Plastic pollution in mangroves located in small islands was not well documented. This study found that mangrove ecosystem in small island was polluted by plastic debris (mainly film: 63% and fiber: 31%). Density of plastic debris in mangrove area was ranging from 10 ± 4 items m⁻² to 230 ± 75 items m⁻², mean density was 92 ± 28 items m⁻². Landward was the most polluted zone mangrove (mean density: 155 ± 58 items m⁻²) or about 61% of plastic debris was distributed in this zone. This is corresponds to the sources of plastic waste was from land such as households and markets. Mean density of plastic debris was significantly correlated with mangrove health (r² = 0.59, p = 0.00). This indicated that plastic debris negatively affected mangrove ecosystem directly and indirectly. Effective land-based plastic waste management and actions such as regular beach cleanup are essential to reduce plastic pollution and to ensure mangrove conservation.

A fuzzy decision tree (FDT) based framework was developed to facilitate the selection of suitable oil spill response methods in the Arctic. Hypothetical oil spill cases were developed based on six identified attributes, while the suitability of three spill response methods (mechanical containment and recovery, use of chemical dispersants, and in-situ burning) for each spill case was obtained based on expert judgments. Fuzzy sets were used to address the associated uncertainties, and FDTs were then developed through generating: i) one decision tree for all three response methods (FDT-AP1) and ii) one decision tree for each response method and the development of linear regression models at terminal nodes (FDT-LR). The FDT-LR approach exhibited higher prediction accuracy than the FDT-AP1 approach. A maximum of 100% accurate predictions could be achieved for testing cases using it. On average, 75% of suitable oil spill response methods out of 10,000 performed iterations were predicted correctly.

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.

Public involvement in beach litter clean-ups can help tackle marine litter while providing experiential learning, raising awareness and stimulating anti-litter behaviour. Beach visitors contribute to litter generation by inappropriate discarding behaviour, and engaging them in litter removal can be beneficial. This study assessed visitors' (N = 512) stated willingness to participate in litter clean-ups at Elegushi Royal Beach, Nigeria, which is under pressure from litter problems visitors contribute to, and potentially emblematic of organised litter clean-ups. Beach visitors recognised marine litter as a global and national problem but did not perceive the case study beach as being littered. Willingness to participate in beach litter clean-ups was marginal. However, it was positively correlated with previous participation in litter clean-ups, perceived collective responsibility and the importance of policy and investments in reducing litter. These results were used to propose a framework to engage and recruit visitors in beach litter removal campaigns.

Microplastics ingested by two bivalve species Perna viridis and Meretrix meretrix collected from three estuaries viz. Ariyankuppam, Panithittu, and Chunnambar in Pondicherry, India was analysed for the first time in this research. Nile Red dye was used for microplastic detection. A survey of 50 local families was conducted to determine the frequency and quantity in which they consume mussels/clams. On an average, the number of microplastics per gram of soft tissue (wet weight) is 0.18 ± 0.04, 1.84 ± 0.61, and 1.76 ± 0.48; and the number of microplastics per bivalve is 0.50 ± 0.11, 1.75 ± 0.35, and 4.80 ± 1.39 respectively for Ariyankuppam, Panithittu, and Chunnambar. 61.02% and 77.42% of the particles belonged to the size group of <100 μm in M. meretrix and P. viridis respectively. A moderate positive correlation of r (18) = 0.6985, p < 0.05 was calculated between bivalve weight and microplastic particles. An average person belonging to the local community is likely to ingest 3917.79 ± 144.71 microplastic particles per year through mussel consumption.

Bacteria play an important role in ecological processes in oil contaminated marine sediments. In this work, bacterial diversity studies with surface sediment samples from the NW Gulf of Mexico were performed, two from continental shelf and two from upper slope. The bacterial communities seem significantly influenced by depth, distance from the shoreline, temperature, dissolved oxygen and aluminum. The most abundant Phylum was Proteobacteria, Class Gammaproteobacteria. However, Class Deltaproteobacteria, Order Desulfuromonadales predominated in continental shelf and Order Alteromonadales (Gammaproteobacteria) prevailed in the upper slope sediments. Many potential hydrocarbon degrading bacterial genera were identified, 71 of the assigned genera were associated to hydrocarbon degradation processes. The genera Desulfobulbus and Haliea were confined to continental inner-shelf, while Shewanella and Fusibacter were mostly detected in deeper sediments. The occurrence and abundance of putative hydrocarbon degrading bacteria in this area, could be indicative of an impacted zone caused by the presence hydrocarbons in the environment.

Biogeochemical monitoring coupled with multi-biomarker approach were performed for the assessment of marine environment, using clam Ruditapes philippinarum and scallop Chlamys farreri to indicate contamination status in sediments and seawater respectively. The bivalves were collected from three stations, Jiaozhou Bay, Rushan Bay and Laizhou Bay, of Shandong coastal area. A series of contaminants (PAHs and TBBPA) and biomarkers (AhR, EROD, GST, SOD, GPx, CAT, DNA damage) were measured. Multi-biomarker pollution index (MPI) and integrated biomarker response (IBR) were carried out to evaluate contamination status and both indexes showed that Rushan Bay was most polluted, where the pollution level of sediments reached “highly polluted” in August, followed by Jiaozhou Bay and Rushan Bay which reached “lightly polluted”. The correlation of IBR values with contaminants' concentrations was verified through the Pearson correlation coefficient (p < 0.05), consolidating this scientific assessment method for marine environment.

We investigated two sediment cores to understand whether a tsunami in Onagawa Bay, Japan caused environmental changes. The value of δ¹³C ranged from −21.9‰ to −24.3‰ and of δ¹⁵N ranged from 5.1 to 5.9‰. We conclude that the source of the sediment in the present study area was mainly oceanic and not terrestrial. The chlorophyll concentration ranged from 1.8 to 4.0 μg/g ww, and did not vary greatly between surface and bottom layers. We inferred that all layers were deposited after the tsunami. The major phytoplankton taxa in sediments were diatoms from DNA sequencing. The presence of harmful dinoflagellates was minor. The concentrations of several heavy metals decreased slightly after the tsunami. We inferred that heavy metals in sediments were diluted by the tsunami disturbance. The land in Onagawa suffered serious damage, but disturbance of the seabed was much less evident.