Microbial communities in wetland soils play vital roles in biogeochemical cycling of nutrients. In this study, the soil samples were collected from Suaeda, reed and Suaeda-reed hybrid zones in Shuangtaizi River Estuary, Northeast China, and the rhizosphere bacterial communities were compared using Illumina MiSeq sequencing. The microbial richness, diversity and structure of bacterial communities varied greatly in reed and Suaeda. Canonical correspondence analysis and Mantel test indicated that pH was the most significant factor (P < 0.05) in bacterial community assembly. Proteobacteria was the most dominant phylum, accounting for 45.7–58.0% of the total sequences. Thioprofundum, Thiohalomonas and Exiguobacterium were the predominant genera in Suaeda, while Exiguobacterium, Gillisia, Desulfomonile, Citrobacter, Thioprofundum and Acinetobacter were the core species in reed. PICRUSt analysis revealed similar functional profiles of rhizosphere microbiota in reed and Suaeda. Nitrate reduction related genes were abundant for nitrogen metabolism, whereas assimilatory sulfate reduction was the major process for sulfur metabolism.

Total metal concentrations and acid-volatile sulfide (AVS) measurements coupled with simultaneously extracted metals (SEM) were determined in heterogeneous sediments from Maluan Bay, China. Zn was the predominant component of SEM, while Cd was the least. In sediment cores, AVS increased with sediment depth, followed by a decrease with large variation, while SEM fluctuated. Multiple empirical sediment quality guidelines (SQGs) and equilibrium partitioning (EqP) approaches were applied to assess the contamination degree, sediment quality and potential risks associated with bioavailable metals, indicating that not all sediments with [SEM]-[AVS] > 0 were capable of causing toxicity because TOC is also an important metal-binding phase. In order to screen out the physicochemical variability and the complexity and large variance of datasets, multivariate statistical techniques were utilized to comprehensively reveal pollution status by visualized factor scores. Collectively, this study favors the integrative utilization of multifarious methods to scientifically diagnose the pollution characterization for sustainable coastal management.

In this study we examined the adsorption characteristics of heavy metals on microplastic through laboratory test and field test. We demonstrated that polyvinyl chloride, polypropylene, polyethylene, polyamides and polyformaldehyde could adsorb lead, copper and cadmium in the simulating solution, and the heavy metals showed higher adsorbance on PVC and PP particles compared with PA, PE and POM. In the field experiment, the adsorption rate and concentration of heavy metals varied significantly among different plastic types and locations. The adsorbability of PP and PVC toward Pb and Mn was strongly correlated with the metal concentration in seawater. We also compared the adsorption quantity of PP to heavy metals and polycyclic aromatic hydrocarbons which resulted in an order of magnitude within one month. During the adsorption, the surface morphology of the microplastics which were washed and corroded by seawater underwent a rough-smooth-rough changing process, and different materials had great differences.

Marine litter pollution has become a complex global problem, because of the negative ecological and socioeconomic impacts as well as the human health risks that it represents. In Colombia, mangroves are affected by inadequate solid waste management, which results in litter accumulation. Additionally, the information related to this problem is limited avoiding the development of prevention and reduction strategies. For the first time, pollution by marine litter and microplastics were evaluated in mangrove soils of the Ciénaga Grande de Santa Marta, where 540 ± 137 and 31 ± 23 items/ha of marine litter were determined in mangroves near and away from populated centers respectively. Plastics represented between 73 and 96% of litter, and microplastic quantity oscillated between 31 and 2,863 items/kg finding the highest concentrations in mangroves near to the population. This study contributes to the knowledge of the marine litter problem in mangroves of the Colombian Caribbean, becoming a help for their conservation.

In this article we compare the efficiency of different methods of rapid-response remediation of beach sand contaminated with microbiological and/or organic matter. Contaminated beach sands were treated in laboratory by different treatment methods (i.e., oxidation, UV-photoexposure, or thermal methods) and the efficiency of disinfection and breakdown of organic matter were evaluated. Contaminants in raw and treated beach sands were measured by membrane filtration method, and by chemical and biochemical oxygen demand, and chromatographic analysis. All the methods tested were efficient for disinfecting beach sand with microbiological contamination, except for the UV-photoexposure method, which showed only moderate disinfection potential. Chemical degradation efficiency of beach sand contaminated by crude petroleum was higher with Fenton and Photo-Fenton (associated with the use of surfactant and ultrasound) methods. Photo-Fenton method improvement can increase the efficiency of contaminated beach sand treatment, and can also help beach managers when selecting which method to adopt for remedial actions.

This paper qualifies, quantifies and localizes seafloor marine debris (SMD) in the Moroccan portion of the Mediterranean Sea. Six scientific trawl surveys were conducted by the Moroccan Institute of Fisheries Research from 2012 to 2015 between Cape Spartel (5°W) and Saidia (2°W), during which a total of 497 kg of SMD has been collected. Statistical analysis show that the mean abundance differed between surveys, generally ranging from 26 ± 68 to 80 ± 133 kg/km2. A typology of SMD indicates that plastic represented 73% of the debris collected, followed by rubber (12%), textile (8%), metal (3%), glass (0.32%), and some unidentified materials (2.70%). Analysis of results shows that the abundance and the distribution of SMD were strongly influenced by the local anthropogenic activities and by rivers inputs. The movements and accumulations in the open sea were also shown to be influenced by the geomorphology and the hydrodynamics of the basin.

Environmental pollution with plastic is a growing problem worldwide. This study investigates the microplastic and mesoplastic pollution of Xialiao Beach in northern Taiwan. Sand from the surface (1 cm depth) was collected in a systematic manner. A total of 80 samples were taken along four transects, and plastic particles (≥1 mm) were extracted and quantified. In total, 1939 microplastic particles were recovered, with an average of 96.8 particles per 1 m2. Statistical analysis showed that the backshore had significantly more microplastic particles than the supra littoral or intertidal. Extrapolating the numbers of plastic particles found, approximately 6.8 million plastic particles (≥1 mm) weighing about 250.4 kg should be found in the surface layer of Xialiao Beach. Resampling curves were created from the data set, which showed that at minimum 20 samples should be taken to adequately estimate the mean particle abundance.

Both oil droplets and gas bubbles have simultaneously been quantified in laboratory experiments that simulate deep-water subsea releases of both live oil (saturated with gas) and additional natural gas under high pressure. These data have been used to calculate particle size distributions (50–5000 μm) for both oil and gas. The experiments showed no significant difference in oil droplet sizes versus pressure (from 5 m to 1750 m) for experiments with live oil. For combined releases of live oil and natural gas, oil droplet sizes showed a clear reduction as a function of increased gas void fraction (increased release velocity) and a weak reduction with increased depth (increased gas density/momentum). Oil droplets were reduced by a factor of 3 to 4 during simulated subsea dispersant injection (SSDI) and no significant effect of pressure was observed. This indicates that SSDI effectiveness is not dependent on water depth or pressure.

The ballast water management convention incorporates principles of risk assessment. A new ballast water management risk assessment model was developed to support the implementation of most efficient management measures, which we also present as a flowchart decision support system model. The risk assessment model was tested using data from port baseline surveys where available, and real shipping and ballast water discharges data. The here presented ballast water management risk assessment and possible management options are applicable elsewhere to support and improve complex decision making in the implementation of management requirements according to the ballast water management convention. If needed, the model may easy be adapted to address local specifics in any other region or area.

Located within the subtropical convergence zone, the Hawaiian archipelago is subject to high debris loads. This paper represents the first study to determine the spatial and temporal trends of floating macro debris quantities and polymer composition within Maui County waters. Ocean surveys were conducted from 2013 to 2017 and collected 2095 debris items of which 90% were plastic. Attempts to categorize items by source resulted in only 6% likely from land, 12% from ocean-based sources, 50% from either land or ocean, and 32% from unknown sources. Results found a multi-step process for debris accumulation, with temporal trends linked to survey day and year and spatial trends linked to ocean processes. High- and low-density polyethylene and polypropylene accounted for the majority of polymer types. The results of this study demonstrate minimal debris in Maui originates from land/local sources, and the importance of baseline data to guide further research and mitigation measures.