Trace metal dynamics were investigated in mangroves developing in semi-arid New Caledonia, where Avicennia and Rhizophora stands grow in the upper and lower intertidal zone, respectively. We collected soil samples and mangrove tissues in an undisturbed site, a mining-influenced site and in a mining and aquaculture-influenced site. Differences in duration of immersion and organic matter (OM) cycling resulted in a sharp decrease of metal concentrations in soils and plants from landside to seaside. Both species were tolerant to metals mainly via exclusion, (i.e. metal bioaccumulation restricted to roots and leaf litter). Strong correlations (p < 0.05) were found between Na and Fe, Mn, Cu and Zn in green and senesced leaves of Avicennia marina, indicating a possible role of those metals in mechanisms to cope with hypersaline conditions.Increasing metal pollution, aridity and sea-level rise are likely to result in a decrease in mangrove efficiency in filtering trace metals seaward.

This study highlights plastics occurrence in five demersal fish species from the Southern Tyrrhenian Sea: the Red mullet Mullus barbatus barbatus, the Piper gurnard Trigla lyra, the Blackmouth catshark Galeus melastomus, the Lesser spotted dogfish Scyliorhinus canicula and the Brown ray Raja miraletus. Overall, 125 fish were examined: 21 Red mullets, 16 Piper gurnards, 75 Blackmouth catsharks, 72 Dogfish and 1 Brown ray. The percentage of fish with ingested plastics was 14.4% with 0.24 items per specimen. The majority of the debris were fibers and the application of infrared and Raman spectroscopy allowed the identification and discrimination of plastic and non-plastic fibers. The plastic debris isolated were mainly microplastics (94.1%), while macroplastics occurrence was very low (5.9%). The plastics were identified as polypropylene, Teflon, nylon, kraton G (triblock copolymer) and polyethylene. Also cellulose was detected. S. canicula was the species with the highest number of plastic pollutants.

There is public concern about the behaviour of spilled diluted bitumen (dilbit) in marine and estuarine waters. We provide a preliminary assessment of the results of laboratory experiments and models, in the context of environmental conditions in the coastal waters of British Columbia. Most dilbit spilled within this region would likely float at the surface and be transported to shore by winds and currents. Fresh dilbit is too light to sink in coastal waters. Highly weathered dilbit could sink where salinity is less than 14, typically only near river mouths and in the top 1–3 m of fjords after heavy rainfall. Subsurface plumes of weathered dilbit could re-emerge at the surface. Sinking oil-particle aggregates are unlikely to form in coastal waters. However, dilbit could be entrained below the surface by wave mixing during storms and to depths of 150 m by coherent mixing in the Haro Strait tidal convergence zone.

We investigated the impact of microplastics (MPs) on marine fish by estimating the uptake and retention by mummichogs (Fundulus heteroclitus) and red seabreams (Pagrus major) of MPs similar in size (≥0.25 mm) and composition (polyethylene) to MPs detected in fish intestines. Results revealed a correlation between MP concentrations in aquarium water and the content of MPs in the gastrointestinal tracts of exposed fish. More than 95% were excreted from both species within 25 h; this retention time is similar to the processing time of food items. The rate of excretion showed little dependence on MP size, but there was some dependence on fish species and MP shape. These results suggest that MPs similar to those we studied have little direct adverse impact on these two marine fish species.

In Australia, some trees of the mangrove, Avicennia marina, growing in a chronic oil polluted site, produce chlorophyll deficient (albino) propagules. We tested the hypothesis that albinism was due to an oil-induced mutant allele that controls photosynthesis. We determined whether there are genetic differences between normal and chlorophyll deficient propagules. Four gene regions (nuclear 18S–26S cistron; chloroplast - trnH-psbA, rsp16 and matK) were sequenced and analysed for normal and albino propagules. Mutations occurred in both nuclear (ITS) and coding chloroplast (matK) genes of albino propagules. There were 10 mutational differences between normal and albino propagules in the matK samples. Analysis of molecular variation (AMOVA) of the matK dataset indicated highly significant genetic differentiation between normal and albino propagules. Our study suggests for the first time that PAHs from a chronic oil polluted site resulted in mutations in both nuclear and chloroplast genes, resulting in the production of albino propagules.

Seabirds are used as bioindicators of marine ecosystems, especially for quantifying and tracking pollution sources. The objective of this study was to evaluate the contamination in feathers of young kelp gulls by lead (Pb), chromium (Cr), mercury (Hg) and zinc (Zn) on three islands of southern Brazil. The highest values for Pb (2.1310 μg g⁻¹) and Hg (0.0010 μg g⁻¹) were observed in Lobos. Zn was common in all samples with a median around 41.7487 μg g⁻¹ and Cr values were below the quantification limit (0.0300 μg g⁻¹). The Kruskal-Wallis test indicated significant differences in Pb (H = 21.84; p < 0.05) and Zn (H = 958.80; p < 0.05), but no differences were observed in Cr (H = 3.08; p < 0.05) and Hg (H = 3.0; p < 0.05). This study was important to show the impact of trace element pollutants on the seabird communities and oceans.

Microplastics' (MPs) abundance, small size, and global distribution render them bioavailable to a variety of organisms directly or by trophic transfer, yet examinations in marine apex predators are currently limited. The present study investigated the occurrence of MPs sized 125 μm–5 mm in the gastrointestinal tract (GIT) of bottlenose dolphins (Tursiops truncatus) stranded in South Carolina, USA from 2017 to 2018. MPs, mostly fibers, were detected in all GITs (n = 7) of stranded bottlenose dolphins. Total suspected MPs ranged between 123 and 422 particles/individual, a high range among international studies. Comparison to other studies likely reflects differences in both methods and location. This is the first study from North America to quantify MPs in a small coastal cetacean outside Arctic waters and the first specifically in bottlenose dolphins (southeastern United States). Findings and methodology from this investigation can aid future studies examining MP in marine apex predators.

Calvo et al. (2020) criticize a new seagrass rehabilitation method proposed by Alagna et al. (2019) and inspired by the Posidonia oceanica spontaneous recovery observed at Capo Feto (Sicily), were recolonization was detected almost exclusively on rubbles deployed to fill a pipeline trench. Calvo et al. (2020) claim that natural recovery occurred consistently also on dead matte along the eastern side of the trench, weakening the assumption on which the method is based. Here we show that the P. oceanica patches reported by these authors as new establishments were already documented in 2003 (Vega Fernandez et al., 2005) and are attributable to the fragmentation of the pristine meadow caused by altered sedimentation rate after an extensive dredging operation. Moreover, we outline the area of applicability of the method tested in Alagna et al. (2019) and provide a point-by-point rebuttal to the complaints of imprecise and misleading contents of the paper.

Swordfish is a widely consumed fish worldwide. The aim of this work was to evaluate levels of As, Zn, Mn, Fe, Cu, Al, Cr, Ni, Se, Cd, Pd and Hg in 28 samples of swordfish muscles, coming from zone of Food and Agriculture Organization (FAO) namely 37.1 and 37.2, in order to assess potential public health risks. 100% of the samples had Cd levels not detectable, 32.14% of samples exceeded European maximum limits set for Hg. Health risk assessment showed a not dangerous condition for Al (0.65% of Tolerable Weekly Intake), Ni (0.27% of Tolerable Daily Intake) and Pb (0.68% of Provisional Tolerable Weekly Intake), but very hazardous states for Hg (159.69% of Tolerable Weekly Intake) and As (1099.45% for minimum value of Benchmark Dose Limit). Target Hazard Quotient (THQ) showed dangerous values only for As and Hg. Analytical data of the present study suggest a swordfish prudent consumption.