Metal pollution in the Bohai Sea in China has posed a potential risk on marine organisms. In this work, crabs (Portunus trituberculatus) were sampled from four sites, namely a reference (site 3934) and three metal-polluted (sites 6151, 6351, and 3562) sites, located in the Bohai Sea. Metal concentrations in crab gill tissues were measured using inductively coupled plasma mass spectrometry. Cu, Zn, and Cd in crab samples from S3562 presented the highest concentrations. Particularly, Cu concentration exceeded the marine biological quality standard II. Cd contents in crab samples from all metal-polluted sites exceeded the marine biological quality standard I. Nuclear magnetic resonance-based metabolomics indicated metal pollution-induced immune stresses in crab samples from all metal-polluted sites. Metal pollution in S6151 and S6351 disturbed energy metabolism through differential pathways. For crab samples from S3562, the metabolic profile suggested that metal pollution mainly induced osmotic stress.

Water, suspended particulate matter (SPM), and sediment samples were collected from Salt River in Taiwan and analyzed the concentrations of 16 types of polycyclic aromatic hydrocarbons (PAHs). The analysis results were used to examine the distribution, source, partition behavior, and potential ecological risks of PAHs in the estuarine water systems. The mean concentration of total PAHs in water, SPM, and sediment samples was 0.485–10.2 μg/L, 26.7–169 mg/kg dw, and 0.343–29.4 mg/kg dw, respectively. The highest concentration was found at the river mouth and decreased toward the river and sea with the tide. The distribution of the diagnostic ratios of PAHs showed that the combustion of coal and petroleum products are the main sources of PAHs in Salt River. The in site organic carbon normalized partition coefficients for SPM-water (K'ₒc₍SPMW₎) and sediment-water (K'ₒc₍SₑdW₎) were 2.8–4.5 and 4.6–6.0 (log units), respectively, increasing with the number of rings in PAHs. The values log K'ₒc₍SₑdW₎ and log K'ₒc₍SPM₋W₎ showed a significant linear correlation with their octanol-water partition coefficients (p < 0.01), and their slopes were 0.427 and 0.316, respectively. The fugacity fraction was used to evaluate the exchange of PAHs in water-SPM-sediment systems. Results showed that in SPM, 2–4-ring PAHs tend to be released into water, whereas 5–6-ring PAHs in water tend to be adsorbed onto SPM. The exchange of PAHs between water and sediment occurs in the direction of adsorption onto sediment from water. The assessment of the mean risk quotient, total toxicity equivalence, and mean effect range-median quotient of PAHs showed that the PAHs in the water and SPM of Salt River may have moderate to high ecological risk. In sediment, PAHs in the lower reaches and estuary may pose moderate to high ecological risk, whereas PAHs in the middle and upper reaches show low to moderate ecological risk.

Pollution in the Arabian Gulf has risen in recent decades due to rapid development in the region. We studied 21 elements in the liver, gastrointestinal (GI) tract and muscles of the Indian anchovy (Stolephorus indicus) to characterize bioaccumulation in this abundant forage fish. Mean concentrations (μg/g wet weight) of elements ranged as follows: Cd: 0.1–8.0; Cr: 0.1–24.0; Cu: 1.2–24.0; Ni: 0.3–76.5; Ca: 1237.0–15,270.0; S: 2966.0–7467.0; Zn: 7.1–247.0; V: 0.1–27.0; Hg: 0.04–0.18 and Sr: 8.1–191.0. Zn, Cu, Cr, and Cd in the tissues exceeded the maximum permissible limit recommended by FAO, WHO and EC. We suggest that bioaccumulation in fish could be a hazard for human consumption. Therefore, further monitoring is needed to better characterize pollutant levels in fish of higher trophic levels in the Arabian Gulf.

Harmful algal blooms involving the dinoflagellate Cochlodinium polykrikoides occur every summer off the Korean peninsula's central southern coast. To determine whether Cochlodinium bloom-derived organic carbon is incorporated into the subtidal macrobenthic food web, we compared the δ¹³C and δ¹⁵N values of suspended particulate organic matter (SPOM) and sedimentary organic matter, and macrobenthic consumers between bloom and non-bloom seasons. Chemotaxonomic analysis revealed the presence of Cochlodinium blooms in summer and a predominance of diatoms in autumn. Both the δ¹³C and δ¹⁵N values of SPOM were higher in the bloom than in the non-bloom seasons. Such temporal shifts in the δ¹³C and δ¹⁵N values were also observed for most macrobenthic consumers collected in both seasons. Consistent temporal isotopic shifts in SPOM and macrobenthos revealed that the Cochlodinium bloom-derived carbon was incorporated into the coastal benthic food web, resulting from its increasing availability during blooms.

The aquatic environment can represent a reservoir of antimicrobial resistance genes. In the present study, phenotypical, biochemical and molecular techniques were used to screen a collection of marine strains isolated in Italian aquaculture farms to investigate their beta-lactam resistance profiles. The genome of 12 carbapenemase and/or beta-lactamase producing strains was sequenced and a phylogenetic analysis of the beta-lactamases found in their chromosomes was performed. Gene annotation and prediction revealed the presence of blaAₘₚC and blaOXA₋₅₅₋ₗᵢₖₑ in all the Shewanella algae isolates whereas in Vibrio anguillarum and Vibrio parahaemolyticus strains, blaAₘₚC and blaCARB₋₁₉ were found, respectively. Multiple alignments of OXA-55-like and AmpC protein sequences showed different point mutations. Finally, comparisons between enzyme phylogeny and strain clusterization based on sampling sites and dates indicate the diffusion of specific Multi Drug Resistant (MDR) Shewanella algae clones along the Italian Adriatic coast.

Tourism is an important socioeconomic activity in coastal communities, which deteriorates marine-coastal ecosystem quality when poorly managed, increasing litter pollution on beaches during the main tourist seasons. This study aims to assess the tourism impact on litter pollution on eleven Santa Marta beaches, Colombian Caribbean. During high and low tourist seasons, people on the beaches were counted, macrolitter and microplastics were sampled, and perception surveys about litter on beaches were conducted. During the high tourist season, the number of people and macrolitter pollution increased, compared to the low tourist season. Plastics accounted for 30%–77% of macrolitter and microplastics ranged from 1 to 355 items/m². Respondents identified tourism as a main litter source and plastics as the most common litter type. All assessed beaches are impacted by tourism causing litter pollution, therefore, stronger controls, educational, and awareness strategies are needed to reduce litter pollution and prevent ecological and socioeconomic impacts.

Human activities in coastal catchments can cause the accumulation of pollutants in seafood. We quantified the concentration of heavy metals, pesticides and PFASs in the flesh of the fisheries species yellowfin bream Acanthopagrus australis (n = 57) and mud crab Scylla serrata (n = 65) from 13 estuaries in southeast Queensland, Australia; a region with a variety of human land uses. Pollutants in yellowfin bream were best explained by the extent of intensive uses in the catchment. Pollutants in mud crabs were best explained by the extent of irrigated agriculture and water bodies. No samples contained detectable levels of pesticides, and only six samples contained low levels of PFASs. Metals were common in fish and crab flesh, but only mercury in yellowfin bream from the Mooloolah River breached Australian food safety standards. High pollutant presence and concentration is not the norm in seafood collected during routine surveys, even in estuaries with highly modified catchments.

The study, for the first time, evaluated the leaching rate of zinc oxide nanoparticles (nZnO) from human skins which were applied with three commercial sunscreens containing nZnO as an active ingredient. The leaching rate of nZnO varied greatly among the sunscreens, with a range of 8–72% (mean ± SD: 45% ± 33%). We further investigated their toxicities to the marine copepod Tigriopus japonicus. We found that 96-h median lethal concentrations of the three sunscreens to T. japonicus were > 5000, 230.6, and 43.0 mg chemical L⁻¹, respectively, equivalent to Zn²⁺ concentrations at >82.5, 3.2, and 1.2 mg Zn L⁻¹, respectively. Exposure to the individual sunscreens at environmentally realistic concentrations for 96 h led to up-regulation of antioxidant genes in T. japonicus, while they triggered the release of reactive oxygen species based on the results of in vivo assays. Evidently, these nZnO-included sunscreens can cause oxidative stress and hence pose risk to marine organisms.

External damages are indicators of the overall quality of fish and fish welfare. Haddock is an important commercial species widespread in the North Atlantic, but few studies related to quality have been carried out on this species. We studied the levels of external damages on haddock captured with a demersal trawl in the Northeast Atlantic. Further, we investigated to what extent the compulsory sorting grid and diamond mesh codend gear configuration employed in this trawl fishery is responsible for the external damages observed during the capture process. We evaluated external damages on 563 haddock captured over 22 hauls. In general, the results showed that catching haddock without any gear inflicted damages using demersal trawls is challenging. However, the results also showed that the severity of most damages is low and the probability to catch haddock with no external damage can be significantly increased removing the grid and changing codend design.

Mangroves in the Northwest Coast of South America are contaminated with heavy metals due to wastewater discharges from industries, affecting the biota from this environment. However, bacteria proliferate in these harsh environmental conditions becoming possible sentinel of these contaminations. In this study, bacterial community composition was analyzed by throughput sequencing of the 16S rRNA gene from polluted and pristine mangrove sediments affected by marked differences in heavy metal concentrations. Core bacteria were dominated by Proteobacteria, Firmicutes, and Bacteroidetes phyla, with strong differences between sites at class and genus levels, correlated with metal levels. Increment of abundance on specific OTUs were associated with either elevated or decreased concentrations of metals and with the sulfur cycle. The abundance of Sulfurovum lithotrophicum, Leptolinea tardivitalis, Desulfococcus multivorans and Aminobacterium colombiense increases when metals rise. On contrary, Bacillus stamsii, Nioella nitrareducens and Clostridiisalibacter paucivorans abundance increases when metal levels are reduced. We propose these OTUs as bacterial sentinels, whose abundance can help monitor the restoration programs of contaminated mangrove sediments in the future.