Plastic pollution is prevalent in all habitats and microplastic ingestion has been recorded in several different species examined to date. However, most studies have focused solely on commercial species. This study investigates microplastics (MPs) by assessing the levels present in a mixed demersal trawl at two sites in a coastal embayment. MPs were recovered from species' gastrointestinal tracts and polymers identified with μFTIR spectroscopic analysis. Particles recovered comprised 20% natural fibres. The majority of MPs were identified as PE, PVDF, and PETE. Results show an average MP range of 0.11–4.67 MPs individual⁻¹. Fluctuating trendlines for MPs within species suggest that their bioavailability is influenced by several factors. Individual species show significant differences in ingested MP between trawls; however, when the entire trawl community is assessed there is no significant difference between sites. These results suggest that future studies should follow an ecosystem-based approach to monitor MPs.

During drier periods estuarine salinization can stimulate the colonization of marine organisms and further bioinvasion, therefore, may cause future ecological change. In this sense, we applied the Rapid Assessment Surveys (RAS) on natural and artificial hard substrates during the most intense drought period (between 2014 and 2016) since 1950, in a tropical estuary in Eastern Brazil. Through the estuary salinization the ascidian Didemnum psammatodes overgrow the dominant native taxa; this dominance taxa shift provided suitable habitat favorable for invasion of Ophiothela mirabilis across the estuary. Even the invasion starts on artificial substrates, the higher resilience of natural substrates were not enough to enable the establishment of invasive species. This baseline is the first evidence of bioinvasion influenced by climate change drought periods in tropical estuaries in South America, which is a great advance for the development of management strategies to mitigate this and future climate change scenarios.

The lagoons of seven French Polynesia and Cook Islands pearl farming atolls (Raroia, Takume, Mopelia, Takapoto, Ahe, Takaroa and Manihiki) were surveyed using multibeam and mono-beam sounders. From the detailed bathymetry, morphometric variables (average and maximum depth, frequency-area of depth, lagoon area and volume) are computed and compared. Remarkable geomorphological structures highlighted by bathymetric variations include deep reticulated structures and pinnacles. The seven atolls appear very different in abundance, size and density of these entities. Considering them as markers of the geological, sedimentological and eustatic processes that shape atoll lagoons, they are discussed in the context of the general theory of atoll lagoon formations involving karstic dissolution during Pleistocene or earlier low sea-level stands. In terms of pearl farming management, accurate bathymetric maps help pearl oyster wild stock assessment, development of circulation and biogeochemical models, better lagoon zoning and strategy to remove pearl farming derelict gears.

This study aims to determinate the background geochemistry values for 23 chemical elements on the Amapá coastline. To do so, 8 cores were sampled (≤70 cm) along the Cuñaní Estuary. The metal concentrations were measured by means of inductively coupled plasma mass spectrometry. In mg.kg-1, the background values for Ba, Sr, Y, Sc, V, Cr₂O₃, Co, Ni, Cu, Zn, Ga, As, Rb, Nb, Sn, Cs, Ta, W, Hg, Pb, Bi, Th, and U were, respectively, 392.41, 133.29, 29.22, 12.80, 109.13, 0.008, 13.82, 22.69, 19.73, 75.09, 19.50, 14.77, 94.81, 15.62, 3.38, 6.59, 1.05, 1.82, 0.04, 19.02, 0.27, 13.25, and 3.57. The background geochemistry values for the region are an important tool for monitoring the metal concentrations and serve as a baseline for comparison with possible incidents of contamination with these elements on the Amapá coast.

Deposits of fluid mud on wave-dominated beaches are rare. Where they happen frequently and periodically, they can be associated with anthropic processes that bring fluid mud to the shoreface and surf zone. To determine the reason for the frequent deposition of fluid mud at Cassino Beach (Southern Brazil) in the 2014–2020 period, the La/Eu and Gd/Yb ratios in marine, beach, and adjacent Patos estuary sediments were investigated. Mud from the beach showed similar ratios of REE to dredged sediments from the harbor basin and navigation channel within the estuary. Industrial and port activity changes REE ratio in sediments of the navigation channel, and they are distinct from naturally deposited marine and estuarine sediments. We conclude that the mud deposition events at the beach are most likely associated with dredging processes in the estuary especially where overflow is the source of fluid mud on the beach shoreface.

The Southern Corniche of Jeddah (SCJ) is located on the centre of the eastern Red Sea coast, Saudi Arabia and is increasingly affected by many anthropogenic activities, making it vulnerable to pollution. Sixty-three sediments and water samples were examined in regard to environmental parameters (temperature, salinity, dissolved oxygen (DO) and pH), grain size, organic matter (OM) and carbonate content and metals concentrations (Fe, Mn, Cu, Pb, Cr, Zn, Ni, and Co) in order to assess the level of contamination in SCJ's bottom sediment. The results showed that the highest concentrations of heavy metals in the shoreline and Lagoon areas are mainly due to the influx of domestic and industrial wastewater into the area where they were correlated with mud, OM, salinity and pH. The contamination factor (CF) for Fe and Co in the bottom sediments exhibited higher values than the threshold 3 value, particularly in the Lagoon and Al-Budhai area. The pollution load index (PLI) values of sediment samples could be classified as contaminated samples, especially in the nearshore samples indicating an increase of metals accumulation with decreasing distance from the source area. PCA has shown that Fe and Mn are positively correlated with all heavy metals, probably due to their high adsorption capacity in the presence of DO. The metals were Normalized with Fe, it was found that the bottom sediments of the SCJ could be reported as metal contaminated and mainly affected by natural and human sources.

Heavy metals in the sediments of urban roads (RDS), storm drains (SDS), and marine areas (MS) were investigated to assess road pollution in a beach town adjacent to the coast in Busan and identify their relationships with the marine environment. RDS were considerably polluted with Zn, Cu, Cr, and Pb, with mean concentrations of 1090, 178, 171, and 199 mg/kg, respectively. MS were severely contaminated with Zn and Cu, exceeding the effects range median (ERM; Cu = 270, Zn = 410 mg/kg). PCA and HCA identified tire and brake wear in RDS as the major sources of Zn, Pb, Cu, and Cd, and that high levels of Zn, Cu, and Pb in RDS originating from traffic activities contaminated MS through the urban storm drain system. The results suggested that traffic-originated metals in RDS are potential pollutants in coastal environments, and further studies on their fate and management should be conducted.

Oil pollution resulting from natural and anthropogenic activities in the Arabian Gulf as well as oil residue in the form of tarmat (TM) deposited on the coast is a major environmental concern. The spatial distribution, chemical composition and weathering pattern of tarmat along the west coast of Qatar has been assessed based on the TM samples collected from 12 coastal regions. The range of TM distribution is 0–104 g m⁻¹ with an average value of 9.25 g m⁻¹. Though the current TM level is thirty-fold lesser than that was found during 1993–1997 (average 290 g m⁻¹), the distribution pattern is similar. The results of ATR-FTIR spectroscopy indicate that aromatic compounds are higher in the north (N) coast TMs than those found in the northwest (NW) and southwest (SW) coasts, and Carbonyl Index values indicate that TM of NW coast is highly weathered compared to those found in the N and SW coasts.

Desalination is perceived as an effective and reliable process for obtaining freshwater from aqueous saline solutions such as brackish water, seawater and brine. This can be clarified by the fact that >300 million people worldwide rely on desalinated water for their daily needs. Although the desalination process offers many advantages, there are rising concerns about possible adverse environmental impacts. Generally, environmental impacts can be generated both in the construction and operation of desalination plants. A major issue of desalination is the co-produced waste called ‘brine’ or ‘reject’ which has a high salinity along with chemical residuals and is discharged into the marine environment. In addition to brine, other main issues are the high energy consumption of the desalination and brine treatment technologies as well as the air pollution due to emissions of greenhouse gasses (GHGs) and air pollutants. Other issues include entrainment and entrapment of marine species, and heavy use of chemicals. The purpose of this review is to analyze the potential impacts of desalination and brine treatment on the environment and suggest mitigation measures.

The Fundão dam collapse occurred on November 2015 in Mariana city (Brazil), provoking a series of ecological impacts over the Doce river basin and its nearshore environment. However many impacts over fishery target fauna (fish and shrimp) are still unknown or underestimated due to the lack of baseline data in the region. In the present study we assessed the isotopic niches modeled from δ¹³C and δ¹⁵N signatures of six estuarine fish species before and after the impact to assign potential shifts at the population- and community-level. We showed isotopic niche has altered in all studied species irrespective of its trophic group and habitat use. Niche community metrics indicated a depletion of trophic diversity and basal resources of the whole community after the impact. Food web changes as we reported here can impair the energy transfer through the food chain and put at risk the sustainability of small fisheries that rely upon local resources.