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The appetite of fish significantly influences aquaculture efficiency and fish welfare. However, accurately assessing fish appetite has posed a challenging problem. Currently, the study of fish feeding behaviour relies primarily on the overall information obtained from images of fish schools, often overlooking the distinctive behavioural traits of individual fish. Analysing the behaviour of individual fish is hindered by challenges such as intraclass variation and cross-occlusion within real aquaculture environments. To address these challenges, this paper introduces a novel method for assessing appetite based on individual fish behaviour. The ByteTrack model was improved to enable stable tracking of each fish within a school under complex conditions. Additionally, this paper employs the spatiotemporal graph convolutional neural network (ST-GCN) to extract the movement characteristics of individual fish, facilitating accurate appetite assessment. The experimental results demonstrate that the proposed method achieves 98.47% accuracy in appetite assessment, surpassing the performance of other state-of-the-art methods. This paper provides a new opportunity and effective means for analysing fish behaviour and appetite in intricate environments. • ·An appetite assessment method based on YOLOv8-ByteTrack and ST-GCN was proposed. • ·The method integrates fish features into spatial-temporal sequences. • ·The method prevents data loss caused by fish school stacking. [ABSTRACT FROM AUTHOR]

Diatoms have long been thought to dominate the marine silicon (Si) cycle, as well as play an important role in the ocean's carbon (C) export, due to density-driven particle sedimentation. Research in the past decade has shed new light on the potential importance of picocyanobacteria to C export, although the sinking mechanism is still unclear. Interestingly, the recent discovery of Si accumulation by picocyanobacteria of the genus Synechococcu s has strong implications for the marine Si cycle, which may also have profound influence on the oceanic C export. Understanding the mechanisms of Synechococcus Si accumulation and its ecological effects are therefore critical for addressing wider issues such as Si and C exports by small cells via biological pump. Here, we show that recent advances in process studies indicate that the presence of Si within picocyanobacteria may be a common and universal feature. Subsequently, we generalize four biochemical forms of Si potentially present in picocyanobacterial cells, which are all different from diatomaceous opal-A, and hypothesize that these various structures of Si phases may be several stage products of Si precipitation. At the same time, several aspects of Si dynamics in Synechococcus are also discussed emphatically. In addition, we provide a first estimate of picocyanobacteria Si stock and production for the global ocean, accounting for 12% of the global Si inventory and 45% of the global annual Si production in the surface ocean, respectively. The implication is that picocyanobacteria may exert a significant influence on the marine Si cycle, which is likely to alter our understanding of the long-term control of the oceanic Si cycling by diatoms. Finally, we summarize three possible mechanisms and pathways through which picocyanobacteria-derived Si can be transported to the deep ocean. Altogether, marine picocyanobacteria, despite very small in cell size, are a non-negligible group for the export of biomineral Si to deeper waters and ocean sediments. • The presence of Si in picocyanobacteria may be a common feature. • Four biochemical forms of Si may be present in picocyanobacterial cells. • There are three pathways for picocyanobacteria transporting Si to the depth. • Picocyanobacteria exert a significant influence on the marine Si cycle. • Quantifying the Si and C export of picocyanobacteria are important in the future. [ABSTRACT FROM AUTHOR]

In this study, a novel visualization framework for fish behavior recognition based on Slowfast networks and spatial-temporal graph convolutional networks (ST-GCN) is proposed. The framework can directly recognize fish behaviors in continuous videos and classify fish states in cases of severe fish stacking. A self-constructed fish behavior dataset containing 10 single fish HD videos and 300 fish schooling video clips covering three action categories and two state categories was collected. The evaluation was performed on this behavioral dataset. The results show that the framework achieves accuracies of 95.00% and 88.61% for state recognition and action recognition, respectively, exceeding those of several benchmark methods. Robustness and generalization experiments, as well as fish feeding experiments, were also conducted to demonstrate the potential application of the framework for guiding smart feeding in real production activities. The framework provides a novel solution for fish behavior analysis in the visual domain and can be extended to other aquatic animals or scenarios. [Display omitted] • Proposed a novel framework for fish behavior recognition based on slowfast and ST-GCN. • Improved ST-GCN to make it suitable for fish. • Validated the framework on a self-built dataset covering five fish action and state categories. • Achieved high accuracy and robustness in individual and school fish scenarios. • Demonstrated the application potential of the framework in guiding intelligent feeding. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers were synthesized by gel–sol method with multi-walled carbon nanotubes as support and enrofloxacin as a template and further modified on the surface of glassy carbon electrode to construct a molecularly imprinted electrochemical sensor. The performance of the imprinted electrochemical sensor was thoroughly investigated by using cyclic voltammetry and differential pulse voltammetry. The influence of imprinted polymers amount, electrolyte pH, and incubation time on the sensor performance was investigated for the detection of enrofloxacin. Under the optimal experimental conditions in a three-electrode system with the modified electrode as the working electrode the differential pulse voltammetry response current of the sensor had a good linear relationship at 0.2 V (vs. saturated calomel reference electrode) with the enrofloxacin concentration within 2.8 pM–28 μM and the limit of detection of the method was 0.9 pM. The competitive interference experiment showed that the imprinted electrochemical sensor could selectively recognize enrofloxacin. The method was applied to analyze spiked natural seawater, fish, and shrimp samples. The recovery was 96.4%–102%, and RSD was less than 4.3% (n = 3), indicating that the proposed imprinted electrochemical sensor was suitable for the determination of trace enrofloxacin in marine environment samples. [ABSTRACT FROM AUTHOR]

Assessing the antimicrobial activity of engineered nanomaterials (ENMs), especially in realistic scenarios, is of great significance for both basic research and applications. Multiple analytical methods are available for analysis via off-line or on-line measurements. Real-world samples are often complex with inorganic and organic components, which complicates the measurements of microbial viability and/or metabolic activity. This article highlights the recent advances achieved in analytical methods including typical applications and specifics regarding their accuracy, cost, efficiency, and user-friendliness. Methodological drawbacks, technique gaps, and future perspectives are also discussed. This review aims to help researchers select suitable methods for gaining insight into antimicrobial activities of targeted ENMs in artificial and natural complex matrices. [ABSTRACT FROM AUTHOR]

Contradicting findings were observed when decadal changes of primary productivity in the eastern Chinese shelf sea were learnt through examination of sediment cores (Lv, 2007; Zhou, 2007; Jin, 2009; Zhao, 2010; Yang et al., 2012). This inconformity may imply the regional differences of decadal environmental changes in different types of seas. To verify the possible regional differences, we examined sediment cores collected in different types of seas in the eastern Chinese shelf sea. 210 Pb activity in the sediment was used to estimate sediment rate, while biogenic silica (BSi) was applied to indicate diatom paleoproductivity. And then the decadal change trends of diatom primary productivities (DPP) over the past 100 years in different areas were achieved. Subsequently, the differences in these DPP changes and the possible controlling mechanism were also discussed. Results reveal the presence of regional differences in DPP decadal changes in the eastern Chinese shelf sea. In all coastal seas, DPP followed similar trends before the 1980s; after the 1980s, DPP increased obviously in Shandong coastal waters where no large river mouth exists nearby, but decreased in the Yangtze River estuary. By contrast, in open waters, DPP in the past 100 years followed almost opposite trends against that in Shandong coastal waters. The differences in DPP changes between coastal and open sea areas before the 1980s could be attributed to the distinct influence mechanism of Pacific Decadal Oscillation (PDO) on DPP variation. However, the regional differences of DPP changes after the 1980s were probably attributed to the differences in influence type and intensity of human activities. Summarily, the disproportion of the influence of human activities and PDO could induce regional differences in DPP decadal changes in the Chinese shelf sea. These actual and probably general existences of regional differences prompt us to comprehensively assess long-term environmental changes in the complex shelf seas, rather than rebuild paleoenvironmental change patterns by using only one or limited sediment cores. [ABSTRACT FROM AUTHOR]

Microplastics pose a threat to marine environments through their physical presence and as vectors of chemical pollutants. However, the impact of microplastics on the accumulation and human health risk of chemical pollutants in marine organisms remains largely unknown. In this study, we investigated the microplastics and polycyclic aromatic hydrocarbons (PAHs) pollution in marine organisms from Sanggou Bay and analyzed their correlations. Results showed that microplastic and PAHs concentration ranged from 1.23 ± 0.23 to 5.77 ± 1.10 items/g, from 6.98 ± 0.45 to 15.07 ± 1.25 μg/kg, respectively. The microplastic abundance, particularly of fibers, transparent and color plastic debris, correlates strongly with PAH contents, indicating that microplastics increase the bioaccumulation of PAHs and microplastics with these characteristics have a significant vector effect on PAHs. Although consuming seafood from Sanggou Bay induce no carcinogenic risk from PAHs, the presence of microplastics in organisms can significantly increases incremental lifetime cancer risk of PAHs. Thus, microplastics can serve as transport vectors for PAHs with implications for the potential health risks to human through consumption. This study provides new insight into the risks of microplastics in marine environments. [Display omitted] • The microplastic and PAHs pollution in organisms from Sanggou Bay were investigated. • Notable correlation were observed between microplastic and PAHs contents in organisms. • The PAHs in organisms pose no cancer risk to humans based on the ILCR analysis. • The microplastic characteristics in organisms affect human health risks of PAHs. [ABSTRACT FROM AUTHOR]

Diatoms and dinoflagellates are two typical functional groups of phytoplankton assemblages, which play a crucial role in the structure and functioning of most marine ecosystems. To date, a novel challenge in ecology and biogeochemistry is to address the influences of environmental changes associated with climate change and human activities on the dynamics of diatoms and dinoflagellates. However, the knowledge of the key environmental factors controlling the diatom-dinoflagellate dynamics remains to be improved, particularly in the coastal ecosystems. Therefore, we conducted four cruises along the Qingdao coastline in spring, summer, autumn, and winter 2022 to explore how diatoms and dinoflagellates varied in response to regional environmental changes. The results showed that the phytoplankton communities were dominated by diatoms and dinoflagellates in terms of abundance and species diversity throughout the year in the study region. Yet, there were significant seasonal variability of diatoms and dinoflagellates across the four seasons. For example, diatom species was the most diverse during autumn, and the higher average abundance was observed in the fall and winter. In contrast, the average abundance of dinoflagellates was maximum during the summer and minimum in the autumn season. Moreover, the abundance and species ratios of diatoms/dinoflagellates (dia/dino) also showed significant seasonal variations in the region. The dia/dino abundance ratio was lowest in summer, while the dia/dino species ratio showed an increasing trend from spring to fall and a slight descending trend during winter. Based on the redundancy analysis, we revealed that diatoms and dinoflagellates responded differently to various environmental variables in different seasons, of which temperature and nutrients (especially dissolved inorganic nitrogen, DIN) had highly significant correlations with both the dia/dino abundance and species ratios. Thus, we suggested that temperature and DIN were the key factors controlling the seasonal dynamics of diatoms and dinoflagellates in the Qingdao coastal area. • The phytoplankton communities were dominated by diatoms and dinoflagellates in the study area. • There were significant seasonal variability of diatoms and dinoflagellates across the four seasons. • Temperature and DIN were the key affecting the seasonal dynamics of diatoms and dinoflagellates. [ABSTRACT FROM AUTHOR]

In this study, a novel sample pretreatment strategy of solid-phase microextraction using graphene oxide molecularly imprinted polymers as adsorbents coupled with high-performance liquid chromatography was developed to detect norfloxacin in the marine environment. As a carrier, the imprinted polymers were synthesized by precipitation polymerization with graphene oxide. Compared with graphene oxide non-imprinted polymers, the graphene oxide molecularly imprinted polymers exhibited higher adsorption capacity towards norfloxacin. The synthesized polymeric materials were packed into a molecularly imprinted solid-phase microextraction cartridge, and critical parameters affecting the extraction process were optimized. Under the optimized molecular imprinted solid-phase microextraction condition, the proposed method was applied to the analysis of norfloxacin for seawater and fish with satisfactory recovery (90.1–102.7%) and low relative standard deviation (2.06–5.29%, n = 3). The limit of detection was 0.15 μg L−1 and 0.10 μg kg−1 for seawater and fish, respectively. The study revealed that the proposed molecularly imprinted solid-phase microextraction represents an attractive sample pretreatment strategy for the analysis of norfloxacin in the marine environment. [ABSTRACT FROM AUTHOR]

Herein voltammetric behaviors of semicarbazide (SEM) are investigated by employing a graphene modified working electrode, which displays attractive electroanalytical properties. In the acetate buffer solution of pH 4.00, there is a well-defined oxidative peak of SEM, attributing to the irreversible and adsorption-controlled electrode reaction with 2 electrons participation. The values of apparent heterogeneous electron transfer rate constant k′s with the redox are 0.0061 s−1 and 0.0009 s−1, respectively, for two scan rate section. After the experimental parameters, which influence the voltammetric responses of SEM, including supporting electrolyte, pH, accumulation time and accumulation potential, etc., are optimized, it is found that the anodic peak current of SEM is proportional to its concentration in the range of 4 - 40 μmol/L with a detection limit of 1 μmol/L (S/N = 3). Then, an electrochemical method for detecting SEM quantitatively is developed successfully. The concentrations of SEM in fortified tap water samples are tested with satisfactory recovery, indicating that the novel method is strongly promising in the environmental monitoring application. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) is ubiquitous and widespread in natural water and influences the transformation and removal of antibiotics. Nevertheless, the influence of DOM molecular weight (MW) on the indirect photodegradation of antibiotics has rarely been reported. This study attempted to explore the influence of the molecular weight of DOM on the indirect photodegradation of two fluoroquinolone antibiotics (FQs), ofloxacin (OFL) and norfloxacin (NOR), by using UV–vis absorption and fluorescence spectroscopy. The results showed that indirect photodegradation was considered the main photodegradation pathway of FQs in DOM fractions. Triplet-state excited organic matter (3DOM*) and singlet oxygen (1O 2) were the main reactive intermediates (RIs) that affected the indirect photodegradation of FQs. The indirect photodegradation rate of FQs was significantly promoted in DOM fractions, especially in the low molecular weight DOM fractions (L-MW DOM, MW < 10 kDa). The results of excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC) showed that terrestrial humic-like substances had a higher humification degree and fluorophore content in L- MW DOM fractions, which could produce more 3DOM* and 1O 2 to promote the indirect photodegradation of FQs. This study provided new insight into the effects of DOM at the molecular weight level on the indirect photodegradation of antibiotics in natural water. [Display omitted] • The highest indirect photolysis rate was found in low molecular weight fractions. • 3DOM* and 1O 2 made more contribution to the FQs indirect photodegradation. • Terrestrial humic-like components contributed more to FQs indirect photolysis. • Low molecular weight DOM contained more terrestrial humic-like substances. [ABSTRACT FROM AUTHOR]

It is difficult to show microbial growth kinetics online when they grow in complex matrices. We presented a novel strategy to address this challenge by developing a high-performance microbial growth analyzer (HPMGA), which employed a unique 32-channel capacitively coupled contactless conductivity detector as a sensing element and fixed with a CellStatz software. It was capable of online showing accurate and repeatable growth curves of well-dispersed and bad-dispersed microbes, whether they grew in homogeneous simple culture broth or heterogeneous complex matrices. Moreover, it could automatically report key growth kinetics parameters. In comparison to optical density (OD), plate counting and broth microdilution (BMD) methods, we demonstrated its practicability in five scenarios: 1) the illustration of the growth, growth rate, and acceleration curves of Escherichia coli (E. coli); 2) the antimicrobial susceptibility testing (AST) of Oxacillin against Staphylococcus aureus (S. aureus); 3) the determination of Ag nanoparticle toxicity on Providencia rettgeri (P. rettgeri); 4) the characterization of milk fermentation; and 5) the enumeration of viable pathogenic Vibrio in shrimp body. Results highlighted that the HPMGA method had the advantages of universality and effectivity. This technology would significantly facilitate the routine analysis of microbial growth in many fields (biology, medicine, clinic, life, food, environment, and ecology), paving an avenue for microbiologists to achieve research goals that have been inhibited for years due to a lack of practical analytical methods. Based on a unique 32-channel capacitively coupled contactless conductivity detector and novel algorithms, the high-performance microbial growth analyzer (HPMGA) was capable of online showing the growth curves of well-dispersed and bad-dispersed microorganisms (e.g. E. coli , S. aureus , L. bulgaricus , P. rettgeri , and pathogenic Vibrio (flora)), whether they grew in homogeneous simple culture broth or heterogeneous complex matrices (e.g. blood, sewage sludge, milk, and shrimp bodies). Moreover, it could decompose the growth curves into growth rate and growth acceleration curves, and report key growth kinetics parameters. [Display omitted] [ABSTRACT FROM AUTHOR]

User-friendly phenotypic antibiotic susceptibility testing (AST) methods are urgently needed in many fields including clinical medicine, epidemiological studies and drug research. Herein, we report a convenient and cost-effective phenotypic AST method based on online monitoring bacterial growth with a developed 8-channel contactless conductometric sensor (CCS). Using E. coli and V. parahaemolyticus as microorganism models, as well as enoxacin, florfenicol, ampicillin, kanamycin and sulfadiazine as antibiotic probes. The minimum inhibitory concentration (MIC) determination was validated in comparison with standard broth microdilution (BMD) assay. The total essential agreements between the CCS AST assays and the reference BMD AST assays are 68.8–92.3%. The CCS has an approximate price of $9,000 (USD). Requiring neither chemical nor biotic auxiliary materials for the assay makes the cost of each sample < $1. The MICs obtained with the automated CCS AST assays are more precise than those obtained with the manual BMD. Moreover, in 72 percent of the counterpart, the MICs obtained with the CCS AST assays are higher than that obtained with the BMD AST assays. The proposed CCS AST method has advantages in affordability, accuracy, sensitivity and user-friendliness. [ABSTRACT FROM AUTHOR]

A method is described to determine viable populations of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The method employs aptamer-magnetic separation combined with resistivity based detection. The bacteria were separated by means of aptamer-functionalized magnetic beads. They were then quantified by measuring their growth kinetics through time-dependent conductivity changes of culture media. The time-course of growth was logged by real-time and contactless measurements that yielded starting concentrations from the duration of lag intervals prior to the log phase of growth. In pure water samples, the linear ranges for measuring E. coli and S. aureus cells are 2.5 × 103–2.5 × 108 CFU·mL−1 and 4.1 × 103–4.1 × 108 CFU·mL−1, respectively. In spiked tap water samples, the lower limits of detection are 2.3 × 104 CFU·mL−1 and 4.0 × 103 CFU·mL−1 for E. coli and S. aureus, with recoveries of 87.0–108.7% and 92.5–105.0%, respectively. The relative standard deviation of these measurements (10.0%) is below that of plate counting method (13.9%). The presence of micro/nanoparticles such as magnetic beads or selenium nanoparticles in the culture media does not interfere, unlike in case of automatted optical density monitoring. The E. coli and S. aureus cells captured on the aptamer-functionalized magnetic beads can be directly tested for their susceptibility to antibiotics. The process of magnetic separation and determination of load burden requires neither bulky, sophisticated equipment nor expensive reagents. [ABSTRACT FROM AUTHOR]

Understanding the feeding selectivity on phytoplankton by shellfish is currently a big challenge. In order to investigate the feeding behavior of bay scallop (Argopecten irradians) on phytoplankton, we compared its compositions of phytopigments in digestive glands with those in the surrounding seawater, and conducted five consecutive investigations between July and November 2016 in a bay scallop culture area along coast of Qinghuangdao City, northwest of the Bohai Sea, China. Phytopigments in four-size fractionated phytoplankton of seawater (micro- (20–200 µm); nano(L)-[10–20 µm]; nano(S)-[2.7–10 µm], and pico-[<2.7 µm]) and digestive glands of A. irradians were examined to investigate the selective feeding of A. irradians. Results show that fucoxanthin and peridinin constituted the major part of taxonomically diagnostic carotenoids (TDCs) in the micro- and nano(L)-phytoplankton in seawater. Compared with total phytoplankton biomass of seawater (TPB, sum of the four sizes), a substantial decrease of fucoxanthin proportion to total DCs in digestive glands was observed while that of peridinin, 19′-butanoyloxyfucoxanthin, alloxanthin and 19′-hexanoyloxy-fucoxanthin showed an obvious increase when those pigments were mainly confined to micro-sized phytoplankton (20–200 µm). However, zeaxanthin and prasinoxanthin were mainly confined to nano(s)- and pico-phytoplankton, of which the proportions in digestive glands were usually lower in TPB. The contribution of lutein to total DCs in digestive glands (with an average of 7.23%) increased compared with TPB of seawater (with an average of 0.63%) during all five sampling times. [ABSTRACT FROM AUTHOR]

Monitoring the ingestion of microplastics by fish in the environment is crucial to understanding the risks posed by microplastics in the marine ecosystem. In this study, we investigated the ingestion of microplastics in deep-sea fish from the northern continental slope of the South China Sea. All fish samples were contaminated by microplastics, reflecting a high level of microplastic pollution in this region. The average abundance of microplastics in the stomachs of sampled fish was 1.96 ± 1.12 items/individual and 1.53 ± 1.08 items/g, and levels in the intestines of sampled fish were 1.77 ± 0.73 items/individual and 4.82 ± 4.74 items/g. Fish were collected from depths of 200 to 209 m and 453 to 478 m, and no significant difference in the quantity of microplastics ingested was detected among different depths in this range. The microplastics ingested by fish were dominated by plastics that were <1 mm in size, film-like in shape, transparent in color and composed of cellophane. Our results suggest that the ingestion of microplastics by fish is closely related with the microplastic pollution in the marine environment. Unlabelled Image • This is the first report on microplastic ingestion in deep-sea fish from South China Sea. • All sampled fish from the South China were contaminated by microplastics. • The seafloor habitats of the South China Sea may be a sink for microplastics. • Microplastic ingestion by fish is closely related with environmental plastic pollution. [ABSTRACT FROM AUTHOR]

• The geographic distribution of tri-trophic-level biomass is heterogeneous; • Contrasting currents drive geographic variability in tri-trophic-level biomass; • The top-down effects by zooplankton or Pacific saury can not cascade down to the phytoplankton. Exploring the biomass relationships among fish, zooplankton, and phytoplankton and the potential mechanisms that drive changes in their biomass are important for us to understand the structure and dynamics of aquatic ecosystems. In this study, we thus measured the biomass of planktivorous Pacific saury (Cololabis saira), zooplankton, and phytoplankton in the less-explored northwestern Pacific to illustrate their biomass relationships, and to explore underlying mechanisms driving the spatial patterns of biomass for these trophic organisms. Our results showed that the sampling area could be divided into the Kuroshio-driven low-nutrient and high-chlorophyll region (i.e, LNHC) and the Oyashio-driven high-nutrient and low-chlorophyll region (i.e, HNLC). In the LNHC, the phytoplankton biomass was on average threefold higher than that in the HNLC. By contrast, the biomass of zooplankton in the LNHC was averagely twofold lower than that in the HNLC. Differently, the average stock of Pacific saury in the LNHC was generally consistent with that in the HNLC. Apart from the positive correlation between zooplankton biomass and the stocks of Pacific saury, there were no linear relationships of biomass across the three organisms. The implication is that the top-down effects by zooplankton grazing or Pacific saury feeding are unlikely to cascade further down to the phytoplankton biomass in the northwestern Pacific. Based on the canonical correspondence analysis, we found that the biomass of Pacific saury, zooplankton, and phytoplankton between HNLC and LNHC responded differently to specific environmental factors (e.g., temperature, salinity, and nutrients), indicating that the contrasting Oyashio and Kuroshio currents had an impact on the geographic variation of the biomass for these organisms. Altogether, our findings provide insights into the biomass relationships among Pacific saury, zooplankton, and phytoplankton, and the researches for the dynamics of these trophic organisms in marine ecosystems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ozonation could effectively eliminate fluoroquinolones (FQs) present in sludge. • Increasing initial pH favored FQ removal during sludge ozone-reduction (SOR). • The SOR process achieved zero yield of excess sludge with stable COD and N removals. • The total FQ input was removed by 75.8 ± 2.0% in the SOR process. Abstract To date, little is known about the removal of fluoroquinolones (FQs) in the in-situ sludge ozone-reduction (SOR) process. Hence, this study investigated the behavior of five commonly used FQs, including ciprofloxacin, enrofloxacin, lomefloxacin, norfloxacin and ofloxacin in the SOR process. Batch experiments indicated that ozonation could effectively eliminate the target FQs present in the sludge, which was accelerated by increasing the initial pH (5.0–9.5). Continuous operation of an anaerobic/anoxic/oxic process coupled with sludge ozonation and phosphorus recovery showed that the SOR process could achieve zero yield of excess sludge. In addition, chemical oxygen demand and nitrogen species were stably removed, with efficiencies comparable to those obtained in the conventional activated sludge (CAS) process. However, an increase in the effluent total phosphorus concentration was observed in the SOR process. The effluent FQ concentrations in the SOR process remained quite stable and were close to those in the CAS process, whereas the FQ concentrations in the sludge decreased remarkably after ozonation. Mass balance analysis revealed that the FQs were released to the environment mainly through excess sludge disposal (69.9 ± 2.3%) in the CAS process, whereas were degraded mainly by ozone in the SOR process (75.8 ± 2.0%). Therefore, the SOR process was able to minimize the excess sludge and the release of FQs to the environment simultaneously. [ABSTRACT FROM AUTHOR]

• High-throughput C4D is used to monitor multichannel titrations. • Portable and affordable electronic sensor-based titrator is developed. • Simple and efficient measurements could be realized. Analytical chemists require multichannel and automatic tools for batch measurements. Herein, an eight-channel electronic titrator (8-CET) system was constructed to facilitate high-throughput titrations. In this system, multichannel piston pumps were used for delivery, and an 8-channel capacitively coupled contactless conductivity detector (8-C4D) was used to monitor the conductivity of the titration solutions in arrays of disposable reaction cells. The delivery and the monitoring were both fully software-controlled allowing a simultaneous formation of eight titration curves. Its capacity for classical acid-base and precipitation titration was characterized with satisfactory results. It was also used to measure the content of CH 3 COOH in batched vinegar samples. The RSD between each reaction cell was 1.9%. There are two outstanding features of this new system: 1) Up to eight samples can be measured simultaneously; and 2) simple operation is realized by avoiding electrode switching and cleaning after each measurement. Therefore, it is reasonable to believe that this 8-CET system is a prospective alternative for developing more automatic and efficient titration platforms. [ABSTRACT FROM AUTHOR]

Abstract Understanding the characteristics of microbial growth is of great significance to many fields including in scientific research, the food industry, health care, and agriculture. Many methods have been established to characterize the process of microbial growth. Online and automated methods, in which sample transfer is avoided, are popular because they can facilitate the development of simple, safe, and effective growth monitoring. This review focuses on advances in online monitoring methods over the last decade (2008–2018). We specifically focus on optic- and electrochemistry-based techniques, either through contact measurements or contactless measurement. Strengths and weaknesses of each set of methods are described and we also speculate on forthcoming trends in the field. Highlights • Advances in online methods for monitoring microbial growth over the last decade are reviewed. • Optic- and electrochemistry-based techniques are specifically focused on. • Strengths and weaknesses of each set of methods are described. • Forthcoming trends in the field are speculated. [ABSTRACT FROM AUTHOR]

Abstract The environmental impacts of mariculture in large scale have attracted worldwide attention. Identifying the sources of sedimentary organic matter plays a key role in elucidating the environmental impacts of the mariculture. In this study, surface sediments of the Sanggou Bay were sampled in October 2014, as well as March, May and August 2015 for grain size, total organic carbon, total nitrogen and stable carbon and nitrogen isotope (δ13C and δ15N) analyses. Results showed that silt was the primary fraction in mariculture areas, and the grain size distribution was closely related with mariculture and hydrodynamic conditions. A significant positive correlation (r = 0.97, p < 0.001) between total organic carbon and total nitrogen indicated that they were homologous. According to the combined analysis of δ13C and C/N, the main source of sedimentary organic matter was shellfish deposition, kelp and soil organic matter. Using a three-end-member mixed model, the contribution rates of shellfish biodeposition, soil organic matter and kelp were found to be 48.53% > 37.44% > 14.03%, respectively. These results highlighted the significant impact of shellfish biodeposition on the benthic environments. Graphical abstract fx1 Highlights • Mariculture and hydrodynamic conditions were responsible for sedimentary grain size. • Total organic carbon was significantly correlated with median grain size. • Total organic carbon and total nitrogen were homologous in surface sediments. • Shellfish deposition was dominant source of sedimentary organic matter in Sanggou Bay. [ABSTRACT FROM AUTHOR]

Nano- and microplastics have been shown to cause negative effects on marine organisms. However, the toxicities of nano- and microplastics toward marine bacteria are poorly understood. In this study, we investigated the toxic effects of polystyrene nano- and microplastics on the marine bacterium Halomonas alkaliphila by determining growth inhibition, chemical composition, inorganic nitrogen conversion efficiencies and reactive oxygen species (ROS) generation. The results showed that both nano- and microplastics inhibited the growth of H. alkaliphila in high concentrations, while nanoplastics rather than microplastics influenced the growth inhibition, chemical composition and ammonia conversion efficiencies of H. alkaliphila at concentration of 80 mg/L. The ROS generation indicated oxidative stress induced by nano- but not microplastics, and the oxidative stress induced by nanoplastics may provide a significant effect on bacteria. Furthermore, the positively charged nanoplastics (amine-modified 50 nm) induced higher oxidative stress toward bacteria than that induced by negatively charged nanoplastics (non-modified 55 nm). The increased extracellular polymeric substances as evidenced by transmission electron microscope (TEM) observation suggested the possible bacterial protective mechanisms. The present study illustrates for the first time the impact of plastics debris on the inorganic nitrogen conversion efficiencies of marine bacteria. Our findings highlight the effects of microplastics on the ecological function of marine organisms. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Microplastics reduced feeding activity and enhanced the shoaling behavior of jacopever. • Microplastics clearly decreased swimming and exploration ability of jacopever. • Polystyrene microplastics accumulated in gill and intestine of jacopever. • Accumulated microplastics significantly damaged gallbladder and liver of jacopever. • Microplastics reduced growth, energy reserve and nutrient quality of jacopever. Abstract Uptake and toxicity of microplastics on marine organisms have been reported elsewhere. However, there is limited knowledge regarding the ecological effects of microplastics on marine organisms. In this study, we investigated the effects of polystyrene microplastics (1 × 106 microspheres per L) on the behavior, energy reserve and nutritional composition of juvenile jacopever (Sebastes schlegelii). Compared to the controls, fish treated by microplastics showed lower sensitivity toward the added food in the tank, and increased foraging time, indicating that microplastics significantly weakened feeding activity of the fish. Interestingly, the microplastics treated-fish obviously reduced swimming speed and range of movement, demonstrating that polystyrene microplastics could have negative effect on hunting behavior. Furthermore, polystyrene microplastics accumulated in the gills and intestine, causing significant histopathological changes in the gallbladder and liver. Moreover, the energy reserve and nutritional quality of fish were influenced by microplastics as evidenced by lower growth, protein and lipid contents. Our results highlighted the potential negative effects of microplastics on marine ecological function and food safety. [ABSTRACT FROM AUTHOR]

Microplastics are emerging contaminants and have attracted widespread environmental concerns about their negative effects on the marine ecosystems. In this study, we investigated the abundances, distributions and characteristics of microplastics in surface seawater and sediments from the North Yellow Sea. The results showed that the abundance of microplastics was 545 ± 282 items/m 3 in surface seawater and 37.1 ± 42.7 items/kg dry weight in sediments, representing a medium microplastic pollution level compared with other sea areas. Small microplastics (<1 mm) made up >70% of the total microplastic numbers. Films and fibers were the dominant shapes of microplastics in both the surface seawater and sediments. Transparent microplastics were generally more common than microplastics of other colors. Based on the identification by a Fourier transform infrared microscope, polyethylene (PE) was the dominant composition of microplastics in surface seawater, while polypropylene (PP) was the most common polymer type in sediments. These results will improve our understanding of the environmental risks posed by microplastics to marine ecosystems. [ABSTRACT FROM AUTHOR]

The indirect photodegradation behaviors of acetaminophen (APAP) were investigated in the presence of four kinds of dissolved organic matter (DOM) and were also assessed in the presence of seawater components and conditions such as salinity, pH, nitrate and bicarbonate. The results showed three important findings: firstly, in the indirect photolysis of APAP, the contributions of 3 DOM*, ·OH and 1 O 2 were >85.0%, 2.3–9.9% and 0.8–2.6% at pH 8.0. Secondly, DOM was divided into four terrestrial humic-like components by Excitation–emission matrix spectroscopy (EEMs) combined with parallel factor analysis (PARAFAC). This study showed a good linearity between DOM fluorescence components and the indirect photodegradation of APAP (R 2  = 0.92) and the differences in photodegradation rates of APAP among various DOM solutions were due to the diverse compositions of DOM. Finally, salinity was an important factor influencing the removal of APAP, and the APAP photodegradation rate constants increased from (3.33 ± 0.07) × 10 −5 s −1 to (1.25 ± 0.05) × 10 −4 s −1 with increasing salinity. The increased pseudo-first-order rate constants for photolysis of APAP with increasing salinity, pH and nitrate were attributed to the enhanced generation of reactive intermediates (RI) and easier reactions between RI and APAP. The increased APAP removal rate constant with increasing bicarbonate was likely ascribed to the yield of ∙ CO 3 − . This is the first report of the roles of DOM components and salinity on the indirect photolysis of APAP. These findings would be essential to predict the photochemical fate of APAP and would also allow for a better understanding of the environmental fate of other phenolic contaminants. [ABSTRACT FROM AUTHOR]

Concerns are raised towards individual effects of ocean acidification (OA) and engineered nanoparticles (NPs) on marine organisms. However, there are scarce studies regarding nanotoxicity under OA conditions. We investigated the combined effects of OA (pHs, 7.70 and 7.40) and CuO NPs on the embryotoxicity of marine medaka Oryzias melastigma and the bioavailability of CuO NPs in embryos. The results showed that OA alleviated the aggregation of CuO NPs and promoted the dissolution of CuO NPs in seawater (increased by 0.010 and 0.029 mg/L under pHs 7.70 and 7.40, respectively). Synergistic effects of OA with CuO NPs on medaka embryos were observed as indicated by much higher mortality and oxidative damage. Importantly, the enhanced toxicity of CuO NPs to medaka embryos under OA conditions mainly originated from the higher bioavailability of particulate CuO (e.g., 30.28 mg/kg at pH 7.40) rather than their released Cu2+ ions (e.g. 3.04 mg/kg at pH 7.40). The weaker aggregation of NPs under OA conditions resulted in higher penetration of individual particles (or small aggregates) into embryos through the micropyle and chorionic pores, causing enhanced bioavailability of NPs. The obtained results provided underlying insights into understanding the risk of NPs to marine ecosystem under OA conditions. [Display omitted] • OA enhanced the toxicity of CuO NPs to medaka embryos. • Synergistic effects of OA with NPs were observed on mortality and oxidative damage. • Enhanced toxicity derived from higher bioavailability of CuO particles rather than ions. • Higher penetration of NPs into embryos was due to their weaker aggregation under OA conditions. [ABSTRACT FROM AUTHOR]

Aquaculture has great potential to feed and nourish the world's growing population. However, the aquaculture products often increase at the expense of the environment. Sustainable aquaculture development is crucial to meeting the growing demand for aquatic food. Recirculating aquaculture system (RAS) is a green and sustainable aquaculture mode, which are not only increase the farm yield, but also significantly decrease the negative impact on the environment. Due to feed addition and excretion of aquaculture organisms, hazardous substances such as particulate matters, ammonia, nitrite and nitrate will accumulate in RAS and endanger the safety of reared organisms, resulting in adverse effects on the operation and production of the system. The water treatment unit of RAS plays a key role in ensuring optimal growth conditions for farmed organisms by filtering or degrading pollutants from aquaculture tail water and recycling the purified water, saving natural resources to a significant extent. Pollutants produced from the RAS farming (particulate matters, nitrogen pollutants, phosphate, carbon dioxide, antibiotics, steroids, heavy metals, etc.) and the hazards posed are reviewed, and the corresponding water treatment processes are summarized, and relevant suggestions are proposed, providing the theoretical basis for the stable operation of the RAS, system optimization and wider application. [Display omitted] • Main hazardous substances in recirculating aquaculture are excess particles, N, P. • Bioreactors such as FSBs, MBBRs and BFTs are recommended to remove N pollutants. • Foam separator, protein skimmer, ozone can effectively remove micro particles. • Biological methods such as EBPR, MBR are suitable for phosphorus removal. • Disinfection unit (UV, peracetic acid, O 3) can remove antibiotics, ARGs and steroid. [ABSTRACT FROM AUTHOR]

Concerns about the environmental effects of engineered nanoparticles (NPs) on marine ecosystems are increasing. Meanwhile, ocean acidification (OA) has become a global environmental problem. However, the combined effects of NPs and OA on marine organisms are still not well understood. In this study, we investigated the effects of OA (pH values of 7.77 and 7.47) on the bioavailability and toxicity of TiO 2 NPs to the marine microalga Chlorella vulgaris . The results showed that OA enhanced the growth inhibition of algal cells caused by TiO 2 NPs. We observed synergistic interactive effects of pH and TiO 2 NPs on oxidative stress, indicating that OA significantly increased the oxidative damage of TiO 2 NPs on the algal cells. Importantly, the elevated toxicity of TiO 2 NPs associated with OA could be explained by the enhanced internalization of NPs in algal cells, which was attributed to the slighter aggregation and more suspended particles in acidified seawater. Overall, these findings provide useful information on marine environmental risk assessments of NPs under near future OA conditions. [ABSTRACT FROM AUTHOR]

Herein, an approach for versatile titration by monitoring the chemical reaction process with a developed capacitively coupled contactless conductivity detector (C 4 D) was developed. A disposable glass reaction cell, in which sub-milliliter titrand was loaded, was inserted into the working head stage of the C 4 D. Upon addition of titrant, the ionic strength and/or mobility of components in the solution changed, causing consequently change of conductivity. The C 4 D monitored the change in real time. A V-shaped titration curve was gained, allowing an easy identification of the endpoint. Between the elapsed time and the initial concentration of titrand, linear relationships were found for classical acid-base, precipitation, complexation and redox reaction over certain ranges, enabling the establishment of quantitative determinations. The new approach had a few charming advantages (e.g. simplicity and cost effectiveness) over contact electrochemical methods because that the solution was isolated from the working electrodes. Therefore, a development of versatile and multifunctional platform for micro-titrations is promising. [ABSTRACT FROM AUTHOR]

Phytoplankton pigment concentrations in the surface sediments of a fish and oyster farm in Dapeng Cove, South China Sea, were measured monthly to investigate the effects of mariculture on the environment from December 2011 to December 2012. The highest contents of the identified phytopigments, sulphides and total organic carbon in the surface sediments were all found at the fish farm, followed by the oyster farm; the lowest contents were detected at the control site. Fucoxanthin in the surface sediments was the most abundant carotenoid and was significantly correlated with chlorophyll a (Chl a; r = 0.922, P < 0.01). This finding suggested that the deposited diatoms could be the main source of the Chl a concentration. Besides a differential sedimentation of phytoplankton (i.e. higher downflux at fish and oyster site than that at control site), we assume that the extent of pigment diminution from the fish site to control site was also controlled by the chemical conditions of the surface sediments. The fish farm provided the most optimum preservation conditions for the phytopigments and was a good sink for phytodetritus among the three sites because of its anoxic and reductive characteristics. Phytoplankton pigments could be useful biomarkers to evaluate the influence of mariculture on sediment environment. [ABSTRACT FROM AUTHOR]

Manufactured nanoparticles (NPs) have caused extensive concern about their toxic effects on the marine environment. However, the chronic toxicity of NPs at predicted environmental relevant concentration on the marine organisms is poorly understood. In this study, we investigated the oxidative stress, neurotoxicity and histopathological effects of TiO 2 NPs at predicted environmental relevant concentration (1 mg/L) to marine scallop Chlamys farreri . The results showed that TiO 2 NPs caused obviously oxidative damage on the scallops as evidenced by the significantly elevated superoxide dismutase (SOD), catalase (CAT) activities and malondialdehyde (MDA) contents. The increased acetylcholine esterase (AChE) activities reflected neurotoxicity of TiO 2 NPs. The histopathological analysis revealed alterations in the gill and digestive gland, such as dysplastic and necrosis. Additionally, integrated biomarker response (IBR) values indicated that TiO 2 NPs can cause strong toxic effects on the scallop. These results suggested that predicted environmental relevant TiO 2 NPs can cause adverse effects on scallops and IBR analysis can be used as an effective approach for risk assessment of NPs on the marine organisms. [ABSTRACT FROM AUTHOR]

Marine plankton are faced with novel challenges associated with environmental changes such as ocean acidification, warming, and eutrophication. However, data on the effects of simultaneous environmental changes on complex natural communities in coastal ecosystems are relatively limited. Here we made a systematic analysis of biological and environmental parameters in the Bohai Sea over the past three years to suggest that plankton communities responded differently to current changing coastal environments, with the increase of phytoplankton and the decrease of zooplankton. These different changes of phyto- and zooplankton potentially resulted from the fact that both the effect of acidification as a result of pH decline and the effect of warming as a consequence of increasing temperature favored phytoplankton over zooplankton at present. Furthermore, water eutrophication and salinity as well as heavy metals Hg, Zn, and As had more or less diverse consequences for the dynamics of phytoplankton and zooplankton. Differently, with ongoing climate change, we also revealed that both phytoplankton and zooplankton would decrease in the future under the influence of interactions between acidification and warming. • Plankton responded differently to current changing coastal environments. • Current coastal environments benefit phytoplankton but harm zooplankton. • Plankton would decrease under future acidification and warming. [ABSTRACT FROM AUTHOR]

Marine picophytoplankton (<2 μm) are the most abundant photosynthetic group and also important contributors to global primary production. However, it is still constrained to incorporate picophytoplankton into dynamic ecosystem models, as a result of our limited understanding of their global distribution and abundance. Here, we applied a large dataset consisted of 1817 in situ observations from the Yellow Sea, Indian Ocean, and Pacific Ocean to suggest that picophytoplankton abundance and distribution had a large variability among the three distinct regions. Based on the correlation analysis, aggregated boosted tree analysis, and generalized additive model, we proposed that water temperature and dissolved inorganic nitrogen (N) were key determinants in driving the large-scale variability of marine picophytoplankton. For example, we revealed that high temperature and low N would stimulate the growth of Prochlorococcus. Therefore, these results could provide some insights into the various environmental factors which affect the dynamics of picophytoplankton, as well as the dynamic ecosystem models. • Picophytoplankton had a large variability among the three distinct regions. • Prochlorococcus was absent in the Yellow Sea but dominated in the open oceans. • Synechococcus and picoeukaryotes had a wider geographical distribution. • Temperature and nitrogen were key determinants for picophytoplankton dynamics. [ABSTRACT FROM AUTHOR]

Marine picophytoplankton (<2 μm) are the most abundant photosynthetic group and also important contributors to global primary production. However, it is still constrained to incorporate picophytoplankton into dynamic ecosystem models, as a result of our limited understanding of their global distribution and abundance. Here, we applied a large dataset consisted of 1817 in situ observations from the Yellow Sea, Indian Ocean, and Pacific Ocean to suggest that picophytoplankton abundance and distribution had a large variability among the three distinct regions. Based on the correlation analysis, aggregated boosted tree analysis, and generalized additive model, we proposed that water temperature and dissolved inorganic nitrogen (N) were key determinants in driving the large-scale variability of marine picophytoplankton. For example, we revealed that high temperature and low N would stimulate the growth of Prochlorococcus. Therefore, these results could provide some insights into the various environmental factors which affect the dynamics of picophytoplankton, as well as the dynamic ecosystem models. • Picophytoplankton had a large variability among the three distinct regions. • Prochlorococcus was absent in the Yellow Sea but dominated in the open oceans. • Synechococcus and picoeukaryotes had a wider geographical distribution. • Temperature and nitrogen were key determinants for picophytoplankton dynamics. [ABSTRACT FROM AUTHOR]

The toxicity of TiO 2 engineered nanoparticles (NPs) to the marine microalga Nitzschia closterium was investigated by examining growth inhibition, oxidative stress and uptake. The results indicated that the toxicity of TiO 2 particles to algal cells significantly increased with decreasing nominal particle size, which was evidenced by the 96 EC 50 values of 88.78, 118.80 and 179.05 mg/L for 21 nm, 60 nm and 400 nm TiO 2 particles, respectively. The growth rate was significantly inhibited when the alga was exposed to 5 mg/L TiO 2 NPs (21 nm). Measurements of antioxidant enzyme activities showed that superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities were first induced and subsequently inhibited following exposure to 5 mg/L TiO 2 NPs. The depletion of antioxidant enzymes with a concomitant increase in malondialdehyde (MDA) levels and reactive oxygen species (ROS) posed a hazard to membrane integrity. A combination of flow cytometry analysis, transmission electron microscopy and Ti content measurement indicated that TiO 2 NPs were internalized in N. closterium cells. The level of extracellular ROS, which was induced by TiO 2 NPs under visible light, was negligible when compared with the intracellular ROS level (accounting for less than 6.0% of the total ROS level). These findings suggest that elevated TiO 2 nanotoxicity in marine environments is related to increased ROS levels caused by internalization of TiO 2 NPs. [ABSTRACT FROM AUTHOR]

Irregular-shaped and partially degraded secondary microplastics (SMP) account for the majority of MPs in marine environments, yet little is known about their effects on marine organisms. In this study, we investigated the embryotoxicity of polyvinyl chloride SMP and primary microplastics (PMP) to the marine medaka Oryzias melastigma. This study aimed to determine the physical impacts of MPs and, for the first time, elucidate the underlying mechanisms of physical toxicity. SMP shortened hatching time and induced higher teratogenic effects on larvae relative to PMP, indicating a higher toxicity from SMP. Physical damage from SMP to the chorion surface appears to be the main toxicity mechanism, caused by their irregular shape and reduced aggregation relative to PMP. In contrast, real-time changes in oxygen demonstrated that hypoxia caused by greater PMP adsorption to the chorion surface contributes to the toxicological responses of this material relative to SMP. Modulation of genes involved in hypoxia-response, cardiac development and hatching confirmed the toxicity mechanisms of PMP and SMP. The chemical contribution to observed toxicity was negligible, confirming impacts derived from physical toxicity. Our findings highlight the negative effects of environmentally relevant SMP on the marine ecosystems. [Display omitted] • PVC SMP cause higher toxicity to Oryzias melastigma embryos than PVC PMP. • Plastic-associated chemicals were not found to contribute to observed toxicity. • Physical damage is the main mechanism of toxicity for the irregular-shaped SMP. • Hypoxia caused by particle adsorption to the chorion contributed to PMP toxicity. • Modulation of embryonic development-related genes confirmed the toxicity mechanisms. [ABSTRACT FROM AUTHOR]

The electrochemical behavior of calcein (CA) has been investigated by using a conductive carbon black paste electrode (CCBPE) as working electrode. It exhibits a single well-defined redox peak in phosphate buffered saline in the range of pH 5.5-8.0, which attributes to the irreversible oxidation with 2 electrons and 2 protons participation. Under the optimized analytical conditions, the proposed linear sweep voltammetry (LSV) method allows the determination of CA in a linear concentration range of 0.64-9.60 µM, with a limit of detection of 0.32 µM. Further, the interaction between CA and DNA were studied by voltammetric and spectrometric methods. Both studies have shown that CA can bind to DNA by the intercalation binding mode. Under the present experimental condition, the binding constant β of CA and dsDNA is 1.10×107. Meanwhile, in the loop-mediated isothermal amplification (LAMP) reaction mixture there is obvious interaction between CA and dsDNA, resulting in a nonignorable decrease of the indicating sensitivity. [ABSTRACT FROM AUTHOR]

The lack of analytical strategies to directly determine the bacteriostatic activity of nanomaterials in complex aqueous media (e.g., environmentally relevant scenarios) seriously hampers the harvest of reliable data for nanomaterial risk assessment. Here, we created an automated phenotypic method based on a developed multi-channel contactless conductometric sensor. Bacterial growth kinetics of E. coli and S. aureus were determined via on-line monitoring of conductivity changes in simple media (e.g., liquid LB broth) and complex media (e.g., relevant river water and seawater samples with diverse pH, salinity, conductivity, turbidity, chemical oxygen demand and total suspended solids). The high temporal resolution growth curves provide detailed information on the bacteria inhibition of the model nanomaterial - Au nanospheres, Au nanorods, Ag nanospheres and Ag nanocubes - at each growth stage, thus enabling users to directly obtain minimum inhibitory concentrations. The method highlights the advantages of universality, simplicity and affordability. It opens up possibilities for the development of a powerful analytical platform for researches in the field of nanoscience, e.g. to assess ecotoxicity of nanomaterials. [Display omitted] ● The developed multi-channel contactless conductometric sensor has wide working window. ● High temporal resolution growth curves of E. coli and S. aureus are generated with the contactless conductometric sensor. ● Growth curves provide detailed information on the bacteria inhibition of diverse nanomaterials. ● Automated determination of accurate bacteriostatic activity is realized in both simple and complex aqueous media. [ABSTRACT FROM AUTHOR]

Microplastic (MP) pollution is attracting growing global attention, but little is known about the factors influencing MP occurrence and distributions in marine sediments. Here, MPs were sampled from the sediments of two semi-enclosed bays (Jinghai Bay and Laizhou Bay) and two coastal open zones (Lancelet Reserve and Solen grandis Reserve) in China. The order of MP abundance was Jinghai Bay > Laizhou Bay > Lancelet Reserve > Solen grandis Reserve. Average MP diversity indices for Laizhou Bay (1.84 ± 0.18), Lancelet Reserve (1.59 ± 0.43), S. grandis Reserve (1.58 ± 0.89), and Jinghai Bay (1.43 ± 0.14) revealed Laizhou Bay had the most complicated MP sources. A significant negative correlation between MP abundance and sediment grain size occurred in the semi-enclosed coastal zones (p = 0.004, r = −0.618) rather than in the open coastal zones (p = 0.051, r = −0.480), indicating small sediment particles can strongly enhance MP accumulation in semi-enclosed costal sediments. Although anthropogenic activities influence the MP distribution at source, the composition of regional and local sediments might impact MP occurrence in semi-enclosed coastal zones from the sink. These results help to improve our understanding of the fate and inventory of MPs in coastal sediments. [Display omitted] • Small sediment particle can enhance MP accumulation in semi-enclosed costal sediments. • Coastal zones with low diversity and high abundance of MPs deserve more attention. • Shannon Weaver Index is a good indicator to reflect the diversity of marine MPs. • Both anthropogenic activities and sediments composition influence the MP distribution. [ABSTRACT FROM AUTHOR]

Loop-mediated isothermal amplification (LAMP) yields a large amount of DNA, as well as magnesium pyrophosphate precipitate, causing a decrease in ionic strength that can be measured with a conductivity meter. There is a clear relationship between the conductivity of the LAMP mixture solution and the duration of biochemical reaction. Moreover, there is also a clear relationship between the change in conductivity and the amount of initial template DNA over the range of 0.08 to 3.2 ng. These results demonstrate the feasibility not only for detecting the LAMP product qualitatively but also for real-time monitoring the biochemical reaction progression quantitatively using conductivity measurements. [ABSTRACT FROM AUTHOR]

The cytochrome cd1-containing nitrite reductase, nirS, plays an important role in biological denitrification. Consequently, investigating the presence and abundance of nirS is a commonly used approach to understand the distribution and potential activity of denitrifying bacteria, in addition to denitrifier communities. Herein, a rapid method for detecting nirS gene with loop-mediated isothermal amplification (LAMP) was developed, using Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) as model microorganism to optimize the assay. The LAMP assay relied on a set of four primers that were designed to recognize six target sequence sites, resulting in high target specificity. The limit of detection for the LAMP assay under optimized conditions was 1.87 pg/reaction of genomic DNA, which was an order of magnitude lower than that required by conventional PCR assays. Moreover, it was validated that P. aeruginosa PAO1 cells as well as genomic DNA could be directly used as template. Only 1 h was needed from the addition of bacterial cells to the reaction to the verification of amplification success. The nirS gene of P. aeruginosa PAO1 in spiked seawater samples could be detected with both DNA-template based LAMP assay and cell-template based LAMP assay, demonstrating the practicality of in-field use. [ABSTRACT FROM AUTHOR]

Carbon paste electrode made of graphite and ionic liquid n-octylpyridinum hexafluorophosphate (OPFP) displays many attractive electroanalytical abilities towards lots of species, allowing sensitive, low-potential, simple, low-cost, and stable performances. Herein a new hypothesis is proposed to explain the formation of these performances based on the results of electrochemical, scanning electron microscopic and transmission electron microscopic investigations. The mechanical force produces mono- or multi-layered graphene during the grinding process. And the OPFP molecules are prone to combine with the graphene, which cause the avoidance of the agglomeration of the exfoliated flakes. The presence of graphene, which is edge plane characteristic, provides high density of electrochemical reactive sites on the surface of the electrode. [ABSTRACT FROM AUTHOR]

Microplastic pollution has become a major global environmental issue. Yet the source identification and inventory of microplastics in mariculture areas remain unclear. Here we investigated the spatiotemporal distribution, source and inventory of microplastics in surface sediments from Sanggou Bay, China. The results showed that average abundance of microplastics in the surface sediments was 1674 ± 526 items/kg dry weight, which represented a heavy level when compared with other sea areas, including coastal waters, estuaries, the open sea and other mariculture areas. Microplastics with a size of <0.5 mm were dominant throughout four seasons. The dominant shape of microplastics was granule in summer, autumn and winter, and film in spring, respectively. The most common color of microplastics was transparent. Polyethylene was the dominant polymer in summer, autumn, and winter, while polystyrene accounted for the largest proportion in spring. Approximately 57.72% of the microplastics in surface sediments originated from the plastic mariculture facilities, suggesting that mariculture makes a significant contribution to microplastic pollution in Sanggou Bay. Estimated inventory of microplastics in surface sediments of Sanggou Bay was 183.73 tons. Our results improve the understanding of risks caused by mariculture-derived microplastics to marine ecosystem and human health. Unlabelled Image • Microplastic pollution in sediments was at a heavy level compared with other areas. • Approximately 57.72% of microplastics derived from mariculture plastic facilities. • Estimated microplastics inventory in sediments of Sanggou Bay was 183.73 tons. • Mariculture is an important contributor to sedimentary microplastics of Sanggou Bay. [ABSTRACT FROM AUTHOR]