Mangroves are ecosystems located in tropical and subtropical regions of the world and are vital for coastal protection. Their unique characteristics make them hotspots for carbon cycling and biological diversity. Studies on isolated filamentous fungi and environmental and anthropogenic factors that influence sediments offer new understandings on how to preserve mangroves. Here we report on the filamentous fungi isolated from four mangroves. We correlated fungal community composition with sediment texture, polycyclic aromatic hydrocarbons concentration (oil pollution), pH, salinity, organic matter, total and thermotolerant coliforms (sewage pollution). In total we identified 34 genera and 97 species. The most polluted sites had highest species richness whereas the best preserved site showed the lowest species richness. Oil spill and sewage pollution were identified as the drivers of fungal community composition in the most polluted sites. We found very distinct fungal communities with no >5 species shared between any two mangrove sites.

Biofouled commercial and recreational vessels are primary vectors for the introduction and spread of marine non-indigenous species (NIS). This study designed and assessed a portable system to reactively treat biofouling in the internal pipework of recreational vessels – a high-risk ‘niche area’ for NIS that is difficult to access and manage. A novel thermal treatment apparatus was optimised in a series of laboratory experiments performed using scale models of vessel pipework configurations. Treatment effectiveness was validated using the Pacific oyster Magallana gigas, a marine NIS with known resilience to heat. In subsequent field validations on actual recreational vessels, treatment was successfully delivered to high-risk portions of pipework when an effective seal between delivery unit and targeted pipework was achieved and ambient heat loss was minimised. In addition to demonstrating the feasibility of in-water treatment of vessel pipework, the study highlights the importance of robust optimisation and validation of any treatment system intended for biosecurity purposes.

Increasing evidence shows that herbivores can facilitate plant growth and maintain the resistance of plant communities to trophic consumption in a variety of ecosystems. However, the positive effects of herbivores on annual saltmarsh plants in coastal ecosystems are relatively understudied. In this study, field investigations and manipulative experiments were conducted to explore whether and how microtopographical modification by the herbivorous crab Helice tientsinensis stimulates the growth of the saltmarsh plant Suaeda salsa. Results showed that, despite grazing on S. salsa, H. tientsinensis can promote density, total biomass, average plant height, average root length, and average biomass through burrowing-generated concave-convex microtopography, which can improve the edaphic environment (decreased soil hardness and salinity, and increased soil moisture content, oxidation-reduction potential, and carbon and nitrogen content), and provide plants more clustered growth opportunities that could facilitate positive intraspecific plant interactions. This study can provide scientific guidance for ecosystem restoration in coastal intertidal saltmarshes.

Organic pollution is a serious environmental problem for the coastal zones of seas. The study tested the hypothesis that allochthonous organic carbon derived from St. Petersburg wastewaters is a significant basal resource of carbon for the benthic food webs. We analyzed stable isotope composition of carbon and nitrogen in suspended organic matter in the Neva Estuary and in the tissues of macroinvertebrates and fish. The Stable Isotope Bayesian mixing model showed that waste waters were an important source of carbon for the most of consumers in the Neva Estuary. The autochthonous carbon produced by phytoplankton was a significant source of carbon only for some macroinvertebrates. The main consumers of the carbon derived from waste waters were tubificid worms, chironomid larvae and alien polychaete, which currently dominate in the zoobenthos of the estuary. These species replaced the former dominants, native crustaceans, which to a lesser extent use anthropogenic carbon.

The Nerbioi-Ibaizabal estuary (Bilbao, Basque Country) suffered an important input of contaminants, including metals and metalloids, between 1875 and 1975. We collected sediments in the tidal part of the river in January 2018 and measured the concentrations of 27 elements in them. At that time, two important construction works were taking place in the area: the extension of the commercial port and the opening of long semi-closed channel. Comparing the current metallic hotspots with the geographical distribution of elements in previous years (2009, 2010 and 2014) showed us that these works seem to have significantly influenced the distribution of toxic elements in the estuary, even if the critical point of the second one is still to arrive with the inundation of the connection to the mainland. Long term pollution monitoring reveals as a powerful tool to check the effects of ongoing engineering works in estuarine environments.

Naturally occurring radioactive material was characterized in selected seafood samples from three areas in the Gulf of Mexico. Relatively desirable and abundant fish such as Red Snapper, Red Drum, Northern Whiting, and Spotted Trout as well as oysters were collected and analyzed using gamma spectroscopy to determine the concentration of ²²⁸Ra, ²²⁶Ra, and ⁴⁰ K. Average total activity concentration from these radionuclides were 0.9 ± 0.6, 1.6 ± 1.2, and 132 ± 57 Bq kg⁻¹ respectively, in the edible portion of wet weight samples. The results were consistent with previous studies for other bodies of water. A small but statistically significant increase in ²²⁶Ra was found in comparison to similar research performed 20 years prior. These measurements provide a reasonable baseline for the examined species from the Gulf of Mexico.

Microplastics are becoming a global concern due to their potential to accumulate pollutants in aquatic environments. In this paper, sulfamethazine (SMT) sorption onto six types of microplastics, including polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was investigated by experimental and molecular dynamics simulation methods. The experimental results indicated that SMX sorption reached equilibrium within 16 h. The kinetics of SMT sorption by PA, PVC, PE, and PP could be fitted by pseudo first-order model, while SMT sorption by PA and PET could be described by pseudo second-order model. The partition coefficient Kd values were 38.7, 23.5, 21.0, 22.6, 18.6 and 15.1 L·kg⁻¹ for PA, PE, PS, PET, PVC and PP, respectively. SMT sorption onto microplastics decreased when pH and salinity increased. The molecular dynamics simulation results indicated that the main mechanisms involved in sorption are electrostatic and Van der Waals interaction.

Marine monitoring in Bohai Sea is delivered within three networks by lacking appropriate sampling and assessment methodologies. Water-quality response grid (WRG)-based sampling design using optimization and multi-factors assessment can reliably detect a variety of environmental impacts. Which includes 5 steps: selects environmental reference factors, divides the sampling grid, sets the initial stations, optimizes the sampling stations, and assesses the proposed network's reproducibility and efficiency. We applied this method to the Bohai Sea, the networks proposed here have 225 stations for optimized special surveys (OSS) and 181 stations for optimized operational monitoring (OOM), accounting for 46.5% and 37.4% of the original station totals, respectively. Besides, the reproducibility and efficiency index (REI) of OSS and OOM stations approximately 15.4% and 13.3% higher than three current monitoring networks on average among multi-factors in 4 seasons. Thus, the method can improve the reproducibility, efficiency and land-sea spatial matching of monitoring network.

The occurrence and estrogenic activities of seven phenolic endocrine-disrupting chemical (EDC) compounds (nonylphenol (NP), octylphenol (4-OP), 2,4-dichlorophenol (2,4-DCP), 4-tertbutylphenol (4-t-BP), 4-tert-octylphenol (4-t-OP), tetrabromobisphenol A (TBBPA), and bisphenol A (BPA)) in the sediments of Qingduizi Bay (NorthernYellow Sea, China) in superficial sediments were investigated to evaluate their potential ecological impacts on the health of aquaculture organisms. All compounds, except 4-OP and 4-t-BP, were recorded in most sampling sites (1.06–28.07 ng g⁻¹ dw in maricultural ponds (MPs), 1.98–8.22 ng g⁻¹ dw in outer bay (OB)). BPA and 4-t-OP were the predominant EDC compounds in MPs and OB, respectively. Correlation between BPA and 4-t-OP indicated these compounds may share a similar source or pathway. Analyzed estrogenic activity revealed a low risk of total EDCs. The ranking of risk quotient showed 4-t-OP posed a median risk and TBBPA posed a high risk to the aquatic ecosystem.

The Bilbao estuary (SE Bay of Biscay) is a recovering ecosystem whose sediments are still contaminated. They represent a potential risk for the biota including benthic and demersal species living in direct contact with the sediment. In this context, the present study aims to survey trends of the health status of the Bilbao estuary based on sediment chemistry and sole (Solea spp.) histopathology. Monitoring campaigns were carried out every autumn from 2011 to 2017 along the estuary. Contaminant levels were measured in sediments; liver, gills and gonads of juvenile fish were collected for histopathology. Overall, contaminant levels fluctuated throughout the years, with highest values recorded in the earlier years of the study period. Sole histopathology showed alterations of mild severity. Results permitted to assess the environmental health status of the Bilbao estuary during 7 years, although no clear temporal trend was detected. Longer-term monitoring programmes are necessary to confirm the ecosystem recovery.