Marine Ecological Environment Research Articles

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.

Sodium Alginate Aerogel as a Carrier of Organogelators for Effective Oil Spill Solidification and Recovery.

Marine oil spills pose a serious threat to the marine ecological environment. Phase-selective organogelators (PSOGs) are ideal candidates for oil spill gelation when used in combination with a mechanical recovery method. However, the toxicity of an organic solvent carrier has become a key problem when it is applied in the remediation of marine oil pollution. In this study, through an inexpensive and nontoxic ionic cross-linking and freeze-drying method, we successfully developed composite oil gelling agents that used a biomass sodium alginate aerogel as the carrier of 12-hydroxystearic acid (12-HSA). Simultaneously, carboxylated cellulose nanofibers (CNF-C) with large specific surface area and graphene oxide (GO) with excellent mechanical properties as reinforcing fillers were combined with an alginate matrix. 12-HSA, as a green and inexpensive organic gelator, was uniformly loaded on the aerogels by vacuum impregnation. The sodium alginate aerogel was capable of absorbing and storing oil due to its three-dimensional network skeleton and high porosity. Rheological studies have demonstrated that the organic gelator 12-HSA can be released from the aerogel substrate and self-assemble to form an oleogel with the absorbed oil quickly. The synergistic effect between absorption and congelation endows the composite oil gelling agent with efficient oil spill recovery capability. Based on eco-friendly, biodegradable, and simple synthesis methods, this composite oil gelling agent shows great potential for application in marine oil spill recovery.

Marine ecological restoration strategies of coastal nuclear power plants in China

Low-carbon and green development model is the choice for responding to climate change. Under the dilemma between ever-growing energy demand and the associated environmental issues, nuclear power is one of the low-carbon and high-efficient energy options which compared to wind power and solar power. It is the only stable power source that can replace fossil energy on a large scale at present and even in the future. This paper briefly describes the operational risks of coastal nuclear power plants (CNPPs) and the upgrade process of nuclear reactors, systematically analyzes and summarizes the ecological environment problems, risk problems and ecological restoration and protection strategies in the construction and operation of CNPPs, including coastal wetland ecological environment, marine ecological environment, and the risk prevention measures for cooling water source. The results show that ecosystem restoration by human does not make up for the weakening of the ecological carrying capacity and ecosystem away from its baseline, nonetheless, the restoration of important wetland habitats is conducive to the improvement of the functions of key marine ecosystems and the maintenance of marine biodiversity.

Salinity Inversion of Flat Sea Surface Based on Deep Neural Network

The distribution and change of sea surface salinity (SSS) have an important influence on the sea dynamic environment, marine ecological environment, global water cycle, and global climate change. Satellite remote sensing is the only practical way to continuously observe SSS over a wide area and for a long period of time. The salinity retrieval model of flat sea surface, which primarily includes empirical model and iterative model, is the key to retrieving satellite SSS products. The empirical models have high computational efficiency but low inversion accuracy, while the iterative models have high inversion accuracy but low computational efficiency. In order to reconcile the contradiction between the computational efficiency and inversion accuracy of existing models, this paper proposes a universal deep neural network (DNN) model architecture and corresponding training scheme, and provides 3 DNN models with extremely high computational efficiency and high inversion accuracy. The inversion error range, the root mean square error (RMSE), and the mean absolute error (MAE) of the DNN models on 311,121 sets of data have decreased by more than 40 times, 150 times, and 150 times, respectively, compared to the empirical model. The computational efficiency of the DNN models on 420,903 sets of data has improved by more than 100,000 times compared to the iterative model. Therefore, the algorithm developed in this paper can effectively solve the contradiction between the computational efficiency and inversion accuracy of existing models, and provide a theoretical support for high-precision and high-efficiency salinity inversion research.

海洋生态环境补偿主体的确定与补偿数额标准的建立路径

海洋生态环境补偿主体的确定与补偿数额标准的建立路径

RETRACTION: Construction of the Rule of Law System of Marine Ecological Environment Protection under the Background of Wireless Network Information Fusion

RETRACTION: Construction of the Rule of Law System of Marine Ecological Environment Protection under the Background of Wireless Network Information Fusion

Responses of photosynthesis-related genes in Sargassum horneri to high temperature stress

Golden tide outbreak threatened the marine ecological environment. Sargassum horneri is a single dominant species of the Yellow Sea golden tide, which growth and development are affected by changes in sea water temperature. This study investigated the photosynthetic physiology of copper algae and found that the growth rate, chlorophyll a content, carotenoid content, Fv/Fm, and maximum electron transfer efficiency were significantly reduced, indicating that Sargassum horneri was under stress under high temperature. In this study, high-throughput sequencing was used to analyze the response mechanisms of photosynthesis-related genes in S. horneri under high temperature stress. The results showed that most of the photosynthesis-related genes in S. horneri were downregulated and photosynthesis was inhibited under high temperature stress. However, the expression levels of ferredoxin, ferredoxin-NADP reductase, light-harvesting protein complexes, and oxygen-evolving complex genes were significantly upregulated (P ≤ 0.05) after five days of high temperature treatment. This study found that photosynthesis related genes play a crucial role in regulating the photosynthetic response of S. horneri to high temperature stress.

Relationship between economic growth and marine ecological environment based on VAR models

This study aims to investigate the inherent correlation between economic growth and marine conservation in the coastal regions of China, specifically the shifting relationship between high and low economic growth periods and marine pollution. A nonlinear model is employed to determine the dynamic relationship based on historical data, with the inclusion of a nonlinear zone system transfer factor to achieve this dynamic relationship. The study's data was sourced from a statistical database of 11 Chinese coastal provinces, containing details on economic growth rates and emissions of industrial waste. In the study, significant differences in the mean, variance and smoothing probability of the different provinces were observed in the different systems. Notably, Shandong recorded the highest mean μ2 in both systems, 0.7261* and 0.7261**, while the correlation coefficient between the two systems in the high growth area was −0.3543. Significant differences exist in the intrinsic links between economic growth and marine environmental protection within provinces and cities. Therefore, targeted strategies must be developed for specific regions when formulating economic and environmental policies.

A deep learning approach for object detection of rockfish in challenging underwater environments

IntroductionPreserving the marine ecological environment and safeguarding marine species is a global priority. However, human overfishing has led to a drastic decline in fish species with longer growth cycles, disrupting the equilibrium of the marine ecosystem. To address this issue, researchers are turning to deep learning techniques and state-of-the-art underwater devices, such as underwater robots, to explore the aquatic environment and monitor the activities of endangered populations. This approach has emerged as a focal point of recent research in protecting the marine ecological environment. This study employs a deep learning-based object detection algorithm to identify fish species in complex underwater environments.MethodsThe algorithm is built upon the You Only Look Once version 7(YOLOv7) algorithm, with the addition of the attention mechanism Convolutional Block Attention Module (CBAM) in the network’s backbone. CBAM enhances the feature maps through the fusion of spatial attention and channel attention, ultimately improving the robustness and accuracy of the model’s inference by replacing the original loss function CIoU with SCYLLAIntersection over Union(SIoU). In this paper, the rockfish pictures in the dataset Label Fishes in the Wild published by the National Marine Fisheries Service are selected, and the underwater image enhancement model (UWCNN) is introduced to process the pictures.ResultThe experimental results show that the mean average precision (mAP) value of the improved model on the test set is 94.4%, which is 3.5% higher than the original YOLOv7 model, and the precision and recall rate are 99.1% and 99%, respectively. The detection performance of the algorithm in the field of complex underwater environment is improved.DiscussionThe underwater fish detection scheme proposed in this study holds significant practical value and significance in promoting the conservation of marine ecosystems and the protection of fish species.

Application of Path Planning and Obstacle Avoidance for Riverbank Inspection.

Most coastal trash comes from land. To prevent and control ocean pollution, it should be handled using sources that can maintain a clean ocean and improve the marine ecological environment. The proposed system can be used to inspect riverbanks and identify garbage on riverbanks. This waste can then be cleaned up before flowing into the sea. In this study, we utilized an unmanned aerial vehicle (UAV) to inspect riverbanks and applied path planning and obstacle avoidance to enhance the efficiency of UAV performance and ensure good adaptability in a complicated environment. Since most rivers in the middle and upper sections of the study area are rough and meandering, path planning was first addressed so that the drone could use the shortest path and less energy to perform the inspection task. Branches frequently protrude from the riverbank on both sides. Therefore, an instant obstacle avoidance algorithm was added to avoid various obstacles. Path planning was based on an Improved Particle Swarm Optimization (IPSO). A fuzzy system was added to the IPSO to adjust the parameters that could shorten the planned path. The Artificial Potential Field (APF) was applied for real-time dynamic obstacle avoidance. The proposed UAV system could be used to perform riverbank inspection successfully.

A comparative study on the measurement of sustainable development of marine fisheries in China

Since 1989, China has been the largest aquatic producer in the world. The marine ecological environment is the “price” for the rapid development of fisheries economy, therefore, the sustainable development of fisheries industry is of great concern at home and abroad. This paper carried out a scientific evaluation of typical coastal provinces and cities by constructing an evaluation indicator system and clarifies the regional differences in the sustainable development capacity of China's marine fisheries industry for the first time. The results showed that since the second decade of the 21st century, the sustainability of marine fishery industry has been rising with fluctuation, among which, Shandong Province and Fujian Province have obvious advantages in sustainable development, while Tianjin, Hebei Province, and Shanghai still have large room for improvement. Resource environment and scientific and technological management factors have a significant impact on the sustainable development of China's marine fisheries, while economic and social factors have relatively little influence. Suggestions are put forward to improve the sustainable development level of marine fisheries in China's coastal areas, such as biological resources protection, fishery technology promotion and fishery industrial structure optimization.

Environmental Concerns in Marine Ecology and Strategies for Sustainable Development

Since the commencement of the Industrial Revolution, there has been a gradual and consistent escalation in the level of carbon dioxide emissions, thus causing a drastic alteration in the global climate. As the most substantial ecological environment system on Earth, the marine ecological environment system has also undergone substantial impacts as a result of these climatic changes. Despite its vast size, minor environmental dilemmas were not emphasized initially, leading to momentous qualitative changes caused by the quantitative ones; consequently, human face critical concerns related to marine ecological environment today. The intent of this study is to delineate corresponding sustainable development approaches for the persisting environmental issues under the theoretical framework of sustainable development. Initially, the causes of climate change are discussed, and the undeniably significant role humans have played is examined. Subsequently, alterations in climate change affect various segments of the marine ecosystem differently concerning seawater hydrological conditions, consequently producing a series of chain reactions that ultimately affect the overall marine ecological environment. Various sustainable development strategies have been proposed under the theoretical framework of sustainable development to address the multiple minor problems that contribute to the overall marine ecological environment issues. This study endeavors to present an extensive summary of the marine ecological environment issue in its entirety; however, it should be followed by further in-depth analysis and consolidation of the ecological environment issues of disparate links in the ecosystem, thereby increasing the effectiveness of the targeting approach. This paper expects that through this study, the specific impact of climate change on the marine ecological environment and the direction that human society must work towards to achieve improvement would be made more evident.

Impact of China's marine governance policies on the marine ecological environment – A case study of the Bohai rim

In 2018, the Chinese government implemented the Action Plan for Comprehensive Management of the Bohai Sea(CMAP-BS) to improve the marine ecological environment in the Bohai rim. This study considered the Bohai rim as the research area to explore the impact of China's marine governance policies on the marine ecological environment and its mechanism of action. To this end, we used panel data of coastal provinces and municipalities from 2010 to 2020 and adopted a Differences-in-Differences model to analyse the impact of CMAP-BS on its marine ecological environment. Results of the baseline regression suggested that CMAP-BS can improve its marine ecological environment. To corroborate our findings, we further conducted a robustness test; the results were consistent. Heterogeneity analysis showed that the policy effect of CMAP-BS is more pronounced in areas with a better level of economic development than in those with less economic development. Further research and analysis showed that the improvement of the marine ecological environment can be achieved by adjusting the model of agricultural development.