Short term stress experiments with dissolved inorganic phosphorus (DIP) and tripolyphosphate (TPP) have been carried out on the staghorn coral Acropora intermedia, collected from Heron Island in the southern Great Barrier Reef, at low and elevated seawater temperatures. Zooxanthellae, chlorophyll a, intracellular and tissue dimethylsulfoniopropionate (DMSP), and extracellular DMSP production were measured to assess the level of stress on A. intermedia at different winter and summer seasons from 2001 to 2003. Whilst no significant changes were measured in these stress indicators in 2001 and 2003, significant changes occurred in winter 2002, reflecting natural stresses on A. intermedia in the field, and stress from added DIP and TPP at high seawater temperatures. These stresses caused corals to bleach, whilst extracellular DMSP, intracellular and tissue DMSP concentrations increased, reflecting the antioxidant role of DMSP in the coral zooxanthellae and coral host to combat stress. These results have important implications for future research in the GBR.

Contamination by metals is among the most pervasive anthropogenic threats to the environment. Despite the ecological importance of marine apex predators, the potential negative impacts of metal bioaccumulation and biomagnification on the health of higher trophic level species remains unclear. To date, most toxicology studies in sharks have focused on measuring metal concentrations in muscle tissues associating human consumption and food safety, without further investigating potential impacts on shark health. To help address this knowledge gap, the present study evaluated metal concentrations in the gills, muscle, liver and rectal gland of coastal sharks opportunistically sampled from Brazilian waters and tested for potential relationships between metal bioaccumulation and general shark health and homeostatic balance metrics. Results revealed high metal concentrations in all four tissue types, with levels varying in relation to size, sex, and life-stage. Metal concentrations were also associated with serum biomarkers (urea, lactate, ALT, triglycerides, alkaline phosphatase, and phosphorus) and body condition, suggesting potential negative impacts on organismal health.

Face masks are playing an essential role in preventing the spread of COVID-19. Face masks such as N95, and surgical masks, contain a considerable portion of non-recyclable plastic material. Marine plastic pollution is likely to increase due to the rapid use and improper dispensing of face masks, but until now, no extensive quantitative estimation exists for coastal regions. Linking behaviour dataset on face mask usage and solid waste management dataset, this study estimates annual face mask utilization and plastic pollution from mismanaged face masks in coastal regions of 46 countries. It is estimated that approximately 0.15 million tons to 0.39 million tons of plastic debris could end up in global oceans within a year. With lower waste management facilities, the number of plastic debris entering the ocean will rise. Significant investments are required from global communities in improving the waste management facilities for better disposal of masks and solid waste.

As evidenced from literature, exposure to non-lethal concentrations of dissolved copper (Cu²⁺) and copper nanoparticles (CuO NPs) promotes blue mussels susceptibility to various bacterial infections. We study whether pre-exposure (3.5 h) with CuSO₄ (100 μg Cu L⁻¹) and CuO NPs (1000 μg Cu L⁻¹) will result in infection of M. edulis L. with pathogenic microalga Coccomyxa sp. under field conditions. In May – September 2019, cages were installed in the site Metis-sur-Mer, St. Lawrence Estuary (QC, Canada) where the native mussel population is known to be infected with the pathogen. Untreated and pre-exposed mussels were grown for up to 130 days. Only the mussels pre-exposed to copper were infected by Coccomyxa. This finding allows proposing that occurrences of Coccomyxa-infected mussels worldwide might have an association with water pollution with xenobiotics. Pre-exposure of caged mussels to copper, as a protocol monitoring for other infectious agents, can be recommended to test.

142 scientific publications have been reviewed on the characteristics of the scyphozoans with respect to their ability to develop blooms and the most significant environmental characteristics that determine them. Special attention was paid to depth, temperature, salinity, chlorophyll concentration, and the habitat of the 39 registered blooming genera. After the review, we find that over the past decades, the number of scyphozoan blooming-species is higher than previously recorded, increasing from circa 14% to 25% of the class.Species that inhabit depths less than 27.1 m are prone to produce blooms, particularly in semienclosed areas with low rates of water renewal and high thermal amplitudes. Temperature appears as the main environmental factor controlling blooms, but food availability is essential to sustain the proliferations. Interspecies variability in the response to environmental factors observed in this work suggest that bloom predictive models should be constructed species-habitat-specific.

Turkey became a major importer of global plastic waste after China banned plastic imports on January 1, 2018. Turkey imported only 261,864 tonnes of plastic waste annually before the ban, but annual imports increased to 772,831 tonnes by 2020. Turkey recently implemented restrictions on importing plastic waste (quotas, %1 contamination limit, banned mixed plastic waste imports), yet illegal dumping and burning is widely reported. Turkey ranks second in Europe and seventh worldwide for plastics production, yet current domestic waste management and recycling programs cannot handle domestic plastic waste generation. Roughly 90% of municipal solid waste produced in Turkey ends up in landfills. Plastic waste mismanagement results in plastic leakage into the Mediterranean Sea with Turkey contributing the highest share (16.8%) of European marine plastic pollution. With this latest import restriction, Turkey now has an opportunity to strengthen and improve its own domestic waste management infrastructure to reduce indiscriminate plastic marine pollution.

Anthropogenic marine litters or microplastics (MPs) accumulation in marine organisms is an emerging environmental threat. In this background, the gastrointestinal tract of Coilia dussumieri (n = 150) was studied in the samples collected from the fishing grounds of the north east coast of Arabian Sea through experimental fishing. Out of the total 150 specimens collected, all showed the incidence of microplastic particulates in the guts. The average abundance of MPs was found to be 6.98 ± 2.73 items/individual whereas gastrointestinal tract recorded with an average number of 28.84 ± 10.13 MPs/g in the gut material. The dominant MPs were found in the size range of 100–250 μm and of fibers type mostly blue in color. The prevalence of MPs in Coilia dussumieri is a matter of serious concern due to its ecological consequences due to trophic transfer in the connected food chains and probable threats to the health of human beings consuming the fish.

Negative human actions on seagrasses affect habitat condition and its associated fauna. Epiphytic hydroid's assemblage response to seagrass condition, water quality, and human impacts was evaluated in two bays of the Sabana-Camagüey Ecosystem of Cuba, using the presence of contamination, causeways, and trawling fishing as impact level proxies to the seagrass meadows. Thirty-eight species composed the hydroid's assemblage including five new records. Symmetroscyphus intermedius was the most abundant species and sensitive to indicators of the seagrass condition. Dynamena disticha and Gastroblasta sp. were sensitive to water quality predictors. Obelia bidentata was exclusive to the most impacted sites. Species richness and abundance were low in impacted sites and were highly affected by fishing trawling and causeways construction. Salinity, depth, NO2, pH, SSV, macroalgae cover, shoot density, and wet weight of Thalassia testudinum were the best predictors for hydroid's assemblages. Results suggest epiphytic hydroids on tropical seagrass meadows as sentinel organisms.

PURPOSE OF REVIEW: PM₂.₅ satellite remote sensing is the most powerful way to acquire the PM₂.₅ distribution and variation at a large scale with high resolution. Thus, PM₂.₅ remote sensing methods have been widely developed and applied in multiple environmentally related research areas in recent decades. Hence, the purpose of this review is to summarize these methods, required input data and main applications of PM₂.₅ and its remote sensing components. RECENT FINDINGS: In general, two-step methods have been used for estimating PM₂.₅, which first retrieves the aerosol optical depth (AOD) and estimates PM₂.₅ from the AOD with other supplemental data containing the temporal or spatial variation impact on PM₂.₅ or data correlated with PM₂.₅ variation by different AOD-PM₂.₅ models. The AOD-PM₂.₅ models have been developed by using different methods, including empirical-statistical models (single or combined statistical models and big data-based machine learning methods), CTM-based models and semi-empirical/physical models. Current research can provide high-resolution (e.g. daily variations at 1 km and hourly variations at ~1 km) PM₂.₅ products, which have been widely used in air pollution management, health impact assessments, numerical data assimilation and climate impact analyses. This review summarizes the current research on method development, application, achievement and remaining challenges in remote sensing of PM₂.₅ and its components, which are essential for further improvement of the methods and accuracy of PM₂.₅ remote sensing and are likely applicable to other PM₂.₅ component remote sensing methods in the future.

Major sources of pollution from shipping to marine environments are antifouling paint residues and discharges of bilge, black, grey and ballast water and scrubber discharge water. The dispersion of copper, zinc, naphthalene, pyrene, and dibromochloromethane have been studied using the Ship Traffic Emission Assessment Model, the General Estuarine Transport Model, and the Eulerian tracer transport model in the Baltic Sea in 2012. Annual loads of the contaminants ranged from 10⁻² tons for pyrene to 100 s of tons for copper. The dispersion of the contaminants is determined by the surface kinetic energy and vertical stratification at the location of the discharge. The elevated concentration of the contaminants at the surface persists for about two-days and the contaminants are dispersed over the spatial scale of 10-60 km. The Danish Sounds, the southwestern Baltic Sea and the Gulf of Finland are under the heaviest pressure of shipborne contaminants in the Baltic Sea.