Marine Ecological Environment Research Articles

Research on ecological and climate impacts of offshore wind farms based on remote sensing images

Abstract. Offshore wind farm (OWF)’s impact on marine ecological environment has attracted widespread attention since its rapid development. The paper uses high-resolution satellite image data to extract the distribution of offshore wind farms (OWFs) in China based on deep learning method. Chlorophyll-a (CHL-a) concentration and sea surface temperature (SST) were used as indicators to analyze the impact of OWFs’ development. We can then draw the following conclusions: 1) From 2016 to 2022, the number of OWFs in China continues to increase, the growth rate reachs 28% in 2022. 2) The construction of OWFs presents a development trend from near sea to far sea and from shallow sea to deep sea. From 2016 to 2022, the new OWFs are mainly concentrated in sea areas with 5-50 meters water depth, accounting for 84.7 % of the total increase in OWFs. 3) The distribution density of OWFs is negatively correlated with CHL-a concentration and SST, the more OWFs, the greater the impact on CHL-a and SST. In one word, our work analyzed the development trend of OWFs in China and evaluated the impact of OWFs’ expansion on marine ecological environment and climate.

Adaptation mechanism of clam Ruditapes philippinarum under polycyclic aromatic hydrocarbon stresses: Accumulation and excretion

Persistent organic pollutants (POPs) are easily accumulated in organisms due to its high lipophilicity. Bivalves are still one of the marine invertebrates with high species diversity despite experiencing with environmental pollution. However, studies investigating the adaptation mechanisms of bivalves towards POPs have been lacking. In this study, we chose benzo[a]pyrene (B[a]P), a typical POPs, to investigate the accumulation and excretion mechanism of clam Ruditapes philippinarum towards B[a]P. Laser confocal microscopy images of ovaries and testes confirmed significant colocalization between lipid droplets and B[a]P. However, B[a]P in the testes might mainly excrete with the excretory fluid. Furthermore, lipidomics results indicated that the upregulated TGs were TGs with 48–58 total carbon atoms and 6–12 double bonds in acyl side chains in ovaries, while the upregulated TGs mainly distributed in 48–58 total carbon atoms and 4–14 double bonds in acyl side chains in testes. In ovaries, gene expression of lipid metabolism and phospholipid metabolism basically presented an upward trend at Pro and Mat stages, while entirely performed a downregulation trend at Gro stage. Testes had the opposite regulation with that. Additionally, B[a]P prompted the excretion ability of female clams, but exhibited a complex effect in the male. This study provides a scientific basis for bivalve toxicology and healthy aquaculture, which is of great significance for marine ecological environment protection and aquatic product safety of China.

Identify and segment microalgae in complex backgrounds with improved YOLO

Microalgae are widely distributed in the ocean, and some species are prone to causing harmful algal blooms that threaten the marine ecological environment. At present, microscopy is the most common method for microalgae analysis, and the combination of computer vision and microscopy is the mainstream trend in algae morphology classification. However, most methods only focus on the species and quantities of algae, without obtaining contour information that can further analyze their survival status and biomass. Therefore, this article proposes a convolutional neural network (AlgaeSeg-YOLO), which can recognize the species, quantities, and contours of algae. Firstly, a dataset of microalgae microscopic images in microfluidic chips was constructed, which includes a total of 2799 annotated images of 6 harmful microalgae, including 3916 instances. Secondly, the AlgaeSeg-YOLO was constructed with stronger feature fusion and pixel-level spatial information modeling capabilities based on YOLOv8n-seg. Finally, compared to other common methods, the experimental results show that the mAP (mean Average Precision) of AlgaeSeg-YOLO reaches 95.61 %, which is 1.64 %, 1.76 %, 5.28 %, 3.34 %, and 5.39 % higher than YOLOv8n-seg, YOLOv5n-seg, Mask R-CNN, Cascade Mask R-CNN, and SOLOv2, respectively, achieving real-time and accurate segmentation of microalgae in complex backgrounds. Meanwhile, the parameters and computation remain relatively low. This work helps to achieve fully automated analysis of microalgae, reduce labor costs, and provide technical support for long-term monitoring of the ecological environment and further research.

Lotus leaf and shark skin-inspired micro-, nano-, hierarchical superhydrophobic surfaces for anti-fouling applications

Fouling, the accumulation and adhesion of unwanted contaminants, is a serious issue around the world in many aspects including industrial transport, marine ecological environment, maintenance of infrastructures, etc. which costs hundreds of millions of dollars and lots of manpower and material resources. Multiscale hierarchical surface structures of superhydrophobic surfaces possess various intriguing properties which provides new platforms for fabricating artificial anti-fouling surfaces. In particular, lotus leaf and shark skin with their unique micro-, nano-, hierarchical surfaces structures are highlighted as emerging tools for anti-bacterial, anti-dust, anti-corrosion, anti-icing, drag reduction applications and so on. In this review, we first provide basic information on two famous superhydrophobic states. After that we outlined the biological models and applications of lotus leaf and shark skin respectively. The self-cleaning effect of superhydrophobic lotus leaf due to their multiscale hierarchical surface structures is discussed after which anti-bacterial applications with three kinds of mechanisms and self-cleaning properties are outlined. Biological models of superhydrophobic shark skin are presented followed by their real-life applications in aircrafts and turbine blades. In addition, we discuss the potential drawbacks of recent biomimetic anti-fouling superhydrophobic surfaces like the loss of anti-fouling hydrophobic materials, adaptability to extreme environments, production and use costs and other problems as well as the possibilities of combine superhydrophobic structures and materials with high temperature resistance, oxidation resistance and other characteristics in order to be applied in more industries fields.

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.

Prevention policies for the marine ecological environment in the South China Sea as a consequence of excessive plastic compound use in Vietnam.

Vietnam suffers from a distressing predicament: It ranks among the most heavily contaminated nations on earth. Its coastal and marine domains are plagued by an excess of plastic waste. Vietnam has consistently discharged a substantial amount of waste into the oceans, ranging from 0.28 to 0.73 million metric tons annually. Numerous areas have emerged as focal points of plastic pollution throughout its extensive seashore and marine areas. The escalating presence of marine litter poses an increasingly grave threat to the intricate equilibrium of Vietnam's marine ecosystems. This comprehensive policy study reveals that the mounting problem of ocean plastic pollution, characterized by the abundance of floating plastic debris, imperils both plant and animal life, placing various marine species such as seabirds, fish, turtles, and cetaceans at risk. The consumption of minuscule plastic particles and the harmful impact of chemical pollutants from plastic waste in the ocean not only endangers the vitality of marine life but also poses a substantial hazard to human well-being because plastic waste infiltrates the food chain. This research reveals that, despite the existence of numerous laws and policies-including the Law on Environmental Protection 2020, the Marine Plastic Waste Management Initiative for the Fisheries Sector 2020-2030, and the National Action Plan for Management of Marine Plastic Litter-a significant amount of plastic waste is infiltrating the river network and eventually infiltrating oceans as a result of improper monitoring and ineffective enforcement of these legislations. Relying primarily on existing data released by the government and other sources and a wide range of gray literature retrieved from reputable databases, this study aims to evaluate the role of Vietnam's legal framework for combating the critical issue of marine plastic pollution in the South China Sea. Integr Environ Assess Manag 2024;20:2088-2106. © 2024 SETAC.

Regional patterns and factors analysis of the sustainable development of benefits in China's national-level marine ranching: Based on shellfish and algae

National-level marine ranching plays an important role in enhancing the marine ecological environment, fostering social and economic development, and bolstering human well-being. Quantitatively analyzing the level of coordinated development of its “ecological-economic-social” benefits and the factors influencing them is of great theoretical significance and practical value for refining the new round of development planning and guiding its construction and management. Therefore, on the basis of establishing a theoretical framework for the interaction of “ecological-economic-social” benefits, shellfish and algae were selected as research objects. We calculated the levels of ecological, economic, and social benefits, explored the interrelationships among the three using the coupled coordination model, and analyzed the influencing factors by using multivariate linear regression and geographically weighted regression. The results showed that: (1) In 2015 and 2021, the ecological and economic benefits of national-level marine ranching for shellfish and algae were better than the social benefits, in which the ecological and social benefits were stable, while the economic benefits were more variable; (2) The degree of coordination of the coupling between the three benefits in each province was mostly low, with most experiencing severe disorder; (3) The level of openness to the outside world and the standard of living of fishermen contributed positively to the coordination of benefit coupling between shellfish and algae. Conversely, the level of science and technology, innovation capacity, and the level of social development had a slightly negative impact. In conclusion, shellfish and algal aquaculture in China's national-level marine ranching significantly contributes to the ecological, economic, and social systems. However, the merits and demerits of natural, social, and economic factors must be comprehensively considered to promote the sustainable development of marine ranching.

Research on the Influencing Factors of Consumer Seafood Consumption Willingness in the Bohai Rim Area Based on Random Forest and Structural Equation Model

With the increasing prominence of environmental issues, the impact of nuclear pollution events on the marine ecological environment has attracted widespread concern. This study aims to explore the influencing factors of consumers' willingness to consume seafood in the Bohai Rim area when facing nuclear pollution events. By combining the use of random forest and structural equation modeling (SEM), this research conducted an in-depth analysis of the collected survey data. Initially, the random forest model was applied to rank the importance of satisfaction scale indicators, factor analysis was used to reduce the scale indicators to obtain factors affecting consumer satisfaction, and finally, the SEM model was employed to study the impact of various factors and indicators on consumer satisfaction, identifying the key factors affecting the willingness to consume prepared dishes. The study results show that consumers pay high attention to the origin, quality, and nutritional value of seafood, and these factors are proven to have a significant impact on consumption willingness through the measurement model. The structural model analysis reveals the importance of business services and product features in enhancing consumers' willingness to purchase. Additionally, the model fit indices indicate that the proposed model structure fits the actual data well. This study provides targeted marketing strategy recommendations for seafood suppliers to adapt to changes in consumer behavior under environmental changes.

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.

The Impact of Fishing Ban Policy on Marine Ecological Environment

This study aims to explore the impact of implementing fishing moratorium policies on the marine ecological environment in the Bohai Sea region. The marine environment in this area has been long degraded, primarily due to excessive fishing and pollution. This study focuses on the before and after effects of the fishing moratorium policy on the marine ecological environment. Research methods include literature review and data analysis, analyzing the marine environmental conditions in the region prior to the implementation of the fishing moratorium policy. The results show that implementing the fishing moratorium policy can effectively restore the marine ecological environment, enhance species diversity, and stabilize the structure of marine biological communities. Additionally, the fishing moratorium policy provides guarantee for the sustainable utilization of fishery resources. However, there are still some issues in the implementation process of the fishing moratorium policy, such as reduction in fishermen's income and decline in fishery output. Future research needs to further explore how to optimize the fishing moratorium policy and balance marine ecological protection with the economic interests of fishermen. In conclusion, the impact of implementing fishing moratorium policies in the Bohai Sea region on the marine ecological environment is significant but still requires further improvement and optimization.

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.