Heavy metal stress changes the morphological and anatomical structure of plant organs. In this study, we determined the anatomical changes and Cd distribution in the roots of Aegiceras corniculatum (L.) Blanco (Black mangrove) under Cd stress. The results showed that Cd levels in A. corniculatum root tissues decreased in the following order: endodermis > pith > xylem > epidermis and exodermis > phloem > cortex. The endodermis secondary casparian strip replaces exodermis casparian strip and plays a role in the “retardation mechanism”, which sort of compensates for the missing exodermis retardation effect. The xylem and pith both show high affinity for Cd and contain enriched Cd. This creates a low-Cd environment for phloem and protects the nutrient transport function of the vasculature against Cd toxicity. The present study provides new evidences suggesting that Cd regional enrichment and anatomical structure changes are an adaptive strategy of mangrove plants to HM tolerance.

Argonauta nouryi Lorois, 1852 is an octopod that inhabits the holopelagic zone, the objective of this study was to describe the occurrence of buoyant fibers adhering to the body and mantle cavity of A. nouryi females found in the stomach contents from Euthynnus lineatus (skipjack), Coryphaena hippurus (dolphinfish), and Istiophorus platypterus (sailfish). Stomach contents from 224 individuals were examined. All female evaluated presented fibers adhering to the mantle cavity; 92.6% of the fibers measured 0.25 to 5 mm in length and hyaline was the dominant color (72%). The amount of fibers in the fish stomach contents with A. nouryi was significantly greater than in stomachs without; this suggests that the fibers might be introduced via A. nouryi. Findings of this work could be related to the discharge of solid materials in the water column.

Akashiwo sanguinea is a harmful—but not toxic—species that causes blooms around the world. In China, the first A. sanguinea bloom was recorded in Yantai in 1998. Until 2017, there were 31 occurrences of A. sanguinea blooms recorded in Chinese four seas, with large spatial distributions. Furthermore, these blooms were recorded in almost every month except November, December and January. It can be concluded that the 1990s represented the initial stage of A. sanguinea blooms, while the 2000s represented the spreading stage and the 2010s represented the burst stage in China.

Exposure to persistent organic pollutants (POPs) is a key factor in predicting the collapse of global killer whale (Orcinus orca) populations due to reproductive and immune impacts. Blubber biopsies from killer whales (n = 25) were collected in the Russian Far East in 2002–2004. Biopsies were analyzed for ΣDDT, ΣPCB, and HCB concentrations. A subset of biopsies was further examined for additional contaminants, ΣPBDE, ΣHCH, ΣCHLD, mirex, and dieldrin. Mean concentrations were compared across resident (fish-eating) and transient (mammal-eating) ecotypes and between sexes. ΣPCB analytes (resident males 18,000, resident females 1200, and transient males 420,000 ng g⁻¹ lw) and HCB (resident males 750, resident females 81, and transient males 6200 ng g⁻¹ lw) differed significantly (p < 0.001). No significant difference was observed between sexes. Notable disparities in contaminant levels between ecotypes support the major toxicological theories of contaminant bioaccumulation and dietary impacts on individual contaminant load.

Microplastics (<5 mm) are ubiquitous in the marine environment, occurring in both sediments and surface waters worldwide. However, few studies have documented the presence of microplastics and tire wear particles in coastal rivers. A survey of microplastics and low-density tire wear particles (≥63 μm) in the sediment and surface water of the three major tributaries within the Charleston Harbor estuary was conducted. Intertidal sediment, subtidal sediment, and sea surface microlayer concentrations ranged from 0 to 652 microplastics/m², 3–4,375 microplastics/kg wet weight, and 3–36 microplastics/L, respectively. Blue fibers and tire wear particles were the two most abundant microplastic types observed, constituting 26.2% and 17.1%, respectively, of total microplastics. Tire wear particles were primarily identified by morphology, and ATR-FTIR analysis was conducted for a small subset (n = 5) of larger particles (≥500 μm). The present study provides the first microplastic field assessment of low-density tire wear particles in estuarine tributaries.

The major and trace metal (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, Li, and Co) concentration profiles along a 60.2-m-long sediment core are investigated to assess their depositional trends and contamination levels in the Jiangsu coastal area, China. All of the metals, except Cd, had similar profiles that exhibited increasing concentrations during the Holocene. Their enrichment factors indicate that the metals were naturally sourced throughout the observed depositional period, with the exception of As, Hg, and Li, which may have also had anthropogenic sources. Their geoaccumulation indices indicate that the sediments were not contaminated by any metals prior to the Holocene, whereas they were contaminated by As, Hg, and Li throughout the Holocene (11–0 ka), and by Pb, Cr, and Zn since 2 ka.

The recent intensification of energy resource exploration and human activities in the Barents Sea (BS) requires a more thorough assessment of the natural and anthropogenic impact of hydrocarbons on the environment. We analyzed a wide set of sensitive indicators, including hydrocarbon molecular markers and organic matter (OM) maturity parameters in the Holocene sediments from three regions of the BS: the Kola-Kanin Monocline (KKM), the Svalbard shelf, and the Shtokman gas-condensate field (GCF). An increase in pyrogenic polycyclic aromatic hydrocarbons toward the core surface traces the intensification of anthropogenic contamination in the KKM region during last century. An input of highly mature OM from the eroded coal rocks of Barentsburg were confirmed by comparison of biomarker distribution in sediments and coals. An increase in biogenic hopanes and hopenes content down-core, and a crude-oil stage of OM maturity in surface sediments of the Shtokman GCF attests to hydrocarbons migration from subsurface strata.

Microplastics have emerged as new pollutants in oceans. Nevertheless, information of the long-term variations in the composition of plastic-associated microbial communities in coastal waters remains limited. This study applied high-throughput sequencing to investigate the successional stages of microbial communities attached to polypropylene and polyvinyl chloride microplastics exposed for one year in the coastal seawater of China. The composition of plastisphere microbial communities varied remarkably across geographical locations and exposure times. The dominant bacteria in the plastisphere were affiliated with the Alphaproteobacteria class, particularly Rhodobacteraceae, followed by the Gammaproteobacteria class. Scanning electron microscopy analysis revealed that the microplastics showed signs of degradation. Microbial communities showed adaptations to plastisphere including more diverse microbial community and greater “xenobiotics biodegradation and metabolism” in metabolic pathway analysis. The findings elucidate the long-term changes in the community composition of microorganisms that colonize microplastics and expand the understanding of plastisphere microbial communities present in the marine environment.

Oil and gas exploration and marine transport in the Arctic region have put the focus on the ecological risk of the possibly exposed organisms. In the present study, the impacts of sea ice, extreme light regime, various polar region-specific physiological characteristics in polar cod (Boreogadus saida) and their effects on xenobiotic distribution and metabolism are studied. A Bayesian belief network is used to model individual fish toxicity. The enzyme activity in the fish liver and other pertinent organs is used as a proxy for cellular damage and repair and is subsequently linked to toxicity in polar cod. Seasonal baseline variation in enzyme production is also taken into consideration. The model estimates the probability of exposure concentration to cause cytotoxicity and circumvents the need to use the traditionally obtained No Observed Effect Concentration (NOEC). Instead, it uses biotransformation enzyme activity as a basis to estimate the probability of individual cell damages.

Oceanic plastic pollution is a growing worldwide environmental concern, endangering numerous marine species. Pinnipeds are particularly susceptible to entanglement, especially in abandoned, lost or discarded fishing gear and packaging straps. We searched three international databases to compile a comprehensive review of all reported pinniped entanglements over the last 40 years, with the aim to identify areas of concern and foci for mitigation. The majority of published records of entanglement emanate from North America and Oceania and are focused on a few populous species (notably, Zalophus californianus and Arctocephalus gazella). Reporting bias, skewed research effort and incomplete understanding of plastic pollution and pinniped abundance overlap, combine to cloud our understanding of the entanglement problem. Broader geographical effort in entanglement data collection, reporting of such data, and improved quantification of the proportions of populations, sexes and ages that are most susceptible, will aid our efforts to pinpoint priority mitigation measures.