To investigate the distribution, source, contamination, and ecological risk status of heavy metals in the Red Sea-Gulf of Aqaba coast, Saudi Arabia, 33 surface sediment samples were collected for Fe, Zn, Sb, Co, Cu, Hg, Pb, Mn, Cr, Ni, Cd, As, and TOC analysis using ICP-MS. Three single and three multi-element contamination indices were used to assess the sediment quality. Evaluation of the three single pollution indices suggested some contamination or anthropogenic inputs with Cu, Cd, Hg, and, to a great extent, As. The potential ecological risk indicated low ecological risk at all sites for Pb, Zn, Ni, Cu, Co, Cr, and Sb; and considerable risk for Cd, Hg, and As. Moreover, the average values of Hg and As were higher than those recorded in the sediment quality guidelines. The multivariate statistical tools revealed that Fe, Mn, Cd, Cu, Co, Zn, and Cr were mostly of terrestrial origin, derived from weathering of the nearby Pre-Cambrian basement rocks, Tertiary, and Quaternary sedimentary rocks; while As, Sb, Hg, Ni, and Pb were mostly attributed to anthropogenic activities from traffic emissions, industrial activities, and the dredging of marine sediments. The results of this work will guide the future projects of environmentally sustainable development in northwest Saudi Arabia.

The coastal waters adjacent to the Changjiang River estuary (CRE) are characterized by nutrient pollution and recurrent harmful algal blooms. In this study, resting cysts of Alexandrium pacificum Litaker and A. catenella (Whedon & Kof.) Balech, two major species within the A. tamarense species complex in Chinese coastal waters, were studied using sediment samples collected from the area adjacent to the CRE in May 2014 and December 2015. Cysts were detected with two real-time quantitative PCR assays, as well as the primuline-staining method. Only cysts of A. pacificum were found in the study area, which mainly distributed in the mud depositional zone near the CRE. A low-abundance region of the cysts present in spring is in accordance with the intrusive pathway of the Nearshore Kuroshio Branch Current (NKBC), suggesting that A. pacificum blooms could be regulated by seasonal intrusion of NKBC.

Understanding the impacts of plastic pollution is a global research priority. Previous research has shown that plasticizers such as phthalate esters detected in seabird tissues can be useful non-lethal biochemical markers of plastic ingestion as compared with more standard necropsy techniques. We examined the concentrations of six phthalate esters in the preen oil of Northern Fulmars (Fulmarus glacialis) in relation to their retained plastics. Contrary to a previous study, we found that the phthalates examined were not analytically detectable in fulmar preen oil. Given that the birds we examined had up to 100 pieces of plastics in their stomachs, and all uropygial glands were completely emptied during the necropsies, it does not appear that measuring phthalates in preen oil of Northern Fulmars is a useful, non-lethal technique to determine if individuals ingest plastics, at least not currently given the available commercial analytical detection limits.

This study investigated the co-effect of microplastic polyvinylchloride and antibiotics tetracycline to partial nitrification process in treating high ammonia wastewater. The average ammonia oxidation rate of all reactors was 53.58, 56.17 and 42.08 mg·N/L·h in round 1, round 7 and round 13, respectively. The ammonia oxidation rate was reduced to 89.40%, 79.08%, 80.60%, 73.37%, 69.50%, 75.72%, 98.93% and 66.04% from 1st round of test to 13th round of test at reactor R1 to R8. The average nitrosation rate was always over 80% in all conditions tested. Tetracycline removal rate was attributed to sludge adsorption in all reactors and was increased continuously with the increment of tetracycline concentration. The nitrous oxide emission was keep decreasing from round 1 to round 13 in all reactors tested. The microbial community results revealed that with the existence of tetracycline and microplastics, the relative abundance of Bacteroidetes were reduced and Proteobacteria were increased.

Heavy metal pollution arising from agricultural and industrial activities poses a significant threat to the aquatic environment, especially the increasing levels of chromium (Cr) that is exacerbating marine pollution. Given the economic importance of the Pacific white shrimp Litopenaeus vannamei (L. vannamei), understanding the impact of marine Cr pollution is deemed to be significant. In this study, we used the transcriptome sequencing (RNA-seq) technique to characterize the molecular mechanism of Cr exposure in L. vannamei. Gene ontology enrichment analysis showed substrate-specific and ion transport-related functions were mainly influenced by Cr exposure. We further identified genes involved in protein digestion and absorption (PEPT1, BAT1, MDU1), chemical carcinogenesis (GST and UGTs), ABC transporters (ABCC2), apoptosis (CAPN1, CASP10, PARP), implying the potentially Cr disintoxication mechanisms in L. vannamei. Genes within pancreatic secretion (ALT, LDH), lysosome (CTSL and HEXB), and peroxisome (ACOX1, ECI2, NUDT12) pathways implied the potentially Cr toxicity mechanisms in L. vannamei.

Spatial variations in summertime phytoplankton community structure from 1991 to 2017 in Daya Bay, China were investigated in this research. The abundance of total phytoplankton and diatoms significantly increased during the study period in all regions of the bay while an increase in dinoflagellates abundance was only significant in the inner and middle bay areas. Pseudo-nitzschia spp. were overwhelmingly dominant followed by Skeletonema costatum. Ceratium furca was the dominant dinoflagellate. Overall, species diversity and evenness indices showed downward trends during the study period. Moreover, the bloom frequency of Scrippsiella trochoidea (associated with red tides) has increased rapidly since the 2000s in the inner bay. These temporal dynamics are largely explained by enhanced dissolved inorganic nitrogen (DIN) concentrations, which increased by 64.58% during 2005–2017 relative to 1991–2004, induced by human activities, along with temperature reductions and salinity increases resulting from open oceanic seawater intrusion.

Although down-the-hole (DTH) pile driving is increasingly used for in-water pile installation, the characteristics of underwater noise from DTH pile driving is largely undocumented and unstudied. This study presents a comprehensive analysis of the noise characteristics during DTH pile driving of two steel pipe piles in shallow waters off southeast Alaska. The results showed that single-strike sound exposure levels measured at 10 m were 147 and 145 dB re 1 μPa²s with a total of 21,742 and 38,631 hammer strikes, with cumulative sound exposure levels to install each pile at 192 and 191 dB re 1 μPa²s, respectively. Though noise levels from a single strike was lower than impact pile driving of a similar pile, the cumulative sound exposure levels are likely comparable due to the much higher striking rate.

St Georges Bay of Lebanon's coast is an open bay to the Mediterranean Sea. It is exposed to numerous anthropogenic activities such as industrial effluent, untreated wastewater discharge and maritime activities resulting in increasing chemical contamination, especially with trace metals. Contamination with trace metals (Cu, Cd, Co, Pb, As, Ag and Hg) and the influence of early diagenesis on their distribution were studied on both sediments and waters. For this purpose, sediment cores were collected, then treated under inert atmosphere to retrieve pore waters and solid fraction. The area appears to be seriously impacted by the materials transported by the Beirut River and/or by direct inputs, and recent land reclamation using dumpsite material. The sediments showed a significant level of contamination. Element mobility was studied by selective extraction on sediments. The mobility of trace elements from solid fraction to pore waters is controlled by the Fe/Mn cycle and organic matter.

Pollutant emissions from ships could increase with expanding international trade and shipping fleet size, posing a severe but often overlooked threat to public health. China houses the three biggest port clusters in the world: the Bohai Bay (BB), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) and must combat pollutant emissions. This study examines the emissions of key pollutants (i.e., NOX, PM₁₀, PM₂.₅, HC, CO, SOX, CO₂, NMVOC, and CH₄) utilizing a bottom-up methodology with the aid of automatic identification system data. Our results show that among the three regions studied, ships in the YRD produce the most emissions, accounting for 47.84% of the combined total emissions in 2018. We evaluate the emissions from different ship types, operation modes, and discharge equipment. Container ships account for ~50% of all emissions, which are mainly generated during the cruising phase. Different power sources produce varying levels of pollutants owing to power, load, and discharge variations. In addition, ship emissions have seasonal characteristics, which are reflected by the decline trend recorded in February, July, August, and December. This baseline dataset could aid comparisons with historic or future emission data and help establish regulatory actions to improve air quality.

There is little evidence documenting the prevalence of plastic nest incorporation for different seabird species and populations, and even less detailing the source of such debris as nesting material. This study presents a baseline dataset on the presence of plastic in the nests of five seabird species on Lady Isle, Scotland using a novel and repeatable methodology for quantifying plastic incorporated into nests. Plastic was found in 24.5% to 80% of nests of all species. We analysed pellets of regurgitated material and the spatial distribution of herring gull nests containing plastic in the context of the tide and nesting habitat. Differences in the types of plastic found in pellets and nests suggests that plastic incorporated into herring gull nests was not derived at foraging sites and likely collected from the local environment. Targeted beach cleans before the breeding season could help minimise the quantity of plastic available to herring gulls.