It is hypothesized that pH fluctuations produced by seagrasses metabolism may confer marine calcifiers resistance to ocean acidification. Here, we tested this thesis by comparing the net population growth rate (NPGR) of a foraminifer species (Rosalina sp.) epiphytic of Mediterranean seagrass (Posidonia oceanica) to average current and projected pH scenarios under either stable conditions or diel fluctuations in pH of 0.3 units; variations similar to that experienced in their habitat. No significant differences were found in NPGRs between the fluctuating and stable pH treatments at current pH levels. NPGRs in treatments where pH fluctuated did not present significant differences to the treatment with high and stable pH conditions. In contrast, foraminifers exposed to stable low pH regimes experienced a steep decline in NPGR. These results suggest that diel pH fluctuations generated by P. oceanica photosynthetic activity could confer resistance to ocean acidification to Rosalina sp.

The distribution of floating litter in marine waters, influenced by currents and wind drag, often determines the dispersal of its encrusting fauna. In the present paper, we observed for the first time the colonization of rafting floats from abandoned, lost or derelict fishing gears (ALDFG) by the four protected deep-sea species: Errina aspera, Desmophyllum pertusum, Madrepora oculata Pachylasma giganteum.Overall, 41 floats, colonized by deep benthic species, were found stranded on the shore of the Sicilian coast of the Strait of Messina, between 2016 and 2019. Species composition, number and occurrence of colonizing organisms were analyzed. On the basis of the species composition (the association between E. aspera, P. giganteum and Megabalanus tulipiformis), the knowledge on their ecology, biogeography, path of local currents, it was possible to define that the area of origin of the most part of these fishing net floats was the Strait of Messina.

Fast growth of air pollution was experienced in China during the past decades, resulting in extremely large aerosol radiative forcing with up to ten times high compared to the global averages. The responses of surface air temperature to aerosol radiative effects range from − 0.1 to 1.1 K across China, with strong spatial and seasonal variations. Aerosol interaction with clouds can also affect radiation and precipitation. Under high pollution conditions, the frequency of heavy rain increases while the frequency of light rain decreases. Aerosols share common emission sources with CO₂, implying that reducing common sources can be another manifestation of the interaction between aerosol and climate. Air pollution controls will contribute to the climate change mitigation by reducing CO₂ emissions stemming from controls of pollution sources. On the other hand, potential co-benefits in reducing air pollution also come from the mitigation of climate change by reducing CO₂ emission that potentially affects the aerosol concentrations. It is suggested that the PM₂.₅ (fine particulate matter with an aerodynamic diameter of 2.5 μm or less) concentration tends to decrease under future climate control scenarios. Such co-benefits are mostly associated with the reduction of common sources of CO₂ and aerosol (noted as emission-driven interaction), rather than the variation of meteorological conditions associated with future climate change (noted as meteorology-driven interaction). Compared to emission-driven interaction, the impact by meteorology-driven interaction on aerosols is relatively smaller and varies geographically as the PM₂.₅ concentration is likely to increase in northern China while decrease in eastern China. The current review suggested that the co-benefits of reducing CO₂ and aerosol pollutant in China, and their response in the context of future climate change, are worthy of further research.

A community-based participatory research was utilized to address the coastal community's concern regarding Deepwater Horizon oil contamination of seafood. Therefore, we analyzed polycyclic aromatic hydrocarbons (PAHs), major toxic constituents of crude oil, in the seafood collected from gulf coast (Louisiana, Alabama and Mississippi) during December 2011–February 2014. PAHs were extracted from edible part of shrimp, oysters, and crabs by the QuEChERS/dsPE procedure and analyzed by gas chromatography–mass spectrometry. The total PAHs data were further analyzed using the General Linear Mixed Model procedure of the SAS (Version 9.3, SAS Institute, Inc., Cary, NC) statistical software. Brown shrimp showed statistically significant differences in PAHs levels with respect to time and locations while white shrimp showed differences at various time points. PAHs levels in oyster and crab samples were not statistically different at the Type I error of 0.05. Overall, the PAHs levels are far below FDA levels of concern for human consumption.

Persian Gulf is a semi-enclosed highly saline reverse estuary that is exposed to the risk of oil spills in offshore oil and gas activities. In the early 2000s, a specific version of NOAA's Trajectory Analysis Planner (TAP II) was developed for Persian Gulf to assist regional organizations in preparing oil spill contingency plans. In this research, a new stochastic model is developed to cover the limitations of TAP II. The new model is based on an advanced trajectory model, which is now linked with high resolution spatiotemporal data of the wind and sea current. In a case study, the developed model is compared with TAP II, and evaluated by multiple tests designed for analysis of uncertainty, sensitivity, reliability and variability. The case study proved the applicability of the new model, and the evaluation tests provided useful information for the future development of the model.

Anthropogenic activities have altered the geomorphological and ecological conditions of the Nakdong River Estuary (NRE) dramatically over the last century. The objectives of this study were to classify NRE sub-environments and to identify their unique ecological functions. The first step in classification was the establishment of 14 a priori sub-environmental groups based on landscape factors. Surface sediments obtained for these groups were analyzed for factors related to grain size and organic matter. Based on the results, the NRE was divided into two primary estuarine environment divisions: (1) a mixed marine and terrestrial environment influenced primarily by land; and (2) a principally marine environment influenced primarily by the ocean. Using multivariate analysis, we subdivided these primary estuarine divisions into six sub-environments, including Sub-1 and -2 in the former and Sub-3, -4, -5, and -6 in the latter.

Microplastics (MP) are detected in aquatic environments worldwide, yet detection is often limited to larger sized MP. To address this data gap, the abundance of MP 3–500 μm was assessed in the Los Angeles River, the San Gabriel River, and the Long Beach Harbor (CA, USA), three areas with highly urbanized surroundings. Whole surface water samples were taken, subjected to a hydrogen peroxide digestion and MP counts were compared between unstained visual examination and Nile Red staining identification techniques. The largest concentration of MP was found in the Los Angeles River, where 13,622 MP m−3 were found using unstained visual examination and 641,292 MP m−3 were found utilizing Nile Red staining. The protocol used to detect smaller sized MP is low cost, time efficient, and reproducible. This work highlights the need for more extensive sampling of smaller sized MP globally and universal testing and reporting standards for MP detection.

Using a laboratory simulation experiment, we studied the trend of change in methylmercury (MeHg) content of sediments in response to the changing salinity of flooding water (deionized water, 0.5%, 1.0%, 1.5%, and 2.0%) and sulfate-reducing bacteria (SRB) content for both the surface layer (0–10 cm) and the bottom layer (10–20 cm) of Suaeda heteroptera wetland sediments in the Liaohe estuary under anaerobic and aerobic conditions, respectively. The results showed that under AAC (anaerobic conditions), the MeHg content in the surface and bottom sediment layers increased first and then decreased over time and was highest at the 14th day. In contrast, under AC (aerobic conditions), the MeHg content in sediments of both layers increased slowly with increasing test time. The MeHg content in sediments increased first and then decreased with rising salinity and was highest at a salinity of 1.0%. Among the samples collected at different experimental stages, the SRB content in the sediments showed a decreasing trend with rising flooding salinity under AAC and AC. The MeHg and SRB contents were higher under anaerobic conditions than under aerobic conditions. Linear fitting results showed that there was no linear correlation between MeHg contents and SRB quantities in surface and bottom sediments under AAC and AC (R² < 0.1). Collectively, these results suggest an important role for flooding salinity and anaerobic-aerobic conditions in the production of MeHg in S. heteroptera wetlands of the Liaohe estuary, and may predict the ecological risk of methylmercury according to the change of salinity.

Knowledge of key species sensitivity for oil spill response (OSR) options is needed to support decision-making and mitigate impact on sensitive life stages of keystone species. Here, Northern shrimp (Pandalus borealis) larvae were exposed for 24 h to a gradient (H-High, M-Medium: 10 times dilution and L-Low: 100 times dilution) of mechanically- (MDO) (H < 6 mg/L total hydrocarbon content) and chemically- (CDO) dispersed oil (Slickgone NS, H < 20 mg/L total hydrocarbon content), followed by a recovery period. Larval mortality, feeding rate and development were evaluated.Overall, the results show that 24 h exposure to field-realistic concentrations of CDO lead to lower survival, reduced feeding rate and slower larval development in P. borealis larvae compared to MDO. These effects persisted during recovery, indicating a higher vulnerability with dispersant use and the need for longer observation periods post-exposure to fully evaluate the consequences for sensitive life-stages from OSR.

This study focused on the determination of seven volatile methylsiloxanes (VMSs) and eleven UV-filters (UVFs) in beach sand from the Oporto's region (Portugal). A QuEChERS methodology (“Quick, Easy, Cheap, Effective, Rugged, and Safe”) was used to extract VMSs from the sand, which has never been employed before. To extract the UVFs, a solid-phase microextraction (SPME) was used. The analyses were performed by gas chromatography–mass spectrometry (GC–MS). Twenty-three beach sand samples were analysed, from two campaigns – summer/winter. VMSs were found in all the samples with concentrations ranging from 0.007 ± 0.001 to 17.8 ± 0.9 ng g−1dw, while UVFs in summer samples from 0.030 ± 0.001 to 373 ± 17 ng g−1dw. Cyclic VMSs and octocrylene (OC) were detected in higher concentrations. In general, higher levels were detected in summer than winter. Hazard quotients were determined and 3-(4′-methylbenzylidene) camphor (4-MBC), 2-ethylhexyl 4-methoxycinnamate (EMC) and benzophenone-3 (BP3) presented values >1, which may indicate that they may pose an ecotoxicological risk.