Wave breaking over a submerged breakwater is simulated based on Lattice Boltzmann Method. By establishing a numerical wave flume and using a push plate to make waves, the interaction between waves and submerged breakwater is simulated. The calculated results are in good agreement with the experimental data, and verify that the model can well simulate the breaking and propagation of waves. It is proved that the wave height shows an attenuation trend due to the obstruction of the submerged breakwater and the breaking of the waves. Under the same wave height condition, with the increasing of wave period, the reflection coefficient increases first and then decreases while it only increases at the low water level.

We studied the ecological characteristics of macrobenthic community in the coastal area of Rongcheng and its ecological health status based on the investigation data collected in four seasons, 2016. A total of 163 macrobenthic species were identified. The dominant species throughout the four seasons were Lumbrineris cruzensis, Tharyx multifilis and Heteromastus filiformis. The average biomass of the macrobenthos was 58.89 g·m^-2 and the average abundance estimated from the four cruises was 301.83 ind·m^-2. The Shannon index (H′) of the macrobenthos community varied between 2.50 and 2.58, the species evenness index (J) varied between 0.80 and 0.87 while the species richness index (d) ranged from 1.20 to 1.89. The Bray-Curtis similarity cluster analysis showed that there is a distinct distribution of macrobenthic community from seashore to offshore, which is closely correlated with the spatial structure of bathymetry in the studying region. The benthic biological indices (AMBI and M-AMBI) indicated that the benthic ecosystem in the coastal area of Rongcheng tends to be moderately disturbed. Our findings revealed the community structure of macrobenthos in the coastal area of Rongcheng, which should provide a reference basis for ecological environment protection.

The South Yellow Sea and its adjacent sea area are selected as the research region, and the statistical characteristics of typhoons passing through this region from 1970 to 2016 are analyzed. The results showed that the frequency of typhoons in the South Yellow Sea region is high, and they are most likely to happen in July and August. Their paths are diverse, but most of them follow two paths: either landing and turning, or moving to the north at offshore. Based on the above two paths, this study uses several typhoon pressure field models and typhoon wind field models to construct and compare the wind fields of three typical typhoons, and to make error analysis with observation data. The result shows that the combined model of Fujita-Takahashi nested pressure distribution model and Jelesnianski wind field model could get a more reasonable simulation of MUIFA (201109) and Kompasu (201007). Myers pressure distribution model and Miyazaki wind field model have the best result on the simulation of Chan-hom (201509).

Large-scale reclamation had been carried out along the coast of the Bohai Sea, in order to alleviate the contradiction between the land supply and demand, until the full stop of approval of new reclamation projects in 2018. Long-term reclamation activities have led to significant changes in the coastline of the bays. In order to reveal the main causes of coastline changes in Laizhou Bay and the response of tidal wave system in Bohai Sea to coastline changes, the coastline data of Laizhou Bay in two typical years of 2000 and 2020 were selected to study the morphological changes in the Laizhou Bay during the 20 years, covering the changes of the coastline length, of the area and of the centroid of the bay. On the basis of the coastline and water depth data, a two-dimensional tidal wave mathematical model was established to study the impact of the coastline changes of the Laizhou Bay on tidal wave system, tidal types and maximum possible tidal range of the Bohai Sea in 20 years. The results showed that the bay area had decreased by 8.02% and the coastline length had increased by 77.65% in the Laizhou Bay during the 20 years from 2000 to 2020. The change of the southwestern coastline of the bay was the most dramatic, resulting in a 2.21 km shift of the centroid to the northeast. Coastline changes of the Laizhou Bay had led to the displacement of amphidromic points and the variation of amplitude for each constituent tide of the Bohai Sea. M₂ constituent tide amphidromic point near the Yellow River estuary moved northwestward by 1.4 km, M₂ constituent tide amphidromic point near Qinhuangdao moved northeastward by 1.7 km, and K₁ constituent tide amphidromic point in the southern part of the Bohai Strait moved eastward by 2.1 km. For the Bohai Sea, M₂ constituent tide amplitude showed a tendency of increasing as a whole, and the variation of K₁ constituent tide amplitude mainly occurred in the east of Bohai Strait. Irregular semi-diurnal tides are the main tides in the Bohai Sea. Affected by the coastline changes of the Laizhou Bay, the sea areas occupied by irregular diurnal tides and regular diurnal tides were reduced near the Yellow River estuary and Qinhuangdao, and the maximum possible tidal range in the Bohai Sea would increase.

When oil spill accident occurs, the spilled oil will spread under the current and wind, which will cause serious threat to the sensitive area of the sea. In order to study the diffusion trajectory of spilled oil, the prediction model of oil spill accident is established by using the Hydrodynamic Module (HD) and Particle Tracking Module (PT) of Mike21FM (DHI). Based on assumed oil spill accident of the project in the Lvhua island, the sweep area of oil film and the fate of oil particles are simulated under different wind conditions. The simulation results show that: (1) When the accident happened in the flood tide, it has great influence on the environment of the island and its surrounding area; (2) The wind has little influence on the oil particles in the early stage of oil spill, and after the oil particles are diffused, the influence become greater; (3) When the effect of the wind and the tide are superimposed, the oil film diffusion is intensified, and the sweep area is enlarged.

A hydrodynamic numerical model of the Zhanjiang Bay area is established using the Delft3D model and the calculated value that was verified with the measured hydrological data. On the basis of the hydrodynamic model, a numerical model of oil spill diffusion in Zhanjiang Bay is established by considering the processes of oil spill drift, diffusion, evaporation, emulsification and adsorption. The oil spill drift and diffusion numerical model simulates the oil spill accidents under different tides (flood, ebb) and different wind conditions (no wind, summer constant wind, winter constant wind and two unfavorable wind conditions) and predicts the main drift path, sea sweep area and the time of oil film to reach environmental sensitive area within 24 h of oil spill. The analysis results show that the oil film drift and diffusion are mainly related to the current field and wind conditions, and the long-term diffusion direction of the oil film is consistent with the wind direction. Within 24 hours of the oil spill, only unfavorable wind conditions would affect the mangrove protection area and fishery aquaculture area in Nansan island. Marine reserve in Techeng island is the most vulnerable to pollution. Under the condition of calm wind, the affected area of oil spill is the widest. Under the condition of flood tide and calm wind, the area of oil film sweeping the sea after 24 hours is the largest, and the affected area of oil spill reaches 57.89 km². The oil film is most easily adsorbed on the top shoreline of Zhanjiang Bay.

Exchangeable phosphorus in natural sediments plays an important role in regulating phosphorus concentration in water columns, and it is one of the focuses considered in the prediction and regulation of water eutrophication. The intercept method is usually used to calculate the concentration of exchangeable phosphorus in sediment which is positively correlated with the solid concentration (C_s). However, this result is contrary to that obtained by the extraction method. This study discusses the potential causes of the contradiction through theoretical and experimental analyses. The results show that the phosphorus from the intercept method is not the total amount of native absorbed phosphorus (NAP), but the amount of phosphorus (Q₀) involved in the exchange process under actual experimental conditions. For the same set of experimental data, the selection of the abscissa for the adsorption isotherm affects the correlation between Q₀ and C_s: negative when C₀ is used, but positive when C_e is used. In addition, if C_e is taken as the abscissa, the physical meaning of the calculated Q₀ is unclear.Therefore, in order to avoid the positive correlation between C_s and Q₀, we suggest that the initial phosphorus concentration (C₀) should be used as the abscissa when obtaining Q₀ by the intercept method.

To investigate the effects of different diets on Scylla paramamosain after feeding for 56 days, multiple indexes including body weight, specific growth rate (SGR) and hepatopancreas index (HSI) were compared among four different diets (HM-Hypophthalmichthys molitrix, CF-crab compound feed, EF-eel feed, SC-Sinonovacula constricta). In addition, biochemical composition, serum biochemical indexes, hepatopancreas biochemical indexes and digestive enzyme activities (Protease, LPS, AMS) were calculated. The results showed that SGR of SC was significantly higher than that of other diets (P<0.05). In terms of serum biochemical, TP content of EF diet was significantly lower than that of other diets (P<0.05). In terms of hepatopancreas biochemical indexes, there was no significant difference in TP content among four diets (P>0.05), ALB content of EF diet was significantly lower than that of other diets (P<0.05). TG content of CF diet was the highest among all diets. Among the biochemical enzyme activity indexes, SOD activity in HM diet was significantly lower than that in other diets (P<0.05) while Na⁺K⁺-ATPase activity in EF diet was the lowest among all diets. In terms of digestive enzymes, there was no significant difference in protease and AMS in four diets (P>0.05) while LPS in HM diet was significantly higher than that in other diets (P<0.05). In terms of the correlation analysis, the specific growth rate of HM diet was positively correlated with protease activity (P<0.05). To sum up, Sinonovacula constricta was the best diet with the best comprehensive index under the condition of "crab apartment", which has great advantages in SGR and biochemical enzyme activity indexes. But crab compound feed has certain advantages in hepatopancreas TG content and hepatopancreas biochemical indexes.

Using mature sporophyte of Laminaria digitata as material, the zoospores are released and attached to form embryo spores, and then cultured under different environmental factors. To explore the optimal environmental conditions for gametophyte formation, ovulation and young sporophyte formation of L. digitata, the process and characteristics from embryo spore to seedling formation were observed. The results showed: nitrogen concentration of 4 mg/L, phosphorus concentration of 0.4 mg/L, temperature of 15℃, light intensity of 20 μmol Photons/(m²·s) was the optimal conditions for gametophyte formation; Nitrogen: phosphorus concentration of 4 mg/L: 0.4 mg/L, temperature of 10 ℃, light intensity of 40 μmol Photons/(m²·s) were the optimal condition for L. digitata gametophyte ovulation; Under the nitrogen concentration of 4 mg/L, phosphorus concentration of 0.4 mg/L, temperature of 10-15 ℃, light intensity of 40 μmol Photons/(m²·s), the formation of L. digitata young sporophyte was most favorable. This study indicates that the optimal environmental conditions at different growth and development stages of L. digitata are different. The data obtained in this study can provide theoretical basis and data support for artificial seed breeding and breeding of L. digitata.

According to survey and analysis of the sediment environment in Xiaohai lagoon of Wanning, the extent of surface heavy metals is used to assess the geoaccumulation index, enrichment factor and potential ecological risk index. The results showed that the average values of Zn, Cd, Pb, Cu , As, Hg in the surface sediment are 36.1 mg/kg, 0.09 mg/kg, 24.7 mg/kg, 4.0 mg/kg, 7.62 mg/kg and 0.100 mg/kg. The TOC is 0.42% and acid volatile sulfide (AVS) is 226.75 mg/kg. The sediment of Xiaohai lagoon area belongs to the first category of marine sediment quality standards. Zn, Cd, Pb, Cu, As and Hg showed a decreasing trend from 2005 to 2011, the average values of Zn, Cd, Pb and Cu were the lowest in 2011. The carbon cycle of Xiaohai lagoon was balanced, which was related to the comprehensive treatment. The ecological environment was improved and less affected by human beings of mariculture. The trend of TOC change rose from 1988 to 2004, reaching its peak of 1.20%, which was related to the vigorous development of mariculture. The trend of TOC was downward after 2004 and approached the value before 1988 in 2011. The correlation analysis shows that AVS, TOC, Cu, As and Hg had the same or similar pollution sources, which are related to mariculture and industrial waste water input. The averaged pollution degree of the geoaccumulation index and enrichment factor of heavy metals was decreased in the following order: Hg＞Cd＞Pb＞As＞Zn＞Cu. The mean potential ecology risk index (RI) value of heavy metal in Xiaohai was 219.76, which belongs to moderately potential ecology risk. The potential ecology risk index of 6 heavy metals was in the following order: Hg＞Cd＞As＞Pb＞Cu＞Zn. Hg and Cd were major potential ecology risk factors. The pattern of RI change was 2008<2011< 2005. Therefore, more attention should be paid to Hg and Cd pollution in order to prevent further deterioration of ecological marine environment of Xiaohai.

Landsat imagesare used to extract the coastline of Yancheng from 1997 to 2017, and the baseline method is used to quantitatively analyze the changes of the coastline. The results show that during the 20 years from 1997 to 2017, the length of the Yancheng coastline has not changed much, but the proportion of artificial shorelines has increased gradually. The eroded coastline is located between Guanhe estuary and Sheyang estuary, with the abandoned Yellow River estuary as the center. The average changes of the coastline is -0.46 m/a. The silt coastline is distributed between the Sheyang and Beiling estuaries,with an average change rate of 140.6 m/a over 20 years, and with a change rate of 305.16 m/a, 160.79 m/a, 121.02 m/a, and 102.86 m/a every 5 years. Coastal silting is slowing down, and the extent of coastline advancement to the sea is decreasing year by year. The north-south erosion and inflection point extend southward to the vicinity of the Sheyang salt field. Agricultural reclamation, breeding reclamation, port and coastal protection engineering construction are the main reasons for the changes of the coastline of Yancheng.

Water depth is an important topographical element in shallow seas. It is an important part of ocean mapping. Using remote sensing to retrieve water depth, underwater terrain can be obtained quickly and efficiently. Using WorldView-Ⅱ multi-spectral remote sensing image and laser measured data, BP neural network model, random forest model and extreme learning machine model are used to conduct water depth retrieval in Ganquan island of Sansha city, Hainan Province, and the accuracy is compared and evaluated. The results show that among the BP neural network model, the random forest model and the extreme learning machine model, the random forest model has the highest water depth retrieval accuracy. The root mean square error of the verification point is 0.85m, the average absolute error is 0.60m, and the average relative error is 3.54%. The coefficient of determination R² reaches 0.97; within the range of 0-10 meters and 15-20 meters water depth, the retrieval of the extreme learning machine model is the best; in the range of 10-15 meters water depth, the random forest model has the best retrieval effect.

Based on the survey data of 46 stations Qinhuangdao sea area in Summer2013, distribution of hlorophyll a concentration and its relationship with environmental factors water temperature, salinity, chemical oxygen demand, dissolved oxygen, active phosphate and inorganic nitrogen were , and the nutritional status of Qinhuangdao sea area was evaluated. The results showed that the concentration of chlorophyll a ranged from 0.50 to 7.79 μg·L^-1 with an average of 2.10±1.38 μg·L^-1. The horizontal distribution of chlorophyll a tended to near shore and off shore. Through the correlation analysis chlorophyll a concentration environmental factors and the analysis of nitrogen/phosphorus ratio (N/P), itfound that the active phosphate the main of chlorophyll a concentration. According to the evaluation of nutritional quality index (NQI) and eutrophication index (EI), the overall nutritional status of Qinhuangdao sea area was poor.

Three investigations of phytoplankton were carried out in Nanwan Reservoir in Mar., May and Sept., 2016. Phytoplankton and water samples were collected simultaneously. The common water quality indicators such as total nitrogen, total phosphorus and the permanganate index were analyzed. The stress response was analyzed based on phytoplankton abundance-biomass curves and the relations between water quality and phytoplankton community. The results showed that the water quality indicators changed significantly. Except permanganate index in May, most of the indicators were lower and can meet with II or III water quality standards. The abundance-biomass curve based on phytoplankton showed that the water body was subjected to a large environmental disturbance in May and reduced to a heavy pollution stage in Sept.. Further analysis of the relationship between water quality factors and phytoplankton community showed that organic pollution (permanganate index) is the main pollution factor which was related to the intense agricultural production activities in spring.

To study the effects of immobilized culturing method on the growth of marine microalgae, their pigment contents and their chlorophyll fluorescence parameters, we conducted this work by using Chlorella sp. as the material, sodium alginate (SA) as the carrier and calcium chloride (CaCl₂) as the linker. The effects of immobilized and liquid suspension culturing methods on the cell density, photosynthetic pigment contents, chlorophyll fluorescence parameters of Chlorella sp. were determined. The results showed that (1) the cell density of the immobilized and suspended Chlorella sp. was significantly different (P<0.05), the cell density of immobilized Chlorella sp. was significantly higher than that of the liquid suspended Chlorella sp. at the late growth stage (days 6 - 10); (2) there was a significant difference in photosynthetic pigment content between immobilized and suspended cultures of Chlorella sp. (P<0.05), the contents of chlorophylls a and b and carotenoids of Chlorella sp. of immobilized alga were all higher than those of the suspended at the middle and late growth stages (days 4 - 10); and (3) the chlorophyll fluorescence parameters of immobilized and liquid suspended Chlorella sp. were significantly different (P<0.05). The potential vigor and actual light energy of immobilized Chlorella sp. at the later growth stage were higher than those of the suspension cultured. The conversion efficiency and quantum efficiency of fixed Chlorella sp. were significantly higher than those of suspension cultured alga (P<0.05). In summary, the immobilization culture significantly promoted the growth and photosynthesis of Chlorella sp.

In order to enhance the prediction ability of the wave risk level in the key notes of the 21^st-Century Maritime Silk Road, in this paper, we evaluated the wave risk index and made statistics on the wave risk level in the Sri Lankan waters based on the ERA-interim reanalysis data. Our findings has a practical reference value for disaster prevention and mitigation, coastal development and coastal zone management in the future. Single index of wave risk based on wave height or wave period cannot replace each other, and single index of wave risk level cannot fully represent the real sea conditions. Under the double indicator assessment of wave risk, the spatial and temporal distribution of wave risk index in Sri Lankan waters shows obvious seasonal differences. The waves with a risk level of III accounts for the largest percentage. The large value area is mainly distributed in the small areas of the west and south of Sri Lanka. According to the distribution of the annual average wave risk index, the risk level of small area has reached level 1, but 75.72 % of sea area is at level III. The assessment of double indicator of wave risk more comprehensively reflects the real sea situation.

The influence of the bioturbation by macrobenthos on the physic-chemical characteristics of the sediment is an important content to understanding biochemical processes in the sediment and on the sediment-water interface, and also plays an active role in the implementation of ecological restoration. Some studies on the bioturbation to the physical and chemical characteristics of the sediments, including experiments in laboratory as well as researches in situ, are reviewed in the present paper. The ability of macrofauna changing the physical structure of sediment is related to biological functional groups, and the bioturbation affects the distribution of particle sizes in sediment. Generally, the bioturbation promotes the migration and releases nutrients as well as heavy metals from sediment to water column, which would reduce the sediment pollution but possibly increases the level of water pollution. The oxidation-reduction state of sediment is also altered by bioturbation and affects other biochemical processes. Finally, based on this review, further studies on bioturbation at community level as well as the functional parameters of bioturbation are suggested.

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.

In recent decades, the traditional marine fishery resources in the coastal waters of China have declined and the offshore fisheries resources have become "hollow", thus the foundation of sustainable development of fishery is not firm. From the perspective of the resource economics, in this paper, we analyzed the economic reasons for the decline of offshore fishery resources and the hollowing of resources. By combining with the blue growth idea put forward by FAO, we probed into the economic and social benefits brought by the green development at home and abroad, and made some suggestions on realizing the capitalization management of fishery resources, expanding the reproduction of resources, and transforming the property right of fishery shared resources among other. Our analysis will provide a reference for the green development of offshore marine fishery of China.

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.

Erosion has a great influence on the bearing capacity and safety stability of the existing structure foundation. The prediction of the final erosion depth of the structure foundation provides a theoretical basis for the design of the structure foundation.The study on protection caused by erosion of structure foundation has been paid more and more attention. Compared with the advantages and disadvantages of traditional protection methods, it is found that the existing traditional protection methods have great limitations in protecting structure foundation in the deep sea.

This article focused on reviewing the main research achievements of domestic and foreign scholars on the path, influence mechanism, seasonal and interannual variability of the Kuroshio intrusion into the South China Sea, as well as its impact on the South China Sea circulation, water mass properties and mesoscale eddies in the past two decades. The path of Kuroshio's intrusion from the Luzon Strait into the South China Sea could be divided into three forms, and the transportation in the Luzon Strait presented a “sandwich structure”. Kuroshio intrusion was influenced by monsoon, sea pressure gradient, mesoscale vortex, β effect, sea pressure gradient, ENSO, PDO, typhoon and other factors. Due to the influence of the Kuroshio's own intensity and the East Asian monsoon, the intensity of the Kuroshio's intrusion into the South China Sea was greater in winter than in summer. Interannual variability depended on El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). ENSO and PDO controlled the kuroshio's intrusion intensity by affecting the location of North Equatorial Current bifurcation. Kuroshio water, as part of Indonesian throughflow, brought high-temperature salty water to the South China Sea, or shed anti-cyclonic eddies to affect the South China Sea mesoscale eddy structure.

Yangtze River Basin is rich in biodiversity and bioresources and an important ecological protection zone in China. In recent years, degradation in Yangtze River Basin wetlands has been becoming more and more serious. The ecological compensation of wetlands is an effective mean of protecting Yangtze River Basin. Taking the planning project of Tongzhousha Ait ecological wetland as an example, the compensation framework for Yangtze Island wetland compensation standards was constructed by drawing on the calculation framework of land acquisition compensation and river basin ecological compensation. Based on economic theory and by using the methods of market price, opportunity cost, replacement cost, shadow engineering, results reference, expense method among other, we found that Yangtze island wetland ecological compensation standards take the opportunity cost as the lower limit and the ecosystem service value as the upper limit. The results showed that the opportunity cost of Tongzhousha Ait ecological wetland is 166.5364 million yuan (RMB), the resident cost (breeding compensation, unemployment compensation) accounts for 4.14%, and the enterprise cost (relocation compensation, resettlement compensation) accounts for 95.86%. The value of ecosystem services is 217.6265 million Yuan (RMB), maintenance services (biodiversity compensation) account for 23.45%, regulation services (gas regulation compensation, pollution purification regulation compensation) account for 19.36%, and cultural services (research and education, leisure tourism) account for 57.19%. The ecological compensation standards proposed by the planning project is 180.83 million Yuan (RMB). Between the upper and lower limits of the compensation standards measured in this study, there is a high degree of agreement with the characteristics of the study area, which has a certain rationality. This provides a scientific guidance for improving the benefits of ecological compensation in Yangtze River Basin.

In order to improve the accuracy of fishery resource abundance prediction, Catch per unit effort (CPUE)used as an indicator of the abundance of albacore tuna (Thunnus alalunga) resourcesmarine environmental factors such as marine remote sensing and Argo. Based on the xtreme gradient boosting model (XGBoost), onvolutional neutral network (CNN)used for feature extraction of high-dimensional marine environment data, and imulated annealing algorithm (SA)used to optimize XGBoost model. An improved XGBoost model CNN-SA-XGBoost model was proposed to realize the regression prediction of the abundance of albacore tuna resources in the South Pacific. Experiments show that in the prediction of abundance of albacore tuna resources in the South Pacific, the root mean square error of the CNN-SA-XGBoost model is 0.486, 12.4% lower than XGBoost. Compared with ultiple linear regression and andom forest(RF), BP neural network and other models reduce the prediction error by 11.828.4%. he improved XGBoost model improved the traditional resource abundance forecasting model to a large extent when it face high-dimensional environmental data and fishery production data with many missing values, which provides a new method for the prediction of pelagic fisheries.

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.

It is clear that the intrinsic relationship between the use fee of non-residential islands and their ecosystem damage cost is crucial. In this paper, we explained the scientific connotation of the use fee of non-residential islands and their ecosystem damage cost by comparing the cost composition, evaluation scope and assessment indicators. The results showed that the intersection between the two aspects of the island body is the natural attribute change fee. The current uninhabited island use fee does not include natural property change fee of the intertidal zone and surrounding waters system of non-residential islands, and their ecological restoration cost. Therefore it is difficult to fully reflect islands ecosystem damage cost. In order to scientifically determine non-residential islands use fee, it is recommended to enrich non-residential islands natural attribute change fee, and add islands ecosystem damage cost to non-residential islands use fee. Our suggestions should provide a reference to non-residential islands use fee assessment.

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 explore the expression and cold tolerance function of LOC_Os10g05490 in rice under cold stress, semi-quantitative analysis was performed for Dongxiang wild rice and 93-11. The results showed that expression level of LOC_Os10g05490 in 93-11 was the same before and after cold stress, but it was down regulated in Dongxiang wild rice after cold stress. This was consistent with RNA-seq data and further study indicated that this gene might be associated with cold tolerance in Dongxiang wild rice. Plant expression vectors with CRISPR/Cas9 genome editing technique were subsequently constructed to target the LOC_Os10g05490 locus, and were transformed into the japonica rice variety TP309. A total of 26 transgenic positive plants were obtained. This study may lay the foundation for subsequent screening of mutant plants and identification of genes associated with cold tolerance in rice.

In order to assess the aquaculture environmental quality of Dongtou sea area, 24 sea water samples and 24 surface sediment samples were collected from aquaculture areas of Dongtou and the contents of heavy metals including Hg, As, Cu, Pb, Zn, Cd and Cr were determined. Then the levels of heavy metal pollution in sea water and surface sediment were evaluated by single factor method and comprehensive pollution index. The potential ecological risk of heavy metals in sediments were evaluated by Hankanson potential ecological risk index. The results showed that the contents of seven heavy metals in sea water of the aquaculture areas investigated were below the standard values by the national standard of mariculture sea water quality. The Hg, As, Pb, Cd and Cr quality in surface sediment conformed to the first grade by the national standard of marine sediment quality which was suitable for aquaculture. However, the single pollution index of Cu and Zn in sediment were a bit more than 1, it means that the sediment quality was slightly polluted. When the geochemical background values of sediments in the Yangtze estuary offshore marine areas were used as reference values, the degree of heavy metals potential ecological risks was in the order: Hg＞Cd＞As＞Cu＞Pb＞Zn＞Cr and Hg contributed the most to the total potential ecological risk. The potential ecological risk indexes (RI) of 7 heavy metals at all aquaculture areas were in the range of 129.31 and 157.45, and posed medium level potential ecological risks for the Dongtou sea area.

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.

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.

According to relevant codes, the durability mechanism of concrete damaged by chloride ion and the durability design contents of port structures are summarized. A port project is taken as an example, based on the natural condition, Life-365 software is used to calculate the design life of concrete structure. The calculation results show that the design life of the concrete based on the model can meet the requirement of the code, which is 50 years. In the meantime, the sensitivity analysis is carried out to find out the factors affecting the durability of port structure. It provides a reference for the durability design of other port project in China, especially in high chloride environment.

MIKE21 BW was applied to study the waves of four design schemes of marina in Colombo port city. The results showed that the layout of the breakwater near the entrance of the marina had a significant influence on the wave protection effect of the marina basin. The breakwater with linear shape near the entrance had the worst wave protection effect on the marina basin, which could not meet the requirement that the effective wave height of 50-year return period was less than 0.4m. The breakwater near the entrance was in the form of inward encircling, which had a good wave protection effect on the marina basin, and the protection effect of the inward encircling curvature of 0.0059 was better than that of the curvature of 0.005. The breakwater with outward flip at the end of the breakwater had the best wave protection effect.

This study used the cross-section topographic data of the river channel of the lower Yellow River reaches to systematically calculate the inter-annual and seasonal erosion-deposition volume of the main river channel from 1992 to 2011. The major results were presented as follows. From 1992 to 1999, the river channel of the lower Yellow River reaches silted continuously, with a cumulative siltation volume of 1.090 km³. After 2000, the channel shifted from siltation to erosion with a total volume of 1.597 km³ by 2011. On seasonal scale, two-stage pattern of channel evolution was presented. During the flood season from 1992 to 1999, the lower reaches of the Yellow River accumulated 1.471 km³, about 1.4 times of the annual siltation volume. Erosion dominated during dry seasons with a total of 0.473 km³, accounting for 32% of the siltation volume during the flood season. During the flood season from 2000 to 2011, the channel shifted from siltation to erosion with an accumulated volume of 1.148 km³, accounting for 75% of the annual erosion of the lower Yellow River. The erosion flux during dry seasons in 2000-2011 gradually decreased, and the cumulative erosion during the period was 0.381 km³, only 25% of the annual amount. Changes in water and sediment conditions as well as river channel features played critical roles in the evolution process of the river channel in the lower Yellow river reaches. After the implementation of the Xiaolangdi reservoir, the coefficient of sediment incoming decreased significantly, resulting that the river channel turned from siltation to erosion. The river regime coefficient of the lower river channel had dropped overall, and the lower river channel had become more stable.

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.

This paper uses the ERA5 grid point data of the European Center for Medium-Range Weather Forecasts, as well as sounding and automatic station observation data, to observe and diagnose a sea fog process that occurred in Qingdao offshore on April 27, 2021. Before the occurrence of the sea fog, the rainfall in the Huanghuai and Jianghuai regions provided abundant water vapor for the surface atmosphere. With the change of the surface wind direction to the southwest wind, the warm and humid air flowed from the northeast of Jiangsu to the offshore of Qingdao under the action of the offshore wind, and generates advection cooling fog when encountering the cold sea surface. Analysis of sounding data shows that there are two temperature inversion layers in this process. Sea fog is generated under a lower temperature inversion layer, and the fog layer is thinner. There are low clouds below the upper inversion layer, and the height continues to decrease due to the weak subsidence movement. The existence of strong southwest warm and humid air flow in the lower layer, coupled with the slow development and movement of cold air, and the relatively stable circulation situation on the sea surface make the sea fog maintain for a long time and with the influence of Northwest air flow, the fog layer dissipates.

Based on the monthly average wind speed and significant wave height of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 from 1979 to 2019, the temporal and spatial characteristics of wind speed and significant wave height were analyzed. The Mann-Kendall test method was used to analyze its inter-annual variation and the Empirical Orthogonal Function (EOF) analysis method was used to study the spatial distribution characteristics. The results showed that: (1) The wind direction of the South Atlantic Ocean rotated counter clock wise with 30°S and 10°W as the center. The areas with high wind speed were mainly controlled by the southeast trade wind belt and the west wind belt, and the low value areas were controlled by the subtropical high and low pressure zone. The wind speed in winter was higher than other seasons, and the wind speed and wind direction distribution throughout the year were related to the seasonal changes of the weather system. (2) There was a strong correlation between wind speed and significant wave height, and both of them were distributed in a zonal ring shape. The overall significant wave height was the largest in winter and smaller in summer. (3) Mann-Kendall test results showed that the inter-annual variation of wind speed and significant wave height both showed an upward trend. The wind speed had abrupt changes around 2006 and 2009, and the significant wave was higher than around 1994 and had abrupt changes. (4) The first mode of EOF of the wind speed showed that the trade wind belt-westerly belt and the subtropical high belt-low pressure belt were distributed in the opposite pattern. The wind speed of the former showed a significant upward trend, and the latter showed a downward trend. The first modal of EOF of the significant wave height showed that the significant wave height variability in the north sea area of 60°S was the positive phase, and the south was the negative phase. The significant wave height in the positive phase region had a significant increasing trend, and the significant wave height in the negative phase region had a significant decreasing trend.

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.