Abstract:The attitude change of ocean monitoring buoys directly affects the measurement accuracy of some sensors mounted on the buoys.Therefore,the stability of buoys is an important indicator that should be paid attention when designing buoys,and the type of buoy body is closely related to its stabil-ity.To address this problem,based on the three-dimensional potential flow theory and wave radiation-winding theory,this paper discussed four common small ocean monitoring buoys with different buoy structure types by taking wave load as the main external excitation.Simulations were used to analyze the hydrodynamic response characteristics of each buoy body in the two degrees of freedom of heave and roll as well as short-term time domain forecasting,in order to obtain a buoy structure with better sta-bility.The results of the simulation experiment showed that judging from the hydrodynamic character-istics and the time-domain results under the wave load only,the dish-shaped buoy had better anti-wave stability in the roll degree of freedom and the wave-following performance in the heave degree of free-dom among the conventional single-body buoys,followed by the cylindrical buoy.The circular trun-cated buoy was slightly inferior.On the same level,the stability of the single-body buoy was obviously better than that of the multi-body buoy.

Abstract:Due to the intensification of human activities,the function of water ecosystem is degraded,and the aquatic biodiversity is seriously threatened.For aquatic ecosystems such as oceans,lakes and rivers,it is of great significance to investigate the species diversity and biomass of aquatic organisms for the monitoring and scientific evaluation of aquatic ecosystems.The environmental DNA(eDNA)can be collected from environmental samples such as water and sediment.The eDNA technology,which is a useful supplement to large-scale biodiversity survey,can effectively monitor the biological species,bio-mass and spatial-temporal distribution in the water environment by high-throughput sequencing.Due to the advantage of environmental friendliness,easy sampling and high sensitivity,eDNA technology has captured widespread attention,and it has been extensively applied in the field of aquatic ecosystem for recent years.Accordingly,this manuscript focused on the technical principle and operation process of eDNA technology.In addition,the research progress and typical cases of eDNA technology in the as-sessment of species diversity and biomass in oceans or lakes were summarized.Furthermore,the key factors affecting the resolution and universality of eDNA technology was identified.The application and development of eDNA technology in marine,lake,river and other water ecosystems were also prospec-ted,in order to provide technical reference for the application of eDNA technology in water ecosystems.

Abstract:In order to enhance the effectiveness of technological collaborative innovation in offshore wind power industry,this paper used evolutionary game model to systematically explore the game process of offshore wind power consortia participating in collaborative innovation.The findings showed that:the stronger the achievement transformation ability,the higher the subsidy amount,the higher the tech-nology absorption ability,the lower the cost sharing ratio,and the higher the benefit sharing ratio,the more both parties of the consortium tend to collaborative innovation;within a certain range,the richer the innovation resources,the higher the penalty coefficient,the higher the probability that both parties tend to collaborative innovation;the higher the excess benefit,the higher the cost,the more both par-ties tend to innovate alone.In response to the above findings,corresponding countermeasures were proposed for the development of offshore wind power industry.

Abstract:Feed is the most important source of nutrients and pollutants in recirculating aquaculture sys-tems(RAS).When RAS industry tries to develop sustainably,the green feed is essential to ensure quality and water quality.An 8-week culture experiment was conducted to investigate the effects of dif-ferent diets on the biology of hybrid grouper and water quality in RAS.Redundancy and Pearson corre-lation analyses were used to establish the association between data.The results showed that the growth efficiency of hybrid grouper is significantly and positively correlated with protein/energy ratio(P/E)and high significantly and positively correlated with dietary apparent digestibility(ADC)in its RAS.The increase of dietary P/E and ADC can reduce the hepatopancreas somatic indices and viscerosomatic somatic indices.When the P/E and ADC were too high,i.e.,when the fish individuals ingest and ab-sorb too much protein which will lead to the decrease of protein efficiency,the serum glutamic oxalace-tic transaminase activity and the increase of total ammonia nitrogen and nitrite nitrogen concentration in aquaculture water will increase.The level of available phosphorus(AP)in feed was positively correla-ted with the concentration of phosphorus pollutants in water.Compared with labile phosphate,availa-ble phosphorus had a greater effect on the concentration of total phosphorus.The water-solubility(WSI)of feed was positively correlated with all water pollutants.In this study,the performance of F3(P/E 36.20 g/MJ,ADC 61.92±1.31％,AP 0.98％,WSI 13.25±0.23％)was the closest to the green feed suitable for hybrid grouper RAS.Our findings provided the data support for the application of green feed in industrial RAS.

Abstract:To establish quality standards for quality hypocotyl of Kandelia obovata Longgang,a good cold-resistant mangrove variety appropriate for Zhejiang Province,the hypocotyl(LG1-5)of'K.obova-ta Longgang was collected at different stages with their fresh weight,length,cross diameter,and starch,crude protein and crude fat contents measured.The changes in seedling height,basal diameter and biomass of outdoor beach-grown seedlings were monitored.An indoor low temperature(-5.5 ℃)stress test was conducted to document the freezing damage and survival rate of its seedlings.The re-sults showed that the hypocotyl changed from long and thin to short and fat as the harvesting period was delayed.The principal component analysis showed that LG4 hypocotyl scored the highest,which was followed by LG1 and LG3.Correlation analysis further showed that there was a positive correlation(P＜0.05)among hypocotyl morphology,storage material and seedling growth with fresh weight and starch as the key factors.The cold resistance of LG1 was stronger than LG4 and LG2.The heavier the fresh weight,the higher the starch content,the better the growth potential of LG radicle.The earlier harvested hypocotyl had a certain amount of energy accumulation and sufficient growth time,and the seedlings were more resistant to cold.For the ecological restoration of Zhejiang mangroves,we recom-mend to harvest Longgang hypocotyl around April 10 and during the concentrated maturation period(mid to early May).

Abstract:The Qiongzhou Strait is located between Hainan island and the Leizhou peninsula in China,and the water transport through the Strait plays an important role in the circulation structure in the northern part of the Beibu gulf.Typhoons are frequent in the area.To understand the influence of ty-phoons on water exchange through the Strait,typical typhoons Sarika(2016),Kalmaegi(2014)and Rammasun(2014)were selected to simulate the material transport and water exchange characteristics of the Qiongzhou Strait under the influence of typhoons.The results showed that the residual current direction in the Qiongzhou Strait in summer was from east to west;Typhoons(Kalmaegi,Rammasun)passing over the northern part of Hainan island changed the direction of the residual current in the Qiongzhou Strait from west to east,while typhoons(Sarika)passing over the central part of Hainan is-land strengthened the residual current from east to west.During typhoons,1.2× 1010 m3 westward un-der typhoon Sarika,1.6×1010 m3 eastward under typhoon Kalmaegi and 5×1010 m3 eastward under ty-phoon Rammasun,the volume of water transport increased by 100％,167％and 760％respectively compared to tidal forcing.The different circulation structures generated by typhoons with different routes caused different directions of water transport in the Qiongzhou Strait.The material residence rate in the Qiongzhou Strait was 81.5％under typhoon Sarika,62.6％under typhoon Kalmaegi and 8.1％under typhoon Rammasun.

Abstract:Delta wetlands play an important role in maintaining ecological balance,sequestration and se-questration,and ensuring the coordinated development of regional ecological economy.Using the rele-vant index data of ecological restoration in the Yellow River delta from 2019 to 2021,this paper evalua-ted the ecological restoration efficiency of the Yellow River delta based on the input-output model from the perspective of Blue Carbon,and the results showed that the ecological restoration input level was good,the ecological restoration output level was average,the input-output ratio of ecological restora-tion efficiency was 0.87,the input-output ratio was less than 1,and the restoration efficiency was aver-age,and the restoration efficiency of the blue carbon function was 1.05,which was slightly higher than the overall ecosystem restoration efficiency.

Abstract:Sea fog is an important weather phenomenon that affects horizontal visibility at sea.The re-mote sensing monitoring of sea fog is of great significance to marine activities such as maritime traffic and oil development.Based on the FY-3D polar-orbiting meteorological satellite data,this paper pro-posed a deep learning-based daytime sea fog remote sensing detection model CA-LinkNet.The model used the LinkNet network as the backbone,and introduced the coordinate attention mechanism(CA)in the skip connection part of the encoder and decoder to make full use of the position and channel infor-mation of the node feature map,and to enhance the localization and recognition capabilities of the net-work.The experimental results showed that compared with FCN,U-Net and LinkNet segmentation networks,the CA-LinkNet network proposed in this paper had higher accuracy in sea fog detection on the test set,with the mean intersection over union,probability of detection,false alarm rate,critical success index and Heidke skill score reaching 0.911,0.900,0.046,0.862,0.905,respectively.The model was used to detect sea fog in the Yellow Sea,the Sea of Japan and the Sea of Khozik and sea fog near the Chiba Islands,and the detection results were in good consistent with the CALIOP data.

Abstract:The Fukushima nuclear power plant planed to begin diluting Fukushima nuclear wastewater into the ocean in March 2023.However,experts had questioned the safety of the Fukushima nuclear wastewater discharge.Based on the latest research on the Fukushima nuclear wastewater,including the distribution,harm and migration rule of radionuclides,this paper summarized and analyzed the treat-ment methods of Fukushima nuclear wastewater,the content of dangerous nuclides,the migration path of nuclear wastewater and the impact on the marine ecological environment,and discussed the potential impact of Fukushima nuclear wastewater discharge on the surrounding sea area.It was hoped to provide some suggestions for marine radioactive safety assessment and for coping with the possible effects.

Abstract:Based on major element analysis,combined with correlation analysis and R factor analysis,paleoenvironment evolution records of Core S01-10 in the central Okinawa Trough since late Pleistocene had been obtained.Major elements data indicated that the content of major element oxides showed ob-vious three depositional units on the Millennium scale:Unit A1(400～143 cm)was formed from Late Deglaciation to Early Holocene,during which the terrigenous sediments mainly came from the Yellow River and a small admixture from the Yangtze River,while the contribution of Taiwan materials could be ignored.Unit A2(143～105 cm)was formed in Early Holocene,and the dominant provenance was still the Yellow River.The contribution of Taiwan materials was relatively increased while the influ-ence of the Yangtze River decreased.Unit A3(105～0 cm)was formed from Early Holocene to Middle Holocene.The dominant provenance was the mixture of the Yellow River and Taiwan,and the contri-bution of the Yangtze River material could be ignored.The results of correlation analysis and R factor analysis of major elements showed that the content of typical element oxides was mainly affected by the input of terrigenous sediments,while the effects of marine biologic deposition,hydrothermal activity and volcanic events were minor.Sea level fluctuation and intensity variation of the East Asian monsoon were the main controlling factors of material provenance in the central Okinawa Trough.Based on the test and analysis of Core S01-10 in the central Okinawa Trough,this paper provides a valuable reference for studying the evolution history of terrigenous sediment input in the region since the late Pleistocene.

Abstract:Microeukaryotes including algae,protozoa and fungi exhibit high abundance,wide distribu-tion and high diversity,which play crucial roles in marine ecosystems.In September 2020,we collected 16 samples from six stations in the typical raft aquaculture area of Gouqi Island,the East China Sea.Microeukaryote communities were analyzed using 18S rDNA high-throughput sequencing to compare their spatial distribution across three habitats including surface seawater,bottom seawater and sedi-ment samples.Our results showed that diatom and dinoflagellates dominate the phytoplankton commu-nity,and ciliates and Noctiluca dominate the zooplankton community.As for microeukaryotes,the dominant species of microeukaryotes were Cerataulina pelagica,Noctiluca scintillans,Alexandrium tamarense,Sargassum fusiforme and Alexandrium catenella.A significant difference among microeu-karyote communities was observed between seawater and sediment samples.The microeukaryote com-munities in sediment samples showed a higher Shannon and evenness diversity than those in seawater samples.Compared with bottom seawater,microeukaryote communities in surface seawater exhibited higher Shannon and evenness diversities but lower species abundance.Redundancy analysis domonstrat-ed that the diversity indices and dominant species distribution in surface seawater were strongly influ-enced by temperature,salinity and Chi a concentration.At station WRC,higher abundances of dia-toms and Phaeophyceae were positively correlated with Chl a concentration.Overall,our findings pro-vided baseline data for researches on the community change and ecological function of microeukaryotes in aquaculture areas of East China Sea.

Abstract:Poyang Lake is the largest freshwater lake with seasonal throughput in China.In this paper,the following data of the Poyang Lake were collected and analyzed,the water level data of hydrological stations,the wind field observation data of the meteorological station and the bathymetry measured in the lake area.Then,the wave height distribution in Poyang Lake was calculated and analyzed with nu-merical simulation methods based on wave action conservation equation.The calculation results of nu-merical methods and standard methods were compared.The results of the comparison showed that the calculation results of the two methods are generally close to each other,and the calculation results of the numerical method are slightly larger than that calculated with the standard method.Finally,we concluded that the significant wave height(H13％)around Poyang Lake under extreme high water level conditions varied between 1.70m and 2.08 m and the mean wave period(Tm)varied between 4.39s and 5.25s.

Abstract:The term stigma is commonly understood as a mechanism for discriminating against or exclu-ding individuals who are associated with negative or derogatory labels,which is also the concept of shark stigma against China.The substantial differences in value,cultural identity,economic system and political structure between China and Western nations contribute to a lack of understanding each other regarding the cultural tradition of China surrounding shark fin consumption.Furthermore,cer-tain countries have intentionally disseminated misleading and negative narratives about this practice,ostensibly hindering Chinese development.As a result,China has endured the repercussions of shark stigma for an extended period,adversely affecting its international reputation,diplomatic relation,eco-nomic progress and social stability.In this context,it is imperative to establish a comprehensive strate-gy to mitigate the shark stigma against China and enhance Chinese reputation expeditiously.First,it is essential to guide effectively the public opinion,bolstering the international image of China,and garne-ring the understanding and support of associating countries.Second,it is crucial to promote interna-tional cooperation,increasing our participation in inter-state regulations and steering the global dis-course on shark conservation.Third,it is necessary to refine domestic laws and regulations,improving the oversight of distant-water fishing vessels,and standardizing practices within the shark fin industry.Finally,it is vital to enhance the public awareness with targeted education initiatives,fostering a ra-tional and sustainable approach to our consumption.

Abstract:Based on the data collected in Oujiang River Estuary from 2021 to 2022,the population struc-ture,the length-weight relationship and the growth and mortality of Coilia nasus were analyzed.A to-tal of 1,153 individuals were caught,from which the length-weight relationship were derived as W=0.001 0L3.4151(R2=0.9845),showing a positive allometric growth pattern.The growth parameters of von Bertalanffy formula estimated by ELEFAN Ⅰ of FISAT Ⅱ were 38.90cm(L∞),0.44(k)and-0.56a(t0).The total mortality Z estimated by length-converted catch curve was 2.47 while the natu-ral mortality M and fishing mortality F were 0.79 and 1.68,respectively,and the exploitation rate was 0.68.Beverton-Holt yield per recruitment model simulation showed that Yw/R trends to increasing and then decreasing with the increase of fishing mortality(F).The biological reference points Fmax and F0.1 were 1.54 and 0.64,respectively.C.nasus stock has been over-exploited.We propose that the body length at first capture should be increased to 22cm,and the fishing pressure reduced to ensure sustain-able use of the resource.

Abstract:In this study,46 Japanese mackerel(Scomber japonicus)individuals collected from the northwest Pacific were used to explore the necessity of the lipid extraction for the stable isotope analysis of Japanese mackerel,and to determine the influence of lipid extraction on the carbon and nitrogen sta-ble isotope ratios(δ13C,815N)of the muscle and liver of thie fish.The relationship between the ratio of carbon and nitrogen content(C:N)and the constant 3.50 was compared and analyzed to determine whether this species needs lipid extraction pretreatment.The δ13C correction model of muscle with liver was proposed.After lipid extraction,δ13C and δ15N of muscle increased by 0.41‰ and 0.61‰,respec-tively,while C:N decreased by 0.21,δ13C of liver increased by 0.73‰,δ15N kept unchenged and C:N decreased by 0.31.Individual analysis of muscle and liver C:N below 3.50 showed significant differ-ences in δ13C after lipid pumping.Accodingly,the relationship between C:N and constant 3.50 is not appropriate for determing whether Japanese mackerel needs a lipid extraction pretreatment.Lipid ex-traction is necessary before 813C analysis for studying Japanese mackerel muscle and liver.The optimal calibration models are Δδ13C=-0.53 × δ13Cbulk-9.85 and Δδ13C=-0.79 × δ13 Cbulk-14.88.Lipid ex-traction was not performed when δ15N of Japanese mackerel in muscle was analyzed while lipid extrac-tion was not necessary for the analysis of δ15N in Japanese mackerel liver.

Abstract:Coastal ecosystems such as salt marshes and mangroves can effectively dissipate wave energy and reduce the risk of coastal disasters caused by waves.Accurate prediction of wave attenuation caused by vegetation is of significant importance for the design of nature-based coastal protection engineering.This study is based on the open-source fully nonlinear Boussinesq equation model FUNWAVE-TVD,incorporating the momentum dissipation term caused by vegetation to simulate wave attenuation by vegetation.The model uses results from 6 different physical model experiments and 113 sets of experi-mental data for simulation and validation,and determines the optimal vegetation drag coefficient CD.The results show that the model can accurately quantify the attenuation of wave height by vegetation,and that the optimal vegetation drag coefficient CD varies greatly under different experimental condi-tions.The calibrated drag coefficients are compared with several mainstream empirical formulas for vegetation drag coefficients in the literature,and the effective calculation method of CD in numerical simulation of vegetation wave attenuation is discussed.The study can provide technical support for the synergy of coastal disaster protection and ecological restoration.

Abstract:Based on the DEA,super efficiency SBM model and Malmquist index,11 coastal provinces and cities in China were selected as case areas in this paper.The input-output indicators reflecting the development efficiency of marine tourism were used to quantitatively characterize and compare the re-gional differences of marine tourism development efficiency.The results showed as follows:(1)From the inter provincial and regional level,the temporal and spatial differences of marine tourism develop-ment efficiency were significant,and the temporal and spatial regularities were obvious.(2)The utili-zation capacity and output capacity of marine tourism resources in different regions were quite different.The overall input factors of marine tourism development in coastal areas had a certain degree of ineffi-cient utilization and idle resources.(3)From the perspective of individual provinces,the comprehensive efficiency of marine tourism in Zhejiang maintained a leading position,with a good overall development level,more input and more output.In recent years,the comprehensive efficiency of marine tourism in Guangxi has shown a relatively positive development trend.The comprehensive efficiency of marine tourism in other regions has changed relatively steadily.

Abstract:Caspase-dependent apoptosis plays an important role in immune defense and degeneration of metamorphic larvae-specific structures of marine invertebrates.However,studies on caspase-mediated programmed death regulating immune response and early development in Apostichopus japonicus are scarce.In this study,qRT-PCR was used to detect expression level of pro-apoptotic caspase-2,-3,-6,-8 genes in tissues and at early developmental stages of A.japonicus.The results showed that in con-trast to gonad where these genes express at the lowest level,the expression level of caspase-3,-6,and-8 mRNA was the highest in coelomocytes while that of caspase-2 was the highest in tube feet and re-spiratory trees(P＜0.05).The expression of caspase-2,-3,-6,-8 was continuous at a low abundance during the cleavage stages from fertilized egg to gastrula,which increased from auricularial phase(P＜0.05).With the rapid enhancement following a metamorphosis process,their expression peaked at the postmetamorphic juvenile stage,significantly higher than that at other stages(P＜0.05).Our findings indicated that apoptotic caspases are likely to be essential in the immune response and metamorphosis of echinoderms like A.japonicus.

Abstract:In this paper,the influence of clay content and penetration rate on the critical state parame-ters and consolidation coefficient of silty soil in the Yellow River delta was discussed by using the labo-ratory geotechnical test method,and the calculation method of the critical state parameters of silty soil in the Yellow River delta was summarized.Based on the CPTU experiment,the influence law of clay content on the skeleton curve of rate effect of silty soil was discussed.The"Nkt-V"and"Bq-V"rate effect of silty soil with different clay content was summarized by adopting the normalized penetration rate V=vD/cv.The results showed that the boundary between fully drained and partially drained re-gions was V=0.45,and the boundary between partially drained and completely undrained regions was V=30.The recommended values of the cone-tip resistance coefficient Nkt for the reconstructed silty soil without drainage were 9.6～10.3,which could be used for the inversion of the strength parameters of silty soil in the Yellow River delta region.The research results can provide reference for the evalua-tion of seabed stability in the region.

Abstract:This paper proposed a new method of measuring coefficient of friction using the texture fea-ture value extraction technology in image recognition.The texture feature value was used to character-ize and quantify the roughness of the surface of an object,so as to obtain the coefficient of friction of the surface of the object.This method can be utilized to solve the problem that is difficult to measure the friction coefficient conveniently in the caisson sliding experiment.The friction coefficient of con-crete test block was measured through physical model test,and the relationship between image texture feature value and coefficient of friction was analyzed.The results showed that there was a good correla-tion between the image texture feature value and the coefficient of friction.Using the functional rela-tionship between image texture eigenvalues and friction coefficient established on this basis,the meas-urement of friction coefficient can be simplified.