Given the implications of microplastics contamination in aquatic ecosystems and information scarcity about microplastic abundances in estuarine sediments, this study aimed to quantify and describe the microplastics in the sublittoral sediments from Guanabara Bay. Sediment samples were collected at four sites and three months, microplastics were separated and classified according to type, color, size, and polymer composition. High abundances of microplastic (160 to 1000 items kg⁻¹ or 4367 to 25,794 items m⁻²) occurred independent of area or period, indicating microplastics are widely spread in Guanabara Bay. The dominant microplastic in the sediment was the translucent polyester microfiber of <1 mm size; which is a secondary microplastic, possibly coming from washing machines wastes. The extremely high availability of microplastics in Guanabara Bay, compared to the majority of studies around the world, suggests high risk of contamination to benthic organisms and demersal fish, as they may be ingesting microplastics.

Climate change and human disturbance threatens coral reefs across the Pacific, yet there is little consensus on what characterizes a “healthy” reef. Benthic cover, particularly low coral cover and high macroalgae cover, are often used as an indicator of reef degradation, despite uncertainty about the typical algal community compositions associated with either near-pristine or damaged reefs. In this study, we examine differences in coral and algal community compositions and their response to human disturbance and past heat stress, by analysing 25 sites along a gradient of human disturbance in Majuro and Arno Atolls of the Republic of the Marshall Islands. Our results show that total macroalgae cover indicators of reef degradation may mask the influence of local human disturbance, with different taxa responding to disturbance differently. Identifying macroalgae to a lower taxonomic level (e.g. the genus level) is critical for a more accurate measure of Pacific coral reef health.

The interaction of anthropogenic litter (by incorporation litter in nests, ingestion, and entanglement) with birds was systematically reviewed using Google Scholar database. A ‘black-list’ of 258 species was compiled. Among them 206 (79.8%) were seabirds. Four seabird orders (Gaviiformes, Phaetontiformes, Procellariformes, Sphenisciformes) showed the highest percentage of interacting species. At family level, >70% of species of Gaviidae, Diomedeidae, Sulidae, Stercoraridae and Alcidae were involved in interactions with litter. We observed (i) a significant correlation between Scholar recurrences and species citations about anthropogenic litter only when considering seabirds; (ii) a low number of references before 1981 with a bimodal pattern showing a first peak in 1986–90 and a progressively increasing trend in the 2000s. Regarding the type of interaction, there was a significantly higher percentage of species involved in ingestion when compared to the percentage involved in entanglement. We suggest the use of consolidated standardized litter nomenclature and characterization and the adoption of a logical causal chain helping researchers in defining suitable frameworks.

Polymer science is one of the most revolutionary research areas of the last century, instigated by the discovery of Bakelite, the first synthetic plastic. Plastic, once a revolutionary material, has gradually become a global environmental threat with ubiquitous distribution.The term ‘microplastics’ coined in 2004, is used to describe the smaller plastic particles recorded, however there is still no all-inclusive definition that accurately encompasses all criteria that could potentially describe what a microplastic is.Here, the authors focus on the currently reported methods for describing and identifying microplastics and propose a new definition that incorporates all the important descriptive properties of microplastics. This definition not only focuses on size and origin, but also considers physical and chemical defining properties. While this manuscript may promote debate, it aims to reach a consensus on a definition for microplastics which can be useful for research, reporting and legislative purposes.

Selenium and mercury were evaluated in tissues and stomachs of the dolphinfish Coryphaena hippurus from two sites in the Southeastern Gulf of California. Hg levels were consistently low and exhibited the following patterns: muscle (0.14 ± 0.01 μg/g wet weight) followed by kidney (0.12 ± 0.02 μg/g), liver (0.11 ± 0.01 μg/g), and gonads (0.04 ± 0.00 μg/g). The maximum of Se was found in the kidney (5.60 ± 0.40 μg/g) and the minimum in muscle (0.60 ± 0.01 μg/g). All the Se:Hg molar ratios were between 3.7 and 697.1, with the minimum in muscle and the highest in gonads. The results indicate a contrasting behavior biomagnification of Hg and Se; smaller fish (<80 cm FL) did not exhibit biomagnification, in contrast with larger fish (>90 cm FL: 100% for Hg; 65% for Se). These results appear to be related to different feeding habits and availability of prey.

Microplastics are small (<5mm) fragments of plastic debris that are ubiquitous in coastal areas and in open ocean. We have investigated the occurrence and composition of microplastics in beach sediments from the micro-tidal Northwestern Mediterranean Sea. Samples were collected on two beaches (northern and southern site) of the western Gulf of Lion showing markedly different characteristics. Sampling was performed along depositional lower, mid and upper beaches and repeated after 1month. Concentrations of microplastics in the northern and southern site were highly variable, ranging from 33 to 798 and from 12 to 187 microplastics per kg of dry sediment, respectively. Highest concentrations were found at three specific locations: nearby a local river mouth, within an accretionary area and in a depositional upper beach. The spatial and temporal distribution of beached microplastics seems to be directly dependent on external forcing such as wind, swell, precipitation, outflow and river mouth proximity.

There has been increasing urgency to develop methods for detecting oil in sea ice owing to the effects of climate change in the Arctic. A multidisciplinary study of crude oil behavior in a sea ice environment was conducted at the University of Manitoba during the winter of 2016. In the experiment, medium-light crude oil was injected underneath young sea ice in a mesocosm. The physical and thermodynamic properties of the oil-infiltrated sea ice were monitored over a three-week time span, with concomitant analysis of the oil composition using analytical instrumentation. A resonant perturbation technique was used to measure the oil dielectric properties, and the contaminated sea ice dielectric properties were modeled using a mixture model approach. Results showed that the interactions between the oil and sea ice altered their physical and thermodynamic properties. These changes led to an overall decrease in sea ice dielectrics, potentially detectable by remote sensing systems.

Previous studies that have investigated marine oil pollution have predominantly focused on petroleum hydrocarbons. Naphthenic acids (NAs), in contrast, are toxins that are less well studied. Following the Dalian oil spill accident, monitoring surveys were carried out to investigate NAs in Dalian Bay sediments. Concentrations of NAs were between 14.826 and 34.279 mg kg−1, with acyclic and motorcycle carboxylic acids (43.28% and 35.12%, respectively) being the dominant components. NAs were 10–30 times more abundant than polycyclic aromatic hydrocarbons (PAHs) in the sediment. Further correlation analysis showed the abundance of NAs was highly correlated with total PAH levels (0.705, p < 0.01, n = 24) and total oil (0.485, p < 0.05, n = 24), indicating that NAs may be a potential marker for oil pollution in coastal sediments. The present study may help to expand the scope of marine environmental monitoring and provide guidance for the remediation of marine pollutants.

We monitored the post-release survival of little penguins (Eudyptula minor) rehabilitated after the 2011 C/V Rena oil spill in New Zealand to assess the effectiveness of the rehabilitation process. Surveys were conducted over a 23-month period after the spill to assess whether survival differed between rehabilitated and control penguins. Survival probabilities from mark-recapture analyses were lower for both oiled and control penguins in the first six months of the study (monthly probability 0.92) but increased and remained high thereafter (monthly probabilities 0.97–1.0). Importantly, survival did not differ significantly between oiled and control birds throughout the study. Post-release survival of rehabilitated birds was not influenced by the degree of oiling, body mass (at admission or release), blood parameters (admission packed cell volume, total protein or blood glucose) or the duration of captivity. Rehabilitation therefore appeared to successfully reverse the negative effects of oiling on the post-release survival of treated penguins.