Ecological concrete (eco-concrete) can reduce excess nutrients (nitrogen and phosphorus) in water, but its effectiveness in removing nutrients in marine coastal sediments and the response of sediment microbial communities to its use are largely unknown. In this study, eco-concrete planted with Bruguiera gymnorrhiza was used to remove nutrients in marine coastal sediment. We found that the mean removal efficiencies of sediment total nitrogen and total phosphorus by using planted eco-concrete were 11.50% and 30.31% on day 60, and were higher than those obtained by only using B. gymnorrhiza (7.14% and 7.36%). the Diatoms and bacterial genera Fusibacter and Anoxynatronum (which belong to Firmicutes) increased and became the abundant microbes by day 60 when using planted eco-concrete, indicating their potential roles in nutrient removal. Moreover, the eco-concrete did not endanger the core microbes in sediment suggesting its environment-friendly character. Our results suggest a potential method to control marine coastal eutrophication.

The Japanese government approved a plan to discharge Fukushima Daiichi Nuclear Power Plant Accident contaminated water (FDNPPACW) into the Pacific Ocean. It immediately caused a new wave of global concern and anxiety. To assess this matter, this work briefly reviewed the dispersion of FDNPPA-derived radionuclides in the Pacific Ocean in the past and the resulting impacts on marine biota. Combining the drafted plan of discharging FDNPPACW and the public's concerns, 5 points, including (1) the detailed plan of discharging FDNPPACW, (2) the isotopes left in the advanced liquid processing system (ALPS)-treated water and their amounts, (3) the stability of the Kuroshio Extension, (4) the fates and transports of the main radionuclides (left in the ALPS-treated water) in North Pacific seawater, (5) and bioaccumulations and the ecological half-lives of the main radionuclides (left in the ALPS-treated water) in marine biota in the North Pacific, remain to be known to understand the impacts of discharging FDNPPACW into the Pacific Ocean.

The principal objective of this study is to assess the saltwater intrusion and hydrogeochemical processes that affect groundwater geochemistry in the coastal aquifers of southwestern India. Groundwater samples were collected seasonally and the physico-chemical parameters determined on-site. Major ions were determined in the laboratory. Hydrochemical diagrams, ionic ratios, and multivariate statistical analysis were adopted for understanding the groundwater chemistry. Gibbs plot identified that rock-water interaction and evaporation were the mechanisms regulating hydrogeochemistry. Ionic ratios have shown that coastal wells were contaminated with saltwater intrusion during the pre-monsoon season. Hierarchical cluster analysis classified the samples based on their quality; sample clusters with high NO₃⁻ were in densely populated areas, whereas sample clusters with moderate salt content in the coastal areas. Another cluster showed high concentrations of salts, typically the zones of saltwater intrusion. The study concludes that influence of seasons, geogenic and anthropogenic factors contribute to the heterogeneous chemistry of groundwater.

While the Mediterranean coastal region of the Nile Delta is critical socioeconomically, it is under significant environmental stress due to the growing load from diverse land-based activities. This study examines the fluctuations in the concentrations of several minerals in sediments from depths ranging from 10 to 50 m. This study is considering the first work that carries the identification of different minerals by using two different techniques: Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction technique (XRD), in this area. At the same time, the particle size was also assessed. The particle size analyzer (PSA) results showed that the grain size analyses in the sediments varied between slightly gravelly sand, slightly gravelly mud, and silty sand. Mineral identification using FTIR and XRD analysis proved that some minerals such as aragonite, calcite, quartz, kaolinite, montmorillonite, albite, muscovite, and microcline have been presented in most of the studied locations.

The concentrations of 37 polycyclic aromatic hydrocarbons (PAHs) and their potential risk to human health were determined in fifty sardine muscle (Sardinella brasiliensis) samples collected along the southern Brazilian shelf. Parental and alkylated PAHs were identified and quantified using a pressurized liquid extraction with in-cell purification method and gas chromatography–mass spectrometry identification and quantification. The concentrations of Σ37 PAHs in muscle ranged between 6.02 and 4074 μg kg⁻¹ wet weight, which are comparable to levels reported for commercially important fish worldwide. The most abundant compounds were pyrene and fluoranthene, which originate from both petrogenic and pyrolytic hydrocarbon inputs. In only 4% of the samples the benzo[a] pyrene equivalent concentration was above the threshold of 6 μg kg⁻¹ suggested for safe fish consumption in Brazil. These findings will serve as baseline data for monitoring the quality of sardines consumed in the country and for studying fish populations.

An aim of the United Nations Decade of Ocean Science is to quantify marine plastic debris in the marine environment. This study analyzes peer-reviewed articles on marine debris monitoring conducted on beaches in the Wider Caribbean Region, with a focus on marine plastic debris. Governance and funding regimes for monitoring events were assessed to determine strategies needed for coordinated and harmonized marine plastic debris monitoring in the Wider Caribbean Region. High variation in standardized survey protocols were observed during monitoring events. Standardization of sampling methodology and reporting metrics among other considerations, are needed to establish a regional marine plastic debris monitoring program that can inform policy for the Wider Caribbean Region.

Caribbean economies depend heavily on a healthy marine ecosystem, but the region includes ten of the top global marine polluters per capita. Regional marine pollution is driven by illegal plastic waste dumping due to poor waste management systems with limited recycling, and weak enforcement. Governments recognize the impacts of marine debris on their social and economic well-being and have responded with policies to curb plastic pollution. Most focus on bans of single-use plastic and polystyrene, which comprises ~80% of Caribbean marine litter. However, there is little comparative analysis of policy responses to determine their efficacy. This paper reviews current policies in 13 English-speaking Caribbean countries, exploring tools used and process of implementation. Eleven have introduced legislative policies, with seven including fines and penalties for non-compliance. All successful policies involve multiple tools, including primary stakeholder engagement, sufficient lead time between policy announcement and implementation, and extensive public education campaigns.

Along 24 beaches of the Central Caribbean Coast of Colombia, plastic items were collected and grouped into 43 different typologies. The average plastic abundance was 4.54 items/m² being eight typologies responsible for 82% of all plastic collected. The application of the Clean Coast Index (CCI) and the Plastic Abundance Index (PAI) allows categorization of the study area as “Extremely Dirty” coastal strip with a “Very High Abundance” of plastics. Beaches were statistically grouped into three specific types: moderate, bad and extremely bad environmental conditions. The typology and magnitudes of plastics found in the study area suggest a combination of sources that primarily include dumping and direct activities on the beach. Plastic medical and sanitary waste, ocean/waterway items, and plastic items related to smoking-related activities also were observed.

Atlantic horse mackerel is one of the most commercially important species in Europe. It can reach a longevity of 30 years, with potential implications in lifespan mercury contamination. This study conducted along the Portuguese coast aimed at evaluating the total Hg content and tissue distribution, to determine the annual mercury bioaccumulation patterns and the associated risk for consumption. The T-Hg accumulation patterns observed followed the order: muscle (0.34) > liver (0.28) > heart (0.19) > gills (0.11) > brain (0.041 mg kg⁻¹). Significant differences between tissues reflect the role of the different tissues in storage and redistribution. Significant relationships observed between age and T-Hg for all tissues highlight the continuous nature of the bioaccumulation process. European food safety guidelines signalled significant risk of consumption in about 30% of the samples. Still, there was an overall low risk from the consumption of this species, which can be further minimized through consumer options to avoid health issues.

Good water quality is essential to the health of marine ecosystems, yet current metrics used to track water quality in the Great Barrier Reef are not strongly tied to ecological outcomes. There is a need for a better water quality index (WQI). Benthic irradiance, the amount of light reaching the seafloor, is critical for coral and seagrass health and is strongly affected by water quality. It therefore represents a strong candidate for use as a water quality indicator. Here, we introduce a new index based on remote sensing benthic light (bPAR) from ocean color. Resulting bPAR index timeseries, based on the extent to which the observed bPAR fell short of the locally- and seasonally-specific optimum, showed strong spatial and temporal variability, which was consistent with the dynamics that govern changes in water clarity in the Great Barrier Reef. Our new index is ecologically relevant, responsive to changes in light availability and provides a robust metric that may complement current Great Barrier Reef water quality metrics.