This study was the first to investigate the pollution and ecological risks of heavy metals in coastal, river/stream and road-deposited sediments (RDS) from Apia in Samoa. Cr and Ni concentrations in sediment samples were higher than those of other metals. River sediments and RDS had relatively high EF values around the intensive commercial areas, with a moderate to significant enrichment of Cu, Zn, Cd, and Pb. The results indicate that Cr and Ni have a natural origin from volcanic parent materials, while Cu, Zn, Cd, and Pb originated from anthropogenic activities, such as traffic emissions and the discharge of municipal wastewater. The assessments of pollution and ecological risk revealed that coastal sediments adjacent to the river are anthropogenically contaminated and present a moderate ecological risk. This study demonstrates that metals that have accumulated in the urban impermeable layer and river/stream bed have flowed into the coastal environment through runoff.

There are few cetacean tissue-specific polycyclic aromatic hydrocarbon (PAH) concentration studies in the Mediterranean, despite this region is among the most subjected to chemical contamination. PAH analyses were conducted in different tissues of striped dolphins (Stenella coeruleoalba, N = 64) and bottlenose dolphins (Tursiops truncatus, N = 9) stranded along the French Mediterranean coastline from 2010 to 2016. Comparable levels were measured in S. coeruleoalba and T. trucantus (1020 and 981 ng g−1 lipid weight in blubber, 228 and 238 ng g−1 dry weight in muscle, respectively). The results suggested a slight effect of maternal transfer. The greatest levels were recorded by urban and industrial centers, and decreasing temporal trends were observed in males muscle and kidney, but not in other tissues. As a conclusion, the elevated levels measured could represent a serious threat to dolphins populations in this region, particularly by urban and industrial centers.

Sponges are a key component of coral reef ecosystems and play an important role in carbon and nutrient cycles. Many sponges are known to consume dissolved organic carbon and transform this into detritus, which moves through detrital food chains and eventually to higher trophic levels via what is known as the sponge loop. Despite the importance of this loop, little is known about how these cycles will be impacted by future environmental conditions. During two years (2018 and 2020), we measured the organic carbon, nutrient recycling, and photosynthetic activity of the massive HMA, photosymbiotic sponge Rhabdastrella globostellata at the natural laboratory of Bouraké in New Caledonia, where the physical and chemical composition of seawater regularly change according to the tide. We found that while sponges experienced acidification and low dissolved oxygen at low tide in both sampling years, a change in organic carbon recycling whereby sponges stopped producing detritus (i.e., the sponge loop) was only found when sponges also experienced higher temperature in 2020. Our findings provide new insights into how important trophic pathways may be affected by changing ocean conditions.

We report the optimization, characterization, and validation of Adsorptive Square Wave Cathodic Stripping Voltammetry on antifouling gel-integrated microelectrode arrays for autonomous, direct monitoring of cobalt(II) metal species. Detection is accomplished by complexation with an added nioxime ligand. The limit of detection established for a 90 s accumulation time was 0.29 ± 0.01 nM in freshwater and 0.27 ± 0.06 nM in seawater. The microelectrode array was integrated in a submersible probe to automatically dose the complexing agent nioxime and realize an integrated sensing system. For the first time ever, the potentially bioavailable Co(II) fraction was determined in La Leyre River-Arcachon Bay continuum, enabling to evaluate the potential ecotoxicological impact of freshwater-carried Co(II) in the Arcachon Bay. The measured potentially bioavailable Co(II) concentrations were hazardous for aquatic biota along the continuum. The electrochemical Co(II) data were compared to ICP-MS data in various fractions to determine spatial Co(II) speciation.

The concentrations and isotopic compositions of carbon (C), copper (Cu), zinc (Zn), and lead (Pb) in coastal sediments were analyzed to identify potential pollution sources. High concentrations of total organic carbon (TOC) and metals were found close to cities and industrial areas. The isotopic compositions of C, Cu, Zn, and Pb tended to decrease as their concentrations increased. Bi-plots between δ65Cu and δ66Zn showed that the isotopic compositions in most coastal sediments, except sediments around a smelter, were similar to the isotopic compositions of road dust in urban and industrial areas of Korea. Our results suggest that heavy metal pollution in coastal sediments is greatly influenced by the pollution source, such that most metals originate from traffic and industrial activities in the urban environment. This analysis of multiple isotopes provides insights concerning the transport mechanisms and clarifies potential sources of metal contamination in coastal environments.

To assess the potential of the sole as sentinel species for ecotoxicological monitoring, the present study compares contaminant levels and biological responses with two closely related flatfish species: the common dab and European flounder. Trace metals, organic contaminants and biomarkers were measured in the three flatfish species collected during the same oceanographic cruise in the Bay of Seine (France). Overall, sole showed lower concentrations of Hg, met-Hg, Cd, Zn and PBDE (lw), higher concentrations of Ag, Cu, PFOS (ww), PCBs, p,p’-DDE (lw) and OH-pyrene, a higher ability to metabolize PBDEs and higher genotoxic (Comet, Micronuclei) and neurotoxic (AChE inhibition) alterations. Sole was the species most frequently occurring in the bay and appeared sensitive to chemical contamination. We therefore recommend promoting the use of the common sole for ecotoxicological monitoring.

Visual pollution is an underexamined form of environmental degradation that affects both aesthetic and ecological aspects of natural and anthropogenic landscapes. This discussion paper provides a comprehensive analysis of visual pollution, with a focus on its exacerbation by political advertising in coastal cities in the Caribbean region of Colombia. Despite existing regulations, such as Colombia's Law 140 of 1994, ineffective enforcement has led to an escalation of the issue. The study proposes a multipronged mitigation strategy that includes regulatory measures, technological solutions, stakeholder collaboration, sustainable campaigning, and monitoring and evaluation. The findings have broader implications for addressing visual pollution globally, emphasizing the need for cross-disciplinary research and stringent policy enforcement.

The aim of this study was to characterize and quantify microplastics (MPs) at the chlorophyll maximum layer (CML), around 30 to 60 m depth, during a cruise dedicated to the study of contaminants in plankton, the MERITE-HIPPOCAMPE project, along a north-south transect in the western Mediterranean Sea (Tedetti et al., 2023). Plankton were collected by horizontal net tows in this layer using a multinet Hydrobios Midi equipped with 60 μm mesh-size nets. The collected plankton were fractionated through a sieve column for various later contaminant measurements and for zooplankton analysis (Fierro-González et al., 2023). For all stations, samples were also fully examined for microplastics (MPs) for fractions >300 μm. MPs were found at all stations in the CML layer (mean: 42.9 ± 45.4 MPs m−3), of which 96 ± 4 % were fibers. The ratios of mesozooplankton/MPs and detritus/MPs in this CML were respectively 223 ± 315 and 2544 ± 2268. These data are analyzed together with MPs concentrations from sea- surface sampled with a 300 μm net-size Manta net at the same stations. Overall, our observations highlight the very high density of fibers at the CML, mainly associated with aggregates, raising the hypothesis of their interactions with marine snow. Therefore, the importance of marine snow and vertical layering will have to be considered in future MP distribution modelling efforts.

The world's oceans are facing plastic pollution, 80 % of which of terrestrial origin flowing from the mismanaged waste of coastal populations and from river discharge. To study the fate of this pollution, the three-dimensional trajectories of neutral plastic particles continuously released for 24 years according to realistic source scenarios are computed using currents from a global ocean-wave coupled model at resolution and from a reference ocean-only model. These Lagrangian simulations show that neutral particles accumulate at the surface in the subtropical convergence zones from where they penetrate to about 250 m depth and strongly disperse over 40∘ of latitude. About 5.3 % of the particles remain at the surface with the wave-coupled model currents, whereas only 2 % for the uncoupled model, with some modulation in the location of the convergence zones. Increased surface retention results from upward vertical velocities induced by widespread divergence of waves-induced Stokes transport in the surface layers.

The uprising interest in gelatinous zooplankton populations must cope with a lack of robust time series of direct abundance observations in most of the ecosystems because of the difficulties in sampling small, fragile organisms, and of the dismissal of jellyfish as a nuisance. Most of the hypotheses about their dynamics are built on a few species and ecosystems and extended to the whole group, but the blooms are registered mainly for the members of the Class Scyphozoa that dwell in temperate, shallow waters. Within the scyphozoans, our knowledge about their phenology relies mainly on laboratory experiences. Here we present a long-term analysis of the phenology and life cycle of three scyphozoan species in an ecosystem affected by eutrophication in a climate change context. We have found that the phenology is directed by temperature, but not modified by different thermal and ecological regimes.