Wave breaking can induce enhanced turbulent mixing at the ocean surface layer, but whether typhoon enhances wave-induced mixing and how it affects the thermocline below the mixing layer remain unclear. In this paper, taking typhoon Nepartak as the research object, based on the coupled ocean-atmosphere-wave-sediment transport (COAWST) model, the effects of turbulent mixing caused by wave breaking on the depth, thickness, and strength of the thermocline in the northwest Pacific were studied. The results showed that: during typhoon Nepartak, the wave-induced mixing significantly strengthened the turbulent mixing below 100m, resulting in the deepening of the mixing layer, the reduction of SST, the obvious deepening of the upper boundary depth of the thermocline, the small change of the lower boundary depth, the thinning of the thermocline thickness and the slight strengthening of the intensity. In addition, the introduction of wave-induced mixing could significantly improve the simulation effect of COAWST model on SST during typhoon.

Based on the KdV theory, finite volume method (FVM) and volume of fluid (VOF) method, the internal solitary wave (ISW) was generated. The encounter problem between the ISW of depression and a submerged body at small pitch angles was simulated. The dimensionless parameters of horizontal and vertical forces of the submerged body over a period of time were plotted. Compared with the small angle of depression with the same absolute value, the submerged body at the small angle of elevation was less affected by the vertical force. In addition, the horizontal resistance was smaller and the horizontal thrust was larger. At small angles of elevation, the larger the elevation angle was, the smaller the horizontal force range and the vertical force envelope area was.

In this paper, the observed data of the eastern sea area of Shandong Peninsula and the reanalysis data of ECMWF ERA5 were used to compare and verify the accuracy of ERA5 data in the sea area and to analyze the variation rules of wind speed and significant wave height from December 2020 to November 2021. The observed wind field data of polyurea buoy was of the same magnitude as that of the reanalysis wind field data of ERA5, and the coincidence was high. The theoretical value of significant wave height calculated according to the observed wind field data was less than the value of significant wave height in the ERA5 reanalysis data in most of the time, and the observed significant wave height was also less than the significant wave height in the reanalysis data. Finally, this paper compared and analyzed the measured significant wave height of “Langlong” wave measuring instrument and the significant wave height of ERA5 reanalysis data by season. The results showed that the ERA5 data and the observed data had a high coincidence in summer, and the worst coincidence in winter, but the abnormal rise of wave height could be obviously observed during the transit of tropical cyclone and cold wave gale. The analysis results could provide a valuable reference for port construction and marine economic development in the nearby sea area.

A physical model experiment was carried out to study the landslide-generated waves, and the FLOW-3D software was used to simulate the measured wave surface, and the results were in good agreement. On this basis, the experimental study of caisson sliding of breakwater under surge was carried out. By solving the dynamic equation of caisson sliding, the caisson sliding under landslide-generated waves was obtained, and compared with the experimental results. The results showed that the experimental values were basically consistent with the theoretical values. Based on the verified theoretical method, the countermeasures to reduce the caisson sliding in practical engineering were put forward, including increasing the caisson mass, reducing the height of the caisson center of gravity and increasing the moment of inertia.

In order to solve the problems of poor engineering properties and low reuse efficiency of waste silty clay, the self-developed high strength fast curing agent (HSF) was used to cure the silty clay. After the HSF solidified silty clay test, the block was subjected to erosion in three water environments, namely seawater, tap water and distilled water. It was recognized by means of unconfined compressive strength test, pH test, XRD and SEM microstructure test as follows: after the HSF solidified silty clay test, the block was eroded in the water environment, the debris falling off the surface was in the sludge state under the erosion of seawater and the aggregate of granular and flaky under the erosion of tap water. Under the erosion of distilled water, it presented large and small flakes. The strength of the middle part of the test block was 80.11% ~ 89.95% of that before erosion. There was no abnormal change in pH under three erosion environments. The XRD patterns showed that seawater erosion replaced more Friedel′s salt and calcium aluminate hydrate. The SEM image observation showed that erosion would lead to the reduction of cement, the increase of pores and the breakage of the growth layer of hydrated minerals.

In this work, a two-dimensional wave-current coupled sediment transport model was established to investigate the erosion and deposition of the Feng River Estuary and its adjacent waters applying Delft3D model. The simulated results showed a good agreement with the observed data, which revealed that the numerical model could effectively reproduce the erosion and deposition process. Based on the validated sediment transport model, the characteristics of erosion and deposition in the study area was discussed. The results indicated that the scouring phenomenon was mainly concentrated on the downstream of the damming lock and near the south bank near the location of the damming lock. However, the siltation phenomenon was mainly located in the upstream of the damming lock and near the north bank near the location of the damming lock. Moreover, different wave conditions have different effects on the characteristics of erosion and deposition at the river estuary. The results of this paper not only provided a scientific theoretical basis for the dredging and erosion prevention measures when the impoundment gate needed to be closed, but also had important practical significance for the sustainable development of the Feng River Estuary area.

The response of beaches to typhoons and their post-typhoon recovery processes have long been a focal point in coastal research worldwide. Based on three months of continuous field observations at Chu Island beach in Weihai, this study comparatively analyzed the morphological changes of the beach under the influence of Typhoon Lekima and its subsequent recovery. The results indicated that Chu Island beach experienced widespread erosion during the typhoon, characterized by slight accretion in the backshore, severe erosion in the high-to-mid intertidal zone of the foreshore, and overall beach face downcutting. Notably, the northeastern profiles exhibited more pronounced erosion. The severely eroded profiles of Chu Island beach recovered rapidly within one month after the typhoon. However, geomorphological adjustments and sediment dynamics varied across different sections of the beach. The overall trend showed accretion in the upper beach and erosion in the lower beach, with the southwestern section recovering relatively slower and the northeastern section recovering faster.

The spatial-temporal distribution characteristics of sea surface temperature rise in the coastal area of Fangchenggang nuclear power plant were analyzed by using Landsat 8 satellite remote sensing images for temperature inversion. The results showed that: 1) from 2015 to 2020, the temperature of the thermal outlet and drainage corridor of Fangchenggang nuclear power plant was about 3 ℃ higher than the average sea surface temperature; 2) the sea surface temperature at the thermal outlet of Fangchenggang nuclear power plant was higher in summer and lower in winter; 3) after the operation of the nuclear power plant, the thermal drainage gallery of the nuclear power plant had obvious water temperature differentiation; 4) after 2015, the area of temperature rise and the level of temperature rise continued to increase. In 2020, the overall temperature rise of the temperature outfall and drainage corridor was above level 1(the temperature difference varied from 1 to 2 ℃), affecting the length of drainage corridor to reach 0.653 4 km, until the end of the corridor to the sea outside the corridor.

In order to understand the water quality pollution status of Laizhou Bay, to achieve total control of land-based pollutants and comprehensive management of pollution in rivers entering the sea, and to protect the water environment of Laizhou Bay, the input fluxes of four typical pollutants from three types of pollution sources, nine major rivers estuarine coastal zones and the port directly discharging into the sea in Laizhou Bay were estimated from 2017 to 2019. The results showed that the annual average marine fluxes of chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and petroleum were 32.64×10⁴ t/a, 11.45×10⁴ t/a, 2 140 t/a and 442.1 t/a, respectively. Rivers were the most important sources of land-based pollutants in Laizhou Bay. For example, the fluxes of four pollutants into the sea accounted for more than 90% in 2018. The largest input source of pollutants in Laizhou Bay was the Yellow River, followed by the Xiaoqing River, which had the highest proportion of pollutant flux into the sea. The four pollutants fluxed into the sea accounted for 34.3%, 50.8%, 47.7% and 38.9% of the total pollutant flux of the remaining eight rivers. Precipitation was the key factor affecting the flux of land-based pollutants to the sea, and TN was the primary land-based pollutant in Laizhou Bay at present.

Heavy rain is an extreme way for substances to flow into rivers, which has a significant effect on the composition and behavior of regional organic matter. Based on the rainstorm process affected by Typhoon Lekima in August 2018, this paper studied the absorption and fluorescence spectra of dissolved organic matter (DOM) in Xiaoqing River Estuary to expound the transport characteristics and influencing factors of DOM in the estuary during heavy rain. The results showed that: the relative concentrations of dissolved organic carbon (DOC) and colored dissolved organic matter (CDOM) fluctuated during the rainstorm decreased at the end of heavy rain, and the total fluorescence intensity of CDOM decreased gradually during heavy rain. CDOM fluorescence was mainly contributed by protein-like substances, which was dominated by tryptophan-like substance. The relative contribution rates of humic-like substance increased gradually during heavy rain. CDOM mainly came from biological activities, but with the process of heavy rain, the microbial-derived components of CDOM decreased and the terrestrial input components gradually increased. The composition of CDOM changed from mainly composed by tryptophan-like components and microbial-derived sources with low molecular weight, to mainly composed by tyrosine-like components, finally to mainly composed by humic-like components with high degree of humification. The composition and structure changes of CDOM were mainly controlled by the gradual change of input sources caused by heavy rain, closely related to the changes of physicochemical conditions caused by heavy rain.

Based on the survey data of fishery resources and hydrological environment in the Yangtze River Estuary from 2017 to 2021, five different habitat suitability index (HSI) models were built to explore the suitable environment and habitat distribution characteristics of Coilia nasus in different seasons. The results showed that the suitable water depth of C. nasus population was below 15m, the suitable salinity varied between 0 and 19.2, and the suitable surface water temperature ranged from 8.2℃ to 30.3 ℃. There were some differences in the best habitat models in different seasons. The geometric mean model (GMM) has a better fitting effect in spring, the continuous product model (CPM) has a better fitting effect in summer and winter, and the minimum model (MINM) has a better fitting effect in autumn. In addition, according to the prediction results of the optimal model, the distribution of the most suitable habitat of C. nasus also changes in different seasons, and the high HSI value area of the whole year appears in summer. In spring, the suitability index of the waters outside the estuary is higher than that in the estuary. In summer, the habitat suitability index of the South Branch was higher than that of the North Branch. In autumn, there are two high HSI waters outside the estuary, which are slightly higher than those inside the estuary. In winter, similar to autumn, the distribution trend outside the estuary is higher than that in the estuary. By exploring the distribution and change of C. nasus habitat in different seasons in the Yangtze River Estuary, our findings can provide a scientific basis for the sustainable utilization of C. nasus in the Yangtze River Estuary, and are of a great significance to the protection and restoration of resources in the Yangtze River Estuary.

In this paper, we investigated the community structure of Zhejiang inshore Larimichthys crocea and its spatial and temporal distribution in relation to environmental factors based on single-vessel bottom trawl surveys and environmental data from spring and autumn (April-May and November) of Zhejiang inshore from 2014 to 2020. The results showed that in spring, the length range of L. crocea varied between 48 and 250 mm, the mean body length was 151.0±26.5 mm, the weight range was from 1.5 to 252.4 g, the mean weight was 60.7±31.2 g in autumn; the length range of L. crocea ranged from 106 to 284 mm, the mean body length was 157.9±21.8 mm, the weight range was from 18.8 to 295.0 g, and the mean weight was 71.6±31.2 g; and significant differences were found in body length and weight of L. crocea in autumn compared with those in spring (P＜0.05). The relationship between body length and body weight of L. crocea was describable with the equation W=4×10^-5L^2.8323 (R²=0.9129, n 564), the b value was less than 3, and L. crocea was experiencing a negative anisotropic growth. The density of L. crocea resources ranged from 0.05 to 447.22 kg·km² during the 7-year period from 2014 to 2020, with a mean of 28.69 kg·km² and a wide distribution range from south to north along the Zhejiang coast. There was a significant difference in the density of L. crocea resources in autumn compared with spring (P<0.05), and they were more widely distributed. The GAM model analysis showed that three factors, latitude, longitude and surface water temperature, had significant effects on the density of L. crocea resources, with surface water temperature being the most significant one. Through the investigation and analysis of the fishery resources of L. crocea in spring and autumn near the coast of Zhejiang Province, we aimed to provide a scientific reference for the restoration of the fishery resources of L. crocea.

Marine aquaculture in China is experiencing a rapid growth. It is of great significance to study the temporal and spatial changes in marine aquaculture areas using remote sensing methods. Based on Landsat remote sensing images taking in 2002, 2008, 2014, and 2019, we used an improved object-based visually salient NDVI (obvs-ndvi) method to extract raft cultivation areas in Zhejiang Province, and utilize normalized vegetation index (NDVI) and green light band reflectance as neighborhood characteristics. The precision for the four years was more than 88%, and the F-measure was more than 82%. During the period from 2002 to 2019, the raft cultivation areas in Zhejiang Province expanded sharply from 1,232 ha to 9,560 ha, showing a trend of doubling every 6 years. The gravity center of the raft culture area shifted 58.1 km to the northeast, reflecting a continuous northward and seaward growth of raft culture area. Our findings can provide an important scientific reference for the sea elaborating management and the cultural seawater areas designating in marine spatial planning.

In order to explore the role of constructed wetlands in the ecological restoration of lakeside wetlands in Bosten Lake, based on the field investigation and laboratory test, a comparative analysis of constructed wetlands was conducted before and after construction in Luoxia Bay, west coast of Bosten Lake, about the difference of water quality index, soil nutrient index and plant diversity index in wetland. The results showed that the removal rates of nitrogen and total phosphorus were 54.05%~77.77% and 74.47%, respectively. The soil nutrient content in the study area was low as a whole, and the soil nutrient content of the constructed wetland in Bosten Lake was higher than that of the control group. The content of available phosphorus at the level of “Abundant”, and the content of other indexes were at the level of “Extremely deficient-slightly deficient”. The construction and operation of constructed wetland in Bosten Lake had changed the wetland habitat, the plant species in the wetland had increased, the dominant species had changed, and the ecological environment of Bosten Lakeside Wetland had been improved obviously.

In order to investigate the ecological damage of Chaetomorpha valida to other algae, Chlorella sp. and Nitzschia closterium were selected with the method of cocultivation. The cell morphology, biomass, growth inhibition rate, superoxide dismutase (SOD), malondialdehyde (MDA) and Chlorophyll A (Chl-a) contents of the two microalgae were determined periodically. The results showed that the colony of Chlorella sp. in the treatment group appeared at the third day of co-culture. With the increase of biomass and time, the colony disintegrated into smaller colony, and the average cell number per colony increased continuously (P<0.01). In the treatment group with 1g algal content, N. closterium rapidly aggregated, and dispersed into smaller and more numerous groups after the 7th day. This phenomenon was not significant when the algal content increased to 2.5g and 4g (P>0.01). Ch. valida had obvious inhibition effect on the growth of two microalgae. With the increase of Ch. valida biomass, the inhibition rate was respectively 97.72±0.79% and 99.37±0.08% on the 11th day. SOD activity of the two microalgae showed a concentration effect of low promoting and high suppressing. Compared with the control, MDA content increased continuously (P<0.01), which means that cell membrane oxidative damage is serious. The content of chlorophyll a in the two microalgal treatment groups was lower than that in the control group and higher than the initial value (P<0.01). In conclusion, Ch. valida is a significant allelopathic stress on the two microalgae; it promoted the aggregation of the two microalgae, destroyed the anti-oxidation system, exacerbated the oxidative damage of cell membrane, and inhibited or degraded chlorophyll a, which ultimately affected the photosynthesis of microalgae and led to the rupture and death of algal cells. Ch. valida possesses allelopathic potential that could possibly facilitate its invasion, and do harm to the surrounding environment.

In order to explore the effects of mechanical damage on the growth and physiological characteristics of seagrass, a greenhouse simulation experiment was conducted, aiming to analyze the effects of damage stress on the growth rate, photosynthesis, antioxidant enzyme activity, and metabolite content of the tropical dominant seagrass Thalassia hemprichii. Six different types of mechanical damage were given to the leaves of T. hemprichii. The results showed that (1) different types of mechanical damage reduced the apparent photosynthetic rate of T. hemprichii leaves by different percentages which varied between 7.95% and 33.33%, the dark respiration rate between 8.08% and 25.01%, and the maximum photosynthetic efficiency (F_v/F_m) between 2.61% and 10.97%, and the leaf growth rate between 20.99% and 37.04%; (2) different types of damage stress induced an increase in the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) of leaves and roots up to 0.54~2.15 times and 0.29～1.62 times, respectively, and the malondialdehyde (MDA) content; (3) damage treatment reduced the content of basal metabolites (soluble protein, soluble carbohydrates, starch) and increased the content of secondary metabolites (total phenols, total flavonoids) of T. hemprichii; (4) the response of the growth and physiological characteristics of T. hemprichii to different types of mechanical damage depended on the area of leaf damage, the length of wounds and the degree of leaf vein damage. Our findings can provide the basis and support for the conservation and restoration of tropical seagrass beds.

According to the data of four ecological surveys of the phytoplankton in Modaomen Estuary collected from 2015 to 2016, a total of 181 phytoplankton species were identified. Diatom are the richest type, which contain about 117 species, account for 63.74% of the total. This type is followed by Pyrrophyta, about 32 species, and the others covering about 32 species. The most dominant phytoplankton are warm-water species. There are richest phytoplankton species in summer, and the species richness is similar among other three seasons. There are both alternation and overlap of species between seasons. Jaccard index between Bailong River and Modaomen River in Winter is lower than that among other three seasons. The phytoplankton abundance each season varies beyween 102.0×10⁴ and 470.67×10⁴cell/m³, with an average of 229.01×10⁴cell/m³. The variation of phytoplankton abundance is the highest in summer, the lowest in winter, while the difference between spring and autumn is not significant. The size determines the dynamic change of the total amount of phytoplankton. The abundance of phytoplankton in Bailong River is higher than that in Modaomen River in spring, summer and autumn; however, such difference is not significant in winter. The Shannon-Wiener diversity index (H′) and evenness index (J′) range from 2.91 to 4.76 and 0.66 to 0.89, respectively. RDA ranking analysis showed that the most significant factors affecting the abundance of phytoplankton were WT, NH₄-N and salt in Bailong River, and WT and NH₄-N in Modaomen River.

With the continuous progress of ecological civilization construction, fishery resource conservation in Huaihe River Basin has been paid more and more attentions. Fish health is closely related to fish resources with the intestinal flora as a key part. However, the report on the characteristics of fish intestinal flora in Huaihe River Basin is very scarce. To explore the composition and influencing factors of fish intestinal flora in Anhui section of Huaihe River, in March 2019, 90 intestinal samples were collected from 6 fish species, Acheilognathus chankaensis, Abbottina rivularis, Coilia nasus, Hemiculter bleekeri, Pelteobaggrus nitidus,and Parabramis pekinensis), and analyzed using 16S rRNA high-throughput sequencing technologies. Result display, Proteobacteria, Cyanobacteria and Verrucomicrobiota were the dominant bacteria in the gut of the six fish species. Furthermore, Bacteroidetes and Firmicutes also occupy a relatively high proportion in fish gut. Affected by feeding habits, the flora structure each group had significant difference (P＜0.01). LEfSe analysis found that the intestinal flora of herbivorous fish species were enriched into 46 iconic differentiating bacteria including Aminobacter, Planctomicrobium, Blastopirellula among others. Pseudomonas and Sphingomonas had significant differences in the intestinal tracts of fish in different resident water layers, and a large number of distinctive differential bacteria were enriched in the fish species of bottom water layer where 17 species of bacteria such as Arenimonas, Blastopirellula and SH-PL14 were documented. In addition, there was no significant difference in the dominant bacteria genera of the fish intestinal tracts among different reaches, but many rare groups were found in the fish intestinal tracts of the middle reaches. In general, the composition of fish intestinal flora is closely related to feeding habits, habitat water layer and habitat reaches, among which phytopherbivorous fish, benthic fish and midstream fish showed obvious differences between their respective groups. Our studies clarified potential influencing factors of fish intestinal flora in the natural environment, provided data support for the establishment of fish intestinal flora database and new ideas for the conservation of fish resources in Huaihe River.

This paper presented a four-level quality control model constructed by integrating statistical analysis and single classification methods based on long time series observations of temperature and salt elements at ocean stations to find anomalous observations and achieve quality control of ocean fixed observation data. The model generated a statistical analysis layer of samples tested by constructing a three-time window from far to near, and statistical analysis was used to filter out a large number of positive samples in order to reduce the size of the anomaly candidate set. Statistical features, fitted features and classification features were extracted to generate the samples to be tested in the single classification layer. Observations suspected of being anomalous were further examined using the single classification method. A final identification of whether being anomalous was given based on the results of the statistical analysis layer and the single classification layer. In this paper, continuous observations from Bayuquan and Shipu stations were selected as experimental data. The experimental results showed that the four-level quality control model constructed in this paper could solve the problem of unbalanced positive and negative samples effectively. At the same time, by comparing the four-tier quality control model with statistical analysis, such as isolation forest and one-class SVM, the results showed that the accuracy of the four-level quality control model proposed in this paper detected anomalies significantly better and could be applied to the actual observation data quality control operation.

A coastal wetland resource evaluation system with 5 aspects and 18 indexes was built for evaluating the present situation of coastal wetland from the perspective of resources. The weight of evaluation indexes was determined with the expert consultation result and by adopting the comprehensive evaluation method of evaluating wetland resources. Based on the survey results of coastal wetlands in Changjiang estuary, a pilot application of wetland resource evaluation was carried out in Dongfengdongsha and Miaogangsha wetlands. The results showed that the wetland resource evaluation index of Dongfengdongsha and Miaogangsha was 52.2, and the wetland resource evaluation grade was medium.

Intertidal wetlands accumulate a large amount of organic carbon, which contributes to climate change mitigation. Monitoring and analyzing their spatial and temporal patterns and carbon stock changes are crucial to protect and manage the carbon pool. In this study, we utilized the Google Earth Engine (GEE) and combined the Maximum Spectral Index Composite-Otsu Algorithm (MSIC-OA) to extract wetlands extents and the Random Forest Algorithm to map vegetation cover in Shanghai. Then carbon stocks were quantified by the integrated valuation of Ecosystem Services and Tradeoffs model (InVEST) during the period of 2000-2020. The results showed that the area of intertidal wetlands showed a decreasing and then increasing trend during the 20-year period, with the lowest wetland area in 2005 and the highest in 2015. The carbon stock of intertidal wetlands showed a yearly increasing trend during the 20-year period. The changes in the area of intertidal wetlands were mainly related to the coastal reclamation. The carbon stock of wetlands was mainly influenced by the composition of the vegetation cover. The results of this study could help to develop carbon storage management strategies for intertidal wetland ecosystems to cope with global climate change and help to achieve carbon neutrality.

Conflict analysis is a fundamental work of marine spatial planning. This paper took the Oujiang Estuary sea area as an example, quantitatively analyzed the conflict intensity and spatial characteristics between sea uses and three types of biodiversity protection objects—benthic organism, fish resources, and coastal wetlands—by computing sea use conflicts. The results showed that conflicts between sea uses and benthic organism got the highest scores, with an overall conflict intensity surpassing that of the others. The construction of tourism infrastructure such as the national marine park in the southeast of Dongtou Island and the installation of cable pipelines from Damen Island to the southern of Luxi Island were the primary contributors to the conflicts between sea uses and benthic organisms. Marine fishing and mariculture activities constituted the primary causes of conflicts between sea uses and fish resources. The region of intense conflicts between sea uses and coastal wetlands were concentrated, with mariculture, port construction, and roads and bridges being the primary impacts. Consequently, the pressure on coastal wetlands may be effectively alleviated by guiding the orderly withdrawal of near-shore mariculture. The study could provide scientific basis for the rational use of marine space resources in the Oujiang Estuary.

Accelerating the revitalization of unused sea areas can implement the national policy to deal with the historical problems left over from reclaimed sea areas, realize the intensive and economical use of resources, and provide new ideas for the treatment of unused sea areas. In this paper, we putted forward the hypothesis that the government and enterprises jointly exploit the unused sea area, constructed the cooperative game model of the government and enterprises joint exploitation of unused sea area, and calculated the net income distribution between the government and enterprises using the modified Shapley value method. Taking the unused sea area of Tianjin Binhai New Area as an example, the hypothesis that the government and enterprises cooperate to exploit the unused sea area was verified. The results showed that (1) the government and enterprises cooperate to exploit and fill the unused sea area, and both parties generate net benefits; (2) after adding the ecological restoration risk factor, the government that bears the higher ecological restoration risk can share higher income; and (3) income distribution was carried out according to the contribution of participants to the alliance and the ecological restoration risks they bear, which solved the problem of income distribution fairness in the process of cooperation. It is effective for the government and marine enterprises to cooperate to exploit and fill unused sea areas. Based on the modified Shapley value method, the income of the government and enterprises can be scientifically and reasonably distributed, and the intensive utilization of resources can be realized.

At present, there are many researches on the performance evaluation methods of urban sewage treatment plants, but there are few researches on the performance evaluation of port sewage treatment. The improvement of port sewage treatment capacity plays an important role in promoting the development of green port construction. The port sewage treatment system needs to build a hierarchical performance evaluation index system to provide specific guidance for the development of green port and for the improvement of sewage treatment methods. In this paper, the DPSIR conceptual model was integrated into the port sewage treatment performance evaluation system, and a three-level evaluation system was established. Five contents of the core layer were corresponded to 16 specific evaluation factors. The research was carried out from the perspective of land and sea overall management. The performance indicator system of port sewage treatment based on DPSIR model was interrelated at the criterion level and the indicator level. The different weight factors could objectively reflect the level of port sewage treatment performance to find the core content of port sewage treatment. Through the theoretical application of the evaluation system method, this paper took Dongjiakou Port sewage treatment performance evaluation of Qingdao city as an example, collected the relevant data of sewage treatment in recent 10 years, and conducted systematic evaluation and verification in two stages. The results showed that the sewage treatment performance in the second stage was obviously superior to that in the first stage, and the factors that had the greatest influence on the evaluation results were the sewage outlet selection method and the sewage facility land layout method.

In order to explore the performance of constructed wetlands in treating seawater shrimp tail water, and the distribution pattern of microbial communities among and between plant roots and different substrates, in this study, we constructed a composite vertical subsurface flow constructed wetland to study the removal effect of pollutants in seawater shrimp tail water, and characterized the microbial community structure of constructed wetlands using high-throughput sequencing technology. The results showed that the system has a high removal effect on nutrients. The removal rate of COD, NH⁺₄-N, NO^-₂-N and NO^-₃-N of the shrimp tail water by the CW selected in this study reached 41.370 ± 6.370%, 70.330 ± 6.040%, 73.810 ± 7.140% and 67.260 ± 7.570%, respectively, and the removal effect of the downstream pool was better than upstream pool. The composition of microbial communities in plant roots and substrates was similar, but there were significant differences in diversity. Compared with plants and other substrates, the diversity of microbial communities in coral layer was the lowest. Proteobacteria, bacteroidota, Firmicutes, actinobacterota and desulfurobacteria were the dominant phylum. α-Alphaproteobacteria, γ-Gammaproteobacteria, bacteroidia, bacillus, actinobacteria were the dominant class. The bacteria with high abundances were Bacillus, rank-f-unclassifie, unclassified-f-Flavobacteriaceae, Aquibacter, unclassified-f-rhodobacteraceae, Nitrospira, Nitratireductor, Methylotenera, Methylophaga, Labrenzia. Nitrospira which mainly distributed in plant roots and fine sand layer, while denitrifying bacteria (such as Bacillus) mainly distributed in coal cinder layer and coral layer with low dissolved oxygen.

In recent years, the global aquatic trade value and per capita consumption have increased significantly, and the quality and safety control of aquaculture products has become an important issue; these issues involve people's food safety, life and health, sustainable development of fishery and ecological environmental protection, and national responsible fishery image. Aquaculture involves pre-production, production and post-production, and it is necessary to establish a sound quality and safety control system including fishery drug and fishery feed testing, traceability management, HACCP management among others. At this stage, there are still many problems in the supervision of the quality and safety of aquaculture products in China. The quality and safety regulations of aquatic product breeding in the United States, European Union, Norway, Japan, South Korea and other countries and regions started earlier, and the relevant control measures are relatively advanced and mature. These experiences can provide important references for China. In view of the problems in the supervision of the quality and safety of aquaculture products in China, relevant improvement measures include improving the legal system and improving the regulatory system; improving the standard system, improving the detection technology and capabilities; strengthening coordinated enforcement of aquaculture across government departments; and strengthening publicity and education on the quality and safety of aquaculture products.

With the deepening of globalization, foreign-related fishery violations have increased significantly. The problem is that when fishery authorities of China and other countries enjoy the power of administrative punishment for the same offence at the same time, if other country has already imposed an administrative penalty on the act, whether our country repeatedly punishes it violates the principle of ne bis in idem. China has the right to punish foreign-related fishery violations that occur in waters under its jurisdiction based on territorial jurisdiction. Subject to the necessary international obligations, the power to punish acts occurring outside waters under our jurisdiction may be exercised ratione personae. The repeated punishment imposed by China′s fishery authorities does not violate international law. Through the interpretation of the administrative subject of Article 29 of the Administrative Punishment Law and the newly added latter paragraph in 2021, it can be seen that the principle of ne bis in idem in China only applies between China′s administrative organs, and repeated punishment of foreign-related administrative violations by China′s fishery administration organs does not violate domestic laws.

Ocean carbon sink is one of the important carbon sink types in nature. Under the background of coping with global climate change, the development of ocean carbon sink can effectively reduce the content of carbon dioxide in the atmosphere, promote the low-carbon transformation of marine industry, improve the utilization efficiency of marine resources, and accelerate the realization of the strategic goal of carbon peak and carbon neutralization, which is an effective path to promote high-quality economic and social development. However, the healthy and sustainable development of ocean carbon sink needs solid and effective institutional guarantee, the ocean carbon sink policy system should be established and improved as soon as possible. In this regard, from the theoretical analysis, the natural science theory, climate responsibility theory, ecosystem service payment theory, land and sea integration theory and building a community of marine destiny etc. theories have built a basic theoretical framework for the future development of ocean carbon sink and become the theoretical basis for the construction of ocean carbon sink policy system. From the perspective of implementation path, China can take the lead in exploring the establishment of an international ocean carbon sink policy system with Chinese characteristics from multiple dimensions such as the international legal system, domestic legal system, trading market system and service guarantee system. For the purpose of improving the ocean carbon sink governance system and governance capacity, we should strive to master the initiative in formulating international rules and international standards for ocean carbon sink, actively seize the international commanding height of ocean carbon sink in the fields of science and technology, standards, rules, industry and market, and establish our country's international leading position and leading role in the field of ocean carbon sink, helping our country move forward from an ocean power to a maritime power.

Evaluating current water pollution prevention and control policies, identifying policy deviations and institutional deficiencies, and proposing optimization strategies can enhance the scientific nature of water pollution prevention and control policies in the Yangtze River Delta region from a strategic perspective, and improve actual governance efficiency. In this article, we take the water pollution prevention and control policies released by the “Three Provinces and One City” in Yangtze River Delta as a sample, and analyze the current situation and policy characteristics of water pollution through policy text content and with policy modeling consistency index model. The results showed that the current water pollution prevention and control policies in the Yangtze River Delta region are generally at a good level, but there are still shortcomings in policy means, areas of action, and policy content. Therefore, we suggested to optimize the combination of environmental policy tools, enhance policy predictability and technicality, and improve the coordination and cooperation mechanism between water environment policy formulation and execution departments in the Yangtze River Delta region.

In this study, we adopted the content analysis method, used the central government and the provincial governments of three provinces and one city adjacent to East China Sea as the issuing units, took the East China Sea marine ecological environment policies issued between 1982 and 2022 as the analysis sample, and conducted a quantitative analysis of the application of marine ecological environment policy tools in the East China Sea following the steps of developing an analysis framework, coding policy content and analyzing statistical data. We found that the frequency distribution of the selection and application of different types of policy tools is uneven; the structure of policy tool selection and application is single; and the selection and application pattern of policy tools by central and local governments are basically consistent with the overall situation. In the future, the central government and the three provinces and one city adjacent to East China Sea should achieve the convergence of policy tool selection and application frequency through independent adjustment and optimization combination. We suggest also to promote diversified development of policy tool selection and application methods by increasing innovation in various types; and enhance the coordination between policy tools through regional collaborative innovation and the implementation of land sea integrated strategy.

Bubble curtain is extensively used as an ecology device, which can be treated as breakwater, oil boom, silt curtain, saline barrier, mixer & aerator, acoustic & explosive screen, and fish curtain. In this paper, the generation principle and characters of the bubble curtain were introduced, and the action mechanism in various application was elaborated. Besides, the effect and application condition in practical usage were reviewed. On this basis, the main utilization characteristics of the bubble curtain were summarized, which could provide an important reference for comprehensive understanding on the relative application theories of the bubble screen and promotion of bubble barrier technology application, and lay a foundation for subsequent research.

In this paper, we reviewed the sources, distribution, pollution characteristics and ecological risks of microplastics in coastal blue carbon ecosystems (BCEs), and the impacts of microplastics on the carbon cycle of coastal BCEs. In future, it is necessary to strengthen the research on the occurrence and influencing factors, the sources, environmental fate and ecological risks of microplastics in the coastal BCEs. Moreover, future efforts are needed to explore the influencing mechanism of microplastics on the carbon cycle of BCEs. Our understanding provided theoretical supports for the pollution monitoring, ecological risk assessment, ecological effects research, and prevention and control management policies of microplastics in coastal BCEs.