Mussels pose health risks to consumers through accumulation of trace metals from the ocean. Saldanha Bay, South Africa, has heavy industry and international shipping, creating concerns over pollution levels for aquaculture facilities. Samples of C. meridionalis and M. galloprovincialis were collected from mussel rafts over two-years and analysed for trace metal content using Inductively Coupled Plasma Mass Spectrometry. Aluminium, Cr, Fe, Zn, Cd and Pb were higher in M. galloprovincialis, while C. meridionalis accumulated more Cu and Mn. Temporal fluctuations occurred for Fe and As concentrations in C. meridionalis, and Fe, As, Hg and Pb in M. galloprovincialis. Arsenic exceeded South African regulatory limits (3 mg/kg) once in each species (max = 3.4 mg/kg w.w.). Lead concentrations in M. galloprovincialis were within EU regulatory limits for bivalves (1.5 mg/kg) but exceeded SA regulatory limits for fish (0.5 mg/kg) four times. Overall, farmed mussels from Saldanha Bay were determined to be safe for human consumption.

The amount and composition of beach litter was assessed, during spring 2018, at 56 sites along the coast of Alicante Province, on the western Mediterranean Sea. Selected sites covered “natural” (19), “village” (17) and “urban” (20) bathing areas and a total of 10,101 litter items was counted in an area of 201,686 m2. Plastic represented the dominant material with 8345 items, i.e. 82.6% of all debris; paper and cardboard numbered 566 items (i.e. 5.6%); pottery and ceramics 348 (3.4%); metal 325 (3.2%); cloth 231 (2.3%); glass 147 (1.5%); rubber 64 (0.6%); wood 46 (0.5%) and other materials summed 29 items, i.e. 0.3% of all debris. Cigarette butts, 45.6% of total items, were observed at different coastal sites: i.e. 1028 units at natural, 1148 at village and 2431 at urban sites. Despite the efforts of local administrations, which enforced cleaning operations at most sites, litter items were essentially related to beachgoers followed by wastewater discharges and fishing activities.

Microplastic particles (<5 mm), which are an emerging threat, are commonly found in marine ecosystems worldwide. This study investigated the effect of different types of coastal land use on microplastic frequency and distribution on the coastline of Bandar Abbas city; this study used a large sample compared to that used in other studies conducted in this region. The average number of microplastics was determined as 3252 ± 2766 microplastics/m² (±SD). ATR FT-IR spectroscopy showed that the dominant microplastic particles are expanded polystyrene, polyethylene terephthalate, polypropylene, and polyethylene. Statistical analysis showed a significant difference in microplastic contamination levels between the urban and nonuse beaches. This shows that heavily urbanized areas and human activities have significant effects on the dispersion and frequency of microplastics in the coastal areas of Bandar Abbas. Periodical coast-based cleanup and studies on microplastic pollution and their fluxes by comprehensive sampling are mostly recommended for the Persian Gulf coastline.

Plastics in the ocean are of great concern nowadays, and are often referred to as the apocalyptic twin of climate change in terms of public fear and the problems they pose to the aquatic and terrestrial environment. The number of studies focusing on the ecological effects and toxicity of plastics has substantially increased in the last few years. Considering the current trends in the anthropogenic activities, the amount of plastics entering the world oceans is increasing exponentially, but the oceans have a low assimilative capacity for plastics and the near-surface layer of it is a finite space. If loading of the oceans with plastics continues at the current rate, the thin sea surface microlayer can have a substantial amount of plastics comparable to the distribution of phytoplankton, at least in the major oceanic gyres and coastal waters in the future. Also, processes like biofouling can cluster microplastics in dense fields in the near-surface layer. Plastics can contribute to the warming or cooling of the water column by scattering and attenuating incoming solar radiation, leading to a potential change in the optical and other physico-chemical properties of the water column. We propose a new notion that changes in solar radiation in the water column due to the plastics have the potential to affect the physical processes in the ocean surface and near-surface layers, and can induce climate feedback cycles. The future can be very different, if plastics evolve as one of the key players affecting the ocean physical processes and hence this is the time to tackle this puzzle with appropriate strategies or let the genie out of the bottle.

It is hypothesized that pH fluctuations produced by seagrasses metabolism may confer marine calcifiers resistance to ocean acidification. Here, we tested this thesis by comparing the net population growth rate (NPGR) of a foraminifer species (Rosalina sp.) epiphytic of Mediterranean seagrass (Posidonia oceanica) to average current and projected pH scenarios under either stable conditions or diel fluctuations in pH of 0.3 units; variations similar to that experienced in their habitat. No significant differences were found in NPGRs between the fluctuating and stable pH treatments at current pH levels. NPGRs in treatments where pH fluctuated did not present significant differences to the treatment with high and stable pH conditions. In contrast, foraminifers exposed to stable low pH regimes experienced a steep decline in NPGR. These results suggest that diel pH fluctuations generated by P. oceanica photosynthetic activity could confer resistance to ocean acidification to Rosalina sp.

The distribution of floating litter in marine waters, influenced by currents and wind drag, often determines the dispersal of its encrusting fauna. In the present paper, we observed for the first time the colonization of rafting floats from abandoned, lost or derelict fishing gears (ALDFG) by the four protected deep-sea species: Errina aspera, Desmophyllum pertusum, Madrepora oculata Pachylasma giganteum.Overall, 41 floats, colonized by deep benthic species, were found stranded on the shore of the Sicilian coast of the Strait of Messina, between 2016 and 2019. Species composition, number and occurrence of colonizing organisms were analyzed. On the basis of the species composition (the association between E. aspera, P. giganteum and Megabalanus tulipiformis), the knowledge on their ecology, biogeography, path of local currents, it was possible to define that the area of origin of the most part of these fishing net floats was the Strait of Messina.

Fast growth of air pollution was experienced in China during the past decades, resulting in extremely large aerosol radiative forcing with up to ten times high compared to the global averages. The responses of surface air temperature to aerosol radiative effects range from − 0.1 to 1.1 K across China, with strong spatial and seasonal variations. Aerosol interaction with clouds can also affect radiation and precipitation. Under high pollution conditions, the frequency of heavy rain increases while the frequency of light rain decreases. Aerosols share common emission sources with CO₂, implying that reducing common sources can be another manifestation of the interaction between aerosol and climate. Air pollution controls will contribute to the climate change mitigation by reducing CO₂ emissions stemming from controls of pollution sources. On the other hand, potential co-benefits in reducing air pollution also come from the mitigation of climate change by reducing CO₂ emission that potentially affects the aerosol concentrations. It is suggested that the PM₂.₅ (fine particulate matter with an aerodynamic diameter of 2.5 μm or less) concentration tends to decrease under future climate control scenarios. Such co-benefits are mostly associated with the reduction of common sources of CO₂ and aerosol (noted as emission-driven interaction), rather than the variation of meteorological conditions associated with future climate change (noted as meteorology-driven interaction). Compared to emission-driven interaction, the impact by meteorology-driven interaction on aerosols is relatively smaller and varies geographically as the PM₂.₅ concentration is likely to increase in northern China while decrease in eastern China. The current review suggested that the co-benefits of reducing CO₂ and aerosol pollutant in China, and their response in the context of future climate change, are worthy of further research.

A community-based participatory research was utilized to address the coastal community's concern regarding Deepwater Horizon oil contamination of seafood. Therefore, we analyzed polycyclic aromatic hydrocarbons (PAHs), major toxic constituents of crude oil, in the seafood collected from gulf coast (Louisiana, Alabama and Mississippi) during December 2011–February 2014. PAHs were extracted from edible part of shrimp, oysters, and crabs by the QuEChERS/dsPE procedure and analyzed by gas chromatography–mass spectrometry. The total PAHs data were further analyzed using the General Linear Mixed Model procedure of the SAS (Version 9.3, SAS Institute, Inc., Cary, NC) statistical software. Brown shrimp showed statistically significant differences in PAHs levels with respect to time and locations while white shrimp showed differences at various time points. PAHs levels in oyster and crab samples were not statistically different at the Type I error of 0.05. Overall, the PAHs levels are far below FDA levels of concern for human consumption.

Persian Gulf is a semi-enclosed highly saline reverse estuary that is exposed to the risk of oil spills in offshore oil and gas activities. In the early 2000s, a specific version of NOAA's Trajectory Analysis Planner (TAP II) was developed for Persian Gulf to assist regional organizations in preparing oil spill contingency plans. In this research, a new stochastic model is developed to cover the limitations of TAP II. The new model is based on an advanced trajectory model, which is now linked with high resolution spatiotemporal data of the wind and sea current. In a case study, the developed model is compared with TAP II, and evaluated by multiple tests designed for analysis of uncertainty, sensitivity, reliability and variability. The case study proved the applicability of the new model, and the evaluation tests provided useful information for the future development of the model.