Excessive use of plastics in daily life and the inappropriate disposal of plastic products are severely affecting wildlife species in both coastal and aquatic environments. Birds are top-predators, exposed to all threats affecting their environments, making them ideal sentinel organisms for monitoring ecosystems change. We set a baseline assessment of the prevalence of marine plastic litter affecting multi-species populations of aquatic birds in southern Portugal. By examining 160 stomach contents from 8 species of aquatic birds, we show that 22.5% were affected by plastic debris. Plastic was found in Ciconia ciconia, Larus fuscus and L. michahellis. Ciconia ciconia ingested the highest amount (number of items and total mass) of plastic debris. Polydimethylsiloxane (PDMS, silicones) was the most abundant polymer and was recorded only in C. ciconia. Plastic ingestion baseline data are of crucial importance to evaluate changes through time and among regions and to define management and conservation strategies.

Subsea blowouts have the potential to spread oil across large geographical areas, and subsea dispersant injection (SSDI) is a response option targeted at reducing the impact of a blowout, especially reducing persistent surface oil slicks. Modified Weber scaling was used to predict oil droplet sizes with the OSCAR oil spill model, and to evaluate the surface oil volume and area when using SSDI under different conditions. Generally, SSDI reduces the amount of oil on the surface, and creates wider and thinner surface oil slicks. It was found that the reduction of surface oil area and volume with SSDI was enhanced for higher wind speeds. Overall, given the effect of SSDI on oil volume and weathering, it may be suggested that tar ball formation, requiring thick and weathered oil, could possibly be reduced when SSDI is used.

Polyethylene is a commonly used polymer in plastic products and is often found as marine litter. Nevertheless there is limited knowledge about what happens to the material when it ends up in the sea. Polyethylene films were therefore thermally oxidised to four different levels of degradation. The films were then placed in stainless-steel cages in the sea off the Swedish west coast for 12 summer weeks. Subsamples were analysed with respect to biofouling, degradation and buoyancy. All levels showed a continued oxidation in the field. The pre-degraded films started fragmenting and the non-degraded films showed a decrease in tensile strain. All levels showed increased biofouling with higher presence of filamentous algae and bryozoans on pre-degraded materials. The density (kg·m−3) of the films was seen to increase slightly, and the apparent density for the pre-degraded films (density of the films with biofilm) showed a strong increase, which resulted in sinking.

Cape monkfish (Lophius vomerinus) is one of the long-lived species and top predators in the northern Benguela region. Studies on bioaccumulation of mercury (Hg) in cape monkfish are limited. This study compared the total Hg concentration between monkfish muscle and liver tissue; and related the monkfish total Hg concentrations to fish body size and capture locations (depth and latitude). Monkfish specimens (n = 529) were collected from 2016 to 2018. The mean total Hg concentration was 0.126 ± 0.005 mg/kg in muscle tissues and 0.106 ± 0.005 mg/kg in liver tissues. No significant differences were observed between total Hg concentrations of muscles and liver tissues. Differences in Hg concentrations between monkfish length classes were observed. No significant correlation was found between total Hg concentrations and latitude. A significant increase of total Hg concentration with the depth was observed. The concentrations of Hg were below the World Health Organization (WHO limits for fish (0.5 mg/kg).

This study was conducted to investigate the amounts of heavy metals in the Gorgan Bay. For this purpose, 12 sediment samples were taken from the Gorgan Bay, and then, the amounts of metals were determined using the ICP-OES spectrometer. Accordingly, the average value of the metals aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) was 1.3 ± 0.2%, 8.1 ± 3.8 ppm, 17.9 ± 4.3 ppm, 16.8 ± 4.2 ppm, 16.6 ± 4 ppm, 7.4 ± 1.3 ppm, 17.6 ± 3.7 ppm, and 29.5 ± 6.9 ppm, respectively. According to the Pearson test, a significant correlation was observed among all metals (except arsenic) in this study (P < 0.01), which indicates that the source of the metals (human or natural) is the same in this gulf. There was also a positive correlation between organic matter and all metals (except lead and vanadium) (P > 0.05). This positive correlation probably indicates that these metals enter the aquatic environment along with organic matter or that they are of the same origin (organic matter and metals). On the basis of the PER index, all the measured metals had a low ecological risk at all stations.

The damaging effects of marine debris on wildlife are often noted through the observation of animals that ingest and/or become entangled in debris. Yet, few studies have evaluated the effects of marine litter on benthic habitats. The aim of this study was to investigate if the presence of plastic bags has any effect on benthic macrofauna in an estuary located in an urban area in North-eastern Brazil. Biogeochemical and macrofauna samples were obtained from 10 different deposition locations (location factor), under, border and distant (treatment factor) from plastic bags. The results did not show any significant alterations in the biogeochemical parameters of the sediment due to treatment effect except for summed microphytobenthic pigments. The macrobenthic community structure responded to treatment. The greatest dissimilarity (34%) was between samples that were under and distant. Effects occurred despite the high dynamics of deposition-resuspension of plastic bags and the dominance of opportunistic species. Changes in community structure are a complex result of plastic bags effects on species ecological interactions in the polluted estuarine environment, attracting deposit feeders, diminishing suspension feeders and providing mechanical protection against predation by seabirds.

Environmental antimicrobial resistance (AMR) has drawn increasing attention due to its great risk to human health. The aim of this study was to investigate AMR and genotyping of Vibrio parahaemolyticus isolates (n = 114) recovered from shrimp mariculture environment in China. The isolates exhibited a high rate of resistance to streptomycin (78.9%), ampicillin (64.9%) and gentamicin (53.5%). Furthermore, multi-drug resistance was highly prevalent (61.4%), in which 95.9% of these ampicillin-resistant isolates were primarily mediated by blaCARB-17. Surprisingly, doxycylcine, florfenicol, and trimethoprim/sulfamethoxazole (TMP/SMZ) resistance genes occurred in susceptible isolates. Moreover, 114 isolates were grouped into unique pulsed field gel electrophoresis patterns. These findings suggest the need for the prudent use of antimicrobial agents on mariculture farms, in order to control the dissemination of antimicrobial resistant V. parahaemolyticus.

Water quality degradation in the Great Barrier Reef, associated with increased loads of nutrients, sediments and pesticides from agriculture, has become a major concern. Improved management practices and water quality targets were set in the Reef Plan 2013, but with limited success. The causality between water quality degradation, ecosystem health and benefits to society remains poorly understood, questioning the relevance of current water quality targets. We argue that ecosystem service valuation may help identify the benefits generated by ecosystems and help prioritise further investments in water quality improvement.We estimate the loss of benefits to society resulting from water quality reduction, concentrating on the influence of pollutants on mangroves, seagrass and coral reefs. Our results suggest that failing to meet Government's water quality targets by 1% would result in losses between AU$22 k/year and AU$6.9 M/year depending on the industry. We then discuss the implications stemming from these results for local policy-making.

Acidification and land-based sources of pollution have been linked to widespread declines of coral cover in coastal reef ecosystems. In this study, two coral species, Acropora cervicornis and Pocillopora damicornis were exposed to increased copper at two CO₂ levels for 96 h. Copper accumulation and anti-oxidant enzyme activities were measured. Copper accumulation only increased in A. cervicornis zooxanthellae and corresponded with photosynthetic toxicity. Enzyme activities in both coral species were affected; however, A. cervicornis was more sensitive than P. damicornis, and zooxanthellae were more affected than animal fractions of holobionts. Generally, activities of all anti-oxidant enzymes increased, with copper exposure in corals; whereas, activities of glutathione reductase and to some degree glutathione peroxidase were observed due to increasing CO₂ exposure alone. Exposure to copper in combination with higher CO₂ resulted in a synergistic response in some cases. These results provide insight into mechanisms of copper and CO₂ impacts in corals.

Maritime shipping transports over 90% of global goods. Ballast water, used to provide vessel stability, has been associated with the introduction of marine invasive species. Thus, understanding ballasting trends is imperative to protecting human and environmental health. This paper examines data from the National Ballast Information Clearinghouse to assess ballasting behavior and shipping trends in the United States. From 2005 to 2017, vessel arrivals have remained relatively constant (annual growth rate of 1.2% per year) while total ballast discharge per vessel has grown at an annual rate of 7.6%. Furthermore, from 2014 to 2016, alternative ballast water management methods have been on the rise, and these treatment options are likely to continue increasing in response to the International Maritime Organization Ballast Water Management Convention that entered into force in September 2017. It is critical that the shipping industry monitors potential cascading impacts on other ballasting behaviors stemming from this shift.