10 April 2022, Volume 44 Issue 2

    

• Research Papers
• Numerical simulation of wave breaking over a submerged breakwater based on lattice Boltzmann method

  WANG Yizhi, HAN Xinyu, DONG Sheng

  2022, 44(2): 1-7. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.001

  Abstract ( ) PDF ( )

  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.
• A study on the applicability of different models totypical typhoons in the South Yellow Sea

  LIU Tao, CHEN Xueen, CHEN Zijian

  2022, 44(2): 8-16. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.002

  Abstract ( ) PDF ( )

  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).
• Study on Numerical Simulation of Oil Spill DiffusionRisk in the Lvhua Island

  GU Yifan, WANG Binyu, NI Yunlin, CHEN Wei

  2022, 44(2): 17-26. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.003

  Abstract ( ) PDF ( )

  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.
• Numericalstudy on impact of coastline changes ofLaizhou Bay on tidal wave system in Bohai Sea

  ZHU Jinlong, ZHU Shuxiang, ZHANG Cuimin, XU Yandong, WEI Xiao, SUN Wei, SUN Guiqin, LIU Ning

  2022, 44(2): 27-34. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.004

  Abstract ( ) PDF ( )

  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.
• Discussions on the relationship betweenexchangeable phosphorus in sediments and the concentration of particulate matter

  OU Zhichao, GAO Zenwen, CHENG chen

  2022, 44(2): 35-40. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.005

  Abstract ( ) PDF ( )

  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.
• Effects of different diets on growth performance, enzyme activities and biochemical indexes of Scylla paramamosain

  SU Guisen, XIAO Guoqiang, CAI Jingbo, ZHANG Xiang , HUANG Xiaolin, CAI Xili, CAI Yilong, CHAI Xueliang

  2022, 44(2): 41-48. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.006

  Abstract ( ) PDF ( )

  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.
• Effects of environmental factors on the sexual reproductionprocess of Laminaria digitata

  WANG Xiao, LIU Fuli, LIANG Zhourui, YUAN Yanmin, ZHANG Pengyan, WANG Wenjun, SUN Xiutao

  2022, 44(2): 49-56. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.007

  Abstract ( ) PDF ( )

  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.
• Effects of immobilized culture on growth, pigment contents andchlorophyll fluorescence parameters of Chlorella sp.

  WANG Yizhe, HAN Chaojie, BU Shixun, HAN Xu, ZHOU Wenli, JIA Xuying

  2022, 44(2): 57-63. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.008

  Abstract ( ) PDF ( )

  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.
• Studies on stress response of phytoplankton community inNanwan Reservoir based on ABC curves

  HU Jun, Chi Shiyun, HU Juxiang

  2022, 44(2): 64-72. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.009

  Abstract ( ) PDF ( )

  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.
• Research Report
• Numerical simulation of oil spilling drift and diffusion in Zhanjiang Bay

  SUN Yan, LIU Dazhao, XU Yuanxing, LI Zhuo, HAN Zewen

  2022, 44(2): 73-83. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.010

  Abstract ( ) PDF ( )

  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.
• Contrastive study on remote sensing retrieval of waterdepth and machine learning model

  JI Qian, SHEN Wei, RAO Yali, MENG Ran

  2022, 44(2): 84-89. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.011

  Abstract ( ) PDF ( )

  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.
• Durability design of concrete materials in chloride environment based on Life-365 software

  HAN Yi, XIE Dongsheng, WU Weidong, MA Lu

  2022, 44(2): 90-96. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.012

  Abstract ( ) PDF ( )

  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.
• Risk assessment of wave disaster in Sri Lankan waters

  XI Lintong , LI Xingfei, ZHONG Wei , YANG Shaobo

  2022, 44(2): 97-102. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.013

  Abstract ( ) PDF ( )

  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.
• Spatial distribution and contamination evaluation of surface sediment in Xiaohai, Wanning*

  LUO Lizhen, ZHU Zhixiong, CHEN Shiquan, Xie Jianhui

  2022, 44(2): 103-111. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.014

  Abstract ( ) PDF ( )

  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.
• Prediction of albacore tuna abundance insouth Pacific based on improved XGBoost model

  YUAN Hongchun, Gao Ziyue, ZHANG Tianjiao

  2022, 44(2): 112-120. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.015

  Abstract ( ) PDF ( )

  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.
• Distribution ofhlorophyll a and its relationship with environmental factors in summer 2013

  WANG Quanying, DU Yumeng, LIU Long, SHI Weijie, ZHANG Yongfeng, LI Li, ZHANG Jianle

  2022, 44(2): 121-127. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.016

  Abstract ( ) PDF ( )

  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.
• Calculation of ecological compensation standards for the Yangtze River island wetland: An example of planning project of Tongzhousha Ait

  XIE Jingyi, ZHANG Yinjiang, CHEN Xuechu, YANG Huaiyu

  2022, 44(2): 128-135. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.017

  Abstract ( ) PDF ( )

  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.
• Analysis of coastline changes andthe influencing factors in Yancheng in the last 20 years

  ZHANG Zhi, CHEN Peng, MAO Shifeng, CHAN Man

  2022, 44(2): 136-142. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.018

  Abstract ( ) PDF ( )

  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.
• Research Review
• Green development of marine fisheries in offshore area of China: From Perspective of resource economics

  CHENG Yuan, CHEN Xinjun, ZHAO Qilei

  2022, 44(2): 143-149. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.019

  Abstract ( ) PDF ( )

  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.
• Review on erosion protection of underwater building foundations

  YAN Zhengyu, TIAN Hua, KANG Wen, ZHOU Chao, DIAO Wenzhou, ZHANG Peng , KOU Hailei

  2022, 44(2): 150-156. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.020

  Abstract ( ) PDF ( )

  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.
• A methodological studyon use gee of non-residential islands:Fron perspective of ecosystem damage cost

  CHEN Junling, CUI Wanglai, XI Henghui

  2022, 44(2): 157-165. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.021

  Abstract ( ) PDF ( )

  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.
• Influence of macrobenthic bioturbation on the Physic-Chemical characteristics of sediment: a Review

  GONG Zijuan, ZHANG Qingtian

  2022, 44(2): 166-172. https://doi.org/10.13984/j.cnki.cn37-1141.2022.02.022

  Abstract ( ) PDF ( )

  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.