Marine fishes are exposed to great human-induced alterations due to the indiscriminate discharges into the sea, increasing marine pollution. For this study, 324 specimens of Sardina pilchardus from the Canary Islands were analized during a period of 2 years (June 2016 to May 2018). The concentration of 11 metals and trace elements (Al, B, Cd, Cr, Cu, Fe, Li, Ni, Pb, V and Zn) was determined in each individual using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) technique. Statistical analyses were carried out considering the following factors: oceanographic season, maturity of the gonads in the seasons, size of the specimens. Sardina pilchardus specimens captured in the hot season presented higher Ni, Li and Pb levels than the specimens caught in the cold season. Immature specimens had higher concentration in more metals than the mature specimens. This fact may be due to the fact that these specimens require a much higher metabolic rate due to their growth and do not detoxify like mature specimens. Significant differences were found in the concentration of metals in all the analyzes performed.

Pollution by marine litter is raising major concerns due to its potential impact on marine biodiversity and, above all, on endangered mega-fauna species, such as cetaceans and sea turtles. The density and distribution of marine litter and mega-fauna have been traditionally monitored through observer-based methods, yet the advent of new technologies has introduced aerial photography as an alternative monitoring method. However, to integrate results produced by different monitoring techniques and consider the photographic method a viable alternative, this ‘new’ methodology must be validated. This study aims to compare observations obtained from the concurrent application of observer-based and photographic methods during aerial surveys. To do so, a Partenavia P-68 aircraft equipped with an RGB sensor was used to monitor the waters off the Spanish Mediterranean coast along 12 transects (941 km). Over 10000 images were collected and checked manually by a photo-interpreter to detect potential targets, which were classified as floating marine macro-litter, mega-fauna and seabirds. The two methods allowed the detection of items from the three categories and proved equally effective for the detection of cetaceans, sea turtles and large fish on the sea surface. However, the photographic method was more effective for floating litter detection and the observer-based method was more effective for seabird detection. These results provide the first validation of the use of aerial photography to monitor floating litter and mega-fauna over the marine surface.

A multinational demersal longline survey was conducted on the Gulf of Mexico continental shelf over the years 2015 and 2016 to generate a Gulf-wide baseline of polycyclic aromatic hydrocarbon (PAH) concentrations in demersal fishes. Tilefish (Lopholatilus chamaeleonticeps) were sampled in all regions of the Gulf of Mexico for biometrics, bile, and liver. Tilefish liver was also obtained from surveys in the northwest Atlantic Ocean for comparison. Liver tissues (n = 305) were analyzed for PAHs and select alkylated homologs using QuEChERS extractions and gas chromatography tandem mass spectrometry. Bile samples (n = 225) were analyzed for biliary PAH metabolites using high-performance liquid chromatography with fluorescence detection. Spatial comparisons indicate the highest levels of PAH exposure and hepatic accumulation in the north central Gulf of Mexico, with decreasing concentrations moving from the north central Gulf counterclockwise, and an increase on the Yucatán Shelf. Hepatic PAH concentrations were similar between the Gulf of Mexico and the northwest Atlantic, however, Tilefish from the northwest Atlantic had higher concentrations and more frequent detection of carcinogenic high molecular weight PAHs. Overall, results demonstrate that PAH pollution was ubiquitous within the study regions, with recent exposure and hepatic accumulation observed in Tilefish from both the Gulf of Mexico and northwest Atlantic.

Microplastics are emerging contaminants in the marine environment. They enter the ocean in a variety of sizes and shapes, with plastic microfiber being the prevalent form in seawater and in the guts of biota. Most of the laboratory experiments on microplastics has been performed with spheres, so knowledge on the interactions of microfibers and marine organisms is limited. In this study we examined the ingestion of microfibers by the sea anemone Aiptasia pallida using three different types of polymers: nylon, polyester and polypropylene. The polymers were offered to both symbiotic (with algal symbionts) and bleached (without algal symbionts) anemones. The polymers were introduced either alone or mixed with brine shrimp homogenate. We observed a higher percentage of nylon ingestion compared to the other polymers when plastic was offered in the absence of shrimp. In contrast, we observed over 80% of the anemones taking up all types of polymers when the plastics were offered in the presence of shrimp. Retention time differed significantly between symbiotic and bleached anemones with faster egestion in symbiotic anemones. Our results suggest that ingestion of microfibers by sea anemones is dependent both on the type of polymers and on the presence of chemical cues of prey in seawater. The decreased ability of bleached anemones to reject plastic microfiber indicates that the susceptibility of anthozoans to plastic pollution is exacerbated by previous exposure to other stressors. This is particularly concerning given that coral reef ecosystems are facing increases in the frequency and intensity of bleaching events due to ocean warming.

Microplastic and microfiber pollution has been documented in all major ocean basins. Microfibers are one of the most common microparticle pollutants along shorelines. Over 9 million tons of fibers are produced annually; 60% are synthetic and ∼25% are non-synthetic. Non-synthetic and semi-synthetic microfibers are infrequently documented and not typically included in marine environment impact analyses, resulting in underestimation of a potentially pervasive and harmful pollutant. We present the most extensive worldwide microparticle distribution dataset using 1-liter grab samples (n = 1393). Our citizen scientist driven study shows a global microparticle average of 11.8 ± 24.0 particles L−1 (mean ± SD), approximately three orders of magnitude higher than global model predictions. Open ocean samples showed consistently higher densities than coastal samples, with the highest concentrations found in the polar oceans (n = 51), confirming previous empirical and theoretical studies. Particles were predominantly microfibers (91%) and 0.1–1.5 mm in length (77%), a smaller size than those captured in the majority of surface studies. Using μFT-IR we determined the material types of 113 pieces; 57% were classified as synthetic, 12% as semi-synthetic, and 31% as non-synthetic. Samples were taken globally, including from coastal environments and understudied ocean regions. Some of these sites are emerging as areas of concentrated floating plastic and anthropogenic debris, influenced by distant waste mismanagement and/or deposition of airborne particles. Incorporation of smaller-sized microfibers in oceanographic models, which has been lacking, will help us to better understand the movement and transformation of synthetic, semi-synthetic and non-synthetic microparticles in regional seas and ocean basins.

When mammals strand, they present a unique opportunity to obtain insights into their ecology. In May 2013, three True's beaked whales (two adult females and a female calf) stranded on the north and west coasts of Ireland and the contents of their stomachs and intestines were analysed for anthropogenic debris. A method for identifying microplastics ingested by larger marine organisms was developed. Microplastics were identified throughout the digestive tract of the single whale that was examined for the presence of microplastics. The two adult females had macroplastic items in their stomachs. Food remains recovered from the adult whales consisted of mesopelagic fish (Benthosema glaciale, Nansenia spp., Chauliodius sloani) and cephalopods, although trophic transfer has been discussed, it was not possible to ascertain whether prey were the source of microplastics. This is the first study to directly identify microplastics <5 mm in a cetacean species.

Oil spill causes extreme environmental damage, from aquatic life to seabirds, disrupting the entire ecosystem. Herein, we have synthesized high scale, economical and bio-compatible, green algae mediated Titanium oxide (TiO₂) nanoparticles and Polyacrylonitrile (PAN) nanofiber mats. We have studied the effect of encapsulation and coating of TiO₂ nanoparticles over nanofiber mats for highly efficient oil spill adsorption. TiO₂ encapsulated and coated PAN (TECP) nanofibers showed a maximum of 62.34 g g⁻¹ adsorption capacity of petroleum oil from the water surface. Moreover, the composite mats show maximum adsorption within 45 s for up to 5 repeated cycles. Further, it has been observed that the adsorption capacity has increased by increasing the weight of the composite nanofiber mats, which confirms its commercial applicability. Thus, this work provides rapid, large-scale, economical, bio-compatible, and highly effective adsorbents for oil spill cleaning and extraction over natural waterbodies.

In this study, 214 surface sediment samples were collected from the offshore area of the Dongying coast and were analysed for heavy metals; particularly, their concentrations and pollution status were evaluated. The copper (Cu) and chromium (Cr) distributions were similar, their concentrations were the highest in the northeast areas and the Xiaoqing River estuary, where dominated by fine-grained sediments. Higher concentrations of lead (Pb), zinc (Zn), cadmium (Cd), and arsenic (As) were generally found in the offshore area of the study location, and the highest Cd concentration was observed in the Xiaoqing River estuary. The sediments were not polluted by Cu, Pb, Zn, and Cr; they were not polluted or moderately polluted by Cd and As. Results of the principal component analysis indicated that Cu, Pb, Zn, and Cr were derived from natural sources and Cd and As were derived from anthropogenic sources.

This study assessed the seasonal variation in the magnitude of marine litter along the Gulf of Guinea coastline, Araromi seaside, Nigeria with a survey of twenty sampling sites. The total number of litter items collected was 29,029 comprising 7358 and 21,671 items in the dry and rainy season respectively. The average number of items per square meter was higher in the rainy season (1.80 ± 0.35) than in the dry season (0.61 ± 0.19). Plastic materials dominated the litter composition with 86 % and 91.8 % in the dry and rainy season respectively. The beach cleanliness assessed as clean coast index (CCI) depicted the beach as dirty (12.26 ± 3.74) during the dry season and extremely dirty (36.13 ± 6.91) in the rainy season. The hazardous item index (HII) also showed the coastline was littered with hazardous items. These results provide baseline data for marine litter management along the Gulf of Guinea coastlines and other coastlines in Africa.