The pollution status of polycyclic aromatic hydrocarbons (PAHs) in seawater, surface sediment, and marine organisms was investigated in Haizhou Bay, which is a traditional marine fish farming region in China. The total concentrations of PAHs in seawater, surface sediment, and marine organisms were 12.4–40.3 ng/L (average 24.8 ng/L), 183.2–496.6 ng/g (average 293.5 ng/g), and 228.1–679.9 ng/g (average 392.6 ng/g), respectively. Source analysis results showed that the PAH sources for seawater and marine organisms were coal and biomass combustion (66.53%), petroleum (28.94%), and traffic (4.52%), while those for the surface sediment were traffic (48.14%), coal and biomass combustion (40.56%). The lifetime cancer risk increment (ILCR) values of marine organisms in the Haizhou Bay were less than 10⁻⁶, indicating no carcinogenic risk. In the future, this study can be used as a reference to understand the distribution and interrelation of PAHs in other semi-enclosed bays in the world.

For the first time, this study explored the dominant features of Marine HeatWaves (MHWs) in the Persian Gulf and Oman Sea (1982–2020). The spatial extent of MHWs has nearly doubled in the last 24 years. Since 1997, the average number of MHW days in the central parts of the Persian Gulf has increased about 19 times compared to the period 1982–1997. The average number of the detected MHW events has increased by about three times. Simultaneously with the increase in MHWs frequency trend, the trend in the average number of MHW days has also increased. Since 1997, the average number of MHW days in the study area has almost increased by 10 times. The mean duration of the detected MHWs ranged from 5 to10 days. On average, in a major part of the Persian Gulf, about 1–2 MHW events occur annually.

Biotic resistance is considered an important driver in the establishment of non-indigenous species (NIS), but experiments in the marine environment have led to contradictory results. In this context, a transplant experiment of fouling communities was carried out over five months. Settlement panels were moved from low impact (species-rich native communities) to high impact sites by NIS in two Italian areas to test the biotic resistance hypothesis. Fouling communities displayed significant differences among treatments before and after the transplant, thus indicating the maintenance of a peculiar fouling community in transplanted panels. On the other hand, newly recruited species were similar between treatments and neither a facilitation nor a mitigation role from native fouling communities on NIS was observed. Our results highlight the importance to better investigate the factors affecting the high variability obtained in experiments testing this hypothesis, with the aim to identify potential solutions for NIS management in ports.

Tracking the subsea oil plume during the 2010 Deepwater Horizon Oil Spill (DWH) was conducted using in situ fluorescence via vertical profilers (n = 1157) and discrete sample chemical analyses (n = 7665). During monitoring efforts, discrete samples provided a coarse picture of the oil plume footprint, but the majority of the samples were below standard analytical detection limits for petroleum hydrocarbons. In situ fluorescence data improved the spatial and temporal resolution of the subsea oil plume characterization. Here we synthesized millions of continuous fluorescence data points from hundreds of contemporaneously discrete samples collected to demonstrate how fluorescence could serve as a proxy for Benzene-Toluene-Ethylbenzene-Xylene (BTEX) concentration. Data mined from Gulf Science Data repository were well correlated, and geographically and temporally aligned to provide direct comparisons. Described here are the methods used to calibrate the fluorescence data and to spatially approximate the three-dimensional geographic extent of the oil plume.

Under eutrophication background, the increasing dinoflagellates blooms relative to diatoms blooms off the Changjiang Estuary has caused much concern. We have provided sediment evidence for the first time that the time window of diatoms-to-dinoflagellates shift off the Changjiang Estuary in the East China Sea is early 1990s. Investigations to the water column revealed different surface-bottom concentration matchup patterns between peridinin (dinoflagellates) and fucoxanthin (diatoms), which suggests that the diatoms-dinoflagellates shift recorded in the sediment may have come from more dinoflagellate blooms since 1990s. Physical-biogeochemical 3D numerical simulations for the past decades suggest that the effect of increasing spring sea surface temperature and increasing N/P ratio on the diatoms-dinoflagellates shift is dominant and recessive, respectively.

Rapa Nui is an important hotspot of endemic marine biodiversity, where diffuse land-based sources (e.g., nutrients and organic matter) entering into coastal waters could develop eutrophication in coastal environments, with deleterious impacts on the marine ecosystem. Stable isotopes (δ¹³C and δ¹⁵N) of intertidal communities (macroalgae and invertebrates) were studied from sites with contrasting human influence (populated and unpopulated), to evaluate the incorporation and transfer of diffuse land-based sources through food webs. Macroalgae showed differences between some sites, and invertebrates showed a ¹⁵N-enrichment pattern at populated areas relative to unpopulated, being these differences significant in gastropods, barnacles and sea urchins. Moreover, trophic structure metrics suggest a higher trophic diversity in populated areas relative to unpopulated and support the isotopic partitioning between sites, associated with the incorporation of sources with ¹⁵N-enriched values. The above suggests that diffuse land-based sources could be incorporated by macroalgae, transferred into benthic consumers, and altering the trophic structure.

Microplastics (MPs) and nanoplastics (NPs) are emerging environmental pollutants, having a major ecotoxicological concern to humans and many other biotas, especially aquatic animals. The physical and chemical compositions of MPs majorly determine their ecotoxicological risks. However, comprehensive knowledge about the exposure routes and toxic effects of MPs/NPs on animals and human health is not fully known. Here this review focuses on the potential exposure routes, human health impacts, and toxicity response of MPs/NPs on human health, through reviewing the literature on studies conducted in different in vitro and in vivo experiments on organisms, human cells, and the human experimental exposure models. The current literature review has highlighted ingestion, inhalation, and dermal contacts as major exposure routes of MPs/NPs. Further, oxidative stress, cytotoxicity, DNA damage, inflammation, immune response, neurotoxicity, metabolic disruption, and ultimately affecting digestive systems, immunology, respiratory systems, reproductive systems, and nervous systems, as serious health consequences.

Surface carbonate chemistry in the Yellow Sea was investigated based on discrete seawater samples collected from 2017 to 2020 at the Socheongcho Ocean Research Station (S-ORS; 37.423°N, 124.738°E). Records of carbon parameters, including seawater CO₂ partial pressure (pCO₂), revealed considerable seasonal variations, with amplitudes comparable to those observed across the western part of the Yellow Sea. The study site acted as a modest sink (−0.13 mol C m⁻² yr⁻¹) for atmospheric CO₂. Biological processes (primary production and respiration) and physical conditions (temperature and degree of stratification) determined seawater pCO₂, which fluctuated on an intraseasonal timescale between oversaturated and undersaturated with respect to atmospheric pCO₂. Variation in pCO₂ was significant in summer, depending on the biological carbon drawdown and tidal mixing-induced upwelling (increased pCO₂ up to ~1000 μatm). The intraseasonal variability in seawater pCO₂ may bias estimated air–sea CO₂ fluxes, if measurements with a coarser (seasonal) time resolution are used.

The trace metals species in surface sediments of the Taiwanese river estuarine mouths and the Taiwan Strait were examined by sequential extraction method. Based on the metal species present in sediments, trace metals can be divided into three groups: (1) Co, Cr, Fe, Ni and Zn; (2) Cu and Hg; and (3) Mn and Pb. The total concentrations of trace metals in the first two groups are dominated by the residual fraction. While, Cu and Hg their organic species also contributes a significant percentage and reduces the residual fraction portion. Lead and Mn are dominated by the labile fraction. The total metal concentrations in the analyzed sediments seem to be influenced by Fe oxides, TOC and grain size. The metals contamination status assessed by three environmental indices suggests that the analyzed sediments are minor contaminated by trace metals, with a few exceptions of Cu and Hg at some stations.

Ballast water is a leading pathway for the global introduction of aquatic nonindigenous species. Most international ships are expected to install ballast water management systems (BWMS) by 2024 to treat ballast water before release. This study examines if ballast water discharges managed by BWMS are meeting standards for organisms ≥50 μm in minimum dimension (i.e., <10 organisms per m³; typically zooplankton). Representative samples of ballast water were collected from 29 ships (using 14 different BWMS) arriving to Canada during 2017–2018. Fourteen samples (48 %) had zooplankton concentrations clearly exceeding the standard (ranging from 18 to 3822 organisms per m³). Nonetheless, compared to earlier management strategies, BWMS appear to reduce the frequency of high-risk introduction events. BWMS filter mesh size was an important predictor of zooplankton concentration following treatment. Greater rates of compliance may be achieved as ship crews gain experience with operation and maintenance of BWMS.