Abstract:In this paper,three columnar sediment cores in the southern waters of the Shandong peninsu-la and 19 surface sediments in four small rivers in the southern part of the Shandong peninsula were used as research objects to identify the sediment sources in the argillary region of the southern Shan-dong peninsula through systematic analysis of the geochemical characteristics of rare earth elements.According to the 210Pb test results,the sedimentation rates of Z02,Z10 and Z16 in the argy region of the southern Shandong peninsula were 0.621 cm/a,0.36 cm/a and 0.4 cm/a,respectively.The stand-ardized results of chondrites showed that the core sediments in the study area showed a negative slope right-leaning pattern of light rare earth element enrichment and a loss of heavy rare earth element.Eu was obviously negative abnormal.The results of the DF calculation of the source discriminant function showed that the contribution of the Yellow River sediment in the past 300 a was significantly reduced,and the contribution of small and medium-sized rivers in the Shandong peninsula was increased,which may be affected by the decrease of the sediment of the Yellow River into the sea.

Abstract:River pollutant flux estimation can provide scientific and technical support for environmental management such as marine water quality early warning and total control.However,the frequency of river water quality monitoring was currently low,and the common low-frequency manual monitoring data of 1-2 times per month could not meet the requirements of accurate pollutant flux estimation.In order to improve the accuracy of the pollutant flux estimation results of the Yellow River,this paper established the regression equation between pollutant fluxes and fluxes based on LOADEST model to estimate the fluxes of major pollutants such as COD,total nitrogen,total phosphorus and oil in the riv-er,using the daily flow data and monthly water quality data of the Lijin section of the river from 2009 to 2019.The results showed that the average annual fluxes of the above four major pollutants in the Yellow River were 31 × 104 t/a,8.9× 104 t/a,1.4× 104 t/a and 2.5× 102 t/a respectively,and the in-tra-year distribution of fluxes was closely related to the flood season,with the highest monthly flux in July and the lowest in February.The uncertainty in the estimation of COD fluxes to the sea in the river was the smallest,within 15％,and the uncertainty in the oil was the largest,around 30％-50％.LOADEST model gave excellent results for COD,TN and TP,but the results for oil were poor,so it is not recommended to use LOADEST model to estimate oil fluxes in preference.

Abstract:In order to explore the purification effect of rice crab cocultivation fields on the circulating wa-ter aquaculture system in a coupled system of rice crab co cultivation ponds,the water quality of the in-lets and outlets and the intermediate water of in-pond raceway system,rice-crab culture and ecological ditch system were tested in 2021.At the same time,five sites were selected to monitor the water quali-ty of the in-pond raceway system.The studies showed that the variation range of dissolved oxygen in pond raceway system is from 3.59 to 11.3 mg/L,the variation range of phosphate is from 0 to 0.129 mg/L,and the variation range of acidity is from pH 8.43 to pH 9.03.In-pond raceway system can pro-vide water with high dissolved oxygen and purify most of the dissolved phosphate.The rice-crab culture can reduce about 91.79％of ammonia nitrogen and 71.15％of nitrite nitrogen.It can purify the tail water of the in-pond raceway system,which is beneficial to the growth of fish.The coupled system of circulating water aquaculture in rice crab cocultivation ponds is an ideal ecological aquaculture model.

Abstract:Laizhou bay is an important spawning ground in the Bohai sea and the temporal and spatial changes of chemical oxygen demand(COD)have an important impact on fishery resources and ecologi-cal environment.In order to understand seasonal changes of chemical oxygen demand(COD)in Laizhou bay,four on-site surveys were conducted during 2020-2021 and the organic pollution index method was employed to evaluate the survey area.Based on the relevant literature and the monitoring data of our laboratory from 1979 to 2021,the temporal and spatial trend of chemical oxygen demand(COD)concentration in Laizhou bay and its impact factors were discussed.The results showed that the seasonal chemical oxygen demand(COD)concentration in the northern Laizhou bay was lower than that in the south bank,and the high values occurred in the Weihe,Yuhe and Xiaoqing river estuaries.The organic pollution index illustrated that the polluted sea area was the largest in summer and mainly concentrated in the southwest coast of Laizhou bay.The spatial distribution of chemical oxygen demand(COD)in different periods indicated that the area with high chemical oxygen demand(COD)content tended to shrink and was still mainly concentrated in the southwest coast of Laizhou bay.The chemical oxygen demand(COD)concentration in Laizhou bay had shown an"M-type"trend in the past 40 years,and it decreased after 2014 obviously.The land-source transportation of rivers such as the Yellow river and Xiaoqing river,and the rapid economic development around the Laizhou bay had a significant im-pact on the temporal and spatial changes of chemical oxygen demand(COD).This work can provide scientific basis for further analysis of the spatiotemporal evolution trend of organic pollution in Laizhou bay.

Abstract:Suspended soils(SS)are the main factor causing physical clogging during artificial recharge.Dissolved organic matter(DOM)exists widely in recharge water and aquifer.It is of great scientific significance and application value to study the influence of DOM on physical clogging.One-dimensional seepage simulation experiments were used to explore the influence of low concentration(1 mg C/L)hu-mic acid(HA),a representative DOM,on the transport and deposition behavior of SS in porous media,and on the physical clogging during artificial recharge.Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and dy-namic light scattering(DLS)were used to reveal the influence mechanism of HA on physical clogging in porous media.The results showed that after adding HA,the transportability of SS was enhanced,the deposition amount of SS was reduced,and the physical clogging in porous media was inhibited.When HA was adsorbed on the surface of kaolinite,the steric hindrance effect between kaolinite was enhanced,and then the agglomeration between kaolinite was reduced,thus enhancing the dispersion stability of kaolinite.

Abstract:To study the impact of marine ranching construction on ecosystem energy flow and provide a reference for later ecological restoration,the ecological model of marine ranching area and contrast area consisting of 14 and 15 functional group was built with Ecopath model.The data stemmed from the ec-ological research data of Tianjin Dashentang National Marine Ranching Demonstration Area in Tianjin Shallow-sea area in 2020.the model simulated the ecosystem well.The results showed that the ecosys-tem structure of the fish marine ranching area is similar with the contrast area,and the benthic organ-isms are abundant.However,the structure of high trophic level part of food web was simple.Com-pared with the contrast area,the total primary production/total respiration(TPP/TR),connectance index(CI),system omnivory index(SOI)and Finn's mean path length(FMPL)in the marine ranc-hing area were 1.14,0.448,0.255 and 3.942,respectively,better than those in the control area(1.16,0.408,0.106 and 3.072,respectively).These findings indicated that the marine ranching makes the structure of the ecosystem more complex,mature and stable.The key species in the marine ranching area were seabirds,Rapana venosa and Eucrate crenata.Through the simulation of the eco-logical capacity of R.venosa and E.crenata biomass,it was concluded that the ecological capacity of R.venosa under this condition is 21.50 t·km-2,and the current biomass has exceeded the maximum sustainable yield,10.75 t·km-2.The follow-up work should focus on the introduction of other medi-um andswimming animals at high trophic levels,so that the growth of economic benefits and the im-provement of ecological restoration efficiency can be achieved.

Abstract:Seagrass refers to a group of monocotyledonous plants growing in marine environment,which perform great ecological functions and hold obvious economic values.In recent years,the global seagra-ss area has been decreasing significantly.How to repair seagrass beds quickly has evolving as a researc-hing hotspot.At present,the methods of seagrass bed restoration,such as transplantation,seed plant-ing and habitat improvement,hold both advantages and disadvantages.In contrast,tissue culture tech-nology of seagrasses has advantages including fast propagation,large yield and low cost,showing great potentials for seagrass bed restoration.In this paper,we summarized the advances in the tissue culture of seagrasses at home and abroad in recent years,analyzed its success and failure factors and main prob-lems,and put forward the corresponding solutions.

Abstract:In this paper,a storm surge and wave coupled inundation simulation model at high resolution was established based on the ADCIRC(a parallel advanced circulation model for oceanic,coastal and es-tuarine waters)and the SWAN(simulating waves nearshore)ocean numerical models,which was ap-plied for the simulation and calculation of the typhoon-induced storm surge in Wenchang.Based on Ty-phoon Kalmaegi(No.1415),a series of paths were designed to perform sensitivity analysis of landing location.The results showed that the landing location had a significant impact on the storm surge.We also designed different intensity path sets to calculate the storm surge and perform hazard assessment.The results showed that the stronger the typhoon intensity,the larger the submerged range,the deeper the submerged depth,and the larger high-risk area.With the decrease of typhoon intensity,the sub-merged area gradually decreased.However,due to the low terrain of Bamen bay and Puqian bay,under the intensity of 990 hPa,there was still more than 1.2 m submerged depth,which was easily sub-merged.It is a vulnerable area and needs more attention and prevention.

Abstract:The local scour characteristics of pile foundation and the protective effect of sandbag throwing are studied when the pile foundations of jack-up platform are shallow in mud.By simplifying the wave-flow interaction,Flow-3D numerical simulation software was used to obtain the scouring condition of pile boot when it was immersed in mud at 1.5 m and 3.0 m.Numerical simulation results show that lo-cal scour is mainly distributed on both sides of the pile boot,and the silt is formed behind the pile boot,and the scour depth can reach 3.5 m and 2.95 m respectively.Local scour affects the seabed bearing layer near the pile boots and reduces the stability of the jack-up platform,which requires scour protec-tion.The sand bag protection was used to protect the pile foundation of jack-up platform from scour,and Flow-3D numerical simulation was used to obtain the scour results under sand bag protection when the pile boot was immersed in mud at 1.5 m and 3.0 m.It was considered that the scour protection effect of sand bag was better.

Abstract:Recreational fishery is one of the five modern fishery industries determined by the 12th five-year plan of national fishery development.In recent years,recreational fishery has developed rapidly in the coastal areas of China.In this study,the grey correlation analysis method was used to select the in-dustry data of recreational fishery and activities associated with recreational fishery performance from 2006 to 2020 in 8 coastal provinces(cities)of China,and compare the industry correlation degree dur-ing the period of 11th,12th and 13th Five-Year Plans.The correlation degree between recreational fishery and related industries in coastal areas shows an upward trend from 2006 to 2020,with an average of 0.6406-0.7456,a moderate to high correlation range.The correlation between recreational fishery and culture,sports and entertainment industry ranked the first in the three periods,＞0.6.During 12th Five-Year Plan,the correlation between recreational fishery and culture,sports and entertainment in-dustry in Shanghai,Zhejiang and Guangdong was higher than 0.8,a high correlation.Compared with 11th Five-Year Plan,the 12th Five-Year was a starker choices-and graver consequences-in period with increased leisure fishery industry.Correlated industry included the information transmission,software and information technology services,accommodation and catering industry,water conservancy,envi-ronment and public facilities management.The correlation declining industries included the wholesale and retail,transportation,warehousing and postal service.The change of correlation degree of related industries in different regions was obviously different.The development of recreational fishery has the most significant driving effect on culture,sports and entertainment industry,but the driving effect of recreational fishery on related industries is different among periods and regions.It is necessary to fur-ther support and promote the integrated development of superior industry and recreational fishery based on local natural resource conditions,and improve the social,ecological and economic benefits of recrea-tional fishery.

Abstract:Based on the measured wave data of Yangjiang sea area for one year(September 1,2021 to August 31,2022),the characteristics of wave parameters are statistically analyzed,and the correlation between wave parameters is fitted and analyzed by the least square method.The results show that:(1)The annual average significant wave height is 0.82 m,the annual average period is 3.8 s,the annual maximum wave height is 10.98 m occurs during the transit of typhoon"Ma-on"in August 2022.(2)The study area is dominated by light waves,accounting for 74.15％;the normal wave direction is SE,the secondary normal wave direction is ESE and SSE;and the strong wave direction is ESE;the signifi-cant wave period is mainly 4～8 s;the normal wave direction is dominated by light waves with a period of 4～8 s.(3)There is a good linear correlation between characteristic wave heights.(4)During the transit of typhoon"Ma-on",the wave spectrum is dominated by double peak spectrum,with the maxi-mum spectrum peak of 53.79 m2/Hz and the corresponding spectrum peak frequency of 0.18 s.

Abstract:In order to investigate the seasonal stability of remote sensing image fusion models in the nearshore region,the Landsat panchromatic(PAN)data and MODIS multispectral(MS)data from four seasons were fused in five ways:nearest neighbour diffusion(NNDiffuse),ratio transform(Brovey),colour transform(HSV),phase recovery(Gram-Schmidt)and principal component analysis(PCA).The quality of the fused images was evaluated in terms of qualitative,quantitative and applica-bility,and the seasonal stability of the remote sensing fusion model was analyzed using variance(S2).The results showed that in terms of qualitative evaluation,NNDiffuse,Brovey and HSV had high sea-sonal stability and good fusion effect.In terms of quantitative evaluation,nine quantitative evaluation indexes were selected.Using normalization to calculate the integrated evaluation index,the HSV fusion model S2 was 2.4× 10-3,which had high stability and could significantly improve the remote sensing image quality in all seasons in the nearshore region.In terms of the inversion accuracy of chlorophyll concentration,the S2 of HSV fusion model was 4.9 × 10-3,which had high stability among the four seasons and was correlated well with the measured chlorophyll concentration(R2＞0.619).Therefore,the HSV fusion model with high seasonal stability,good fusion quality and high accuracy of chlorophyll inversion was the optimal model for nearshore remote sensing image fusion.

Abstract:The conservation and management of shark resources is an important part of global fishery resources governance.With the continuous decline of shark resources in the world,the Indian Ocean Tuna Commission,as one of the five major tuna regional fisheries management organizations in the world,has also paid increasing attention to the conservation and management of shark resources.From 2005 to 2022,the Indian Ocean Tuna Commission adopted a total of 17 resolutions on the conservation and management of shark resources,and the fishery management systems formulated,which include mandatory data statistics requirements,fishing vessel position regulation among others,and greatly en-sured the effective implementation of the resolutions.Based on the analysis of the current situation of the conservation and management of shark resources,in this paper,we pointed out the future develop-ment trend of shark resources,which includes strengthening the statistics of shark data,stricter con-servation and management measures,increasingly strengthening fishery management cooperation,and assuming greater responsibility of flag states.These developments are of great significances to form a shark resources conservation and management system with the guiding concept of promoting the bal-ance between the scientific and rational development and utilization of shark resources and the healthy and sustainable development.

Abstract:Xiong'an new area is a millennium plan and it is a great national event.The lake Baiyangdi-an,located in the central-south part of Xiong'an new area,plays a regulating role in the weather,cli-mate,and water resources in both the local and the North China region due to its lake effects.This study analyzed the multi-scale variations in the land-lake breeze characteristics in different areas of the lake Baiyangdian using observations of 13 stations in the lake and its surroundings.The meteorological and statistical methods were applied.The results showed that the land-lake breeze phenomenon existed in all areas,with alternating wind directions between day and night in 2023.On average,the mean wind speeds at the stations near the lake in both the v-direction(north-south)and the u-direction(east-west)exhibited an obvious out-of-phase feature.The maximum lake breeze reached 0.5 m/s and typi-cally occurred in the afternoon(13:00-16:00),while the maximum land breeze was 0.4 m/s and ap-pears in the morning(6:00-09:00).In general,the lake breeze was stronger than the land breeze,with the lake breezes in the northern and eastern parts of the lake Baiyangdian being stronger and lasting lon-ger than those in the southern,western,and central regions.Within the lake,the v-direction lake breeze formed one hour later than in the u-direction,and the northern area's lake breeze was the stron-gest,reaching 0.5 m/s.In the Xiong'an north urban area,which was farther from the lake,a distinct land-lake breeze pattern was observed in the v-direction,whereas it was less pronounced in the u-direc-tion.Anxin experiences the earliest land-lake breeze,and Rongcheng the latest,with the maximum lake breezes ranging from 0.6 to 0.7 m/s,which were stronger than those in both the lake interior and the areas near the lake.Significant monthly and seasonal variations also existed in the land-lake breeze,which was the strongest from January to June,followed by October to December,and weakest from July to September.Spring was the strongest,followed by winter,and relatively weak in summer and autumn.A specific land-lake breeze case from April 18 to 19,2023,along with Xiong'an Ruisi real-time field data,showed consistent results with the general characteristics of land-lake breeze,high-lighting the alternating wind directions between day and night and the increase in wind speed across dif-ferent areas of the lake Baiyangdian.

Abstract:The starting flow rate and erosion resistance of the soil bed surface composed of cohesive sed-iment and non-cohesive sediment particles were important factors in studying the stability of the bottom bed surface of hydraulic buildings such as rivers and open channel.In this study,the starting flow rate and erosion resistance of the reshaped sediment samples were explored by the laboratory test,based on the cohesive and non-cohesive sediment particles collected from the Yellow River delta.The results showed that the starting flow rate of the reshaped clay in the Yellow River estuary had a sudden change in the clay content between 10％and 30％.Moreover,there was a significant nonlinear relationship be-tween the relative depth of scour pit and the overshear stress of bed surface.The dimensionless formula for calculating the relative scour depth of reshaped sediment was further derived in this study.

Abstract:Nitrogen pollution of groundwater is a global environmental problem,and fertilization and ir-rigation measures are the key factors affecting nitrogen leaching.On the basis of field investigation and laboratory test,this paper quantitatively studied the distribution characteristics and leaching failure ef-ficiency of dissolved organic nitrogen,ammonium and nitrate in the unsaturated zone by different ferti-lization and irrigation measures.The results showed:(1)The concentrations of dissolved organic ni-trogen,ammonium and nitrate in the soil surface increased with the proportion of organic fertilizer,but in the root zone and vadose zone,the concentration of nitrate nitrogen increased with the proportion of organic fertilizer;however,the concentration distribution of dissolved organic nitrogen and ammonium was not affected by any fertilization measures;(2)Under the same irrigation amount,irrigation fre-quency was the main factor affecting the amount of nitrogen leaching into the ground,the lower the ir-rigation frequency,the higher the amount of nitrogen leaching;however,the ratio of organic fertilizer-inorganic fertilizer and the number of top dressings could only affect the amount of nitrogen leaching in the surface and root zone,and the amount of nitrogen stored in the vadose zone;(3)Only the ratio of organic fertilizer-inorganic fertilizer could affect the contribution rate of dissolved organic nitrogen and ammonium to nitrate leaching.When the proportion of organic fertilizer was 25％,50％and 75％,the contribution rate was 32％,50％,71％and 31％,23％,13％.This study provides reliable technical support for the prevention and assessment of groundwater pollution.

Abstract:The data of cross-calibrated multi-platform(CCMP)(1991-2020)wind field were used as the background wind field to reconstruct the wind field in the Yellow Sea and Bohai Sea for 30 years.By comparison,the observed wind field and the reconstructed wind field were in good agreement.Using the reconstructed wind field data to drive the SWAN model,the calculated significant wave height and the measured data at the Caofeidian station were in good agreement.Based on the calculation results of SWAN,the wave elements of the 10-year return period were calculated to provide input boundary con-ditions for MIKE21 SW model.By calculating the wave fields near the fishing ports,the hidden dan-gers of marine disasters in ten fishing ports in Tangshan were analyzed.The results showed that there were no hidden dangers of marine disasters in the ten fishing ports in Tangshan,but there were poten-tial marine disaster risks in Xindaihe fishing port.

Abstract:In this study,we analyzed the hourly precipitation observation data collected at 7 national basic ground stations and 144 densely-distributed automatic weather stations in Qingdao region from 2006 to 2017,in combination with the NCEP/NCAR global analysis products(FNL).Our analysis fo-cused on the features of circulation backgrounding the hourly heavy rainfall events.The results showed that Qingdao experiences the hourly heavy rainfall events three times each year in average with the highest number in July and August.The spatial distribution of the hourly heavy rainfall event frequen-cy is closely related to terrain.The large value area located along the windward slope of mountain area,and the small value area located along the coast of Jiaozhou Bay.The main influencing systems on the hourly heavy rainfall events included westerly trough,cold vortex in northeastern China,low-pressure vortex or inverted trough,typhoons and their interactions with small-and medium-scale systems.The range of heavy precipitation produced by different large-scale weather systems varied significantly;local and small-scale hourly heavy rainfall events were mainly caused by the western trough and the low-pressure vortex or inverted trough while regional and large-scale ones were mainly caused by the low-pressure vortex or inverted trough.Multiple systems may interact each other,and"the north though and the south vortex"weather conditions were more likely to cause large-scale hourly heavy rainfall e-vents.Various weather systems provided different large-scale backgrounds against and effects on the hourly heavy rainfall events.The warmed low-pressure vortex or inverted trough increased the ground humidity,decreased the air pressure,and weakened the stability of atmosphere.In case of cold vortex in northeastern China,the upper-level cold air mass added the instability to atmosphere.In case of ty-phoons,there was strong vertical updrafts and convergences of airflow which resulted in significant ver-tical wind and rainfalls.

Abstract:The application of drones and VR(virtual reality)technology in the teaching is a trend.The landform of rocky coast in the Shilaoren area in Qingdao,China,was taken as a case in this paper,to create the VR spherical panorama of the bedrock coastal landform with a UAV and field work.Firstly,the types,features and evolution of bedrock coastal landform in the Shilaoren area were generalized.Secondly,the production steps and key technology of the VR spherical panorama of bedrock coastal landform were presented.Finally,a VR spherical panorama of bedrock coastal landform with functions of non-contact,immersion,and remote interactive operation,was created.In addition,the influence of tide and wave on panorama making and its solution were discussed.Through online and offline teaching practices,the VR spherical panorama of bedrock coastal landform had proven to be a beneficial tool for class teaching,arousing great interests and getting high recognition.Besides online teaching,this VR spherical panorama could also be applied to ocean science popularization and ocean tourism.

Abstract:The submerged breakwater is mainly used for coastal protection due to its function of elimina-ting waves,so that the beach from the submerged embankment to the shoreline is subject to less wave impact.The traditional submerged breakwater is mainly composed of trapezoidal or vertical wall sec-tions.The movement of the wave particles hits the embankment which breaks the waves.However,it faces the problem of erosion and damage due to the strong action of the water in front of the embank-ment on the foundation and the embankment.If the cross section of the submerged breakwater is de-signed as a concave curved surface,the water quality points of the waves will come along the curved surface of the breakwater to impact the upper water body to achieve the function of wave attenuation,and at the same time,the impact on the foundation and the breakwater will be reduced,so that the cross section size of the submerged breakwater will be reduced and the safety will be ensured.In order to explore the wave dissipation performance of the concave curved submerged embankment and the rec-tangular vertical submerged embankment under different wave heights and water depths,an indoor model test was carried out in a wave tank.The results showed that:the shape of the headwind surface had a significant influence on the wave elimination effect of the submerged embankment.The influence of wave height and water depth factors was smaller than that of rectangular vertical embankment.