management measures and policies, with the aim of achieving 'good ecological status' for waterbodies.

The role of environment descriptors and seagrass biometrics in shaping macrobenthic assemblages' structure in intertidal Zostera noltei meadows.

The present study describes macroinvertebrate assemblages in three Zostera noltei meadows, following a salinity gradient along the Aveiro lagoon (Portugal). The main environmental descriptors and Z. noltei biometrics were studied to provide a model of the multivariate macroinvertebrate assemblage structure. The macroinvertebrate assemblage structure in the meadow close to the lagoon opening was significantly different. This could be explained by its higher organic matter content and salinity values. Our model highlighted that 72% of the variation on macroinvertebrate assemblage structure was explained by the studied variables, being organic matter, salinity and sediment median grain size the most relevant factors. Moreover, the number of Z. noltei shoots, and cover of the invasive species Agarophyton aff. vermiculophyllum were also significant. The strong relationship between macroinvertebrates, environmental descriptors and Z. noltei biometrics validates the usefulness of macroinvertebrates as indicators of the seagrass condition in intertidal environments. This study provides baseline data that will be crucial to detect anthropogenic disturbances and preserve Z. noltei meadows, including their associated biodiversity. These data will also allow focusing on certain environmental factors and Z. noltei biometrics that have proved shaping the macroinvertebrate assemblages' structure.

Spatial distribution of PAHs, nickel, and vanadium in sediments from a large coastal lagoon near a petroleum extraction area in the southern Gulf of Mexico.

One of the world's crucial areas for crude oil exploration and extraction is the southern Gulf of Mexico, where Terminos Lagoon (TL) is located. Sediments from the TL region were used to assess the spatial patterns, origins, and ecotoxicological risks associated with 16 priority polycyclic aromatic hydrocarbons (PAHs; 3.1-248.9 ng⸳g-1 dry weight basis, dw) and trace metals (Ni = 11.0-104.0 mg⸳kg-1; V = 2.0-35.0 mg⸳kg-1 dw) linked to anthropogenic activities. Although origin indices based on PAHs and metals concentrations indicate no crude oil pollution in the region, sources of pyrogenic PAHs were identified. A chemometric approach demonstrated associations between organic matter and PAHs, and that metal accumulation depends mostly by the input of lithogenic materials. Ecotoxicological risk estimations showed a higher risk of possible adverse effects in sites near swamps and mangrove zones, highlighting the need of future monitoring. This study provides a reference for policymakers to conserve Mexico's largest coastal lagoon and other oil-impacted coastal areas worldwide.

Effects of anthropogenic activities on the microbial community diversity of Ologe Lagoon sediment in Lagos State, Nigeria.

The impact of pollution on the Ologe Lagoon was assessed by comparing physicochemical properties, hydrocarbon concentrations and microbial community structures of the sediments obtained from distinct sites of the lagoon. The locations were the human activity site (OLHAS), industrial-contaminated sites (OLICS) and relatively undisturbed site (OLPS). The physicochemical properties, heavy metal concentrations and hydrocarbon profiles were determined using standard methods. The microbial community structures of the sediments were determined using shotgun next-generation sequencing (NGS), taxonomic profiling was performed using centrifuge and statistical analysis was done using statistical analysis for metagenomics profile (STAMP) and Microsoft Excel. The result showed acidic pH across all sampling points, while the nitrogen content at OLPS was low (7.44 ± 0.085 mg/L) as compared with OLHAS (44.380 ± 0.962 mg/L) and OLICS (59.485 ± 0.827 mg/L). The levels of the cadmium, lead and nickel in the three sites were above the regulatory limits. The gas chromatography flame ionization detector (GC-FID) profile revealed hydrocarbon contaminations with nC14 tetradecane > alpha xylene > nC9 nonane > acenaphthylene more enriched at OLPS. Structurally, the sediments metagenomes consisted of 43 phyla,75 classes each, 165, 161, 166 orders, 986, 927 and 866 bacterial genera and 1476, 1129, 1327 species from OLHAS, OLICS and OLPS, respectively. The dominant phyla in the sediments were Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi. The principal component ordination (PCO) showed that OLPS microbial community had a total variance of 87.7% PCO1, setting it apart from OLHAS and OLICS. OLICS and OLHAS were separated by PCO2 accounting for 12.3% variation, and the most polluted site is the OLPS.

Short-term in situ Exposure of Guinean Tilapia and Blue Crab Near a Sawmill Wastes-impacted Coastal Ecosystem Reveal Significant Oxidative Stress Effects.

Coastal ecosystems are characterized by various human activities with potential adverse impacts. This study aimed to evaluate the potential oxidative stress effects in representative aquatic biota deployed in situ at a sawmill wastes dump (test site) and reference site in a coastal ecosystem for a short term (28 days) period. PAHs and OCPs were analysed using GC-FID and GC-MS respectively in surface water and sediments. Oxidative stress indices (malondialdehyde, glutathione-s-transferase, reduced glutathione, catalase and superoxide dismutase) were evaluated following standard methods in Coptodon guineensis (Guinean Tilapia) and Callinectes amnicola (Blue crab) over a period of 28 days. Sum PAHs in the test site sediments, oxidative stress indices in C. guineensis liver and C. amnicola haemolymph after 28 days exposure were significantly higher (p < 0.0.5) compared to the reference site. The results showed the adverse impacts to biota of sawmill wastes which are continuously burnt at the test site with potential for long-term effects. Sustainable sawmill wastes management at the test site are recommended to sustain life below water (UNSDG 14).

Salinity tolerance of the invasive blue crab Callinectes sapidus: From global to local, a new tool for implementing management strategy.

The latest report from the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) raises concerns about the global proliferation of non-native species (NIS) driven by increasing temperatures. In 2023, the invasive blue crab Callinectes sapidus experienced a significant range expansion in the French Mediterranean lagoons, now present in over 20 lagoons and numerous estuaries with different invasion gradients. It has been established that this species is eurytherm (tolerates a wide range of temperatures; 0-40 °C), rendering temperature a non-limiting factor for its proliferation. On the other hand, salinity is a critical factor to consider, as C. sapidus requires brackish water for copulation and saline water for egg maturation. In this study, we present the salinity tolerance of C. sapidus using the metabolic performance to define the tolerance of the species to a large range of salinities (13 levels from 0 to 65 psu). Results showed that C. sapidus tolerates a large range of salinities with a minimum critical threshold (CTmin) at 0 psu, an optimum at 18.5 psu, and a CTmax at 62.4 psu. Using the performance curve equation, we applied the curve to real salinity data measured each month in 2023 in 20 lagoons invaded. Using this approach, we were able to map, on a fine spatial scale, the distribution of suitable habitats for C. sapidus in the year 2023. Additionally, we have developed a tool to prioritize the lagoons based on their suitability, thereby providing a decision-making framework for management measures in each lagoon. It emerged that 50 % of lagoons were priority areas, 10 % were intermediate and 40 % required monitoring. On the basis of this approach, we can respond to European regulations to help decision-makers implement action plans and/or early detection programs for invasive species management.

Genetic Variability in Mediterranean Coastal Ecosystems: Insights into Ostrea spp. (Bivalvia: Ostreidae).

Oysters are sessile, filter-feeding bivalve molluscs widely distributed in estuarine and coastal habitats worldwide. They constitute a valuable resource for fisheries and extensive aquaculture and provide essential ecological services. Yet, their genetic diversity and distribution remain understudied. The variability in shell morphology complicates species classification, which is influenced by environmental and genetic factors. Although molecular phylogenetics research has refined oyster taxonomy and identified approximately 100 extant species, numerous taxonomic uncertainties persist. In the present study, we aimed to document the occurrence of small flat oysters of the genus Ostrea along the Mediterranean coastal areas of Liguria and Sardinia (Italy). Specifically, 16S rRNA sequence data were used to identify Ostrea species. Our findings offer novel insights into the O. stentina species complex and O. neostentina, a new species in the Mediterranean coastal areas of Italy. The study data further our understanding of Ostrea species diversity, distribution, and evolutionary patterns.