Globally, the environmental impacts of microplastics (MPs) as emerging pollutants have drawn a lot of attention. This study aimed to assess the distribution and associated potential ecotoxic risk of MPs in the water and sediment of Nigeria\'s offshore waters. Water and sediment samples were collected from sixteen (16) stations in October 2023 and analysed using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and stereomicroscopy. For physical characterization, the composition of MPs in sediment and water was 73 particles/kg and 48 particles/L, respectively, while the ATR-FTIR composition at the Eastern Zone (EZ) was 705 particles/L and 1033 particles/kg, the Central Zone (CZ) was 212 particles/L and 338 particles/kg, and the Western Zone (WZ) was 223 particles/L and 218 particles/kg. The identified MPs shapes were filaments, plastic films, fibre, and microbeads. Polychloroprene (CR) (18.10% and 16.86%) at EZ and CZ and polyvinyl alcohol (PVA) (20.64%) at WZ were most abundant in sediment, respectively. In comparison, PVA (22.3%, 22.2%, and 21.08%) was most abundant across EZ, CZ, and WZ in water. The polymer-based plastic contamination factors (ppCf) and pollution load index (pPLI) showed low contamination and pollution load, and the polymer risk index (pRi) showed medium and low risk in water and sediment, respectively. The polymer ecological risks index (pERI) showed a high-risk level (pERI: 1,001-10,000) in water and sediment across the EZ, CZ, and WZ of the Nigerian offshore waters. In marine environments, an extensive environmental monitoring program and trend forecasting for microplastics are crucial. This study will provide theoretical and technical support for developing efficient legislation or policy on the prevention and control of plastic pollution.

Organic additives are incorporated during the manufacturing of plastics, and these additives are gradually released into the environment from plastic debris. Among these, phthalate acid esters (PAEs) are the most prevalent. PAEs can be found in the atmosphere, aquatic ecosystems, terrestrial regions, soil, and within animal and human bodies. They are released from industrial activities and have a significant impact on the natural environment. This study reviews research on PAEs from various regions worldwide, with about 47.8 % of the studies published between 2020 and 2024. The highest concentrations of PAEs were detected in fish samples from rivers in Taiwan, ranging from 13.6 to 70.0 mg/kg dry weight. PAEs tend to accumulate more in benthic organisms and sediments. DEHP was the most prevalent PAE in fish samples, showing the highest levels and detection frequency among the analyzed PAEs. Some studies found a strong correlation (r2 = 0.85) between PAEs concentrations in fish and water. The findings of this study can help in assessing the fate and behavior of PAEs in the environment and provide a basis for developing future management strategies to control phthalate acid esters pollution in aquatic environments.

Several Dinophysis species can produce potent lipophilic toxins that pose a risk to human health when contaminated seafood is consumed, especially filter-feeding bivalve mussels. In the mussel farms of the Northwestern Adriatic Sea, seawater and seafood are regularly monitored for the presence of Dinophysis species and their associated toxins, but the current methodological approaches, such as light microscopy determinations, require a long time to make results available to local authorities. A molecular qPCR-based assay can be used to quantify various toxic Dinophysis species in a shorter timeframe. However, this approach is not currently employed in official testing activities. In this study, field samples were collected monthly or bi-weekly over one year from various mussel farms along the Northwestern Adriatic coast. The abundance of Dinophysis species in the seawater was determined using both traditional microscopy and qPCR assays. In addition, the concentration of lipophilic toxins for DSP in mussel flesh was quantified using LC-MS/MS focusing on the okadaic acid group. Dinophysis spp. site-specific single cells were isolated and analysed by qPCR yielding a mean rDNA copy number per cell of 1.21 × 104 ± 1.81 × 103. The qPCR assay gave an efficiency of 98 % and detected up to 10 copies of the rDNA target gene. The qPCR and light microscopy determinations in environmental samples showed a significant positive correlation (Spearman rs = 0.57, p-value < 0.001) with a ratio of 2.24 between the two quantification methods, indicating that light microscopy estimates were generally 44.6 % lower than those obtained by the qPCR assay. The qPCR approach showed several advantages such as rapidity, sensitivity and efficiency over conventional microscopy analysis, showing its potential future role in phytoplankton monitoring under the Official Controls Regulations for shellfish.

Benzothiazoles (BTHs), benzotriazoles (BTRs), and benzotriazole ultraviolet absorbers (BUVs) have garnered significant attention owing to their persistent nature in the environment and adverse impacts on aquatic organisms. However, there remains a dearth of investigations and studies conducted in tropical marine environments. In this study, we undertook the inaugural distributional survey and ecotoxicological relevance of BTHs, BTRs, and BUVs in seawater and sediments of the western South China Sea (WSCS). Elevated concentrations of BTHs, BTRs, and BUVs in the seawater and suspended particulate matter (SPM) were primarily observed in the Pearl River Estuary (PRE) and the western region of the WSCS, attributed to terrestrial runoff and hydrodynamic processes. Moreover, the transport of these compounds at the seawater-SPM interface was influenced by both the intrinsic properties of the contaminants and temperature variations. Spatially, concentrations of BTHs, BTRs, and BUVs in surface sediments exhibited a diminishing trend with increasing distance from the coast to offshore areas, reflecting notable anthropogenic impacts. Concentration profiles of these compounds in sediment cores displayed a bottom-up increasing trend, with total organic carbon (TOC) identified as the primary determinant governing their accumulation within sediment cores in the WSCS. Terrestrial runoff inputs and atmospheric deposition as major contributors to the occurrence of BTHs, BTRs, and BUVs in the WSCS. Simultaneously, the study underscores the non-negligible moderate mixture risk quotient associated with BTHs, BTRs, and BUVs in the sediments.

Otoliths are frequently used as proxies to examine the impacts of climate change on fish growth in marine and freshwater ecosystems worldwide. However, the large sensitivity differences in otolith growth responses to typical changing environmental factors (i.e., temperature and CO2 concentration), coupled with unclear drivers and potential inconsistencies with fish body growth, fundamentally challenge the reliability of such otolith applications. Here, we performed a global meta-analysis of experiments investigating the direct effects of warming (297 cases) and CO2 acidification (293 cases) on fish otolith growth and compared them with fish body growth responses. Hierarchical models were used to assess the overall effect and quantify the influence of nine explanatory factors (e.g., fish feeding habit, life history stage, habitat type, and experimental amplitude and duration). The overall effects of warming and acidification on otolith growth were positive and significant, and the effect size of warming (effect size = 0.4003, otolith size of the treatment group increased by 49.23% compared to that of the control group) was larger than that of acidification (0.0724, 7.51%). All factors examined contributed to the heterogeneity of effect sizes, with larger responses commonly observed in carnivorous fish, marine species, and young individuals. Warming amplitudes and durations and acidification amplitudes increased the effect sizes, while acidification durations decreased the effect sizes. Otolith growth responses were consistent with, but greater than, fish body growth responses under warming. In contrast, fish body growth responses were not significant under acidification (effect size = -0.0051, p = .6185) and thus cannot be estimated using otoliths. Therefore, our study highlights that the reliability of applying otoliths to examine climate change impacts is likely varied, as the sensitivity of otolith growth responses and the consistency between the growth responses of otoliths and fish bodies are context-dependent.

Climate change is causing ocean warming (OW) and increasing the frequency, intensity, and duration of extreme weather events, including Marine Heat Waves (MHWs). Both OW and MHWs pose a significant threat to marine ecosystems and marine organisms, including oysters, oyster reefs and farmed oysters. We investigated the survival and growth of juveniles of two commercial species of oyster, the Sydney rock oyster, Saccostrea glomerata, and the Pacific oyster, Crassostrea gigas, to elevated seawater temperatures reflecting a moderate and an extreme MHW in context with recent MHWs and beyond. The survival and size of Pacific oysters to moderate MHWs (22-32 °C; 14 days) was greater than that for Sydney rock oysters (24-32 °C; 15 days). While survival and growth of both species was significantly impacted by extreme MHWs (29-38 °C; 5-6 days), Sydney rock oysters were found to survive greater temperatures compared to the Pacific oyster. Overall, this study found that Pacific oyster juveniles were more tolerant of a moderate MHW, while Sydney rock oyster juveniles were more resilient to extreme MHWs. These differences in thermal tolerance may have consequences for aquaculture and coexistence of both species in their intertidal and latitudinal distributions along the south-eastern Australian coastline.

Solar-powered seawater production of clean hydrogen fuel is highly prospective. In this work, Ni3C/Mn0.5Cd0.5S (NCMCS) Schottky junctions with excellent visible-light correspondence and photogenerated carrier separation properties are constructed using electrostatic attraction. The material achieves a hydrogen evolution rate of 6472.9 μmol h-1 g-1 in simulated seawater, which is 11 times higher than that of a single Mn0.5Cd0.5S (MCS). More attractively, the composite exhibits excellent hydrogen evolution rates in natural river water, groundwater and tap water, with significantly enhanced practical applicability. The underlying hydrogen evolution mechanism was extrapolated from a combination of experimental and theoretical calculations. The present work provides a low-cost and efficient hydrogen evolution photocatalyst for practical application, which can help promote the efficient conversion of solar-hydrogen energy.

Two bacterial strains, Y60-23T and HN-65T, were isolated from marine sediment samples collected from Xiaoshi Island, Weihai, and Dongzhai Harbour, Haikou, PR China, respectively. Based on the 16S rRNA gene sequences, strain Y60-23T exhibited 96.0% similarity to its most related type strain Hyphobacterium vulgare KCTC 52487T, while strain HN-65T exhibited 97.3% similarity to its most related type strain Hyphobacterium indicum 2ED5T. The 16S rRNA gene sequence similarity between the two strains was 95.8%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains Y60-23T and HN-65T belonged to the genus Hyphobacterium. Cells of strains Y60-23T and HN-65T were rod-shaped, Gram-stain-negative, aerobic, non-motile, prosthecate and multiplied by binary fission. The major cellular fatty acids (>10.0%) of strain Y60-23T were C18 : 1  ω7c and C17 : 0, while those of strain HN-65T were iso-C17 : 1  ω9c, iso-C17 : 0 and C18 : 1  ω7c. The major respiratory quinone in both strains was ubiquinone-10 (Q-10) and the major polar lipids were monoglycosyl diglyceride, sulfoquinovosyl diacylglycerol and glucuronopyranosyl diglyceride. The genomic DNA G+C contents of strains Y60-23T and HN-65T were 63.9 and 60.7 mol%, respectively. The average nucleotide identity value between the two strains was 72.1% and the DNA-DNA hybridization value was 18.4%, clearly distinguishing them from each other. According to the results of the phenotypic, chemotaxonomic, phylogenetic and genomic analyses, the two strains represented two novel species within the genus Hyphobacterium, for which the names Hyphobacterium marinum sp. nov. and Hyphobacterium lacteum sp. nov. were proposed with the type strains Y60-23T (=MCCC 1H01433T=KCTC 8172T) and HN-65T (=MCCC 1H01434T=KCTC 8169T), respectively.

Identifying and quantifying water nitrate pollution is crucial for managing aquatic environment of a bay. Dongshan Bay, a significant semi-enclosed bay in the southeastern coastal area of Fujian Province, features mangrove and coral reef ecosystems at its estuary and bay mouth, respectively. Dongshan Bay is impacted by human activities such as mariculture. We quantified and analyzed nitrate pollution status in the surface waters of Dongshan Bay by measuring physicochemical parameters, stable isotopes (δ15N-NO3-, δ18O-NO3- and δ15N-NH4+) of the surface waters, and using statistical methods including the MixSIAR isotope mixing model. The results showed that the concentrations of chlorophyll a and dissolved inorganic nitrogen in the surface waters exhibited a noticeable gradient change, decreasing from the estuary of the Zhangjiang River to the mouth of Dongshan Bay. The maximum concentrations of chlorophyll a, NH4+, NO3- and NO2- were 45.2 μg·L-1, 52.67 μmol·L-1, 379.2 μmol·L-1 and 3.93 μmol·L-1, respectively. The nitrogen and oxygen isotope values of NH4+ and NO3- in the surface waters showed significant spatial variations. According to the MixSIAR model results, nitrogen sources in the surface waters of Dongshan Bay were mainly freshwater inputs of the Zhangjiang River estuary, aquaculture wastewater, and groundwater. The freshwater input from the Zhangjiang River estuary contributed the most (25.2%), while aquaculture wastewater, groundwater and urban sewage accounted for 24.6%, 19.0%, and 15.1%, respectively. It is evident that freshwater input from the Zhangjiang River estuary is the primary source of nitrate in the surface waters of Dongshan Bay.
识别和量化海湾水体硝态氮污染,对管理海湾水体环境至关重要。东山湾是福建省东南沿海重要的半封闭海湾,湾头漳江河口和湾口分别存在红树林和珊瑚礁生态系统,同时也伴随着海水养殖等人类活动影响。本研究通过测定海湾表层水体理化参数、稳定同位素(δ15N-NO3-、δ18O-NO3-和δ15N-NH4+),结合MixSIAR同位素混合模型等统计方法,定量化分析漳州东山湾表层水体硝态氮污染。结果表明: 东山湾表层水体叶绿素a和溶解无机氮浓度呈现较为明显的梯度变化,表现为由漳江河口向东山湾湾口方向逐渐下降,叶绿素a、NH4+、NO3-和NO2-浓度的最大值分别为45.2 μg·L-1、52.67 μmol·L-1、379.2 μmol·L-1和3.93 μmol·L-1;表层水体NH4+和NO3-的氮、氧同位素值则表现为明显的空间异质性。MixSIAR模型结果显示,东山湾表层水体潜在氮源主要来源于漳江河口的淡水输入、养殖废水以及地下水等,其中漳江河口淡水输入的贡献最大,占25.2%,养殖废水、地下水以及城市污水分别占24.6%、19.0%和15.1%。可见,漳江河口淡水输入是东山湾表层水体硝酸盐最主要的来源。.

BACKGROUND: The backbone of the eukaryotic tree of life contains taxa only found in molecular surveys, of which we still have a limited understanding. Such is the case of Picozoa, an enigmatic lineage of heterotrophic picoeukaryotes within the supergroup Archaeplastida, which has emerged as a significant component of marine microbial planktonic communities. To enhance our understanding of the diversity, distribution, and ecology of Picozoa, we conduct a comprehensive assessment at different levels, from assemblages to taxa, employing phylogenetic analysis, species distribution modeling, and ecological niche characterization.
RESULTS: Picozoa was among the ten most abundant eukaryotic groups, found almost exclusively in marine environments. The phylum was represented by 179 Picozoa\'s OTU (pOTUs) placed in five phylogenetic clades. Picozoa community structure had a clear latitudinal pattern, with polar assemblages tending to cluster separately from non-polar ones. Based on the abundance and occupancy pattern, the pOTUs were classified into four categories: Low-abundant, Widespread, Polar, and Non-polar. We calculated the ecological niche of each of these categories. Notably, pOTUs sharing similar ecological niches were not closely related species, indicating a phylogenetic overdispersion in Picozoa communities. This could be attributed to competitive exclusion and the strong influence of the seasonal amplitude of variations in environmental factors, such as temperature, shaping physiological and ecological traits.
CONCLUSIONS: Overall, this work advances our understanding of uncharted protists\' evolutionary dynamics and ecological strategies. Our results highlight the importance of understanding the species-level ecology of marine heteroflagellates like Picozoa. The observed phylogenetic overdispersion challenges the concept of phylogenetic niche conservatism in protist communities, suggesting that closely related species do not necessarily share similar ecological niches. Video Abstract.