Based on the observations originated from satellites and archived in IFREMER, the sensitivity analysis and adaptive modification were conducted on the wind input source term, dissipation caused by white-capping and bottom friction and their parameters of SWAN model with unstructured mesh grid in the China adjacent sea. The applicability of the modified model was validated by performing 25 years numerical simulation. Results indicated that the reanalysis wind speed data from NCEP were consistent with observations in China sea and could be used as the wind forcing for wave simulation. The Komen pattern with the coefficient of 1.86×10^-5 for both the wind input source term and the dissipation caused by white-capping was considered as the optimal parameter combination for this sea area. As for calculating the dissipation due to the bottom friction, COLLINS model with default parameter was the most suitable. And the calibrated SWAN model was stable and could simulate the significant wave height more accurately in the China adjacent sea.

The research and development of radar systems generally require repeated tests. In order to solve the problem of wasting a lot of manpower and material resources in field tests, this paper established an echo simulator mainly based on sea clutter, which was used for radar tests to reduce costs. Based on the Elfouhaily spectrum, the nonlinear dynamic sea surface was established by using the Choppy wave model,and the sea surface was divided into different resolution units by using the grid mapping method. This paper combined the gridded sea surface with the backscatter characteristics of the echo to generate a simulated echo for the first time. And in the simulation process, an algorithm for correcting the grazing angle based on the characteristics of the waves was proposed. Finally, the simulated echo was analyzed and fitted with the measured and theoretical data, which proved the effectiveness of the simulated echo.

Since the 21^st century, the coastline of Laizhou Bay has changed significantly due to coastal reclamation activities such as port dam construction and aquaculture dikes, which have caused the change of the hydrodynamic environment of the bay. In order to investigate the response of the tidal prism and water exchange capacity of Laizhou Bay to its coastline change during the past 20 years, the influence of the coastline change on tidal prism and water exchange capacity was analyzed with two-dimensional flow and advection-diffusion models for the two typical years, 2000 and 2020. The results showed that from 2000 to 2020, aquaculture dikes have caused an increase in the potential energy of tidal waves, and the maximum possible tidal range of Laizhou Bay also shows an increasing trend. The head of the bay between Weifang Port and Guangli Port increased significantly with the maximum increase of 8 cm. The spring tidal prism was decreased by 2.91%, the neap tidal prism by 1.42% and the mean tidal prism by 2.33%, and decreased bay area was the main reason for the decrease of tidal prism. The decrease in the sea area of the bay has led to a reduction in its self-cleaning capacity and water exchange, increasing the bay half-life time by 15 days. As for the local water exchange capacity, the water exchange capacity in the western part of the bay was decreased by port dam construction and a deposition trend of the Yellow River Estuary, resulting in an increase of half-life time in the western part of the bay by 40 d.

Disasters such as strong winds and huge waves caused by typhoons have a significant impact on the offshore area of Shandong peninsula. In this paper, by using the third-generation wave model SWAN, the driving field of the model was formed by ERA5 background wind field and the typhoon model wind field nested with Takahashi and Fujita. t formulas. The typhoon waves in the process of No. 9 typhoon "LIKEMA" in 2019 were simulated. According to the simulation results, the distribution of effective wave height, average period and wave age of typhoon wave was analyzed numerically, and the spatial distribution characteristics of typhoon wave during typhoon "LIKEMA" were preliminarily explored, which provided technical support for typhoon wave warning, disaster prevention and mitigation in Shandong province. The research results have certain scientific significance and application value.

In the design phase of a coastal power plant, numerical simulation is usually used to predict the influence scope of thermal water discharge needing the realistic heat transfer coefficients. The coefficient was almost judged based on experience and lack of systematic research actually so far. To solve this problem, this paper analyzed the comprehensive heat dissipation of the Meizhou bay power plant, and proposed a method for measuring the coefficients. The measured data showed that heat transfer coefficients fluctuated dramatically during high and low tides, so the empirical constant was not completely reliable with deviation. Conversely, the model results could reflect the temperature rise change more accurately caused by external factors, which was more consistent with the measured. This simulation method increased the accuracy of the heat transfer coefficients, and it had an important progress in rationally determining the influence of thermal water drainage.

Based on the FVCOM ocean model, a high-resolution three-dimensional ocean numerical model was established for the adjacent sea area of Liuheng island. The main characteristics of tides and tidal currents in the adjacent sea area of Liuheng island were simulated in detail. The results of the model were in good agreement with the observation data of one tide station and two current stations, which could reflect the movement characteristics of tides and tidal currents in the adjacent sea area of Liuheng island. Meanwhile, main tidal components, such as M₂, S₂, K₁, O₁, M₄ and M₆, and the elliptical spatial distribution of surface tidal currents as well as two shallow water tidal components were given. Finally, the surface flow field and the spatial distribution of residual current in the surface layer, 0.6 layer and bottom layer were analyzed. The results showed that M₂, S₂ and O₁ were high in the south and low in the north, and the amplitudes of M₂, S₂ and O₁ were 115-145 cm, 15-30 cm and 19-24 cm, respectively. K₁ was 20-30 cm, and the main tidal components propagated in the same direction. At the same time, the spatial distribution and propagation direction were opposite to the main tidal components. Based on the results of harmonic analysis, the tidal pattern coefficient and the maximum possible tidal range were calculated. The whole sea area was characterized by regular semidiurnal tide, and the maximum possible tidal range could reach 600-650 cm in the southern sea area and 450-550 cm in the northern sea area. According to the calculation of tidal asymmetry, the ebb tide speed in the south of Liuheng was higher than that in the north. Under the four tidal conditions, the maximum velocity of the ebb flow field was 22 cm/s, and the maximum velocity of the four main tidal components was 160 cm/s, 60 cm/s, 22 cm/s and 12 cm/s, respectively. The spatial distribution of the ebb flow field was characterized by offshore rotating current and inshore reciprocating current. In the distribution of residual current, the maximum of surface layer, 0.6h layer and bottom layer could reach 25 cm/s at the headland, but the residual current gradually weakened with the increase of water depth.

Under the action of waves and currents, offshore wind power foundations may experience local erosion, resulting in an increase in the length of the foundation cantilever, which seriously affects the stability and safety of the foundation. To investigate the local erosion characteristics of offshore wind power tripod foundations under the combined action of waves and currents, local erosion tests were conducted on tripod foundations with different installation angles in a wave current tank. The characteristics of local erosion depth, influencing factors, and the morphology of erosion pits were studied. The research results indicated that under the action of individual waves, the central column provided a certain protective effect on downstream piles, weakening the development of erosion. When waves and currents acted together, waves provided drag force on the bottom bed, while water flow provided sediment transport force, resulting in a significant increase in scouring depth. When the installation angle was 30°, the water blocking effect on the double pile side of the tripod was greater, and some water flow was directed towards the single pile side, resulting in an increase in the scouring depth. As the flow velocity, wave height, and KC increasing, the depth of erosion around the foundation gradually increased. An empirical formula using KC to predict the equilibrium scour depth had been proposed, which could accurately predict the equilibrium scour depth of local scour on a tripod foundation under wave action and wave current combined action.

Mangroves, seagrass beds and salt marshes are important components of marine "blue carbon" and marine ecosystems with strong carbon sinks. Based on the relevant studies at home and abroad, in this paper, we reviewed the studies on the carbon sequestration capacity of several typical coastal wetlands like mangrove, seagrass beds and salt marshes, the impact of wetland damage on such capacity, and the difficulties met in restoring and improving their carbon sequestration capacity. The reviewed included also the existing monitoring methods of coastal wetland carbon sink at home and abroad. We put forward suggestions and prospects from several aspects which include current monitoring of coastal wetland carbon sink, wetland protection and sink enhancement. Globally, coastal wetlands have a strong carbon sequestration capacity, 10 times that of terrestrial ecosystems. With urban expansion, human exploitation and utilization, the coastal wetlands may be transformed into industrial and construction lands, which is the main influencing factor for the loss of carbon sequestration capacity of coastal wetland ecosystem. Wetland restoration is difficult, has a long cycle and holds more uncertainties. At present, the monitoring methods of coastal wetland carbon source and sink mainly include inventory, direct measurement, remote sensing monitoring and ecosystem model methods. While countries are constantly exploring and improving the researches on coastal wetland carbon sink survey, there are still many problems. Therefore, the researches on coastal wetland survey should be strengthened in the following aspects including conduction of coastal wetland carbon sink and habitat quality surveys, establishment of the blue carbon survey system of coastal wetland, changing wetland use into account, integration of existing carbon sink survey data into databases supporting the optimization of policy making model, and exploring continuously the application of new survey methods in carbon sink investigation.

In this paper, the species, distribution area and biomass per unit area of macroalgae in the subtidal zone of Gouqi Island, Zhejiang Province, were investigated through acoustic side scanning and SCUBA diving. At the same time, the organic carbon content of different macroalgae was detected, and based on the biomass per unit area, the biomass and carbon sequestration capacity of the subtidal algal field in Gouqi Island were estimated. The results showed that the distribution area of the subtidal zone algal field is about 22.33 hectares in Gouqi Island, and there were 19 species of 3 phyla of macroalgae are distributed. The content of organic carbon in different species ranged from 29.11% to 36.85%. Brown algae contain a special blue light effect and have the highest average organic carbon content (32.62%) which was followed by Chlorophyta (31.82%) and Chlorophyta (29.39%). The macroalgal carbon sequestration capacity per unit area was estimated to be 176.15g·C/m², and the total carbon sequestration in the sea area is about 38.28 tons, equivalent to about 129.07 tons of CO₂ emission reduction. The results of this study can accumulate basic data for the study of carbon sequestration capacity of macroalgae farms in coastal waters, and also provided a scientific basis for the study of negative emission reduction path in the ocean.

In order to describe the species composition and taxonomic diversity of fish inhabiting Dongping Lake, downstream of Yellow River, the species composition was analyzed and the taxonomic diversity and G-F diversity indexes were calculated based on the survey data of fish resources from 1979 to 1980 and the survey data of fish from 2020 to 2021. In total, 55 species belonging to 39 genera, 15 families and 8 orders of fish were recorded from 1979 to 1980, and 41 species belonging to 39 genera, 15 families and 7 orders of fish were recorded from 2020 to 2021, among them fish species in Cypriniformes were absolutely dominant. From 1979 to 1980 and from 2020 to 2021, the average taxonomic difference index (Δ⁺) of fish inhabiting Dongping Lake was 77.19 and 79.39, the taxonomic difference variation index (Λ⁺) was 581.9 and 561.5, the family diversity index (F index) was 5.05 and 4.15, the genus diversity index (G index) was 3.70 and 3.65, and the standardized G-F index was 0.27 and 0.12 respectively. Fish diversity of Dongping Lake displayed an overall downward trend. Fish germplasm resources protection and habitat restoration of Dongping Lake should be strengthened.

Typhoon disaster is one of the most important factors that should be considered in the construction of marine structures. In present study, 31 typhoons affecting the coastal areas of Gudong oil production plant in Dongying City during 1960 and 2019 were simulated and the tide levels near the project site were calculated. The generalized extreme value (GEV) distribution model was applied to fit the marginal distributions of both extreme tide level and storm surge duration. The dependence structure of these two environmental conditions was described by a Gumbel-Hougarrd copula function. Considering the effect of the typhoon frequency on the design values, the Poisson compound extreme value distribution was used to perform the statistical analysis. The results indicate that the joint return period estimated by the proposed model acts as a reasonable representation of the storm surge disaster grade, and thus provides essential information for coastal disaster prevention and mitigation and marine structure design.

Jumbo flying squid Dosidicus gigas is a pelagic and economically important squid species widely distributed off Peru. The purposes of this study were to understand the relationship between spatio-temporal fishing grounds of D. gigas and environmental conditions, and to provide a scientific basis for the sustainable utilization and management of D. gigas resources. Based on the fisheries data of D. gigas in the southeast Pacific Ocean off Peru from September to December, 2006 thorough 2015 provided by National Data Center of Distant-water Fisheries of China, in this study, we determined the position of longitudinal and latitudinal gravity center of fishing ground, and quantified the temporal and spatial changes of fishing ground. In addition, the cluster analysis on the fishing ground gravity centers was performed. The relationship between fishing effort and sea surface temperature (SST) was examined based on frequency distribution analysis and the influence of SST on the changes of fishing ground gravity centers was further evaluated. The responses of fishing ground gravity centers to the La Niña and El Niño events were finally explored. Significant monthly and interannual variations were found in the longitudinal and latitudinal gravity centers of the fishing ground. Cluster analysis divided the fishing ground gravity centers into three categories. The fishing effort distribution in the longitude, latitude and SST showed a large difference from month to month. Compared with the El Niño year (2015), the SST on the fishing ground in the La Niña year (2007) was lower, leading to the northwestward shift of the most preferred temperature front for D. gigas. Therefore, the gravity centers of fishing ground in 2007 moved northwestward. The results indicated that spatio-temporal distribution of D. gigas was closely related to large-scale climate variability-induced SST change.

Seawalls play an important role in preventing coastal areas from storm surges, but the seabed in front of seawalls usually suffers serious erosion after their construction, which would threaten the safety of seawalls. To analysis the scour problem in Gudong Seawall, we recovered the scouring process according to the water depth during the past 20 years, discussed the scour mechanism and calculated the maximum scouring depth. The results showed that: (1) Gudong seawall was under the erosion background in the abandoned sub-lobes of the underwater delta of the Yellow River Delta, and the seabed within 500 m offshore suffered more severe erosion, which was called background scouring and toe scouring respectively in this manuscript. The background water depth had deepened from 2-3 m in 2000 to the present depth of 6 m, and the maximum water depth at the toe of the seawall had exceeded 7 m. (2) Background scouring was mainly caused by the diversion of the river course and the reduction of sediment into the sea. Waves were the main driving factor for seabed scouring. Seawall toe scouring was caused by complex hydrodynamic processes in front of the Gudong Seawall, such as wave reflections, wave breaking, turbulence, coastal current, offshore current, etc. (3) It was predicted that the maximum scouring depth for background erosion in the Gudong Sea area was 7 m, whilst for toe scouring was 1.7-2.5 m, so the maximum water depth in front of the Gudong seawall was 8.7-9.5 m.

Return value calculation of extreme marine environmental parameters induced by typhoon is of great significance for engineering disaster prevention. The rationality of the calculation depends on the sampling method and probability distribution model. In this paper, the sampling method of typhoon process was combined with exponentiated Weibull distribution model. A Poisson-exponentiated Weibull compound extreme value distribution model was established based on the compound extreme value distribution theory. This new distribution model was applied to the probability prediction of extreme marine environmental parameters under typhoon, and the corresponding return values were calculated. The study showed that the annual typhoon frequency at the selected calculation points conformed to Poisson distribution, and the exponentiated Weibull distribution fitted the sequence of extreme wave height induced by typhoon well. It was reliable to calculate the return values by using Poisson-exponentiated Weibull compound distribution model. This compound model was more perfect in physical and statistical sense, and the calculation results were stable and reasonable.

Saline tolerant plant plays an important role in marine aquaculture wastewater treatment and seawater agriculture development. In order to explore the salt tolerance and nitrogen and phosphorus purification ability of S. portulacastrum, in this study, we carried out the indoor hydroponic experiments of S. portulacastrum salinity treatment and nitrogen and phosphorus concentration treatment. S. portulacastrum plants were grown in Hoagland nutrient solution at salinities of 0, 10, 20, 30 and 35, respectively, in salinity experiment, and were cultured in artificial seawater with N∶0 (P∶0.5) mg/L, N∶1 (P∶0.1) mg/L, N∶5 (P∶0.5) mg/L, N∶20 (P∶2) mg/L, N∶50 (P∶5) mg/L, respectively. The treatment period was 20 days. We found that 1) the absorption effect of nitrogen and phosphorus was obvious under the condition of medium and low salinities (0～20) while the absorption effect was significantly weaker than that of the low-medium salinity groups under the condition of high salinities (30～35) (P<0.05); 2) the Na⁺ content in S. portulacastrum tissues increased continuously with the increase of salinity while the K⁺ content showed a decreasing trend; and the effect of nitrogen and phosphorus concentration on the content of Na⁺ and K⁺ was not obvious; 3) under the conditions of all nitrogen and phosphorus treatments, S. portulacastrum grew normally and showed a high nitrogen and phosphorus removal ability, significantly reduced the nitrogen and phosphorus concentrations in the water. S. portulacastrum had a strong salt-tolerance ability and effectively alleviated the eutrophication, which can be used to purify the aquaculture wastewater and improve the aquaculture environment.

Three-dimensional wave-current coupling numerical model was established based on the FVCOM (Finite-Volume Community Ocean Model) circulation model and wave model. Numerical simulation on the hydrodynamic environment characteristics of Zhoushan island sea area was performed. The tidal current and wave characteristics of Zhoushan island sea area were mainly investigated. The results showed that the reciprocating current was dominate in the nearshore area and the rotating current was dominant in the offshore area of Zhoushan islands. The ebb tide was stronger than the flood tide in most areas of the Zhoushan islands. The vertical current velocity in the bottom layer was about 59%~70% of that in the surface layer. The significant wave height during the spring tide was higher than that during the neap tide, and the significant wave height gradually decreased from the offshore to nearshore area. The effect of wave on the tidal current velocity was related to the water depth, where the current velocity in the nearshore area at small water depth was mostly affected by waves.

Current researches on the resuspension process of marine sediments were mainly divided into two aspects: the dynamic action of marine fluids and the dynamic response process of sediments under the dynamic action. Internal solitary waves can move hundreds of meters between oceanographic thermocline, which not only has horizontal flow, but also can induce extremely strong vertical flow, which further causes the migration of sediment and pollutants. Therefore, the phenomenon of sediment resuspitation caused by the internal solitary waves shoaling and propagating on the slope has attracted much attention. With the flume experiment based on the researches, the setting up sediment slope and sediment layer in the control group, with controlling seepage condition, controlled the dynamic response of seabed sediment. By making the concave type internal solitary waves, the changing of sediment grain-size composition and internal solitary wave amplitude, comparison and analysis of different internal solitary wave under the condition of shallow broken cause of sediment resuspension phenomenon, were discussed about the influence of the dynamic response process of resuspension of sediments. The main research results were found that under the action of internal solitary waves, the faster the flow rate was, the faster the sediment suspended matter concentration changed; and the increased value of suspended matter concentration presented a positive correlation trend. For sediment slope area, with seepage conditions under the action of internal solitary wave could sustain high suspended sediments concentration for a longer time; the duration of continuous change was obviously longer than that of sediment layer. And with the slower velocity, slope area after achieving the highest suspended sediment concentration, concentration change rate was less than the sediment layer. For sediments with different grain-size composition, with the more clay content, the response speed to the internal solitary waves became more slowly, and the specific variation law was also different. When sediment components were sandy silt, under the action of internal solitary wave, variation of suspended sediment concentration in layer area was larger than it in slope area. And in the gap of two waves, the duration of higher suspended sediment concentration in slope area was much longer, the maximum could reach 2.5 times of that in the layer area. When the composition of sediment was clayey silt, the increased value of suspended matter concentration in the sediment slope area was 1.6-2.2 times of that in the sediment layer area.

The seahorse (Hippocampus abdominalis) inhabits southwestern Pacific Ocean and the waters near Oceania and New Zealand. Its large size, strong disease resistance and high survival rate in seedling cultivation make this species high in medicinal and economic values. In recent years, continuous global climate change has been impacting the marine ecosystems and reducing the natural resource of this species. Such scenario is even becoming worse due to the market demand increase. As a result, H. abdominalis has been listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora(CITES). The researches relating to its resource conservation and development, reproductive biology and aquaculture technology are receiving intensifying attentions. In 2016,H. abdominalis was introduced into China where its artificial breeding of seedlings has met success and boomed currently. In this paper, we summarized the research findings in the biology and artificial breeding of H. abdominalis, and prospected the research direction, trying to provide a powerful reference for the resource protection and artificial breeding technology development of H. abdominalis.

It is of a great significance for the utilization and protection of Antarctic krill to study the distribution of and predict the suitable habitat of Antarctic krill in the Cosmonaut Sea. Using krill distribution data from the Krillbase and data from the global ocean data assimilation reanalysis system (GLORYS), the spatial distribution characteristics of krill in Astronaut Sea and the characteristics of sea surface temperature, sea surface salinity, chlorophyll and sea ice in krill collection points were analyzed. At last, the suitable habitat of Antarctic krill in Astronaut Sea was obtained. Results showed that the density of krill was high in the south and low in the north, and high in the west and low in the east of the Astronaut Sea. The high density was concentrated in the coastal area to the west of Enderby, and mostly located in the south of 65°S. Results showed that Antarctic krill prefers to habitat sea surface temperature of 271.4K-271.9K, salinity of 33.9-34.1, chlorophyll of 0.28 mg·m^-3~0.36 mg·m^-3, sea ice concentration of 0.67-0.81. The suitable habitat of the Antarctic krill distributed in the south of 65°S, and was paralleled to the coastline.

Marine fishing villages are the unit form in overall rural area. Strengthening studies on the ecological environment management should prompt the implementation of rural revitalization strategy. By combing the current practicing effect of the ecological environment management of marine fishing villages, we found that the social capital plays a significant role. Selecting S Village of Shanwei City and K Village of Jiangmen City as the case sites, we compared the degree of social capital participation in environmental governance, the mechanism of action, and the difference in effectiveness through questionnaires and in-depth interviews. The results showed that the environmental governing ability and quality of governors, and the difference in social capital stock of fishing village communities are the main reasons for the obvious differences in governance effectiveness. It is believed that the follow-up of the ecological environment management of marine fishing villages should focus on improving the governance capabilities and political literacy of local governments and fishing village leaders, cultivating and making good use of the social capital of marine fishing villages to encourage the endogenous role of multi-participation, and promoting the modernization of marine fishing village ecological environmental governance.

The fishmen retreated from Yangtze River fishing have been facing many difficulties in adapting society, among them losing power is particularly prominent. Enhancing their rights is a key factor to their social adaptation and an important guarantee for the effective implementation of fishing banning. Based on the analysis of the field surveying findings, in this article, we concluded that the withdrawal of fishermen is mainly reflected in economic loss of power, social environmental loss of power and psychological loss of power. Therefore, the fishermen should be assisted as soon as possible from three perspectives, system empowerment, organizational empowerment and individual empowerment, which should aid to realizing social adaptation and finally the goals of retirement, stability and prosperity.

In this study, according to the human-computer interactive interpretation and GIS analysis, the distribution of coastal wetlands in Shantou city was obtained since 1980s by analyzing the multi-temporal landsat remote sensing image data. According to wetland classification system, Shantou coastal wetland was divided into natural wetlands and constructed wetlands (first classification), including 9 types. They were shallow sea areas, rivers, lakes, beaches/coastal, mangroves forest, reservoirs/ponds, water fields, salterns and aquaculture ponds (secondary classification). The variation characteristics and the influencing factors of coastal wetlands in Shantou city were analyzed by dynamic degrees of single wetland type, wetland transition matrix and correlation analysis. The results showed that: from 1982 to 2020, the coastal wetlands in whole area were increased slightly by 19.08 km². The natural wetlands shrank significantly with a total area loss of 51.18 km², while the constructed wetlands expanded significantly, with a total area increase of 70.26 km². The main driving force of the change came from a series of human activities such as tideland reclamation, land reclamation, sea reclamation and river aquaculture, construction of fishing port wharf and water conservancy facilities in the rapid urbanization process of Shantou city. Secondly, the changes of sediment discharge and sea level rise of the major rivers also played a certain role in the wetland change.

The temporal and spatial distribution characteristics, physical parameters, and fallout forecasts of strong convection under different weather typologies in Shandong peninsula from 2015 to 2020 were analyzed and studied. The results showed that: strong convective weather mainly occurred under five weather situations, namely, low trough, high-altitude cold vortex, northwesterly flow, edge of the sub-tropical height and transverse trough; strong convective weather events mainly concentrated in June-August, and were most likely to occur in the afternoon to the nighttime, and were mostly unevenly distributed; the spatial distribution mainly exhibited four characteristics, namely, western-type, eastern-type, area-wide-type, and local-type, with local-type events being the most frequent. The physical parameter characteristics differed greatly among different weather situation configurations, and the physical parameter characteristics varied greatly among different weather situations. The physical parameters of different weather configurations varied greatly, with the CAPE value and K index of the sub-tropical height edge type being larger than those of other situations, the vertical wind shear SHR6 and the total index TT of the high-altitude cold vortex type being the largest, the CAPE value and K index of the northwesterly flow type being small, and the SI value being positive. Strong convection caused by weak cold fronts and sea-breeze fronts was most likely to occur in the western part of Yantai, and then moved eastward to become weaker, and the eastern type was more likely to happen at night. The eastern type mostly occurred at night, mostly due to the influence of the surface convergence line, and the different positions of the inversion trough also determined the different fallout areas of the strong convection. The region-wide type mainly occurred under the influence of the upper-air cold vortex or the strong trough cold front; the local type corresponded to the edge of the subduction plateau and the northwesterly airflow type, with the surface convergence line as the main triggering system, which had a very good correlation with the sea-land topography and the mountainous topography.

To understand Yangjiang, Guangdong nearshore sea surface water content and potential ecological risk of heavy metals, samples surface waters were collected at 14 stations. The content distribution characteristics of 7 kinds of heavy metals were analyzed in surface waters including Cr, Cu, Zn, Cd, Pb, As, and Hg. The Hakanson method was adopted to evaluate their ecological risk index and potential ecological harm. The results showed that the average concentrations of heavy metals Cr, Cu, Zn, Cd, Pb, As and Hg in the surface waters off Yangjiang were 1.10 μg/L, 5.25 μg/L, 9.91 μg/L, 0.027 μg/L, 0.945 μg/L, 1.06 μg/L and 0.027 μg/L, respectively. Among them, Cr, Zn, Cd, Pb, As and Hg met the quality standards for class I seawater, while Cu met the quality standards for class II seawater. There was a strong correlation among the 7 heavy metals, and each heavy metal also had a certain correlation with different environmental parameters. Based on the analysis of the potential ecological risk index, the average value of RI was calculated to be 6.59, which was a slight ecological hazard and the overall level of cleanliness.

Nutrient assay is essential in the routine oceanographic surveys. The nutrients of seawater are determined on a continuous flow analyzer usually requires artificial seawater or aged low-nutrient natural seawater as the basal solution of standard calibration and the rinsing solution of the assaying system when seawater sample is changed. In this study, the concentrations of components (phosphate, nitrite, nitrate, ammonia nitrogen and silicate) in Sigma, Aladdin and Sinopharm sodium chloride (GR grade) solutions and aged West Pacific seawater were determined. The results showed that the concentrations of nitrite, nitrate, ammonia nitrogen and silicate varied in the three commercial sodium chloride salt solutions except phosphate. In contrast, the concentration of silicate was relatively high and trace amount of nitrite was found while the other three nutrients were not detectable in the aged West Pacific seawater.

According to the principle of remote sensing water depth inversion, this paper used the WorldView-2 multi-spectral satellite remote sensing image and airborne Lidar data for four machine learning models, including extreme gradient boosting (XGBoost), support vector machine (SVM), kernel ridge regression (KRR) and least absolute shrinkage and selection operator (LASSO), to explore the impact of different machine learning models on the accuracy of water depth inversion. For deepth data, when the training sample and the test sample were the same, the grid search method was used to find the optimal parameter combination of the machine learning algorithm, and the water depth inversion experiment was carried out on the shallow waters around Ganquan island. Through the comparison and analysis of the inversion results of four types of machine learning models, the results were as follows: in the shallow water depth area of 20m, XGBoost model had strong learning ability, with correlation coefficient (R²) of 0.97, root mean square error (RMSE) of 0.85 m, average absolute error (MAE) of 0.63 m and average relative error (RME) of 19%, which was better than the other three machine learning models, and the overall effect was the best. It can be used to predict the water depth around Ganquan island and provide reference for subsequent water depth inversion research.

The coastal zone is a fragile area affected by the global ecological environment and is extremely sensitive to global changes. Due to the change of climate environment and the excessive exploitation of groundwater, coastal geological hazards such as coastal erosion and seawater intrusion in Jiaodong peninsula have gradually become a serious threat to the sustainable economic development and people’s property security in this region. In this paper, based on the relevant data of coastal geological hazards in the coastal zone of Jiaodong peninsula, the qualitative analysis was carried out to determine that the main coastal geological hazards in this region were seawater intrusion and coastal erosion. On this basis, the risk assessment index system was established by selecting representative indicators. The quantitative risk assessment and GIS-based zoning of seawater intrusion and coastal erosion in Jiaodong peninsula were then carried out. The results showed that the comprehensive risk level of seawater intrusion in Jiaodong peninsula was ranked from high to low as Qingdao, Weihai, south Yantai and north Yantai. The comprehensive risk level of coastal erosion was ranked from high to low as Qingdao, north Yantai, Weihai and south Yantai. Accordingly, this paper proposed to rationally exploit groundwater in Weihai city and Yantai city, to protect coastal sand mines and vegetation in north Yantai and to move sand making beaches, to strengthen coastal defense projects in Qingdao and to pay attention to the pre-disaster investment.

Rocky reef habitat is an essential part of marine ecosystems because it boasts complex plant and animal communities, high biomass, stable material cycles and energy flows. However, human activities and frequent weather disasters have caused rocky reef habitat loss and biodiversity loss. Therefore, restoring degraded rocky reef habitats is considered a top-priority action. In this paper, we applies ecological theories such as ecological niche theory, succession theory, edge effect theory and disturbance-stability theory to restore the concrete rock reef ecosystem. As eco-concrete has a complex pore structure, rough surface and high strength, its application can offer an attachment base and habitat for marine organisms. Therefore, eco-concrete can be used to restore oyster reefs, algal reefs, coral reefs and ecological seawalls, to build an ecosystem with engineering values, to purify water, to provide biological habitat, to maintain biodiversity and to resist wave erosion and to achieve sustainable development. We aimed to protect and restore ecology by conducting research on eco-concrete in terms of its design, production, and construction technology. By doing so, the reef ecosystem survey technology, and an eco-concrete reef ecosystem modular restoration technology system were established, which should improve the management of the eco-concrete reef ecosystem.

Based on the synchronized data of suspended sediment and sea current, this paper analyzed the suspended sediment transport mechanism and the main mechanical control factors in study areas using sediment flux mechanism decomposition method. The sedimentary dynamic environment was divided into different zones using Flemming triangle diagram method on the basis of the distribution characteristics of the surface sediments in the study area. The results showed that the Lagrangian advection transport was the main governing factor in transport of suspended sediment and the vertical net circulation came second. And the transport direction of the tidal average single-width net sediment transport was in SW, which corresponds to the direction of the remaining flow in the study area. The average single tidal-width sediment transport at the outer station showed a decreasing trend from northeast to southwest, while the inner station showed the opposite, the average single tidal-width sediment transport increased from the northeast to the southwest. It was indicated that there was nearshore erosion or river sand transport. Observation showed that the study area was covered largely by sand and the local area was silty sand, gravel sand, and sandy gravel, with a small number of shells or coral reefs. The dynamic environment could be divided into zone S, zone A and zone B. The motion of surface sediments were three types: moving, jumping, and overhanging. The jumping was the main route of the surface sediment. The surface sediments had a lower content of transitional components in sediments and the increase of suspended-transition components with the hydrodynamic environment became weaker.

With the bibliometric method and the help of the literature analysis function of CiteSpace software, in this study, we took 662 literatures using key word combination of Acipenser sinensis and protection included in China National Knowledge Network (CNKI) as the data source, and collated and analyzed their annual distribution, publishing institutions and cutting-edge trends. The results showed that the academic research results on Acipenser sinensis showed a general trend of fluctuating upward in recent years. The number of papers published in the core journals of related literature was small. Fisheries research institutes and universities were the main publishing institutions. Current researched focus on the hot points such as the protection of the Yangtze River estuary and Yangtze River. The academic protection of Acipenser sinensis in China needs to be further studied, and multi-disciplinary interaction and communication should be carried out to expand research methods, so as to provide new ideas for the future research and protection of Acipenser sinensis.

Based on a total of 49a sea surface temperature (SST) data of SODA and net sea surface heat flux data of ECMWF from January 1960 to December 2008, the climatic evolution characteristics of the coupled main mode of the two anomalies were studied in the tropical Indian Ocean by using moving SVD method. The main results were as follows: (1) The coupling effect was gradually strengthened in the evolution process, the correlations between the two fields maintain well. (2) The sea surface net heat flux anomaly can better explain the basin variations of the SSTA field itself in most periods with the largest variations locating in the coastal area of Sumatra-Java and the sea area south of 20°S. And under its influence, the sea basin showed a warming trend in most periods. (3) The spatial distribution of the two fields of the coupled main mode changed significantly once from 1961~1970 to 1962~1971, under the significant influence of the year 1971. (4) The SSTA field changed significantly in the northeast Indian Ocean and the South China Sea with obvious positive change areas, while the sea area south of 20°S showed obvious negative changes. The net sea surface heat flux anomaly filed showed significant positive and negative changed in the South China Sea, the equatorial eastern Indian Ocean and somewhere east of Madagascar, respectively.

Tidal data reflects changes in coastal sea level, and plays a very important role in various fields. The lack of tidal data brings inconvenience to the use of tide level data. Based on the tidal data of the Chongwu and Jinjiang ocean stations in 2017, this paper proposed a method of filling missing data based on the LSTM model (long short-term memory neural network model). Compared with traditional interpolation methods such as linear interpolation and spline interpolation, the LSTM method had stable performance, high accuracy and easy implementation. Especially when the lack of measurement time was long, the LSTM method was obviously better than the traditional interpolation method. At the same time, this method was also suitable for filling other missing data including water temperature.

Towards the problems of color distortion of the marine ranching observation video and low accuracy of traditional fish identification methods, a marine ranching fish identification and classification method based on Faster-RCNN was proposed. SDI (Serial Digital Interface) signal color compensation system was used first to improve the poor video quality caused by the particularity and complexity of the marine environments, and then the optimized video was applied to produce data sets with diverse qualities. The Faster-RCNN works following a deep learning model with the feature extraction network and region proposal network (RPN) optimized and used to identify and classify marine ranching fish. The tentative experimental results showed that the mean average precision (mAP) of this method reached 81.63%, significantly improved the accuracy of recognition compared with traditional machine learning target detection algorithms.

The pore water pressure in seabed sediments is sensitive to hydrodynamic changes, and investigating the response of pore water pressure in sediments under different sea conditions is of great significance to the study of seabed instability and dynamic evolution of seabed boundary layer. In the sea area of Zhoushan Zhujiajian, Zhejiang Province, the dynamic changes of the hydrodynamic conditions and the pore water pressure of seabed sediments at 1m, 3m, 5m and 7m below the sea bed before and after typhoon Lekima were recorded by using the pore water pressure monitoring system. The monitoring data showed that the variation of pore water pressure in seabed sediments was affected by hydrostatic pressure and sediment properties, and had obvious response to wave action in short term. During the typhoon, the hydrodynamic force was greatly enhanced, and the effective wave height could reach more than 5 times of that under the calm sea condition. The oscillation amplitude of the excess pore water pressure in the sediment at the shallow 1m layer could reach 1-2 kPa, and the change of the excess pore pressure value was strong consistently with the wave strength. In the process of wave load acting on seabed sediment, the wave pressure had obvious amplitude attenuation, and the attenuation could reach more than 70% at the shallow layer of 1 meter. The influence of waves could be almost ignored below 1 meter. The influence of rod stop plate was an important reason for the attenuation of pore pressure amplitude. The presence of gas in seabed sediments and the interaction between shallow active silt layer and waves could significantly reduce the influence of wave load on seabed pore water pressure, which was an important factor of wave energy consumption.

Under the action of external factors, the deep gas in seafloor sediments moves upward, which is easy to accumulate at the interface of shallow coarse-fine sediments and form gasbags. When the gas in the gasbag escapes, it will induce a variety of submarine geological disasters and bring harm to human engineering construction. Therefore, real-time monitoring of the formation-growth-dissipation process of gasbags is of great significance for effectively judging its development law and predicting the occurrence of follow-up potential disasters. In this study, the multi-point pore water pressure monitoring technique was used to simulate and monitor the forming and dissipation of gasbags in saturated fine-grained sediments by mathematical simulation and physical simulation experiments. The variation characteristics and mechanism of typical excess pore water pressure of fracture formation, gasbag formation and gas release were discussed in detail. According to the results of mathematical simulation and physical simulation experiments, combined with theoretical analysis, the formation-growth-dissipation process of gasbag was divided into three stages: transverse crack generation, gasbag longitudinal expansion and oblique or vertical crack generation, and its corresponding excess pore water pressure was concave. The formation of gasbag began with the transverse cracks at the interface of coarse and fine sediments, and excess pore water pressure attenuated rapidly. The gasbag showed the expansion of longitudinal cavity, and excess pore water pressure remained almost unchanged; oblique or vertical cracks appeared at the end of the evolution of gasbag, and excess pore water pressure accumulated and dissipated again. The variation curve of excess pore water pressure in gas release stage had obvious saw-tooth fluctuation characteristics, and it could be used to distinguish whether the gas was released intermittently or continuously. The accumulated extreme value of excess pore water pressure could be reduced during gas reinjection, which meant that a lower pressure could create cracks and reopen the gas channel, destroying the sediment and causing the gas to escape.

Methods such as spatial interpolation, principal component analysis, and the Nemero pollution index were used to analyze and evaluate the water pollution of Bosten lake. According to the result, the total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH₃-N), potassium permanganate index (COD_Mn), suspended solids (SS) and turbidity of Bosten lake water quality indicators indicated an obvious spatial difference, with the concentration of the southwest shore and the northeast shore of the lake being higher than that of central lake. the dissolved oxygen (DO) showed decreasing from east to west, and the pH value increasing from the southwest shore of the lake to the center and the middle zone of the north shore. There was a strong correlation between the water quality indicators. The DO and TN, TP, NH₃-N, COD_Mn and turbidity were significantly negatively correlated while TP and TN, NH₃-H, COD_Mn, turbidity, NH₃-N and COD_Mn and turbidity. COD_Mn and turbidity were significantly positively correlated. Organic matters such as DO, TN, TP, NH₃-N polluted the waterfront in the lake area heavily, with the pollution level of the south shore being the highest, then the north shore, the west shore, lake centre, followed by the east shore. The results of the pollution assessment showed that the east shore, centre and west bank of Bosten lake were lightly polluted with class III water quality, and the north shore and the south shore of the lake were medium pollution with class IV water quality. The spatial variation characteristics of water quality could reflect the main pollution factors and the pollution level of lake water quality, thus providing a reference for the protection and treatment of water resources in inland lakes in arid areas.

Vulnerability represents a certain state of a system, and vulnerability analysis is an inevitable requirement for each system to respond to global changes and a necessary path to practice sustainable development. In order to make the fishery system better respond to external changes and maintain the sustainability of fishery resources and its economy, in this paper, we studied the vulnerability theories and methods and their application research progresses in fishery. Through the collation of relevant literature, it is found that vulnerability research has been applied and developed in multiple disciplines and fields, and the theoretical system such as conceptual methods is rich, but there is no unified standard ye. Fishery vulnerability research is still in its infancy, mainly about the vulnerability analysis of species, ecosystem, and coupled systems, with a relatively mature concept definition and a variety of evaluation methods. The literature mainly focuses on the quantitative research on the vulnerability of the coupled system and the qualitative and semi-quantitative research on the vulnerability of the species. Only a small amount of literatures studies the vulnerability of the ecosystem. The studies have been conducted on different scales and angles around inland, marine, and special fishery (especially coral reef fishery). Among them, there are more studies on marine fishery, and less on inland fishery, all of which focus on the vulnerability to climate change. The findings of this study can provide a reference for fishery vulnerability assessment in China.

In the world, many coastal underground brine resources are distributed in the muddy tidal flat area, but the research on the subterranean estuary in this area is only in the primary stage, and the model has not been established. In this paper, the southern bank of Laizhou bay was selected as a typical study area. Electrical resistivity tomography monitoring, pore water conductivity monitoring, seawater and groundwater conductivity measurement were carried out in the areas with different vertical permeability coefficients of surface sediments. The sediment-physical relationship of muddy tidal flat was clarified. A standard for the division of seawater-groundwater mixed zones was established. This standard combined with the electrical resistivity tomography monitoring results at each tidal time to analyze the complex exchange mode of seawater-groundwater and its influencing factors, and to reveal the temporal and spatial distribution of the mixing zone. The research results showed that the biological channels clustered in the silt layer were the main ways of seawater-groundwater exchange during the tidal cycles. The formation mechanism of "upper saline plume" and "groundwater discharge tunnel" in the muddy tidal flat subterranean estuary and the seawater-groundwater exchange process were different from those of sandy tidal flats. Decreasing the permeability of tidal flat sediments would cause the direct exchange rate of seawater-groundwater through sediments to decrease, leading the main exchange path to shift to high-permeability channels. The flow rate of intrusion and excretion in the channels would increase.

The relations about BOD₅, DO and COD were researched, which were acquired from water of marine outfalls near a coastal city, south China. The results indicated that preferable one-variable linearity existed between COD and BOD₅, but relatively weak linearity between BOD₅ and DO, as weakly between DO and COD. A binary linear function was established to express the relation about the three parameters, with a better linear determination coefficient and a larger F-test value. When COD ≥ 100mg/L, the fitting degree of the binary linear function was better than the one-variable linear function between COD and BOD₅. Monitoring data of BOD₅, DO and COD from water of marine outfalls of this city in 2015 year was used to verify the binary linear function. The relative error between COD values fitted by the binary linear function and COD values detected in a lab, was less than 25%, which accorded with the precession of quality control criterion, and verified the binary linear function reliable.

Oceanic fronts and mesoscale eddies, as two significant features in the open seas, are ubiquitous in the global ocean and make profound impacts on global ocean circulation and ocean ecology. Ocean fronts and mesoscale eddies are closely related to pelagic fishery resources. The foraging, migration, and stock recruitment of fishery resources are all influenced by these mesoscale oceanographic structure. The in-depth study of mesoscale oceanographic processes helps overcome the limitations of the researches of fisheries oceanography at large scales, lay the foundation for ecosystem-based fishery management as well. This paper provided a concise review of the impacts of ocean mesoscale variability, including fronts and mesoscale eddies, on pelagic fishery resources with feature extraction methods applied in researches involved briefly summarized. This review focused on the fish responses to fronts and mesoscale eddies and the underlying scientific mechanisms. The response of fishery resource organisms to fronts and mesoscale eddies varied, and it was speculated that they were dominated by feeding conditions and temperature suitability. The suggestions for the future research on the ecological effects of ocean fronts and eddies should be as follows: 1) considering the effects of fronts and mesoscale eddies together to obtain more comprehensive results; 2) making a more detailed discrimination of fronts and mesoscale eddies of different properties and development stages; 3) establishing a more complete observation, investigating and tracking system for marine organism.