Marine Ecological Environment Research Articles

Composition and distribution of nutrients and environmental capacity in Dapeng Bay, northern South China Sea

Seawater physicochemical parameters and environmental capacity are important ecological indicators and typical features of the marine environment. It has great significance in the marine material cycle and ecological health. In September 2021 (wet season) and March 2022 (dry season), two voyage investigations were conducted at 12 stations (D1-D12) on Dapeng Bay (DPB), northern South China Sea. The distribution of nutrient, water-quality status, environmental capacity, and impact of ecological environment were discussed. Results showed that NH4-N was the main form of dissolved inorganic nitrogen (DIN) during the wet season, with concentrations ranging from 0.008 mg/L to 0.109 mg/L, accounting for ~53 % of DIN. Conversely, NO3-N was the main form of DIN during the dry season, with concentrations ranging from 0.005 mg/L to 0.117 mg/L, accounting for ~50 % of DIN. The DIP concentration ranged from 0.002 mg/L to 0.019 mg/L, accounting for ~51 % and 31 % of the total dissolved phosphorus in the wet and dry seasons, respectively. The distributions of NH4-N, NO3-N, NO2-N, and DIP were relatively similar, decreasing from the inner bay to the outer bay. The eutrophication indices of 12 stations <1, indicating a poor eutrophication state. Single-factor indices including chemical oxygen demand (COD), DIN, and dissolved inorganic phosphorus (DIP) were less than the class I seawater-quality standard. However, except for station D1, the overall water quality was good. Dissolved oxygen with DIP had a significantly negative correlation during the dry season, indicating that DIP was primarily dominated by marine biological activity and organic-matter decomposition. The remaining environmental capacities of COD, DIN, and DIP in DPB were calculated to be 13,742, 1418, and 141 tons, respectively. Based on the functional-zone division of the sea area, the remaining environmental capacities of COD, DIN, and DIP were exceeded 75 % of the total environmental capacity. This study provided a scientific basis for the protection of marine ecological environment and the sustainable development of DPB.

MXene@MnIn2S4‐Gated Organic Photoelectrochemical Transistors with Nanozyme‐Mediated Multiple Quenching Effects for Ultrasensitive Detection of Okadaic Acid

AbstractOrganic optoelectronics have attracted widespread interdisciplinary research interest but lags far behind in the application in marine environmental detection. The organic photoelectrochemical transistor (OPECT) shows promise as a powerful tool for comprehensive monitoring and early warning of marine conditions, which can be further enhanced by the valuable signal amplification strategy of nanozyme‐mediated catalytic precipitation. Herein, OPECT technology is integrated with nanozyme‐mediated catalytic precipitation for the first time, establishing an ultrasensitive detection platform for okadaic acid (OA). Specifically, MXene@MnIn2S4 (MXMnIS) hybrid composed of Schottky‐junction is synthesized via a hydrothermal method, which can efficiently modulate the device with high current gain. Linking with a sandwich immunoassay, the Ru‐C3N4 nanozyme with peroxidase‐mimicking activity can catalyze the oxidation of 4‐chloro‐1‐naphthol (4‐CN) to form an insoluble precipitate on the electrode surface, resulting in a decrease in the photocurrent and altering the transistor response. Importantly, the proposed OPECT biosensor presented an excellent sensitivity and a low detection limit (32.5 pM), fully satisfying the fundamental requirements for the quantitative detection of intracellular and extracellular OA in the practical culture media of Prorocentrum lima at different growth stages. This OPECT platform based on the nanozyme‐mediated quenching effect is significant for effectively monitoring the safety of the marine ecological environment and food safety.

Temporal variations of biological nitrogen fixation and diazotrophic communities associated with artificial seaweed farms

Diazotrophic communities contribute inorganic nitrogen for the primary productivity of the marine environment by biological nitrogen fixation (BNF). They play a vital role in the biogeochemical cycle of nitrogen in the marine ecological environment. However, there is still an incomplete understanding of BNF and diazotrophs in artificial seaweed farms. Therefore, this study comprehensively investigated the temporal variations of BNF associated with Gracilariopsis lemaneiformis, as well as the diazotrophic communities associated with macroalgae and its surrounding seawater. Our results revealed that a total of 13 strains belonging to Proteobacteria and Bacteroidetes were identified as N2-fixing bacteria using azotobacter selective solid medium and nifH gene cloning. Subsequently, BNF and diazotrophic communities were characterized using the acetylene reduction method and high-throughput sequencing of the nifH gene, respectively. The results showed that nitrogenase activity and nifH gene abundance of epiphytic bacteria on G. lemaneiformis varied significantly among four different cultivation periods, i.e., Cultivation Jan. (CJ), Cultivation Feb. (CF), Cultivation Mar. (CM), Cultivation Apr. (CA). Among them, the nitrogenase activity and nifH gene abundance of epiphytic bacteria on G. lemaneiformis in CM were significantly higher than those in CJ, CF, and CA, indicating that the BNF of eiphytic bacteria on G. lemaneiformis was markedly enhanced. Combined with the data on environmental factors, it was found that the low concentration of nitrogen and phosphorus in CM might considerably boost the BNF of epiphytic bacteria in G. lemaneiformis. The sequencing results of the nifH gene showed that the α-diversity of diazotrophic communities associated with G. lemaneiformis and seawater in CM was higher than that in other cultivation periods. In addition, the diazotrophic communities on G. lemaneiformis were significantly different in CJ, CF, CM, and CA, and they were significantly diverse from diazotrophic communities in seawater. LEfSe analysis indicated that Rhodobacterales, Hyphomonadaceae, Robiginitomaculum, and Robiginitomaculum antarcticum within α-proteobacteria played a remarkable role in BNF in response to nitrogen nutrient deficiency. Taken together, these results provide a unique insight into the interaction between macroalgae and its epiphytic bacteria and lay a foundation for further research on the mechanism of action of nitrogen-cycling microorganisms associated with macroalgae.

Impact of typhoons on the ecological environment of the Pearl River Estuary in the summer of 2021—a study of an algal bloom event

In the summer of 2021, two typhoons, Typhoon Cempaka and Typhoon Lupit, passed through the Pearl River Estuary (PRE), resulting in a noticeable chlorophyll-a (Chla) bloom event on the west side of the PRE. Utilizing a coupled hydrodynamic-ecological model (ROMS-CoSiNE), we investigated the changes in the marine environment during the two-typhoon period and explored the underlying mechanisms involved. Our model effectively reproduces the spatial characteristics of the typhoon-induced algal blooms. The results suggest that the westward invasion of the Pearl River plume has a predominant impact on the alterations in biochemical elements. For further quantitative analyses, we utilized the model to determine the Chla concentration budget in algal bloom region to assess the dominant mechanism, particularly focusing on horizontal advection. Our findings indicated that algal bloom events are mainly attributed to a straightforward physical mechanism, namely, phytoplankton transportation, rather than to nutrient-induced phytoplankton growth. The study also revealed that the different growth processes of the two simulated phytoplankton species did not contribute positively to the increased Chla concentrations. However, further research is needed to investigate the impacts of different phytoplankton functional groups on the marine ecological environment under the influence of typhoons. This study enhances the understanding of the response of ecological environments in coastal areas to typhoons.

The review of how ocean acidification affect organisms and ecological environment

The pH of our sea water is decreasing nowadays. Therefore, ocean acidification has gradually become a problem that people have to face. Human activities since Industrial Revolution are making sea water more and more acidic. Human activity has done some damage to the environment that will directly or indirectly increases the amount of hydrogen ions in seawater, which will finally make the seawater more acidic. One of the result of this changes is ocean acidification. People should start playing attention on this problem. If people do not intervene in advance to acidify the oceans, this issue can cause some consequences that will hurt our environment. The following is the main content of this paper. The reason why carbon dioxide can cause ocean acidification, effects of ocean acidification on Marine ecological environment, the shape of Balanophyllias bones changes in different PH environment and Changes in metabolic pathways of phytoplankton under ocean acidification.

Factors influencing marine ecological environment governance toward sustainability: a case study of Zhejiang Province

At present, the marine ecological environment is facing enormous pressure from human activities, and there is an urgent need for coordinated governance by multiple entities to ensure that the marine ecological environment can continuously meet the needs of sustainable development. Marine ecological environmental governance plays multiple roles in the sustainable development of the ocean characteristics. Most existing studies have explored this field from the perspective of the government and public, while failing to adequately account for the factors influencing enterprises’ participation in marine ecological environmental governance. This paper is an effort to provide some empirical research on the influencing factors of enterprises’ participation in marine ecological environmental governance. Based on existing literature, empirical research (213 middle managers were surveyed from 68 coastal enterprises in Zhejiang, China), this study extracts eight core factors that influence corporate participation in marine ecosystems and uses the Fuzzy Decision-making Trial and Evaluation Laboratory approach (Fuzzy DEMATEL). Furthermore, experts from Chinese backgrounds elucidated the complex interdependencies among the factors, based on which key influencing factors were identified. The empirical results indicate that government attention and support, legal and regulatory requirements, and cost-benefit accounting have a positive net effect on corporate participation in marine ecosystem management; when these factors are improved, they drive improvements in other factors(Corporate Capital Capability, Corporate Social Responsibility, Government Enforcement and Appraisal, The Attention of Corporate Leaders, Corporate Internal Management System). Additionally, interviews with Chinese business people support the robustness of the findings and suggest that policymakers cannot ignore government enforcement and assessment efforts. Overall, the study findings can help advance corporate participation in marine environmental governance.

New insights on the spatial and temporal distribution characteristics of Chinese marine environmental quality and its driving factors from 2003 to 2021

As land and sea integration continues to accelerate, it will inevitably have an effect on the marine ecological environment. However, the study on spatial and temporal distribution characteristics of Chinese marine environmental quality and its driving factors was lacking. This paper employs Regression Analysis, Spearman Correlation Analysis, Canonical Correlation Analysis, Boston Consulting Group Matrix and Environmental Kuznets Curve to examine the spatial–temporal distribution characteristics and correlation factors of Chinese jurisdictional sea areas environmental quality. The environmental quality of the waters under China's jurisdiction improved on average from 2003 to 2021, the area of sea with excellent water quality increased by 7.21 × 104 km2. The spatial distribution showed “South superior, North inferior” trend. The accumulated red tide area is 2.01 × 105 km2, and the green tide has the average maximum area of distribution is 3.13 × 104 km2. The marine dumping area's volume of waste has a three stages of slow rise (2003–2007), steady (2008–2014) and rapid rise (2015–2021). The average percentage of seawater bathing areas with good water quality is 82.10 %. Urban Environmental Infrastructure Investment and Urban Drainage Construction Investments are positively correlated with excellent water quality and negatively correlated with light-sewage water quality. The typical correlation for the group “Environmental Quality/Environmental Governance” is 0.911, and the strongest correlation is between excellent water quality and urban drainage construction investment. The typical correlation coefficient for the “Environmental Quality/Socioeconomic” group is 0.960, and the strongest correlation is between excellent water quality and per capita GDP. The Gross Ocean Product, Per Capita GDP, Proportion of Non-agricultural Industries, Year-end Resident Population, and excellent water quality are positively correlated whereas light-sewage water quality is negatively correlated. Liaoning, Tianjin, Shandong and Guangdong shift from high-pollution-low-investment to low-pollution-low-investment model. Shanghai, Zhejiang, Fujian and Hainan maintain high-pollution-low-investment model, Hainan maintains high-pollution-high-investment model. Jiangsu maintains low-pollution-low-investment model. Hebei and Guangxi shift from low-pollution-low-investment to low-pollution-high-investment model. Liaoning, Hebei, Tianjin, Shandong, Guangxi and Shanghai show inverted “N” shape, Jiangsu shows positive “N” shape, Zhejiang and Fujian show monotonic decline shape, Guangdong and Hainan show positive “U” shape. The results could provide valuable suggestions for coastal provinces to accomplish economic development and environmental improvement, which to prevent the old way of “pollution first and treatment later”.

Optimization of convolutional neural network with dual attention mechanism: Estimation of chlorophyll-a concentration in the Taiwan Strait using MODIS data

Chlorophyll-a (Chl-a) concentration plays a crucial role in monitoring marine phytoplankton, holding significant implications for marine ecosystems and human livelihoods. Remote sensing serves as a valuable method for directly estimating Chl-a concentration and facilitating marine monitoring activities. In order to accurately estimate Chl-a concentration and effectively monitor the marine ecological environment of the Taiwan Strait, this paper introduces a novel neural network model called Convolutional Neural Network with Dual Attention Mechanism Optimization (CNN-CBAM). Additionally, the spectral bands derived from MODIS 500 m imagery are subjected to various processing techniques to generate four distinct sets of feature data. These datasets are subsequently merged with in-situ measurements of Chl-a concentration obtained from buoy stations. Given the limited availability of buoy stations, the temporal continuity of data is leveraged to overcome the spatial distribution constraints. This enables the estimation of Chl-a concentration at various time intervals within the research area of the Taiwan Strait. To evaluate the performance of the model, metrics such as root mean square error (RMSE), mean absolute percentage error (MAPE), and R2 are employed. The results demonstrate that the CNN-CBAM model, utilizing MODIS temporal data, effectively retrieves Chl-a concentration in the research area of the Taiwan Strait with high accuracy. For the CNN-CBAM model, the RMSE is 0.34 μg L−1, MAPE is 22%, and R2 is 0.86. In comparison, the traditional empirical model using the Band Ratio (BR) model has an RMSE of 0.61 μg L−1, MAPE of 57%, and R2 of 0.31. The results indicate that the CNN-CBAM model has improved R2 by 0.55 compared to the traditional BR model. Additionally, the RMSE and MAPE have decreased by 0.27 μg L−1 and 35%, respectively. The superiority of the CNN-CBAM model over the traditional BR model is evident, showcasing a substantial enhancement in the accuracy of Chl-a concentration retrieval. Given the challenges posed by the intricate and ever-changing marine environment, particularly the scarcity of in-situ buoy stations, this study offers a practical solution for monitoring Chl-a concentration. It establishes a framework for leveraging satellite-based multispectral sensors to enable large-scale and multi-temporal remote sensing retrieval of Chl-a concentration in the research area of the Taiwan Strait.

Assessment of waste management scenarios toward marine plastic debris mitigation and cost reduction

The increase in solid waste volume and change in composition due to urban development cause negative effects on the marine ecological environment. The aim of this study was to assess the amount of plastic waste leaking into the environment from the municipal solid waste (MSW) management system and propose mitigation measures towards sustainable development in Hue city, Viet Nam. The method of modelling MSW management system applying Material Flow Analysis (MFA) and simulating models through scenarios were used to propose strategic solutions to improve and develop the system. As a result, the implementation of segregation at source and improvement of the current collection system are urgently needed. Integrated treatment system including material recovery facility combined with transfer station, incineration, centralized and decentralized composting treatment can reduce the landfilled amount to 5% and the quantity of mismanaged plastic waste infiltrating the ocean has undergone a substantial reduction of several hundred-fold.

Superior mechanical performance polyurethane-silicone coatings for synergistic antimicrobial and antifouling coatings

With the increasing awareness of marine ecological environment, biocide-free marine antifouling coatings have been gaining increased attention in the field of marine antifouling. Among all the antifouling approaches, constructing fouling-release coatings (FRCs) may be the most effective and economical way caused by the biocide-free. However, the low mechanical strength, weak adhesion to substrates, and poor static fouling resistance of traditional silicone-based FRCs, which limiting their applications. In this work, we synthesized a polyurethane with hydroxyl terminated polydimethylsiloxane (PDMS), polytetrahydrofuran (PTMG) and isophorone diisocyanate (IPDI) as main chains, 2,2'-Bis (hydroxymethyl)butyric acid (DMBA) as chain extender, and γ-aminopropyl triethoxysilane (KH-550) as crosslinker by condensation polymerization. Meanwhile, Triclosan (TCS) was used as an antibacterial agent and mixed into the polymer system with uniformly dispersed. We introduced urethane groups into silicone, which improved the mechanical strength (ultimate tensile strength: 1.379 MPa, elongation at break: 282%). As a result, the laboratory bioassays using bacteria (E. coli, and S. aureus) showed that the anti-bacterial efficiency could respectively reach ∼95% and ∼93%, which demonstrated an outstanding antifouling property of the D:K = 0.7:1.3/1.0. This work overcomes the low strength issue of traditional fouling-release coatings and provides a simple strategy for silicone-based polyurethane antifouling coatings.

Characteristics and mechanism of winter marine heatwaves in the cold tongue region of the South China Sea

Marine Heatwaves (MHWs) are persistent anomalous sea surface temperature warming events that can affect the marine ecological environment and ecosystems. Here, we study the winter MHWs in the cold tongue region of the South China Sea (SCS) from 1982 to 2022. Our results show that the winter MHWs in the cold tongue region have the strongest cumulative intensity in the SCS, exceeding 45°C·day/time. These strong MHWs are due to their high mean intensity and long duration. Significant interannual variations are observed in these MHWs, with extreme MHW events occurring in the El Niño winters of 97/98 and 15/16. By employing a mixed layer heat budget analysis, we reveal that the extreme MHW event in the winter of 97/98 is caused primarily by the surface heat flux term, and secondarily by the vertical entrainment term. While the 15/16 extreme event is caused by a combination of the surface heat flux term, the vertical entrainment term and the horizontal advection term.

The coupling relationship between marine industry agglomeration and ecological environment system from the perspective of ecological environment

To analyze the coupling relationship in marine industry agglomeration and ecological environment system, this study used the formula of location entropy coefficient for measuring the development agglomeration status of marine industry. Meanwhile, it also separately measures the degree of agglomeration of the primary, secondary, and tertiary industries in the ocean to reveal their degree of agglomeration in the region. In addition, a coupled correlation analysis model was designed. It uses grey relational analysis to reveal the relationships between data series in situations of insufficient data. Finally, a coupled coordination evaluation model was proposed. It evaluates the coupling status between the marine industry cluster and the ecological environment by calculating the capacity coupling coefficient, coupling degree, and coupling co scheduling. The results show that from 2013 to 2022, the agglomeration trend of the marine industry in Jiaodong Peninsula Province has undergone different changes. The location entropy coefficient of the primary industry increased from 1.3047 to 1.0987, while the location entropy coefficient of the secondary industry gradually increased from 0.2486 to 1.1141. The coupling coordination degree R between the marine industry agglomeration system and the ecological environment system has increased from 0.3986 to 0.6253. From 2018 to 2022, the coupling between the marine industry and ecological environment development has increased, gradually moving towards stability and coordination. This indicates that over the past decade, the development of the marine industry in Jiaodong Peninsula Province has placed greater emphasis on ecological protection, and has formed a positive interaction, promoting the coordinated development.

Transcriptome analysis reveals ABA involved in the detoxification mechanism of macroalga Gracilariopsis lemaneiformis to cadmium toxicity

IntroductionCadmium (Cd) is a significant threat environmental pollutant in the marine ecological environment offshore. The macroalga, Gracilariopsis lemaneiformis, of significant economic value, is widely cultivated along China’s coastline. Yet, little is known about the molecular mechanisms underlying Cd tolerance in macroalga.MethodsHere, we examined the transcriptome of G. lemaneiformis exposed to Cd to identify the responses to Cd stress.Results and discussionOur findings revealed that Cd led to the retardation of growth rate in G. lemaneiformis, accompanied by a notable reduction in the content of photosynthetic pigments and a decrease in the expression of genes associated with the photosynthetic system and nitrogen metabolism. When exposed to Cd, there was a rapid increase in Cd levels through the upregulation of genes encoding GlZIP6 and GlIRT1. Additionally, the expression of Cd efflux transporters, GlZIP1 and GlABCG22, and the ABCC7 transporter for compartmentation to the vacuole, was induced to mitigate Cd toxicity. Cd also activated crucial genes involved in the ABA biosynthesis and enhanced ABA content, thereby inducing ABA signaling pathway. Furthermore, exogenous ABA reduced the growth inhibition of G. lemaneiformis under Cd stress. Redox homeostasis was adjusted to adapt to Cd toxicity, with thioredoxin, glutaredoxin cycle and ascorbate-glutathione cycle identified as playing significant in maintaining reactive oxygen species homeostasis. Moreover, transcription factors such as several MYBs, signal transmission factors G protein and heat shock proteins (sHSPs, HSP 40, HSP 90, HSP101) were involved in the detoxification of Cd. Collectively, this study provided a comprehensive understanding of the molecular mechanisms underpinning the of responses of macroalga G. lemaneiformis to Cd exposure.

The Impact of Japan’s Discharge of Nuclear-Contaminated Water on Aquaculture Production, Trade, and Food Security in China and Japan

The aquaculture and fisheries sectors play critical roles in promoting a global nutritious and climate-friendly food system. The Japanese government started implementing the discharge of nuclear-contaminated water (NCW) into the Pacific Ocean in August 2023, which was followed by stopping the import of seafood from Japan to ensure the safety of imported food for Chinese citizens. The discharge of NCW into the ocean by Japan will directly harm the marine ecological environment and the global ecosystem due to the importance of China as the largest producer, processor, and exporter of aquatic products (APs). This paper employs the Global Trade Analysis Project (GTAP) model to simulate the future impacts of discharging the NCW under three different scenarios. The results showed that discharging NCW will lead to a global decline in AP production and also has negative repercussions on the macroeconomic landscape. Japan will face the most significant negative impact on its national macroeconomy, e.g., Japan’s GDP, total imports, total exports, household income, and social welfare will decrease by 2.18%, 3.84%, 8.30%, 2.61%, and $130.07 billion; similarly, for China, the decrease will be 0.03%, 1.21%, 0.08%, and $728.15 billion, respectively. If China’s AP consumption decreases by 10% and 20%, it will result in protein deficits of 1.536 million tons and 3.132 million tons, respectively. Japan’s deficit will reach 138,000 tons and 276,000 tons. This necessitates supplementation via the consumption of other protein-rich foods, posing a significant threat to the nutritional security of food in both China and Japan.

Mariculture may intensify eutrophication but lower N/P ratios: a case study based on nutrients and dual nitrate isotope measurements in Sansha Bay, southeastern China

The mariculture industry has grown rapidly worldwide over the past few decades. The industry helps meet growing food demands and may provide an effective means of carbon sequestration; however, it may harm the marine ecological environment, and the extent of its impact depends on the type of mariculture. Here we focus on the impact of mariculture on the nutrient status and eutrophication in Sansha Bay, which is a typical aquaculture harbor in southeastern China that employs a combination of shellfish and seaweed farming. Nutrient concentrations and dual nitrate isotopes were measured in Sansha Bay during the winter of 2021. The average concentrations of nitrate and phosphate were 31.3 ± 10.5 and 2.26 ± 0.84 µM, respectively, indicating that the water was in a eutrophic state. However, the N/P ratios were relatively low (14.3 ± 2.2). Nitrate isotope measurements were 8.8‰–11.9‰ for δ15N-NO3− and 2.2‰–6.0‰ for δ18O-NO3−. Source analysis based on the nitrate isotope measurements indicates that nitrate in Sansha Bay is derived mainly from the excretion of organisms and sewage discharge from mariculture. The isotopic fractionation model of nitrate assimilation by organisms indicates that surface waters in Sansha Bay experience strong biological uptake of nitrate, which is likely related to seaweed farming in winter. The low N/P ratios may be attributed to excessive nitrogen uptake (relative to phosphorus) during shellfish and seaweed farming, as well as nitrogen removal through sediment denitrification, which is fueled by the sinking of particulate organic matter from mariculture. Overall, our study shows that mariculture activities dominated by shellfish and seaweed cultivation in Sansha Bay may exacerbate eutrophication but reduce N/P ratios in the water column in aquaculture areas.

Multi-omic insights into the cellular response of Phaeodactylum tricornutum (Bacillariophyta) strains under grazing pressure.

Phaeodactylum tricornutum, a model organism of diatoms, plays a crucial role in Earth's primary productivity. Investigating its cellular response to grazing pressure is highly significant for the marine ecological environment. Furthermore, the integration of multi-omics approaches has enhanced the understanding of its response mechanism. To assess the molecular and cellular responses of P.tricornutum to grazer presence, we conducted transcriptomic, proteomic, and metabolomic analyses, combined with phenotypic data from previous studies. Sequencing data were obtained by Illumina RNA sequencing, TMT Labeled Quantitative Proteomics and Non-targeted Metabolomics, and WGCNA analysis and statistical analysis were performed. Among the differentially expressed genes, we observed complex expression patterns of the core genes involved in the phenotypic changes of P.tricornutum under grazing pressure across different strains and multi-omics datasets. These core genes primarily regulate the levels of various proteins and fatty acids, as well as the cellular response to diverse signals. Our research reveals the association of multi-omics in four strains responses to grazing effects in P.tricornutum. Grazing pressure significantly impacted cell growth, fatty acid composition, stress response, and the core genes involved in phenotype transformation.

An analysis of the tripartite evolutionary game for building the ecological security barrier in the Bohai Sea under the threshold of land-sea integration

The construction of marine ecological security barriers (MESBs) is fundamental for the sustainable development of the marine ecological environment and of the marine economy, and is an important component of the strategy of land-sea integration. It is difficult to build an effective MESB simply by relying on the power of the government; therefore, to this respect, it is urgent to encourage the multiple participating subjects to work together. This study takes the Bohai Sea as the research object, and uses evolutionary game theory to construct a game model of decision-making behavior among marine enterprises, local governments, and the public in the process of construction of the MESB in the Bohai Sea, so as to explore the strategic stability equilibrium point through the analysis of the interests of the three decision makers, and lay the foundation for promoting this process. The results are as follows: (1) Local government regulation is key to promote the transformation of the Bohai Sea MESB from policy documents to behavior and from goal to practice; moreover, it directly influences whether the main sources of land-based pollution, i.e., marine enterprises, will abandon the traditional approach to production and development and actively promote the construction of the Bohai Sea MESB. (2) The supervision and reporting of the public can be used as a synergistic, auxiliary supervision means. Thanks to the government’s publicity and education, the public will develop social awareness of marine ecological security, which in turn will ensure a better public supervision of the behavior of local governments and, thus, promote the active participation of marine enterprises in the MESB in the Bohai Sea. (3) Participation costs, ecological benefits, corporate social image, fines, and other factors are the main factors considered in the strategic choice of marine enterprises, with different factors having different marginal effects at different stages. Finally, this study proposes effective measures to further clarify the roles and functions of the stakeholders in the construction of the MESB in the Bohai Sea, balance the interests of the game subjects, and provide an effective implementation path for the realization of the “Ocean Power”.

The coordination of technological and financial innovation concepts on the marine economy and its ecological development

This study first constructs an evaluation index system based on the pressure state response model, and assigns weights through entropy method and coefficient of variation method, providing theoretical and methodological support for comprehensive measurement and evaluation. Second, the least squares decision model is introduced and the PVAR model is used to analyze the development level of China's marine economy, ecology, and technological and financial innovation. The results indicated that from 2012 to 2022, the marine economic development level, marine ecological development level, and marine technology and financial innovation development level of 9 coastal provinces in China all showed a certain growth trend. However, in terms of the level of marine ecological development, various provinces had shown a downward trend, with Hebei performing the best, with an average of 0.230. Although various regions have achieved significant development in marine economy, ecology, and technological and financial innovation, the level of development varies among regions, and some regions have relatively low levels of technological innovation. The pressure and challenges between the marine economy and ecological environment protection caused by these real environments remain significant.

Blue carbon development in China: realistic foundation, internal demands, and the construction of blue carbon market trading mode

Promoting the inclusion of blue carbon in market trading is crucial for recognizing its value and protecting the marine ecological environment. However, China currently does not have an internationally influential blue carbon market trading platform, which hampers the transmission of supply and demand in the blue carbon market and prevents the realization of blue carbon value. In this study, we analyze the feasibility and necessity of establishing a trading mode for the blue carbon market in China. The introduction of futures trading in the blue carbon market’s trading mode allows for the use of futures pricing methods and multiple financial instruments to address the challenges of income cost mismatch in blue carbon project development. The paper also discusses key strategies for the development of China’s blue carbon market, including the creation of a blue carbon trading methodology, the improvement of preservation and appreciation mechanisms, and the establishment of a unified trading platform. These strategies aim to provide intellectual support and decision-making reference for the construction of the market.

Towards ecosystem-based management in Chinese coastal areas: Judgement criteria for water-passable structure based on permeability

China is actively building intelligent oceans to develop the marine economy and protect the ecological environment. Over the past 30 years, China has developed a large number of marine projects for economic development, such as sea reclamation, the establishment of water-passable or water-impassable jetties, dykes, and approach bridges. To reduce the impact on marine hydrodynamics and the ecological environment, China has banned most of its sea-enclosing activities, and water-passable structures are more and more developed and applied in practical projects in China. However, there are no clear judgment criteria for the definition of water-passable structures, and there is a lack of reference for the criteria in the management and development of water-passable structures. This has led to mismanagement, such as the fact that sea enclosures that have a subtle permeability but have a significant impact on the marine environment have been judged to be water-passable structures, which has harmed the marine ecosystem. At the same time, the foundation of the intelligent ocean includes comprehensive access to information on sea-related activities (ocean management, resource development, ecological civilization construction, etc.), and the lack of uniform determination standards makes the information on offshore structures mixed and makes it impossible to establish a standardized management system, which is not conducive to the further development of the intelligent ocean. To put forward the judgment criteria of water-passable structures, this paper establishes a conceptualized hydrodynamic model of linear shaped structures offshore China by analyzing actual data from a survey. According to the simulation results, in typical cases, based on the principle of ecological priority and strict control, this study suggests that linear shaped structures with a permeability greater than or equal to 70% should be recognized as water-passable linear shaped structures, and those with permeability less than 70% should be recognized as water-impassable linear shaped structures. The judgment criteria of water-passable linear shaped structures from the perspective of permeability can help the development and management of water-passable structures in Chinese coastal areas (e.g., sea area use demonstration) to be more accurately carried out, to protect the marine ecological environment and to realize sustainable development. At the same time, it provides a reference basis for China to further build a unified management method for marine structures and promotes the construction of the Chinese intelligent ocean.