Responses of different sexes of farmed Strongylocentrotus intermedius to chronic CO₂-induced seawater acidification were investigated in 120-day lab-based experiments. Four experimental groups were set up as one control group and three seawater acidification groups. The results showed that 1) Specific growth rate and the numbers of mature gamete cells declined in a pH-dependent way in both sexes of adult S. intermedius. 2) There were differences in SDMs identified in females and males reared in acidified seawater reflecting sex-specific response variation in adult S. intermedius. 3) The number of altered metabolic pathways exhibited a linear increasing trend as seawater pH declined in both sexes of adult S. intermedius. Meanwhile seawater acidification might affect metabolic processes via changing the relative expression and activity of key enzymes controlling the corresponding metabolic pathways of adult S. intermedius.

Anthropogenic lead (Pb) has been the overwhelming Pb source to the global ocean, primarily contributed from Pb gasoline and industrial emissions. However, since Pb gasoline has been phased out globally, questions about whether there was a decrease in seawater Pb concentration, or if there are other sources taking over remains unclear in Southeast Asia. Here, combining Pb concentrations in seawater from Singapore Strait in 2010–2017; trap sediment in 2018–2019; and the previously published coral reconstruction covering 1975–2010; we found that the seawater Pb concentration in Singapore Strait over past decades followed the regional gasoline emissions, and no additional major source had contributed the Pb in the seawater since ~2010. The present-day Pb in Singapore Straits' water mainly follows the monsoonal current reversals, with variable degrees of scavenging that peak in inter-monsoon season. Minor Pb sources still contribute to some local-scale variabilities, despite a decadal-scale decreasing trend of Pb in seawater.

This paper presents the development and testing of a gamma radiation dose rate calculation model for the marine environment, and evaluates the potential use for such a model in both short term nuclear emergency response management and emergency response planning. This is believed to be the first implementation of a full field gamma radiation mapping model (including air attenuation and buildup) to be incorporated within a Lagrangian marine dispersion model. Calculated surface gamma ray dose rates for nine generic release scenarios are presented and used to undertake an emergency countermeasure optioneering assessment.

During the COVID-19 pandemic, face masks became a common type of litter invading many different environments, including tourist beaches. However, the presence of face masks on beaches threatens the marine environment with a new form of plastic pollution. In this study, we monitored the occurrence and density of face masks on five tourist beaches along the Moroccan Mediterranean during five months starting from February until June 2021. A total of 321 face masks were recorded on the five beaches, 96.27% of which were single use. The mean density of face masks was 0.0012 ± 0.0008 m⁻². Recreational beaches were the most polluted in the study area. This is related to the important influx of beachgoers on urban beaches compared to resort beaches. With the large number of masks introduced on the beach, we hypothesize that microplastic pollution could increase drastically in the Moroccan Mediterranean in the coming years. Significant efforts are required to reduce this type of waste.

Organochlorine pesticides (OCPs) were investigated in surface sediments and seawater from three major estuaries at Cirebon coastal water, West Java Province, Indonesia. Total concentrations of OCPs in seawater and sediment varied from 10 to 120 ng/L (32 ± 36 ng/L) and 1.5 to 17 ng/g dw (mean of 7.4 ± 4.0 ng/g dw), respectively. OCPs concentrations in Sukalila estuary were higher than those detected in Bondet and Kejawan estuaries. The drins group was the predominant OCPs contaminant in seawater and sediment samples. Historical application of DDT, recent use of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), and application of technical hexachlorocyclohexanes (HCHs) are significant sources of DDTs and HCHs, respectively. The concentrations of γ-HCH and heptachlor epoxide in marine sediment elevated the value of Threshold Effect Limit (TEL) in 48% of the total study stations but lowered the value of Probable Effect Limit (PEL), suggesting that they ocassionally trigger adverse effects on benthic organisms.

French Polynesia atolls are spread on a vast 2300 by 1200 km Central Pacific Ocean area exposed to spatially and temporally dependent wave forcing. They also have a wide range of closed to open morphologies and several have been suitable to develop from black-lipped pearl oysters a substantial pearl farming activity in the past 30 years, representing nowadays the 2nd source of income for French Polynesia. Considering here only the component of lagoon renewal that is driven by waves, we investigate for 74 atolls different lagoon renewal metrics using 20 years of wave model data at 0.05° spatial resolution. Wavelet spectral analyses highlight that atolls, even in close vicinity, can be exposed to different and characteristic periodicities in wave-driven flows and water renewal. These characteristics are discussed in relation to pearl farming atolls, including atolls known to be efficient oyster spat producers, a critical activity for pearl farming sustainability.

The increased use of disinfectants due to the spread of the novel coronavirus infection (e.g. COVID-19) has caused burden in the environment but knowledge on its ecotoxicological impact on the estuary environment is limited. Here we report in vivo and molecular endpoints that we used to assess the effects of chloroxylenol (PCMX) and benzalkonium chloride (BAC), which are ingredients in liquid handwash, dish soap products, and sanitizers used by consumers and healthcare workers on the estuarine rotifer Brachionus koreanus. PCMX and BAC significantly affected the life table parameters of B. koreanus. These chemicals modulated the activities of antioxidant enzymes such as superoxide dismutase and catalase and increased reactive oxygen species even at low concentrations. Also, PCMX and BAC caused alterations in the swimming speed and rotation rate of B. koreanus. Furthermore, an RNA-seq-based ingenuity pathway analysis showed that PCMX affected several signaling pathways, allowing us to predict that a low concentration of PCMX will have deleterious effects on B. koreanus. The neurotoxic and mitochondrial dysfunction event scenario induced by PCMX reflects the underlying molecular mechanisms by which PCMX produces outcomes deleterious to aquatic organisms.

Concentrations of heavy metals, namely, cadmium, copper, zinc, lead, and chromium were measured in the muscle tissue of Scomberoides commersonnianus and Cynoglossus arel from the northern waters of the Oman Sea. Human health risk assessment for Iranian child and adult consumers were also evaluated. The mean concentration of zinc and copper were lower than international standards of maximum permissible limits (MPL). The estimated daily and weekly intakes (EDI and EWI) of all metals were lower than permissible tolerable daily intake (PTDI). The permissible frequency of fish consumption (CRmm) of S. commersonnianus and C. arel showed that they are safe for both children and adults even at a high meal frequency (>16 meals/month). Target hazard quotient (THQ) and risk index (HI) values were higher than 1 for Cu in adults, Cu and Zn in children with consumption rate of 7 times per week. Therefore, consumption of these spices of Oman Sea more than 7 times per week can threaten the health of consumers.

Anthropogenic pressures such as the introduction of non-indigenous species (NIS) have impacted global biodiversity and ecosystems. Most marine species spreading outside their natural biogeographical limits are promoted and facilitated by maritime traffic through ballast water and hull biofouling. Propagule pressure plays a primary role in invasion success mixed with environmental conditions of the arrival port. Moreover, with the current ocean sprawl, new substrates are offered for potential NIS recruits. Here, differences in the fouling assemblages thriving inside three different ports/marinas facilities in Madeira Island were assessed for comparison. The locations showed significant differences concerning assemblage structure. Most NIS were detected in plastic floating pontoons. Funchal harbour receives most of the marine traffic in Madeira, acting as the main hub for primary NIS introductions, being recreational boating involved in NIS secondary transfers. Our results highlight the need for future management actions in island ecosystems, particularly monitoring and sampling of recreational boating.

Since 1990s, harmful algal blooms (HABs) of Kareniaceae, primarily caused by species of Karenia and Karlodinium and rarely by Takayama species, have been substantially increasing in frequency and duration in the coastal waters of China. In this study, we recorded a bloom of high abundance of T. acrotrocha in the Haizhou Bay, the Yellow Sea in September 2020, which is the first record of a Takayama bloom in the temperate coastal waters of China. We found that high concentrations of DON and DOP accelerated the proliferation of T. acrotrocha in the Haizhou Bay. Intensive mariculture, and terrestrial nitrogen and phosphorus input may be responsible for the eutrophication in the Haizhou Bay featuring high concentrations of DON and DOP, and high DIN/DIP ratios. The results suggested that, under ocean warming, the HABs of Kareniaceae are becoming increasingly dominant in eutrophic temperate coasts with intensive mariculture activities.