Knowing the polycyclic aromatic hydrocarbons (PAHs) pollution properties in ocean is highly needed to protect the open sea. In July to August of 2020, twenty surface water samples were obtained from the East China Sea to the Philippine Sea. The ranges of Σ₁₅PAHs concentrations were 3.188–5.29 ng L⁻¹ in dissolved phase, 0.455–1.305 ng L⁻¹ in particulate phase in the Philippine Sea. 3, 4-Ring PAHs were the most abundant PAHs. Their spatial differences in dissolved phase were mainly caused by human activities, the summer monsoon from the Philippine Islands and the Northern Equatorial Current, and the Kuroshio Current and Subtropical Countercurrent. The source analysis showed that PAHs in surface water in the Philippine Sea may come from coal combustion. It is the first time to analyze the occurrence and distribution of PAHs in the Philippine Sea.

Interactions between corals and macroalgae are important in influencing benthic community structures on coral reefs and have become increasingly common occurrences. However, little is known about their temporal variation as most studies have only documented them from single surveys. To investigate the dynamics of coral–macroalgal interactions, we surveyed three urbanised reefs in Singapore bi-monthly for three years. We found that the frequency of coral–macroalgal interactions varied greatly across sites and seasons. The extent of coral–macroalgal contact was positively correlated with macroalgal abundance, but the correlation differed significantly among macroalgal genera. The growth rates of Goniopora, Montipora and Pavona corals, but not Platygra, were also negatively correlated with the extent of macroalgal interactions. Overall, our results highlight that coral–macroalgal interactions are spatially and temporally dynamic, with varying effects among coral species. It is critical to consider seasonal fluctuations of macroalgae if the overall long-term impacts of macroalgae are to be understood.

A study on mercury (Hg) and selenium (Se) concentrations in the liver and muscle of brown smooth-hound shark Mustelus henlei and its principal prey items, was conducted in the western coast of Baja California Sur, Mexico. Average Hg concentrations were found to be high in the muscle than in the liver; however, Hg concentrations were below the maximum permissible limits, and hence, the consumption of this species does not constitute a risk to human health. The mean Se concentrations were higher in the liver than in the muscle. The results of Hg: Se molar ratio revealed that Se counteracts the toxicity of Hg in hepatic tissues, whereas the contrary occurs in the muscle. Significant differences in Hg and Se accumulation were observed between females and males. Biomagnification factor values >1 demonstrate a biomagnification process from its principal prey species (i.e., red crab, Pleuroncodes planipes and Pacific mackerel, Scomber japonicus).

Marine fishes are consumed in large quantities by humans as nutritious food. However, the intake of fish polluted by chemicals may pose a severe threat to human health. This study measured the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in the muscles of 22 species of marine fish from two coastal regions, i.e., Tanmen and Zhuhai, identified the source of PAHs, and assessed the human health risk by dietary exposure. Total PAH (Σ₁₆PAHs) levels in Tanmen and Zhuhai fish were in the range of 24.29–684.83 ng g⁻¹ dry weight (dw) and 13.74–42.59 ng g⁻¹ dw, averaging 161.46 ng g⁻¹ dw and 31.21 ng g⁻¹ dw, respectively. Compared with other regions in the world, PAH concentrations in Tanmen fish were at median levels, and Zhuhai fish were at low levels. Low molecular weight PAHs (with 2- and 3-rings) were the predominant compounds detected. Molecular diagnostic ratios suggested that PAHs in Tanmen mainly originated from petrogenic sources such as vessel operations or tanker accidents, while Zhuhai fish were mainly polluted by pyrolytic sources such as combustion of coal and wood. The human health risk assessment results indicated that the risk of PAH intake via fish consumption from Zhuhai was negligible, while five species from Tanmen may pose potential health risks to local residents.

With increasing maritime activities in the proximity of coral reefs, a growing number of manmade structures are becoming available for coral colonisation. Yet, little is known about the sessile community composition of such artificial reefs in comparison with that of natural coral reefs. Here, we compared the diversity of corals and their competitors for substrate space between a centuries-old manmade structure and the nearest natural reef at St. Eustatius, eastern Caribbean. The artificial reef had a significantly lower species richness and fewer competitive interactions than the natural reef. The artificial reef was dominated by a cover of crustose coralline algae and zoantharians, instead of turf algae and fire corals on the natural reef. Significant differences in species composition were also found between exposed and sheltered sites on both reefs. Our study indicates that even a centuries-old manmade reef cannot serve as a surrogate for natural reefs.

In this study, we identified the in situ bacterial groups and their community structure in coastal waters influenced by anthropogenic inputs. The use of environmental DNA (eDNA) and high throughput sequencing (HTS) were employed to derive accurate and reliable information on bacterial abundance. The V3 and V4 hypervariable regions of the 16S rRNA gene were amplified and the sequences were clustered into operational taxonomic units to analyze the site-specific variations in community composition. The percentage composition within the bacterial orders varied significantly among nearshore anthropogenic hotspots and offshore (5 km) samples. The microbial network constructed taking the bacterial abundance as nodes displayed strong positive and negative correlations within the bacterial families. Overall, the use of eDNA coupled with HTS is an incredible means for monitoring and assessing the abundance of bacterial communities and also serves as a biomonitoring tool to understand the degree of anthropogenic contamination in coastal waters.

Although the ingestion of plastics and other anthropogenic debris by seabirds is a global problem, few studies have employed standardized protocols to quantify and classify the debris ingested by seabirds in the Southwest Atlantic. We evaluated the ingestion of marine debris (items >0.1 mm) by 126 coastal and pelagic birds (19 species) along the coast of Espírito Santo, Eastern Brazil. Debris were found in 30% of birds examined (11 species). Particles <1 mm accounted for 35% of all debris items. Most ingested debris were plastics (97%). Ingestion of >0.1 g of plastic debris was recorded in five species: Atlantic yellow-nosed albatrosses (Thalassarche chlororhynchos), Cory's shearwaters (Calonectris borealis), Manx shearwaters (Puffinus puffinus), brown boobies (Sula leucogaster), and Magellanic penguins (Spheniscus magellanicus). Our findings suggest that the ingestion of marine debris, especially plastics, is a common problem for coastal and pelagic birds in tropical Southwest Atlantic waters.

This study initially investigated the coral status during the unexpected bleaching event in three coastal areas in Northwest Hainan coastal areas and analyzed changes in coral holobionts of the healthy and bleached Galaxea fascicularis. Coral coverage had declined severely, and the bleaching rate was extremely high during heat stress. The bleached corals had lower maximum photosynthetic yield, actual photosynthetic yield, zooxanthellae density, and chlorophyll a content than the healthy G. fascicularis, but there was no significant difference in protein, carbohydrate and lipid in eutrophic waters. The diversity and community composition of Symbiodiniaceae and symbiotic bacteria between healthy and bleached G. fascicularis showed no difference. Function prediction of the symbiotic bacteria revealed that the metabolism process was the main pathway of annotation. Present findings suggested that energy reserve functioning and high stability of the holobiont structure and might provide opportunities to G. fascicularis to adapt to eutrophication and heat stress.

Microplastics as emerging environmental pollutants, its effect to the bioprocess of water and wastewater treatment has aroused concern. This study investigated the effects of microplastic polystyrene (PS) particle size to the activated sludge nutrient removal process. The ammonia, nitrite, nitrate and phosphorus removal under various PS particle size during nitrification and denitrification process was tested. The results indicated that with PS particle size 150–300 μm, the ammonia oxidation during nitrification process was inhibited to 71%, 92%, and 80% as compared with the blank reactor, for PS concentration at 0.01 g/L, 0.05 g/L and 0.10 g/L, respectively. The nitrite accumulation during nitrification process was also high at PS particle size 150–300 μm and concentration no less than 0.05 g/L. The nitrate reduction during the denitrification process was all inhibited to 69%–94% as compared with the blank, except for reactor No.4. The phosphate removal during nitrification process was not affected by the existence of microplastics PS, the average removal rate was over 80% after 2 h and over 95% after 3 h, respectively. The microplastics particle size plays important role in affecting the activated sludge nutrient removal process.

This study explored the physiological responses of the coral Pocillopora damicornis to high nitrate concentrations and thermal stresses. The expression of heat shock proteins Hsp60 and Hsp32, Symbiodiniaceae density, Chl a concentration, Fv/Fm, H₂O₂ scavenging, and caspase 3 activity varied during 60 h incubations at 28 °C or 32 °C, ambient or high nitrate (~10 μM) concentrations, and their combinations. In combined stresses, corals showed a rapid and high oxidation level negatively affecting the Symbiodiniaceae density and Chl a concentration at 12 h, followed by caspase 3 and Hsps upregulations that induced apoptosis, bleaching and tissue detachment. Corals under thermal stress showed the highest oxidation and upregulation of Hsps and caspase 3 resulting in coral discoloration. High nitrate treatment alone did not seriously affect the coral function. Results showed that combined stress treatment severely affected coral physiology and, judging from the condition of detached tissues, these corals might have lower chances to recover.