Marine microplastic pollution has become one of the highly concerned global environmental issues. In this study, microplastic pollution in tidal flats seawater and rivers of Sishili bay were investigated along the coastal zone of the North Yellow Sea. The average abundance of microplastics in the surface water, river and tidal flat were （5.2±1.6） N/L, 5.2 N/L and （163.2±151.3） N/kg (d.w.), respectively. The fibers were dominated in microplastic types, which was primarily from aquaculture farming and river inputs, followed by fragments, films, foams and particles. The majority size of microplastics was < 1 mm (>50%). The distribution of microplastics in the water and tidal flat of Sishili bay showed significant spatial differences, which are mainly affected by aquaculture farming, daily living and hydrodynamics. More data are required in the future to understand the mechanism of microplastics distribution in the coastal open bay.
Based on the field data obtained in Modaomen estuary during the salt intrusion period in January 2018, the contamination level and distribution characteristics of heavy metals in this area were analyzed and the influence of environmental factors on the transformation and partitioning of heavy metals were studied. The study area was divided into fresh water zone, mixed zone and salt water zone based on salinity and water stratification level. The contents of particulate and dissolved heavy metals had significant difference between fresh water zone and salt water zone. The particulate heavy metals showed a decreased trend with the increase of salinity. The order of variation coefficients in the spatial distribution of particulate heavy metals was Cd>Cr>Zn>Pb>Cu>As>Ni>Co. The concentrations of dissolved Pb, Cr, As and Co increased gradually in the seaward direction, while the concentrations of Cd, Cu, Ni and Zn showed a "low-high-low" distribution pattern. The order of variation coefficients in the spatial distribution of dissolved heavy metals was Zn>Cr>Cd>Pb>Cu>Co>As>Ni. The partitioning coefficients decreased gradually in the seaward direction. Results of the principal component analysis showed that salinity and suspended sediment concentration are the main environmental factors that affect the partitioning of heavy metals in the estuary.
Port regional emission has become an important factor affecting the environmental air quality of coastal port cities in China. Port low emission area is one of the important measures to control port pollution. China's port pollution control started late, but with the introduction of a series of policies, laws and regulations, it laid a solid foundation for comprehensively promoting the prevention and control of vessel and port pollution. The establishment of port low emission area has become a new and important measure for some countries and regions to solve the problem of port air pollution. In a China southern city, port area emission has become an important local air pollution source. From large to small, the contribution rate of all kinds of pollution sources in this port is ocean going vessel, transportation vehicles, inland vessel and operation machinery. By calculating the PM2.5 equivalent of pollutant emission, it can see that after the implementation of the port low emission area scheme, the reduction of particulate matter is 1.2 times of the required emission reduction. Although China's port pollution control has achieved some results at present, it still needs to strengthen regional cooperation and policy support to further promote port pollution control. At the same time, the management experience of other countries in low-row areas of ports is also worth learning, which is beneficial to ensure the implementation of port pollution control plans.
A numerical model based on Delft 3D, an open source three-dimensional hydrodynamic model, was built to simulate the temporal and spatial distribution of tidal level, tidal current, temperature and salinity in Xiangshan bay. Calculated results were found to match the measured data closely, which demonstrated the model was able to simulate the hydrodynamic characteristics of Xiangshan bay accurately. Based on the validated flow model, a water quality model was built to investigate the migration and transformation process of pollutants in Xiangshan bay. The simulation results were again found to match with the measured data and the model is capable of reproducing the variation trend of the most water quality variables in Xiangshan bay. The verified water quality model was then applied to analyze the influence of the sewage outlets on the water quality variables in Xiangshan bay considering the timing of the discharge (during ebb tide), variation of discharge rate and layout of the sewage outlets. The simulation results showed that the water quality environment of Xiangshan bay was clearly affected by the locations of sewage outlets and the three design scenarios considered could all directly reduce the DIN concentration in the bay with different scenarios shown different influencing characteristics.
The experimental study on transport and diffusivity of pollutant in the surf zone can provide a basis for the design of nearshore water environmental protection and pollutant discharge. In the actual situation, the coastal incident waves are irregular waves, this paper studies the horizontal two-dimensional transport and diffusivity of dye under five irregular incident waves based on physical model experiments, image processing and centroid tracking, focuses on the calculation and analysis of the transport velocity in the alongshore and the transport velocity and diffusion coefficient in the cross-shore direction of the dye patch under different wave conditions. The results show that the cross-shore dye transport velocity Vx is about 4.4%～64.7% of the alongshore direction Vy in the case of irregular incident waves; the alongshore dye transport velocity is about 35% of the mean longshore current maximum; the diffusion coefficient in the cross-shore direction is within the range of 2.3×10−4 ～2.2×10−3 m2/s under irregular waves, which is decreases as the increase of irregular incident wave period, and the incident wave height has no significant effect on it.
Based on nutrients and hydrological data of one fixed station and twelve navigation stations in 2018 flood season in the Sansha bay, Fujian province, this paper found: (1) The average concentrations of SiO3-Si、NO3-N、NH4-N、PO4-P and SSC in ebb (includes drainage of the Ningde city) are about 1.2, 3.6, 6, 2.5 and 2 times higher than that in the flood (seawater) in Dajinxi estuary, respectively. (2)The concentrations of NO3-N and SiO3-Si decrease by 31% and 50% with the increased of salinity, the result indicated SiO3-Si and NO3-N variation were controlled by river discharge. However, with increase of salinity, the concentrations of NH4-N and PO4-P showed a slight decrease trend, and NO2-N even showed an increase trend, the result implicated that change of NH4-N、PO4-P and NO2-N were mainly controlled by aquaculture in the bay. (3) The average concentrations of inorganic nitrogen (DIN) on twelve navigation stations was 57.33>21.41 μmol/L, PO4-P (DIP) was 2.28>1.45 μmol/L, and DIN/DIP was between 8～30, such level of above parameters indicated that the water quality in the Sansha bay had exceeded the grade IV water quality standard and reached the state of eutrophication.
In order to research the influence on the hydrodynamic characteristics of single-drain marine aquaculture tank with different double-inlet pipes distances, especially the velocity distribution of the bottom and near discharge outlets. The RNG k-ε turbulence model was applied to simulation the flow field in rectangular arc angle aquaculture tank , the computational fluid dynamics study is performed to analyze the impact of different layout positions under double-inlet pipes structure conditions on the flow field of the tank, and the fluid dynamics characteristics variables were adopted to analyze the complex the flow field in the near of sewage outlet. The results indicate that the position of the inlet pipe in the double-inlet pipe structure has a significant influence on the velocity distribution at the bottom of the tank; the double-inlet pipes at the arc angle is conducive to improve the hydrodynamic characteristics at the bottom of the tank.
This study evaluated the potential risk for a harmful benthic dinoflagellate Prorocentrum lima (strain HN45), which was isolated from the South China Sea. In this experiment, P. lima was cultured in laboratory under different temperatures（20 ℃, 25 ℃, 30 ℃）and nitrogen phosphorous limitation conditions (nitrogen-to-phosphorus ratio, N/P: 4.08, 8.17, 16.3, 24.5, 73.5, 147). Then the physiological characteristics, including cell density, growth rate and pigments, as well as the production characteristics of diarrhetic shellfish toxins (DSTs) were investigated and analyzed. Based on the multi-factor analysis of variance, the results showed that the temperature and phosphorus-limited levels had significant effect on cell density, peridinins (the typical pigments of dinoflagellates) and intracellular toxin of P. lima. The DSTs production ability of single cells reached to the highest value (11.34 pg/cell) at the temperature of 25 ℃ and phosphorus concentration of 6 μM. Phosphorus deficiency reduced cells density and specific growth rate of P. lima, but significantly increased their ability to produce DSTs. Moreover, esterified toxins accounted for 3% to 14% of intracellular total toxins in P. lima, which was much lower than the free content toxins. In addition, chlorophyll a concentration of P. lima was negatively correlated with DSTs content. Which further confirmed the competition of the production of chlorophyll a and DSTs. Further research was needed to study the survival selective strategies of Prorocentrum lima under the ambient pressures.
The life cycle of Rhopilema esculentum involves pelagic medusa and benthic polyp. Asexual reproduction is the main reproduction method of R. esculentum. As one of the asexual reproductions, the strobilation is the only way to transform polyps to medusae, which is mainly regulated by temperature. In order to investigate the effects of low temperature induction and the molecular regulation mechanism in the strobilation, R. esculentum polyps were cultured at low temperature for a short period, and the transcriptome differences between the low temperature group and control group were compared and analyzed. Results showed that there were 1655 differential expressed genes in the strobilation, which involved in TGF-β (transforming growth factor beta), MAPK (mitogen-activated protein kinase), Wnt (wingless-int) and Cell Cycle signaling pathways. Under the induction of low temperature, the above signaling pathways responded, but the Wnt signaling pathway was inhibited and the other three pathways were activated. This study preliminarily demonstrates the molecular regulation pathways involved in low temperature-induced R. esculentum polyps, which provides a help for further investigation of molecular regulation mechanism in strobilation of R. esculentum.
Based on the phytoplankton and environment data collected from the deep-water cage aquaculture area of Houshui bay and its adjacent waters between April 2018 and January 2019, this paper analyzed the seasonal variation of phytoplankton community and its relationship with environmental factors, as well as the impact of deep-water cage aquaculture on the environment. In this research, 214 phytoplankton taxa were identified, which belonged to five phyla and 65 genera, with Bacillariophyta being the main group. The dominant species were Skeletonema costatum, Pseudo-nitzschia delicatissima, Skeletonema tropicum, Thalassiosira subtilis and so on. There were obvious seasonal variations in species composition of the dominant. The phytoplankton abundances and the biodiversity indices (Margalef richness index, Shannon-Wiener diversity and Pielou evenness) were significantly different in season, and they were generally higher in summer and autumn than in winter and spring. The results of Bray-Curtis analysis and non-metric multidimensional scaling analysis showed that the composition of phytoplankton community had significant seasonal differences, but there was no significant difference between the aquaculture area and the control point. Redundancy analysis suggested that the main factors affecting the community structure were temperature, salinity, nutrition, and various phytoplankton respond to these main factors in different ways. The water quality of Houshui bay was fine during the investigation. There was no significant difference in phytoplankton community composition and environmental factors between the aquaculture areas and the control points in each season. Deep-water cage culture had no significant effect on the water quality and phytoplankton in Houshui bay.
The sensitive grain-size component is one of the important approaches to analyze sedimentary environment change. Tidal flat around Qidong cape is located at the intersection between the coast of Jiangsu and the river line of the Yangtze River, where with intense land-sea interactivities. With economic development, the area is affected by human activities heavily. Four cores are collected during field investigation. After grain size analysis, the sensitive grain-size components are identified based on standard deviation. The results are as follows: (1) there is a distinct negative correlation between fine components and coarse components. The fine components of <22 μm, <26 μm, <22 μm in the core QDZ-1, QDZ-2 and QDZ-3 sediments gradually increases from bottom to top, which could reflect general law of tidal flat sedimentation. (2) The coarse components suddenly increase under the influence of extreme environmental changes such as floods and storm surges. The coarse components of >22 μm, >26 μm and >22 μm in the core QDZ-1, QDZ-2 and QDZ-3 sediments increased sharply to 84%, 85% and 80% at depths of 172.5 cm, 242.5 cm and 142.5 cm respectively. (3) The fine components are more likely to leach than the coarse components under the influence of human activities, and as a result, that sediment tends to coarsen. The coarse components of >26 μm of QDZ-2 showed an increasing trend in the upper part of the section A. The reason is due to the combined effects of agricultural activities and rainwater leaching. The coarse components of 22 μm～88 μm and >88 μm of QDZ-3 show an increasing trend in the upper part of the section A. The coarse components of >63 μm of QDZ-4 showed the same. The reason is that the sedimentary dynamic enhanced by reclamation dikes constructed. As a result, coarse components are easier than fine components to adapt to high-energy environment and to deposit.
For the problem of flow around the cylinder, many domestic and foreign scholars have done a lot of research, but there is limited research on the pollution caused by the surface coating of the column to the marine environment. In this paper, the concentration field caused by the wall surface contaminant flow under the action of two-dimensional cylinder is numerically simulated. Under the oscillating eddy current field generated by the flow around a cylinder with a Reynolds number of 75～175, the cylindrical surface pollutants are used as the wall condition, the concentration field under various oscillating eddy current fields is analyzed, and the correlation and distribution law between the concentration field and the eddy current field are analyzed. The numerical simulation results show that under the action of the oscillating eddy current field, the concentration distribution of the pollutants is synchronized with the distribution of the vortex, the concentration of the center of the vortex is relatively high, and the concentration at the edge of the vortex is relatively low. As the Reynolds number increases, the concentration of the vortex position decreases.
Thirty-three surface sediment samples were collected from Jiaozhou bay, Laoshan coastal area and Qingdao amphioxus reserve area in November 2017. Biogenic elements including total organic carbon (TOC), total nitrogen (TN), total phosphate (TP) and biogenic silica (BSi) were analyzed. Concentrations of TOC, TN, TP and BSi were in the range of 0.21%~1.43%, 0.02%~0.13%, 0.06%~0.15%, 0.26%~0.60%, respectively. TN and TP were high in Jiaozhou bay, and TOC was high in Laoshan coastal area. While, BSi was high in amphioxus reserve area. In addition, BSi in Jiaozhou bay showed a significant decreasing trend compared to the previous studies, indicating the decrease of diatom productivity. Based on the molar ratios of TOC/TN, TOC in Jiaozhou bay and amphioxus reserve area was originated from mixture inputs of terrestrial and marine sources, while was mainly originated from marine sources in Laoshan coastal area. Results from pollution assessment of biogenic elements indicated that TOC in the surface sediments from Qingdao coast belonged to the uncontaminated level, however TN and TP reached moderate pollution level.
Marine dinoflagellate Protoceratium reticulatum producing yessotoxins was mass cultured. Then obtained algal cells were extracted by ultrasonic crushing with methanol for yessotoxins. Macroporous adsorption resin (HP20) was used to adsorb the extracellular toxin secreted in the culture medium, and the yessotoxins adsorbed on the resin were eluted with 70% ethanol. Nine of yessotoxin and their analogues were detected by high performance liquid chromatography-tandem mass spectrometry in extracts. The toxin of yessotoxin accounted for 95.1% of the total toxin group in the extracts, derivative 41YTX accounted for 3.65%, and other trace analogues accounted for 1.25%. Yessotoxin was purified through high performance preparation liquid chromatography for 5 times. The molecular weight and molecular formula was confirmed as 1142.4747 and C55H82O21S2, respectively, by high resolution mass spectrometry. The purity of yessotoxin detected by quantitative nuclear magnetic method was more than 99%, meeting the requirement for preparation of yessotoxin standard material.
The verification of ecological compensation standard is the key to the research on marine protected area ecological compensation, and the willingness of ecological compensation of stakeholders and its influencing factors are important foundations for formulating reasonable ecological compensation standard and improving compensation efficiency. Taking the Shengsi Ma'an Islands marine protection area (MPA) as an example, this paper determined the main recipients of the ecological compensation as residents and the main compensators as the government, tourists and non-local businessmen according to stakeholder analysis. On this basis, through the questionnaire survey of residents and tourists in the MPA, contingent valuation method (CVM) was selected to analyze the willingness to accept (WTA) of residents and the willingness to pay (WTP) of tourists. The results show that 68.54% of the surveyed residents have the WTA, and they are willing to accept an annual average of about 248.03 yuan. Their WTA is mainly affected by age, occupation and other factors, while the acceptance value is mainly affected by age, family income and other factors. Most tourists (97.62% of respondents) have the WTP, and they are willing to pay an annual average of about 203.55 yuan. The payment value is mainly affected by the family annual income, residence location and understanding of ecological compensation.
An algicidal bacterium (FDHY-C3) with high-efficiency algicidal activity was isolated from the surface water of Changle coastal area, Fujian province. The morphological, physiological, biochemical and 16S rDNA sequence analysis was performed and the results indicated that the strain FDHY-C3 belongs to the genus of Alternaria. This strain showed a broad algicidal activity on diatoms, dinoflagellates and raphidophytes. The highest algicidal rate was detected on Skeletonema costatum, the algicidal rate can reach 98.18% in 72 h. The algicidal compounds was detected in extracellular secretions of FDHY-C3 cells through an indirectly dissolve way on target algal cells. The algal-lytic compounds of FDHY-C3 were not affected by freezing, but were affected by acidity and alkalinity and high temperature. The compounds can be extracted by ethanol and ethyl acetate, and was estimated to be protease. The molecular weight of this compound was between 10 kD and 14 kD.
Focusing on the Pacific, four error statistical indicators: average deviation, absolute deviation, standard deviation, and correlation coefficient are selected to conduct a consistency analysis of two SST data, MODIS SST and AVHRR SST, from July 2002 to December 2009 in this paper. The results show that: (1) The difference between the two SST data is unevenly distributed in space and time. Before the anomaly, the area with better consistency is distributed in the low-latitude on the south and north sides of the deviation band (around 10° N) and the eastern seas of Australia, and the deviation is stable within ± 0.4 ℃ for a long time; (2) In the seas of central and western South America and near the Malay Islands, the difference between the two SST data have obvious seasonal rules, and the two sensors have a certain degree of mechanism difference near the Malay Islands; (3) Season is not the main reason for the difference between the two SST data In the central of the mid-latitude of Pacific in the southern and northern hemisphere; (4)After the anomaly, the area with better consistency is mainly distributed in the low-latitude on the south and north sides of the deviation band (around 10° N) and the eastern seas of Australia. The difference in the other areas after the anomaly are closer to the same level;(5)Of the two SST data, the difference between the night derailment (Night) data is greater than the daytime ascension (Day). After the anomaly, this difference is greatly reduced.
There have been a number of marine biological outbreaks in coastal nuclear power projects in China, which lead to exception of water intake system of nuclear power plants. Nuclear plants carry out marine ecological investigation at the feasibility study stage. At present, the investigation and evaluation of marine organisms in the early stage of nuclear power plant construction are lack of pertinence to the marine organisms causing disasters. In this paper, the actual work feedback of disaster causing marine organisms and nuclear power plant cold source safety has been combined. The deficiencies of marine biological investigation in the early stage of nuclear power project construction are analyzed and the optimization measures of investigation scheme are provided. To try to enhance the relationship between marine biological investigation and the defense system of NPP’s cold source safety in depth.
Oil spills are the most common marine emergencies, and serious marine oil spills often cause significant damage to the marine ecosystem. Petroleum hydrocarbon components in the environment are complex and difficult to degrade. In addition, petroleum hydrocarbons have the three effects of carcinogenic, teratogenic and mutagenic, easy to be enriched in marine organisms, and cause serious impacts on the growth, survival and reproduction of marine organisms. This paper reviews recent studies about the toxicity of petroleum hydrocarbon to bivalve shellfish at home and abroad, including the toxicity of petroleum hydrocarbons, the accumulation rule in bivalve shellfish. In addition, it also includes the impacts on the health of the body, such as the damage of petroleum hydrocarbons to the antioxidant enzyme system in bivalve shellfish, as well as the impacts on the bivalve shellfish genes. At last, the future research direction of petroleum hydrocarbon toxicity to bivalve shellfish are prospected. These results provide references for further studies on toxicological mechanism and marine ecological restoration.
Viruses are the most abundant life forms on the earth and widely distributed in various environments including the deep biosphere. Viruses infect microbial hosts and affect their physiological characteristics, ecological processes and biogeochemical cycles. Recently, the latest results have shown that viral lysis is the main driver for the death of benthic prokaryotes. These findings have attracted extensive attention of researchers on benthic viruses. In order to have a comprehensive understanding the ecological roles of benthic viruses, we summarized the important findings in viral ecological features (distribution, abundance, biodiversity, and lifestyle), dynamics and impact factors, interactions with the host and viral ecological effects in the carbon cycle. Meanwhile, the future research directions of benthic viruses in biology, ecology and biogeochemistry field were also prospected. The aim of this review is to enhance the understanding of the ecological role in benthic viruses and provide reference for the development of benthic viral ecology and its related disciplines.