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Keywords = Zhejiang sea area

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23 pages, 6633 KiB  
Article
Investigating Catching Hotspots of Fishing Boats: A Framework Using BeiDou Big Data and Deep Learning Algorithms
by Fen Wang, Xingyu Liu, Tanxue Chen, Hongxiang Feng and Qin Lin
J. Mar. Sci. Eng. 2025, 13(5), 905; https://doi.org/10.3390/jmse13050905 - 1 May 2025
Viewed by 429
Abstract
Illegal, unreported, and unregulated (IUU) fishing significantly threatens marine ecosystems, disrupts the ecological balance of the oceans, and poses serious challenges to global fisheries management. This contribution presents the efficacy of China’s summer fishing moratorium using BeiDou vessel monitoring system (VMS) data from [...] Read more.
Illegal, unreported, and unregulated (IUU) fishing significantly threatens marine ecosystems, disrupts the ecological balance of the oceans, and poses serious challenges to global fisheries management. This contribution presents the efficacy of China’s summer fishing moratorium using BeiDou vessel monitoring system (VMS) data from 2805 fishing vessels in the East China Sea and Yellow Sea, integrated with a deep learning framework for spatiotemporal analysis. A preprocessing protocol addressing multidimensional noise in raw VMS datasets was developed, incorporating velocity normalization and gap filling to ensure data reliability. The CNN-BiLSTM hybrid model emerged as optimal for fishing behavior classification, achieving 89.98% accuracy and an 87.72% F1 score through synergistic spatiotemporal feature extraction. Spatial analysis revealed significant policy-driven reductions in fishing intensity during the moratorium (May–August), with hotspot areas suppressed to sporadic coastal distributions. However, concentrated vessel activity in Zhejiang’s nearshore waters suggested potential illegal fishing. Post-moratorium, fishing hotspots expanded explosively, peaking in October and clustering in Yushan, Zhoushan, and Yangtze River estuary fishing grounds. Quarterly patterns identified autumn–winter 2021 as peak fishing seasons, with hotspots covering >80% of East China Sea grounds. The framework enables real-time fishing state detection and adaptive spatial management via dynamic closure policies. The findings underscore the need for strengthened surveillance during moratoriums and post-ban catch regulation to mitigate overfishing risks. Full article
(This article belongs to the Special Issue Resilience and Capacity of Waterway Transportation)
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15 pages, 5105 KiB  
Article
Spatiotemporal Characteristics of Sea Level Changes in Hangzhou Bay over the Past 40 Years
by Ye Liu, Chengfei Hu, Lidong Fan, Yingbiao Shi, Cunhong Pan and Kun He
J. Mar. Sci. Eng. 2025, 13(2), 203; https://doi.org/10.3390/jmse13020203 - 22 Jan 2025
Viewed by 873
Abstract
To investigate the spatiotemporal characteristics of sea level changes in Hangzhou Bay over the past 40 years, we collected tide gauge data from six stations within the bay. Various mathematical and statistical methods, including linear regression, empirical orthogonal function (EOF) analysis, and wavelet [...] Read more.
To investigate the spatiotemporal characteristics of sea level changes in Hangzhou Bay over the past 40 years, we collected tide gauge data from six stations within the bay. Various mathematical and statistical methods, including linear regression, empirical orthogonal function (EOF) analysis, and wavelet analysis, were employed to reveal the long-term variation patterns and spatiotemporal characteristics of sea levels in Hangzhou Bay. The results show that the overall trend of sea levels in this area is characterized by a fluctuating rise, with the rate of rise at the top of the bay (Ganpu Station) reaching 6.74 mm/year, higher than the average rise rate of 3.5 mm/year along the coastal areas of Zhejiang Province. Since the 2010s, the rate of sea level change has accelerated. There is a significant seasonal variation in sea levels, with high values occurring in summer and autumn and low values in spring and winter. The sea level in Hangzhou Bay exhibits multi-timescale periodic changes, including astronomical tides, solar activity cycles, and seasonal cycles. It is projected that the sea level will transition from a rising cycle to a declining cycle after 2026. The rise in sea level in the open sea is the main factor contributing to the rising trend of sea levels in Hangzhou Bay. The contracted river for regulation and morphological evolution of the estuary have intensified tidal wave deformation, resulting in a significant impact on local sea level changes. Full article
(This article belongs to the Special Issue Sea Level Rise and Related Hazards Assessment)
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25 pages, 8814 KiB  
Article
Study on the Aquaculture of Large Yellow Croaker in the Coastal Zone of Zhejiang Province Based on High-Resolution Remote Sensing
by Jie Yin, Lina Cai, Jiahua Li, Xiaojun Yan and Beibei Zhang
Remote Sens. 2025, 17(1), 9; https://doi.org/10.3390/rs17010009 - 24 Dec 2024
Cited by 1 | Viewed by 1107
Abstract
This study applied high-resolution satellite data to address the siting and evaluation challenges for potential cage aquaculture areas of large yellow croaker in Zhejiang Province. A typical template of water environmental factors for large yellow croaker cage aquaculture was developed, incorporating various environmental [...] Read more.
This study applied high-resolution satellite data to address the siting and evaluation challenges for potential cage aquaculture areas of large yellow croaker in Zhejiang Province. A typical template of water environmental factors for large yellow croaker cage aquaculture was developed, incorporating various environmental parameters and considerations that were not fully addressed in previous studies. This paper established the Site Selection Method for Large Yellow Croaker potential aquaculture (SSM-LYC) based on the template. Site selection and grading evaluation of potential cage aquaculture areas were performed using SSM-LYC. The findings include the following: (1) Potential aquaculture sites for large yellow croaker include 11 areas with water depths of 15–60 m along the coast of Zhejiang Province from 27° to 31° north latitude, of which 7 are in water depths of less than 40 m, and 4 are in water depths of 40–60 m. (2) Assessment and scoring for potential aquaculture sites were performed, pinpointing 4 central locations of first-level aquaculture areas offering scientific evidence for the feasibility of deep-sea aquaculture of large yellow croaker along the Zhejiang coast. (3) The conclusions drawn from this research provide significant guidance for future aquaculture strategies and regional planning. Moreover, SSM-LYC can be applied to other coastal waters in the world. Full article
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12 pages, 2514 KiB  
Article
Seasonal Distribution of Key Small-Sized Fish in the South Inshore of Zhejiang, China
by Minghao Xu, Xiaodi Gao, Weicheng Liu and Jiaqi Wang
Fishes 2024, 9(10), 412; https://doi.org/10.3390/fishes9100412 - 13 Oct 2024
Viewed by 1055
Abstract
Small-sized fish are a vital food source for large predatory commercial fish and play a key role in marine food webs, bridging lower and higher trophic levels. They are indispensable in maintaining the energy flow and material cycling within aquatic ecosystems. This study [...] Read more.
Small-sized fish are a vital food source for large predatory commercial fish and play a key role in marine food webs, bridging lower and higher trophic levels. They are indispensable in maintaining the energy flow and material cycling within aquatic ecosystems. This study utilized bottom-trawl survey data from 2017 to 2020 along the south inshore of Zhejiang, China, complemented by concurrent environmental data, to examine the influence of environmental factors on the resource density and seasonal distribution patterns of four dominant small-sized fish species. The research findings indicated that SSH (sea surface height) and Chl (chlorophyll-a concentration) emerged as the key environmental factors influencing resource densities, with all four species exhibiting similar preferences toward these variables. However, significant disparities were observed in their preferences for SST (sea surface temperature), SSS (sea surface salinity), and DO (dissolved oxygen). The various species’ resource density and distribution patterns underwent significant seasonal variations. Additionally, the seasons and regions with the highest resource densities consistently aligned, occurring predominantly in autumn within the northern waters of the study area. This research further elucidated the environmental predilections and seasonal spatial distribution traits of small-sized fish in the south inshore of Zhejiang, an important feeding ground for economic fish species in the East China Sea. This provides scientific backing for forecasting alterations in coastal fishery resources under environmental and climate change scenarios and supports ecosystem-based fisheries management strategies. Full article
(This article belongs to the Special Issue Biodiversity and Spatial Distribution of Fishes)
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17 pages, 3207 KiB  
Article
Seasonal Analysis of Spatial Distribution Patterns and Characteristics of Sepiella maindroni and Sepia kobiensis in the East China Sea Region
by Min Xu, Shuhao Liu, Hui Zhang, Zhiguo Li, Xiaojing Song, Linlin Yang and Baojun Tang
Animals 2024, 14(18), 2716; https://doi.org/10.3390/ani14182716 - 19 Sep 2024
Cited by 8 | Viewed by 1491
Abstract
Climate change is having important effects on the migration routes and seasonal–spatial distribution patterns of aquatic animals, including the cephalopods Sepiella maindroni de Rochebrune (Hoyle, 1886) and Sepia kobiensis (Hoyle, 1885) in the East China Sea region. We conducted bottom trawling surveys from [...] Read more.
Climate change is having important effects on the migration routes and seasonal–spatial distribution patterns of aquatic animals, including the cephalopods Sepiella maindroni de Rochebrune (Hoyle, 1886) and Sepia kobiensis (Hoyle, 1885) in the East China Sea region. We conducted bottom trawling surveys from 2018 to 2019 in the East China Sea region to identify the seasonal–spatial distribution patterns, including the locations of spawning and nursery grounds of both species, and to determine how they are related to environmental variables. We used random forests and boosted regression trees to identify the distribution patterns of both species from spring to winter to estimate the annual mean situations. We also predicted the habitat distribution variations in 2050 and 2100 under the SSP1-2.6 and SSP5-8.5 climate change scenarios. From our survey data, we detected increasing biomass densities of S. maindroni from 29.50° N to 28.50° N, where the largest value of 213.92 g·ind−1 occurred. In spring, juvenile groups were present in coastal areas and larger individuals were found in offshore areas. We identified potential spawning grounds at 29.50°–33.00° N 122.50°–123.00° E adjacent to the Zhejiang coastline, and larger individuals and higher biomass densities in south of the 29.50° N line in summer. In autumn, the average individual weight increased in the 28.00° N 122.00° E→124.00° E area. We located potential S. kobiensis spawning grounds at 27.00° N 122.00°–123.50° E in spring. Growing overwintering juveniles migrated to the area of 29.50°–30.50° N 125.00°–127.00° E in winter. The sea surface temperature of the areas inhabited by both species showed obvious seasonal variation. The SSP1-2.6 and SSP5-8.5 scenarios indicated that the habitat of S. maindroni would shift to the south first and then to the north of the study area with the intensification of CO2 emissions, and it would first expand and then greatly decrease. However, the habitat area of S. kobiensis would increase. Our results will contribute to a better understanding of the life history traits of both species and the changes in their distribution patterns under different climate scenarios to ensure sustainable exploitation and fisheries management. Full article
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14 pages, 4876 KiB  
Article
Rotation Culture of Macroalgae Based on Photosynthetic Physiological Characteristics of Algae
by Xiaopeng Cheng, Xu Zhao, Jun Lin, Shouyu Zhang, Zhenhua Wang, Hong Huang, Kai Wang and Jianqu Chen
Biology 2024, 13(6), 459; https://doi.org/10.3390/biology13060459 - 20 Jun 2024
Cited by 2 | Viewed by 1664
Abstract
Seaweed farming has made outstanding contributions to food supply and the restoration of the ecological environment despite the limitations in production and ecological effects due to the current intensive farming of single algae species. These limitations can be overcome by selecting suitable algal [...] Read more.
Seaweed farming has made outstanding contributions to food supply and the restoration of the ecological environment despite the limitations in production and ecological effects due to the current intensive farming of single algae species. These limitations can be overcome by selecting suitable algal species based on their physiological characteristics and by constructing a large-scale seaweed rotation model. This study carried out a trial culture in aquaculture sea areas, and performed in situ monitoring of the environmental conditions and physiological characteristics of Saccharina japonica, Hizikia fusiformis, and Gracilariopsis lemaneiformis. Additionally, a comparative analysis of the three macroalgae at different times was conducted to determine their response characteristics to environmental factors. The results showed that: (1) The three macroalgae had varying light tolerance. The effective quantum yield of Hizikia fusiformis and Gracilariopsis lemaneiformis remained unchanged during the changes in light environment, while that of Saccharina japonica first decreased and then recovered. (2) The relative electron transport rates of the three macroalgae were significantly different under different temperature conditions. Hizikia fusiformis and Saccharina japonica exhibited the highest relative electron transport rates (70.45 and 106.75, respectively) in May (20.3 °C). Notably, Gracilariopsis lemaneiformis demonstrated good growth and exhibited the highest relative electron transport rate (93.07) in September (27.5 °C). These findings collectively support the feasibility of establishing a macroalgae rotation model. Based on the combined environmental conditions of the seas in Shandong, Zhejiang, and Fujian, a macroalgae rotation model was proposed. The application of this model in the construction of artificial seaweed farms in marine ranches can provide a stable output of large-scale seaweed production and ecological benefits. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Aquatic Macrophytes and Algae)
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30 pages, 39898 KiB  
Article
Inundation Characteristics’ Prediction of Storm Surge under Relative Sea Level Rise Scenarios: A Case Study of Taizhou, Zhejiang Province
by Tangqi Zhao, Xiaomin Li, Suming Zhang, Qi Hou, Xuexue Du and Jie Zhang
J. Mar. Sci. Eng. 2024, 12(6), 1030; https://doi.org/10.3390/jmse12061030 - 20 Jun 2024
Cited by 1 | Viewed by 1570
Abstract
Storm surge is the most serious marine disaster in China, and the inundation characteristics of storm surge are the key indicators of disaster severity. Especially in the context of relative sea level rise (RSLR), it is very important to rapidly and accurately estimate [...] Read more.
Storm surge is the most serious marine disaster in China, and the inundation characteristics of storm surge are the key indicators of disaster severity. Especially in the context of relative sea level rise (RSLR), it is very important to rapidly and accurately estimate the inundation characteristics of storm surge for the risk assessment and emergency management of storm surge disasters. Taking Taizhou city, Zhejiang Province, as the study area, this paper constructed an RSLR scenario library considering absolute sea level rise, land subsidence and storm surge water increase. The scenario library includes 72 scenarios, consisting of a combination of four absolute sea level rise scenarios, three land subsidence scenarios, three timescales (2030, 2050 and 2100) and two storm surge water increase scenarios. Then, an improved passive inundation method was used to predict and analyze the inundation characteristics of storm surge under each scenario. This improved method combines the advantages of the accurate active inundation method and the rapid passive inundation method, and is suitable for rapid and accurate estimation of the storm surge inundation characteristics, which can meet the needs of a storm surge disaster risk assessment and emergency response. The prediction and analysis results show that a minor RSLR can also cause a large-scale inundation in coastal areas of Taizhou. When the value of RSLR exceeds the critical value (0.6 m), it may significantly increase the expansion of the inundation area of storm surge. At a relative sea level rise of 1.57 m (extreme scenario in 2100), the inland storm surge inundation of low-risk areas may become high-risk areas. Finally, the quantitative measures for preventing storm surge disasters were put forward according to the current situation of the coast in Taizhou. Without considering storm surge and superimposed general surge, the existing 20-year return period standard seawall can effectively protect against storm surge under various scenarios. In the case of maximum water increase, it is expected that effective protection will remain until 2030, but the standard of the seawall defense will need to be improved in 2050 and 2100. Full article
(This article belongs to the Special Issue Sea Level Rise and Related Hazards Assessment)
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14 pages, 4172 KiB  
Article
The Factors Driving the Spatial Variation in the Selection of Spawning Grounds for Sepiella japonica in Offshore Zhejiang Province, China
by Tian Wu, Jun Liang, Yongdong Zhou, Wendan Xuan, Guangjie Fang, Yazhou Zhang and Feng Chen
Fishes 2024, 9(1), 20; https://doi.org/10.3390/fishes9010020 - 31 Dec 2023
Cited by 3 | Viewed by 2449
Abstract
Due to overfishing and marine pollution, the status of fishery resources and the ecological environment in the sea areas have considerably changed. The proliferation and release of fishery resources have become the main means of human intervention to maintain and conserve the resource [...] Read more.
Due to overfishing and marine pollution, the status of fishery resources and the ecological environment in the sea areas have considerably changed. The proliferation and release of fishery resources have become the main means of human intervention to maintain and conserve the resource populations. The annual output of Sepiella japonica (S. japonica), once one of the four major seafood species in the East China Sea, has now recovered to a level of 4000 t. However, do the traditional spawning grounds of S. japonica still exist? Have the spawning grounds shifted? These scientific questions are worthy of attention. Based on the survey data of fishery resources and environment at 120 stations in coastal Zhejiang waters from 2015 to 2022, the spatial and temporal distribution and resource center of gravity of S. japonica in springtime were analyzed. Random forest (RF) was used to explain the importance of six environmental variables, including water depth, sea surface temperature, sea surface salinity, chlorophyll a, pH, and dissolved oxygen. The generalized additive model (GAM) nonparametric smoothing function was used to analyze the relationship between environmental factors and the distribution of S. japonica inhabiting the offshore areas of Zhejiang province, and the effects of environmental factors on spawning habitat selection of S. japonica were revealed. This study found that there was a significant interannual variation in S. japonica resources, with an overall increasing trend in the resource. The spawning grounds were mainly distributed in the Jiushan Islands Marine Reserve, the Dachen Islands Marine Reserve, and their nearby sea areas. The resource peaked at latitude 28.3° N. Additionally, the most important variables affecting the distribution of S. japonica were depth of water, followed by sea surface salinity, pH, dissolved oxygen, sea surface temperature, and chlorophyll a. S. japonica mainly inhabited sea areas with a depth of 15~25 m and a sea surface salinity of 26~32. When the pH ranged from 7.6 to 8.3, dissolved oxygen ranged from 6 to 9 mg/L, sea surface temperature ranged from 14 to 17 °C, and chlorophyll a ranged from 2.5 to 5 µg/L, S. japonica was more likely to be present. This study provides insights into the spatial distribution of S. japonica in offshore Zhejiang province, offering a reference for the rational utilization and scientific protection of this resource. Full article
(This article belongs to the Special Issue Biodiversity and Spatial Distribution of Fishes)
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17 pages, 2855 KiB  
Article
Analysis of the Vertical Distribution and Driving Factors of Aerosol and Ozone Precursors in Huaniao Island, China, Based on Ground-Based MAX-DOAS
by Jinping Ou, Qihou Hu, Chengzhi Xing, Yizhi Zhu, Jiaxuan Feng, Xiangguang Ji, Mingzhu Zhang, Xinqi Wang, Liyuan Li, Ting Liu, Bowen Chang, Qihua Li, Hao Yin and Cheng Liu
Remote Sens. 2023, 15(21), 5103; https://doi.org/10.3390/rs15215103 - 25 Oct 2023
Cited by 3 | Viewed by 1768
Abstract
Urban air pollution has become a regional environmental problem. In order to explore whether island areas were affected by the urban development of surrounding areas, in this paper, we systematically study the vertical distribution characteristics of atmospheric components, meteorological drivers, potential pollution sources, [...] Read more.
Urban air pollution has become a regional environmental problem. In order to explore whether island areas were affected by the urban development of surrounding areas, in this paper, we systematically study the vertical distribution characteristics of atmospheric components, meteorological drivers, potential pollution sources, and the population health risks of fine particulate matter in island cities in China. The vertical profiles of three atmospheric pollutants (aerosols, NO2, and HCHO) in the lower troposphere of Huaniao Island in the East China Sea (ECS) were obtained using ground-based multi-axial differential optical absorption spectroscopy (MAX-DOAS). The results show that the aerosol extinction coefficients, NO2, and HCHO were primarily distributed at altitudes below 1 km, and the atmospheric pollutants in Zhoushan were obviously affected by high-altitude transfer. The main meteorological driving factors of aerosols, NO2, and HCHO were different at different altitudes. The key factor contributing to the high column concentrations of NO2 and HCHO in the upper air (greater than 400 m) was the transport of pollutants brought about by changes in wind speed. By exploring the main potential sources of atmospheric pollutants, it was found that the main sources of aerosols, NO2, and HCHO are coastal cities in the Yangtze River Delta, including southeast Zhejiang Province, southeast Fujian Province, Shanghai, ECS, and the Yellow Sea. Compared with aerosols and HCHO, local primary emissions are an important source of NO2, which are mainly related to industrial activities in Zhoushan Port. In addition, using the expose-response function model, the number of attributable cases of PM2.5 air pollution in Zhoushan City in 2019 accounted for 6.58% of the total population. This study enriches our understanding of the vertical distribution characteristics of atmospheric composition and health risk assessment on Chinese islands. Full article
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13 pages, 4740 KiB  
Article
Appropriateness Evaluation of Releasing Area for Four Marine Organisms in Stock Enhancement: A Fatty Acid Approach
by Zichen Wang, Zehua Lv and Junbo Zhang
Fishes 2023, 8(10), 489; https://doi.org/10.3390/fishes8100489 - 1 Oct 2023
Viewed by 1945
Abstract
In light of the ongoing depletion of global fishery resources, there has been a growing trend towards increasing the scope of stock enhancement activities. The objective of these efforts is to replenish the diminishing fishery resources and restore the ecological balance within marine [...] Read more.
In light of the ongoing depletion of global fishery resources, there has been a growing trend towards increasing the scope of stock enhancement activities. The objective of these efforts is to replenish the diminishing fishery resources and restore the ecological balance within marine biological communities. Nevertheless, the efficacy of the stock enhancement project has been hindered by the differential growth and environmental adaptability of released species, which can be attributed to the influence of abundant food resources. As a consequence, the project has not yielded the anticipated outcomes. One useful strategy for enhancing the efficacy of stock enhancement is the deliberate allocation of appropriate habitats for diverse released organisms. Fatty acids were extracted by the Folch method and the composition and content of muscle fatty acids were determined by gas chromatography mass spectrometry. This study examines the fatty acid composition of four commercially important species, namely, little yellow croaker (Larimichthys polyactis), red sea bream (Pagrus major), swimming crab (Portunus trituberculatus), and ridgetail white prawn (Exopalaemon carinicauda). The sum of available docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) is employed as an indicator to assess the appropriateness of the marine environment for releasing these species (DE). The red sea bream exhibited the lowest DE value of 13.69% in the northern coastal water of the Bohai Sea, and the little yellow croaker displayed the lowest DE value of 10.91% in the southern coastal water of the Shandong Peninsula. Conversely, the DE values of other seas were comparable, averaging 20.16%. The range of the DE value of the swimming crab across various coastal waters was observed to be between 33.59% and 45.21%. The ridgetail white prawn had a DE value of 21.10% in the coastal water of Yancheng City, Jiangsu Province, as well as the southern coastal water of the Shandong Peninsula, and a DE value of 31.75% in the southern and central coastal waters of Zhejiang Province. The findings of the study indicate that the Bohai Sea and the northern region of the Yellow Sea are the appropriate stock enhancement areas for red sea bream. Similarly, the Yellow Sea and the northern part of the East China Sea are identified as suitable habitats for the little yellow croaker. The swimming crab, on the other hand, is adapted to be released in the Yellow Sea, the Bohai Sea, and the East China Sea. The north of the central part of the East China Sea is an appropriate release area for the ridgetail white prawn. Full article
(This article belongs to the Special Issue Fisheries and Aquaculture Engineering)
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19 pages, 10810 KiB  
Article
Numerical Simulation Calculation of Thermal Discharge Water Diffusion in Coastal Nuclear Power Plants
by Xuri Zhang, Hongyuan Shi, Chao Zhan, Jun Zhu, Qing Wang and Guoqing Li
Atmosphere 2023, 14(9), 1371; https://doi.org/10.3390/atmos14091371 - 30 Aug 2023
Cited by 5 | Viewed by 2151
Abstract
Coastal areas have become the primary location for nuclear power plant sites due to the convenience of seawater cooling. In China, the diffusion range of thermal discharge water has always been a hot research topic as the basis for sea use areas. The [...] Read more.
Coastal areas have become the primary location for nuclear power plant sites due to the convenience of seawater cooling. In China, the diffusion range of thermal discharge water has always been a hot research topic as the basis for sea use areas. The main physical process of heat loss in the numerical simulation of thermal discharge from power plants is heat exchange between the water surface and air. Currently, the methods for calculating this heat loss include the heat flux method and the water surface heat exchange coefficient method. Taking a power plant in Zhejiang as the research object, the MIKE 3 temperature–salinity module (heat flux method) and MIKE ECO Model (water surface heat exchange coefficient method) were used for modeling, and the diffusion of thermal discharge water under different modules was compared and analyzed. The results show that the calculated area of the water temperature rise envelope between the two modules differed significantly under the same conditions. The surface 4 °C temperature rise area, as calculated using ECO Model, was 45.8% smaller than that of the temperature–salinity module. The MIKE 3 temperature–salinity module can simulate the heat accumulation of water under thermal buoyancy, producing a significant thermal stratification phenomenon; the ECO module does not accurately represent the heat exchange process between the water surface and the air, and it does not adequately capture the significant vertical stratification that occurs in real-world scenarios. On this basis, this study not only lays a foundation for further exploring the impact of thermal discharge water from this powerhouse on the structure of surrounding marine biological communities and dissolved oxygen content in water bodies but also provides scientific evidence for the selection of modules when simulating thermal discharge water with the MIKE model. Full article
(This article belongs to the Section Atmospheric Techniques, Instruments, and Modeling)
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21 pages, 39903 KiB  
Article
Invasive Trends of Spartina alterniflora in the Southeastern Coast of China and Potential Distributional Impacts on Mangrove Forests
by Jiaying Zheng, Haiyan Wei, Ruidun Chen, Jiamin Liu, Lukun Wang and Wei Gu
Plants 2023, 12(10), 1923; https://doi.org/10.3390/plants12101923 - 9 May 2023
Cited by 15 | Viewed by 3083
Abstract
Mangrove forests are one of the most productive and seriously threatened ecosystems in the world. The widespread invasion of Spartina alterniflora has seriously imperiled the security of mangroves as well as coastal mudflat ecosystems. Based on a model evaluation index, we selected RF, [...] Read more.
Mangrove forests are one of the most productive and seriously threatened ecosystems in the world. The widespread invasion of Spartina alterniflora has seriously imperiled the security of mangroves as well as coastal mudflat ecosystems. Based on a model evaluation index, we selected RF, GBM, and GLM as a predictive model for building a high-precision ensemble model. We used the species occurrence records combined with bioclimate, sea–land topography, and marine environmental factors to predict the potentially suitable habitats of mangrove forests and the potentially suitable invasive habitats of S. alterniflora in the southeastern coast of China. We then applied the invasion risk index (IRI) to assess the risk that S. alterniflora would invade mangrove forests. The results show that the suitable habitats for mangrove forests are mainly distributed along the coastal provinces of Guangdong, Hainan, and the eastern coast of Guangxi. The suitable invasive habitats for S. alterniflora are mainly distributed along the coast of Zhejiang, Fujian, and relatively less in the southern provinces. The high-risk areas for S. alterniflora invasion of mangrove forests are concentrated in Zhejiang and Fujian. Bioclimate variables are the most important variables affecting the survival and distribution of mangrove forests and S. alterniflora. Among them, temperature is the most important environmental variable determining the large-scale distribution of mangrove forests. Meanwhile, S. alterniflora is more sensitive to precipitation than temperature. Our results can provide scientific insights and references for mangrove forest conservation and control of S. alterniflora. Full article
(This article belongs to the Special Issue Ecology and Management of Invasive Plants)
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16 pages, 6089 KiB  
Article
The Ocean Surface Current in the East China Sea Computed by the Geostationary Ocean Color Imager Satellite
by Youzhi Ma, Wenbin Yin, Zheng Guo and Jiliang Xuan
Remote Sens. 2023, 15(8), 2210; https://doi.org/10.3390/rs15082210 - 21 Apr 2023
Cited by 6 | Viewed by 4444
Abstract
High-frequency observations of surface current field data over large areas and long time series are imperative for comprehending sea-air interaction and ocean dynamics. Nonetheless, neither in situ observations nor polar-orbiting satellites can fulfill the requirements necessary for such observations. In recent years, geostationary [...] Read more.
High-frequency observations of surface current field data over large areas and long time series are imperative for comprehending sea-air interaction and ocean dynamics. Nonetheless, neither in situ observations nor polar-orbiting satellites can fulfill the requirements necessary for such observations. In recent years, geostationary satellite data with ultra-high temporal resolution have been increasingly utilized for the computation of surface flow fields. In this paper, the surface flow field in the East China Sea is estimated using maximum cross-correlation, which is the most widely used flow field computation algorithm, based on the total suspended solids (TSS) data acquired from the Geostationary Ocean Color Imager satellite. The inversion results were compared with the modeled tidal current data and the measured tidal elevation data for verification. The results of the verification demonstrated that the mean deviation of the long semiaxis of the tidal ellipse of the inverted M2 tide is 0.0335 m/s, the mean deviation of the short semiaxis is 0.0276 m/s, and the mean deviation of the tilt angle is 6.89°. Moreover, the spatially averaged flow velocity corresponds with the observed pattern of tidal elevation changes, thus showcasing the field’s significant reliability. Afterward, we calculated the sea surface current fields in the East China Sea for the years 2013 to 2019 and created distribution maps for both climatology and seasonality. The resulting current charts provide an intuitive display of the spatial structure and seasonal variations in the East China Sea circulation. Lastly, we performed a diagnostic analysis on the surface TSS variation mechanism in the frontal zone along the Zhejiang coast, utilizing inverted flow data collected on 3 August 2013, which had a high spatial coverage and complete time series. Our analysis revealed that the intraday variation in TSS in the local surface layer was primarily influenced by tide-induced vertical mixing. The research findings of this article not only provide valuable data support for the study of local ocean dynamics but also verify the reliability of short-period surface flow inversion of high-turbidity waters near the coast using geostationary satellites. Full article
(This article belongs to the Special Issue Recent Advancements in Remote Sensing for Ocean Current)
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19 pages, 3020 KiB  
Article
Larval Dispersal Modeling Reveals Low Connectivity among National Marine Protected Areas in the Yellow and East China Seas
by Jiaying Lu, Yuanjie Chen, Zihan Wang, Feng Zhao, Yisen Zhong, Cong Zeng and Ling Cao
Biology 2023, 12(3), 396; https://doi.org/10.3390/biology12030396 - 2 Mar 2023
Cited by 13 | Viewed by 3983
Abstract
Marine protected areas (MPAs) are vital for protecting biodiversity, maintaining ecosystem integrity, and tackling future climate change. The effectiveness of MPA networks relies on connectivity, yet connectivity assessments are often skipped in the planning process. Here we employed a multi-species biophysical model to [...] Read more.
Marine protected areas (MPAs) are vital for protecting biodiversity, maintaining ecosystem integrity, and tackling future climate change. The effectiveness of MPA networks relies on connectivity, yet connectivity assessments are often skipped in the planning process. Here we employed a multi-species biophysical model to examine the connectivity patterns formed among the 21 national MPAs in the Yellow and East China Seas. We simulated the potential larval dispersal of 14 oviparous species of five classes. Larvae of non-migratory species with pelagic larval duration (PLD) were assumed to be passive floating particles with no explicit vertical migration. A total of 217,000 particles were released according to spawning period, living depth, and species distribution, and they were assumed to move with currents during the PLD. Most larvae were dispersed around the MPAs (0–60 m isobaths) and consistent with the currents. Larval export increased with PLD and current velocity, but if PLD was too long, few larvae survived due to high daily mortality during pelagic dispersal. The overall connectivity pattern exhibited a north-to-south dispersal trend corresponding to coastal currents. Our results indicated that the national MPAs in the Yellow and East China Seas did not form a well-connected network and nearly 30% of them were isolated. These MPAs formed three distinct groups, one in the Yellow Sea ecoregion and two in the East China Sea ecoregion. Four MPAs (all in coastal Zhejiang) emerged as key nodes for ensuring multi-generational connectivity. Under the pressure of future climate change, high self-recruitment and low connectivity present significant challenges for building well-connected MPA networks. We suggest adding new protected areas as stepping stones for bioecological corridors. Focused protection of the Yellow Sea ecoregion could have a good effect on the southern part of the population recruitment downstream. Conservation management should be adjusted according to the life cycles and distributions of vulnerable species, as well as seasonal changes in coastal currents. This study provides a scientific basis for improving ecological connectivity and conservation effectiveness of MPAs in the Yellow and East China Seas. Full article
(This article belongs to the Special Issue Integrating Science into Aquatic Conservation)
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17 pages, 13798 KiB  
Article
Assessing the Prospect of Joint Exploitations of Offshore Wind, Wave, and Tidal Stream Energy in the Adjacent Waters of China
by Zhan Lian, Weiye Yu and Jianting Du
J. Mar. Sci. Eng. 2023, 11(3), 529; https://doi.org/10.3390/jmse11030529 - 28 Feb 2023
Cited by 1 | Viewed by 2046
Abstract
The exploitation of marine renewable energy sources, such as offshore wind (OW), wave (WA), and tidal stream (TS) energy, is essential to reducing carbon emissions in China. Here, we demonstrate that a well-designed deployment of OW-WA-TS joint exploitation would be better than OW [...] Read more.
The exploitation of marine renewable energy sources, such as offshore wind (OW), wave (WA), and tidal stream (TS) energy, is essential to reducing carbon emissions in China. Here, we demonstrate that a well-designed deployment of OW-WA-TS joint exploitation would be better than OW alone in improving performance in terms of the total amount and temporal stability of integrated power output in the northern Bohai Sea/Strait, the Subei Shoal, and the surrounding areas of Taiwan and Hainan Island. The design principles for an efficient joint energy deployment can be summarized as follows: first, a small ratio of WA output favors a temporally stable performance, except for areas around Taiwan Island and southwest of Hainan Island. Second, more TS turbines will contribute to steadier integrated outputs. Meanwhile, in the coastal waters of Guangdong and Zhejiang, the potential of WA to increase the total amount of power output is very high due to its minor impact on temporal stability. Finally, joint exploitation significantly reduces diurnal power fluctuations compared with OW alone, which is crucial for the steady operation of power grids, power sufficiency, and controllability in periods with low or no wind. Full article
(This article belongs to the Section Marine Energy)
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