Abstract:In this paper,the high-order spectral model HOS was used to simulate the waves in the northern South China Sea.First,the wave model WAVEWATCH Ⅲ was used to simulate the waves in the target sea area,extracted the two-dimensional wave spectrum of the extreme process,and used it as an open boundary condition to simulate the wave surface time series of 12 typhoons in the northern South China Sea under extreme wave conditions.Through the processing and analysis of the wave sur-face time series,it was concluded that the waves in the target sea area were strongly nonlinear,and ab-normal waves appeared at some measuring points.

Abstract:The study of the statistical characteristics of the sea clutter amplitude of the high-resolution millimeter wave radar is of great significance to improve the detection technology of small targets at sea,but there are relatively few studies on this problem.This paper was based on a large number of measured data on the amplitude statistical characteristics of the calm sea surface and the broken sea sur-face under the action of the 77GHz radar.Firstly,the logarithmic accumulation parameter estimation formula of the classical K distribution model was innovatively derived,and then the commonly used Rayleigh distribution,lognormal distribution,weibull distribution,generalized gamma distribution,K distribution moment estimation,maximum likelihood estimation and logarithmic accumulation method estimation method were analyzed in combination with the measured data,and the best amplitude fitting distribution under different scenarios was discussed.The results showed that the K distribution model of the logarithmic accumulation method estimated by the logarithmic accumulation method under the calm sea surface was optimal,followed by the generalized gamma distribution,the lognormal distribu-tion under the broken sea surface,and the generalized gamma distribution was the best under the bro-ken sea surface.

Abstract:Correctly identifying the spatial variation characteristics of lake water quality and analyzing the pollution sources are the basis for scientific and efficient comprehensive lake management,monito-ring and management.Based on the multivariate statistical analysis method,the spatial variation char-acteristics of water quality in Bosten Lake were explored and the main pollution sources of the lake were analyzed.The results showed that the chemical oxygen demand and suspended solids in Bosten Lake were highly variable(coefficient of variation＞1),indicating that the two indicators were uneven in spa-tial distribution and highly sensitive in characterizing the spatial variation of water quality in the lake.The other water quality indicators were of medium variability(0.1＜coefficient of variation＜1).The sampling points were divided into two groups by Q-type cluster analysis:the sampling points of group I basically covering the large lakes(except sampling point N19)and the southern part of the small lakes,and the sampling points of group Ⅱ mainly located in the northern part of the small lakes.Dur-ing the study period,group Ⅰ was class Ⅲ water and met the objectives of class Ⅱ water function zone,and group Ⅱ was class Ⅳ water,which was inferior to the objectives of water function zone.The water quality in the great lakes region and the southern part of the small lakes region was relatively good,while the water pollution in the northern part of the small lakes region was relatively serious,mainly organic pollution,nitrogen and phosphorus nutrient salt pollution and physical pollution.The sources of pollutants were urban domestic sewage,farmland drainage and industrial wastewater.This study can provide reasonable guidance for the prevention and control of targeted pollution in Bosten Lake.

Abstract:A new round of shoreline survey led by Ministry of Natural Resources has established the le-gal and managemental basis for the separation of land and sea,which takes the average spring tide high tide line as the boundary between land and sea.Such adjustment of coastline position has made the sea area certificate landside and the land certificate seaside more prominent,resulting in a special situation of regional spatial planning and use control.Based on sorting out these two types of problems,and in combination with relevant research and policies,in this paper,we put forward corresponding policy guidance and work suggestions according to the actual situation.We suggested to(1)accelerate the promotion of the statutory coastline and establish the annual coastline change investigation system and the five-year survey mechanism;(2)guide and control the development and protection of two sides with spatial planning;(3)define the policy of land certificate renewal for reclamation in stock;and(4)issue special documents to clarify the regional management policy of land certificate in the sea,strictly control the new reclamation,ease the ownership contradiction by new ways such as three-dimensional confirmation of rights,and explore the establishment of a voluntary exit mechanism of land certificate on the sea side.On the premise of obtaining land use approval procedures,stock land should be ap-proved once non construction land was determined by the third national land survey,and construction land should be managed once the construction land was determined.Actively exploring the mechanism underlining the linkage of disposal of stock reclamation with the total amount of new construction land indicators in the region,and implementing the requirements of development concession distance and the lower limit control of ecological space reservation were highly appreciated.

Abstract:The Optimum Interpolation Sea Surface Temperature data(OISST V2)was tested by using the anchor buoy data in the Bohai Sea area from two aspects of data reproducibility and statistical eigen-value calculation.OISST V2 data has high reliability.The TOISST V2 data was used to study the long-term variation trend of surface sea temperature in the Bohai Sea from 1981 to 2021.The results showed that the whole Bohai Sea area had a warming trend.The annual average variation rate of SST in 41 years was 0.028 ℃/a,the maximum annual average variation rate appeared in the south of the Bohai Bay,and the minimum annual average variation rate appeared in the east of Liaodong Bay.In winter,the average warming trend of the Bohai Sea was 0.005 1 ℃/a.The central part showed a warming trend,while the coastal Bohai Bay,Laizhou Bay and Liaodong Bay showed a cooling trend.In summer;the Bohai Sea had a warming trend,with an average warming rate of 0.011 ℃/a.EOF decomposition of OISST V2 sea surface temperature anomaly data was used to analyze the spatiotemporal characteristics of SST in the Bohai Sea.The main modes of its spatial distribution had overall consistency,and the sig-nificant period of time coefficient was annual period.

Abstract:To know the community structure of zooplankton in the sea area near Xiaoqing River estuary of Laizhou Bay and its relationship with environmental factors,the eutrophication degree of water qual-ity,species composition,dominant species,community structure of zooplankton and the correlation be-tween species diversity and environmental factors were analyzed based on the investigation data in March(spring),2022.The results showed that eutrophication occurred in all stations in the investiga-ted sea area,and a total of 12 species and 3 taxa of zooplankton were found.The average individual density of zooplankton was 1100.0 inds./m3,the average biomass(wet weight)was 732.0 mg/m3,the average Shannon-Wiener index(H'),Margalef's species richness diversity(d)and Pielou's evenness index(J')were 1.71,0.93,0.67,respectively.The dominant species were Pseudodiaptomus pople-sia,Sinocalanus tenellus,Acartia omorii and Eurytemora pacifica.Cluster analysis showed that the zooplankton in the investigation area can be divided into three groups.The results of correlation analy-sis showed that water temperature was an important environmental factor affecting the biomass and in-dividual density of zooplankton in the sea area.

Abstract:Algae are the most important primary producers in aquatic ecosystems.However,in recent years,harmful ecological phenomena like"water bloom"in freshwater,and"red tide","green tide"and"golden tide"in seawater have frequently been appearing,which have greatly impacted the aquatic ecosystems including lakes,ponds and oceans.The buoyancy control and regulation of these algal blooms is the key to determine their floating life and becomes an important link in the process of algal blooms.In this paper,the regulation mechanism of algal buoyancy and the latest research progress of the effects of light,nutrients,CO2 and other important water environmental factors on algal buoyancy were summarized.Some special structures of algae,such as air bags and hollow tubular bodies,provide positive buoyancy for algae when they are filled with air,while the cell ballast mainly composed of car-bohydrates can counteract the positive buoyancy.Algae float up at the lower light level,and sink at the higher light level.Nitrogen limitation reduces the buoyancy of algae more significantly,compared with phosphorus limitation.The buoyancy of algae rises at high CO2 concentration and high temperature.Therefore,the vertical position of algae in water is comprehensively affected by multiple environmental factors.In this review,we summarized the research progresses in algal buoyancy,provided some theo-retical references for further prevention and control of harmful algal blooms.

Abstract:To explore the community characteristics of microorganisms and biomasses of large organ-isms attached to the surface of different types of artificial reefs,three types of hanging plates were set up in this study with the surfaces sprayed with nutrient solution(YY and YY2),preservative(FF and FF2),and the control without any substance(DZ and DZ2).The hanging plate experiment was carried out at an artificial reef zone in Laoshan Bay under different temperature conditions.Two months after the hanging plates were released into the sea,the biomass of the surface samples collected from the plates was measured with dry weight method,and the microbial community structure and function each sample were analyzed using metagenomic sequencing method.The results showed that the attached or-ganisms on the surface of the hanging plates were mainly barnacles and carex.The biomass on different hanging plates was in an order of YY＞DZ＞FF,YY2＞DZ2＞FF2.Spraying nutrient solution showed proliferation effect on the attached organisms whereas spraying preservative had inhibition effect.At phylum level,the attached microorganisms mainly included Ascomycota,Proteobacteria,Firmicutes and Bacteroidetes.The category of attached microorganisms on the three types of hanging plates are highly consistent with slight difference in abundance.At the genus level,the main microor-ganisms are Colletotrichum,Bacillus,Vibrio,Pyricularia,Cycloclasticus and Nitrosopumilus.There are many bacteria with harmful effects on plants,among them marine ammonia-oxidizing and PAHs degrading bacteria reproduce more vigorously in low temperature environment.In terms of mi-crobial gene function,the genes functioning inof"replication,recombination and repair","amino acid transport and metabolism","translation,ribosome structure and biosynthesis"among others are the most common.The gene of"replication,recombination and repair"are more advantageous at high tem-perature than that at low temperature.Our findings can provide a scientific basis for reef material selec-tion,ecological restoration and follow-up study of ecosystem functions in artificial reefs.

Abstract:In this paper,a novel π-shaped plate-type permeable breakwater with wave baffles arranged on the arc plate was proposed to improve the wave dissipation performance.The numerical model sol-ving the wave-breakwater interaction was established based on OpenFOAM and validated using experi-mental results.The effects of relative submergence depth,relative wave height,relative height of wave baffles,and relative width of plate on the wave dissipation performance of the proposed breakwater were studied numerically.The results showed that the transmission coefficient decreased with increas-ing relative width of plate and relative height of wave baffles,and increased with increasing relative submergence depth.The reflection coefficient presented the opposite trend with the transmission coeffi-cient.The amplitudes of decrement of transmission coefficient and increment of reflection coefficient both decreased with increasing relative height of wave baffles.The results of this paper provide valua-ble information and significant guidance for designing an effective permeable breakwater in practical en-gineering application.

Abstract:Silky shark(Carcharhinus falciformis)is caught as an important bycatch in tropical tuna longline fishery,which situates at the top of the marine food chain as an apex predator and plays an im-portant role in maintaining the balance of the marine ecosystem.Silky shark stock is in decline under o-verfishing and it has been listed for protection under Appendix Ⅱ of the Convention on International Trade in Endangered Species of Wild Fauna and Flora in 2017.Based on the sample data(5 617 ind.)collected by Chinese longline fishery observers in tropical Pacific(90°55′W～139°58′E,37° 20′ N～36°49′S),preliminary analyses of catch rate,sex ratio and fork length were conducted.Higher catch per unit effort(CPUE)was found in area of 105°W～165°E and 10°N～20°S.There was a decline trend of CPUE of silky sharks from year 2015 to year 2019(the highest in 2017).There was a significant difference between years(P＜0.05),but monthly CPUE was higher from June to October,with a sig-nificant difference in CPUE between months(P＜0.05).The overall dominant fork length(FL)of fe-males and males ranged from 90 to 170 cm.The ratio of females to males conformed to 1∶1(P＞0.05).The dominant fork lengths varied between 90 and 110 cm for females and males in tropical west-ern and central Pacific,and between 150 and 170 cm for females and males in tropical eastern Pacific.There were significant differences between the mean fork lengths of females and males in both seas(P＜0.05).

Abstract:The aerogels were prepared from chitosan and coconut shell fiber with freeze-drying method.The properties of the material and the removal efficiency of nutrients from mariculture wastewater by immobilized degradation bacteria were investigated.The experimental results showed that the modified aerogel has a good floatability and a mass transfer performance,the adsorption kinetics accords with quasi first order kinetic model and sorption isotherm with Langmuir model.The improved aerogel could efficiently adsorb COD(chemical oxygen demand),ammonium and nitrite degrading strains,with an increase of 48.82％,9.14％and 40.74％compared with free bacteria,respectively.In the simulated shrimp pond,the degradation rates of COD,ammonium and nitrite were 52.6％,55.55％and 98.49％respectively within 10 days.

Abstract:During the penetration process of the side-rounded caisson,the soil in the caisson will be high.Too high soil height will make the bucket foundation unable to be installed to the specified depth,thus failing to provide the designed bearing capacity.In practical project,bucket boots are used to im-prove the penetration capacity of the caisson.Therefore,it is necessary to analyze the penetration re-sistance of the caisson under different bucket boots forms and the height of the soil in the caisson to provide a reference for engineering applications.This paper used the Coupled Euler-Lagrangian(CEL)method to simulate the penetration process of the side-rounded caisson,and compared it with the field test data.The result fitted well,which confirming the effectiveness of this method.The influence of the bucket boots form on the end resistance and the height of the soil in the bucket,the influence of the wall thickness and soil weakening parameters on the volume of the soil in the bucket were analyzed.The results showed that the larger the chamfer of the bucket boot,the smaller the end resistance,and the outer chamfer of the bucket base was easier to reduce the height of the soil in the bucket during the penetration process.The greater the wall thickness of the caisson and the sensitivity coefficient of the soil,the greater the soil volume increased ratio of the caisson,the greater the ductility coefficient of the soil,and the smaller the soil volume increased ratio.Finally,the soil volume increased ratio in the bucket was fitted according to the calculation results.The formula of the soil volume provides a refer-ence basis for the engineering installation.

Abstract:Fish composition diversity is an important part of aquatic biodiversity,and it is difficult to in-vestigate fish diversity with traditional resource investigation methods.In order to understand the main fish species and structural characteristics in Liuheng sea area,in this study,we used environmental DNA technology to investigate the fish communities in Liuheng sea area of Zhejiang Province.Water samples were collected from different stations and the environmental DNA was extracted.Through PCR amplification and high-throughput sequencing,37 common fish species were detected among 23 samples of environmental DNA,whicn belong to 36 species in 30 genera of 8 orders,18 families and 8 orders of Actinopterii,and 1 species in 1 order,1 family and 1 genus of Chondrichthyes.Among them,Harpadon nehereus,Larimichthys polyactis,Sebastiscus marmoratus,Muraenesox cinereus and En-graulis japonicus had relatively high abundance.The results showed that the environmental DNA technology has a high similarity with the traditional survey methods.Although it can not completely replace the traditional resource survey methods,it can be used as a supplementary tool to evaluate the existing situation of fish resources in Liuheng sea area and provide a basis for supplementing the diversi-ty of fish resources and population structure in Liuheng sea area.

Abstract:With the increasingly strengthening of conservation,management and enforcement imple-mented by regional fisheries management organizations(RFMO),new technical methods are needed to improve data collection and enforcement implementation.As a feasible technical method,electronic monitoring(EM)has been tested among some countries and RFMO.In order to catch up with the de-velopment speed of EM tested by RFMO,the domestic fishery EM system of China should urgently be established,especially in the tuna longline fishery managed by regional fisheries organizations,which should meet the technical standards of tuna longline fishery EM adopted by RFMO.Therefore,the dis-tant water fishery EM system of China could be adjusted and established to meet the increasingly strin-gent fishery management.In this paper,we introduced the composition,operation principle,interna-tional application and cost advantage of EM.Taking the development of EM in tuna longline fishery of the Western and Central Pacific Fisheries Commission(WCPFC)as an example,we summarized the progress of EM in the WCPFC,and clarified the development trend of EM in the organizations which may benefited by development of EM in China fishery.We investigated the trial results of EM in long-line fishery in different countries in the central and western Pacific.On the basis of combining foreign experience and the domestic development status of EM in tuna longline fishery,we made suggestions in infrastructure,technology development,system standards,talent construction among others,which may provide references for the development of EM in the longline fishery of China.

Abstract:Based on the analysis of the carbon and oxygen isotopic characteristics of planktonic foramini-fera and magnetic susceptibility in the columnar samples of TS6 core from the southern part of south-west Taiwan basin of the South China Sea,the climate evolution history of the area since the last degla-ciation was discussed.Oxygen isotope and magnetic susceptibility showed multiple climatic fluctuations since the last deglaciation,and these climatic fluctuations included Heinrich event 1,Bølling-Allerød,Younger Dryas,and multiple cold events in the Holocene.Carbon isotope records showed high produc-tivity of surface seawater in the periods of 16 kaBP～8 kaBP,which was related to the prevalence of winter and summer monsoons.Since the last deglaciation,the overall trend of the magnetic susceptibil-ity was very consistent with that of the winter monsoon.The analysis showed that the change of the magnetic susceptibility was mainly controlled by the strength of the winter monsoon.

Abstract:Tuna fishery occupies an important position in the world fishery,and is the key development industry of fishery countries and regions in the world.Based on the major tuna catch data of the world from 1950 to 2019,combined with tuna trade data,population data and GDP data of countries and re-gions around the world,the status of the world tuna fishery was summarized.The results showed that the catch of major tuna trends obviously to increase from 1950 to 2019,but the catch each species vary each other.The cumulative total catch of Katsuwonus pelamis was the highest and its average growth rate each generation was the highest.The catch of the three major bluefin tuna was low,and the aver-age growth rate of Thunnus thynnus and Thunnus orientalis was negative each decade.The catch of tu-na was greatly different among countries and regions.The total catch of major tuna of 6 developed countries and regions including Japan and the United States accounted for 56.68％of the total while that of Chinese mainland only accounted for 1.02％.In addition,the total tuna catch of 11 island coun-tries with the highest per capita tuna catch and Marshall Islands sparsely populated and rich in resources was only 4.30× 104t in 2013,Less than 10％of Japanese catch.The United States,Japan and other de-veloped countries and regions stood at the top of the world in the global economic development firmly controled the fisheries regulations of tuna in the high seas and the right to set quotas,and then the global trade in tuna.Among them,the trade volume of major tuna in Japan accounted 25％of the glob-al trade volume.The results also indicated that the tuna in the high seas are the precious resources for universal,not specific to a small number of countries and regions.To truly realize the sustainable de-velopment for world tuna fishery and the blue growth target advocated by FAO,the existing system of rule of inequality and injustice should be broken,the principle of humanity sharing blue ocean economy of new rules and new order should be formulated newly.

Abstract:The south coast of the Hangzhou Bay had significant ecological functions such as climate reg-ulation,carbon sequestration and sink enhancement,water purification and so on.However,the tem-poral and spatial distribution pattern of wetland vegetations had changed in recent years,especially the trend was more obvious after the construction of the 11th seawall in 2010,which had a certain impact on the ecological function of the wetland.Thus,our objective was to explore the change and influencing factors of the salt marsh wetland vegetations outside the 11th seawall after its construction.We princi-pally used six remote sensing images from 2010 to 2020 in this paper,we also created and used DSPI formula on the basis of NDVI index to improve the classification accuracy of vegetation,and ENVI ex-pert knowledge decision tree method was used for interpretation and analysis.The results implied that since the construction of the 11th seawall,the vegetation of the salt marsh outside the seawall had been replaced by the distribution pattern of Phragmites australis(high intertidal zone)-Spartina alterniflo-ra(middle and high intertidal zone)-Scirpus mariqueter(middle and low intertidal zone),which was originally dominated by Scirpus mariqueter.The comprehensive analysis showed that the major influ-encing factors of vegetation distribution pattern change in the study area were the environmental fac-tors,the biological factors and the human activities,in which the influencing factors would gradually change from environmental stress to biological competition with the increase of wetland elevation,while human activities would directly interfere with the natural succession of wetland vegetation.

Abstract:The seagrass bed ecosystems of coastal wetlands have important ecological functions in slo-wing down water flow,purifying water and fixing carbon.In this paper,the carbon sink effect,heavy metal absorption and enrichment effect of seagrass beds are reviewed,the sources of organic carbon in seagrass beds,the absorption,transferring and tolerance mechanisms of seagrass heavy metals are ex-plored,the impact of seagrass on the distribution of heavy metals in sediments,and the potential appli-cation of seagrass as indicator species of heavy metals in the environment are analyzed,and the environ-mental factors affecting the accumulation of organic carbon are explained.The research prospects on the carbon sink estimation of seagrass bed,seagrass monitoring and management,heavy metal form,source and ecological risk analyses,interaction studies between sediment organic carbon and heavy met-als,and application potential of seagrass as the pioneer species of ecological restoration are put for-ward.

Abstract:In the national ecological security system,the importance of coastal zone ecological security is increasingly obvious,and the demand for coastal zone ecological security research is also increasing.The coastal zone is the area with the highest concentration of human-sea relations,the most densely populated and the most active socio-economic activities.In order to scientifically evaluate the ecological security of Dalian Bay coastal zone,based on the Pressure-State-Response model,17 indicators were screened to construct an evaluation system,and the weight of the indicators was determined by using the entropy right method,and the ecological safety of the coastal zone in Dalian Bay from 2009 to 2019 was analyzed and evaluated and corresponding countermeasures were proposed.The results showed that the ecological security level of Dalian Bay increasing steadily,followed by relatively danger,early warning,relatively safe and safe.In the criterion layer,the pressure index tended to be generally stable and slightly increased;the status index showed a"downward-upward-stable"trend;the overall re-sponse index increased year by year.In the index layer,the energy conservation and environmental pro-tection expenditure,forest greening rate and fishery production had the largest weight.Therefore,it is suggested to improve the ecological security level of Dalian Bay coastal zone by implementing precise control and remediation,strengthening marine industry and export-oriented economy,and strengthe-ning land-based pollution control and ecological restoration.

Abstract:Based on the catch of southeast Atlantic from 1950 to 2019,FAO,we used dominance analy-sis to analyze the catch and catch species composition in the southeast Atlantic,the composition of cat-ches,the contribution of major catches and the contribution of catches in coastal and non-coastal coun-tries and regions each decade.This results showed that the total catch of the southeast Atlantic increa-ses first and then decreases,and the total catch is low,accounting for less than 3％of the world total marine catch;Merluccius capensis,Engraulis capensis,Trachurus capensis and Sardinops sagax are the dominant species in the southeast Atlantic;catches of South Africa is the coastal state highest;cat-ches from non-coastal countries and regions such as Russia(Soviet Union),Japan,Spain,Poland,U-kraine,Bulgaria and Taiwan Province of People's Republic of China contribute significantly to the to-tal.The fishery resources in the southeast Atlantic have potential for exploitation,but the catch varies greatly among countries and regions;the main catch in coastal countries and regions such as South Af-rica is of low economic value while the developed countries such as European Union and Japan capture most of the high economic value fish like tuna.We suggest that the assessment of fishery resources in the southeast Atlantic should be strengthened,and a scientific and reasonable management and develop-ment system should be established among both coastal and non-coastal countries and regions so as to improve the fishing capacity and level and promote the sustainable development of fishery resources in southeast Atlantic.