Pub Date : 2025-02-15DOI: 10.1016/j.rsma.2025.104069
Zhanyi Lin, Qiuchi Wan, Fan Zhang, Jing Zhong, Zhongle Zhou, Kunshan Bao
Mangrove wetlands, situated between terrestrial and marine environments, are highly sensitive to environmental changes. This study investigates the grain-size characteristics of mangrove sediments in four wetlands along Guangdong's coast, South China, to infer deposition processes and environmental changes. Using the Basic End-Member Model Algorithm (BasEMMA), we identified four sediment end-members (EMs): fluvial clay (EM1), tidal current suspending load (EM2), fluvial silt (EM3), and storm surge deposit (EM4) for Guangdong mangrove wetlands, with distinct modal sizes ranging from 1.78 φ to 8.58 φ. Mangrove sediment grain-size is mainly influenced by sediment sources, with tidal inputs (EM2) predominating. EMs compositions display significant differences in estuarine mangroves in different regions of Guangdong, but not in bay mangroves. In addition to sediment sources, anthropogenic disturbances and management practices, including logging, mangrove planting and construction, also affect mangrove sediment grain-size, and planted mangroves exhibit larger particle sizes compared to natural counterparts within the same region. After the introduction of mangroves into estuaries, the wetland sedimentary environment became stable, and the sediments have more significant changes than those in bays. The study demonstrates the utility of EMMA in precisely distinguishing mangrove sediment components, offering insights into sediment source dynamics and environmental changes throughout mangrove ecosystem development.
{"title":"Using end-member model algorithm to infer sedimentary processes from mangrove sediment grain-size in Guangdong, South China","authors":"Zhanyi Lin, Qiuchi Wan, Fan Zhang, Jing Zhong, Zhongle Zhou, Kunshan Bao","doi":"10.1016/j.rsma.2025.104069","DOIUrl":"10.1016/j.rsma.2025.104069","url":null,"abstract":"<div><div>Mangrove wetlands, situated between terrestrial and marine environments, are highly sensitive to environmental changes. This study investigates the grain-size characteristics of mangrove sediments in four wetlands along Guangdong's coast, South China, to infer deposition processes and environmental changes. Using the Basic End-Member Model Algorithm (BasEMMA), we identified four sediment end-members (EMs): fluvial clay (EM1), tidal current suspending load (EM2), fluvial silt (EM3), and storm surge deposit (EM4) for Guangdong mangrove wetlands, with distinct modal sizes ranging from 1.78 φ to 8.58 φ. Mangrove sediment grain-size is mainly influenced by sediment sources, with tidal inputs (EM2) predominating. EMs compositions display significant differences in estuarine mangroves in different regions of Guangdong, but not in bay mangroves. In addition to sediment sources, anthropogenic disturbances and management practices, including logging, mangrove planting and construction, also affect mangrove sediment grain-size, and planted mangroves exhibit larger particle sizes compared to natural counterparts within the same region. After the introduction of mangroves into estuaries, the wetland sedimentary environment became stable, and the sediments have more significant changes than those in bays. The study demonstrates the utility of EMMA in precisely distinguishing mangrove sediment components, offering insights into sediment source dynamics and environmental changes throughout mangrove ecosystem development.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104069"},"PeriodicalIF":2.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-15DOI: 10.1016/j.rsma.2025.104068
Lina L. Fernandes, Pratima M. Kessarkar, Rajni Magotra
Environmental magnetism, in combination with Scanning electron microscopy (SEM) and X-ray diffraction (XRD), was carried out on the surface sediments of six rivers from the Goa and Karnataka regions (India). The main focus was determining the magnetic properties of sediments from different depositional environments (marine, estuarine and fluvial) and assessing their variation with the provenance. In addition, various factors (catchment rocks, anthropogenic activities, river morphology) that influenced the magnetic signatures were explored. Most rivers showed higher magnetic concentrations in the wet period compared to the dry period. The magnetic concentrations (χlf) in the Goa rivers (Terekhol, Chapora, Sal, Talpona) were 6–10 times higher than that of the Karnataka rivers (Nethravati and Gurupur) and displayed a systematic decrease from the river towards the estuary mouth/sea reflecting hydrodynamic sorting. In the Karnataka rivers, on the other hand, irregular χlf profiles were attributed to factors such as dredging, river geomorphology, abundant quartz minerals and variations in Estuarine Turbidity Maxima’s locations. Based on magnetic parameters and elemental composition obtained from SEM-EDS analysis and confirmed by XRD results, magnetite was identified as the main magnetic mineral in the Goa rivers, while a mix between magnetite and hematite was proposed in the Karnataka rivers. Anthropogenic activities (sand mining) and local geological background contributed to magnetic enhancement in the Goa rivers, while river morphology (meandering) and hydrodynamic processes controlled the magnetic properties in the Karnataka rivers. The negative correlations between χlf and finer sediment fraction, as opposed to other global studies, suggested the possibility of such occurrence in similar systems worldwide. The biplot between magnetic grain size and χlf in the Karnataka rivers could fingerprint the source and track the environmental changes. Thus, the magnetic measurements were helpful in the discrimination and identification of different depositional environments.
{"title":"Comparative study of magnetic properties of sediments from six monsoonal rivers during the wet and dry periods, west coast of India","authors":"Lina L. Fernandes, Pratima M. Kessarkar, Rajni Magotra","doi":"10.1016/j.rsma.2025.104068","DOIUrl":"10.1016/j.rsma.2025.104068","url":null,"abstract":"<div><div>Environmental magnetism, in combination with Scanning electron microscopy (SEM) and X-ray diffraction (XRD), was carried out on the surface sediments of six rivers from the Goa and Karnataka regions (India). The main focus was determining the magnetic properties of sediments from different depositional environments (marine, estuarine and fluvial) and assessing their variation with the provenance. In addition, various factors (catchment rocks, anthropogenic activities, river morphology) that influenced the magnetic signatures were explored. Most rivers showed higher magnetic concentrations in the wet period compared to the dry period. The magnetic concentrations (χ<sub>lf</sub>) in the Goa rivers (Terekhol, Chapora, Sal, Talpona) were 6–10 times higher than that of the Karnataka rivers (Nethravati and Gurupur) and displayed a systematic decrease from the river towards the estuary mouth/sea reflecting hydrodynamic sorting. In the Karnataka rivers, on the other hand, irregular χ<sub>lf</sub> profiles were attributed to factors such as dredging, river geomorphology, abundant quartz minerals and variations in Estuarine Turbidity Maxima’s locations. Based on magnetic parameters and elemental composition obtained from SEM-EDS analysis and confirmed by XRD results, magnetite was identified as the main magnetic mineral in the Goa rivers, while a mix between magnetite and hematite was proposed in the Karnataka rivers. Anthropogenic activities (sand mining) and local geological background contributed to magnetic enhancement in the Goa rivers, while river morphology (meandering) and hydrodynamic processes controlled the magnetic properties in the Karnataka rivers. The negative correlations between χ<sub>lf</sub> and finer sediment fraction, as opposed to other global studies, suggested the possibility of such occurrence in similar systems worldwide. The biplot between magnetic grain size and χ<sub>lf</sub> in the Karnataka rivers could fingerprint the source and track the environmental changes. Thus, the magnetic measurements were helpful in the discrimination and identification of different depositional environments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104068"},"PeriodicalIF":2.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-15DOI: 10.1016/j.rsma.2025.104066
K.P. Vivek , K.H. Afnitha , Niya Benny , K.S. Amal , P. Ajayakumar , Lathika Cicily Thomas , K.B. Padmakumar
A contemporary taxonomical overview of the euglenophytes with significant insights into the euglenophyte genera and species diversity in the intertidal pools of the Southwest coast of India is provided. This study is the first to thoroughly examine euglenophytes in the interstitial water of five nearshore sandy intertidal pools, showcasing their diversity. It also builds on previous research conducted in India by providing insights into the physical and chemical parameters and the species composition of euglenophytes. A total of 31 species of euglenophytes belonging to two families (Euglenoidae and Phacaceae) were identified up to species level based on the cell morphology using standard identification keys, among which Euglenoidae dominated the most. Trachelomonas sp. was commonly observed across all stations in the study, likely due to its resilience, tolerance for high organic content, and status as a cosmopolitan thecate species. The variety, prevalence, and species diversity of euglenophytes within a particular area are shaped by temperature, salinity, pH, sunlight exposure, habitat features, climate, and various physicochemical and biological components. A positive correlation was confirmed between nitrate, phosphate, silicate, DO, pH, organic matter, total nitrogen, chlorophyll a, clay %, and silt % with euglenophytes' diversity and cell density.
{"title":"Assemblage and diversity of euglenophytes in the intertidal pools along the southwest coast of India","authors":"K.P. Vivek , K.H. Afnitha , Niya Benny , K.S. Amal , P. Ajayakumar , Lathika Cicily Thomas , K.B. Padmakumar","doi":"10.1016/j.rsma.2025.104066","DOIUrl":"10.1016/j.rsma.2025.104066","url":null,"abstract":"<div><div>A contemporary taxonomical overview of the euglenophytes with significant insights into the euglenophyte genera and species diversity in the intertidal pools of the Southwest coast of India is provided. This study is the first to thoroughly examine euglenophytes in the interstitial water of five nearshore sandy intertidal pools, showcasing their diversity. It also builds on previous research conducted in India by providing insights into the physical and chemical parameters and the species composition of euglenophytes. A total of 31 species of euglenophytes belonging to two families (Euglenoidae and Phacaceae) were identified up to species level based on the cell morphology using standard identification keys, among which Euglenoidae dominated the most. <em>Trachelomonas sp.</em> was commonly observed across all stations in the study, likely due to its resilience, tolerance for high organic content, and status as a cosmopolitan thecate species. The variety, prevalence, and species diversity of euglenophytes within a particular area are shaped by temperature, salinity, pH, sunlight exposure, habitat features, climate, and various physicochemical and biological components. A positive correlation was confirmed between nitrate, phosphate, silicate, DO, pH, organic matter, total nitrogen, chlorophyll <em>a</em>, clay %, and silt % with euglenophytes' diversity and cell density.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104066"},"PeriodicalIF":2.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-15DOI: 10.1016/j.rsma.2025.104074
Konstantin S. Tkachenko , Vu Viet Dung , Vo Thi Ha
Khanh Hoa Province of South-Central Vietnam has extended coastline with many bays, coves and islands, which historically formed favorable conditions for the development of coral reefs in the South China Sea. The area is characterized by a high diversity of reef-building corals (more than 350 species). However, since the beginning of the 2000s, local coral communities have been in a state of increasing decline resulting from the enhancement of stressful natural and anthropogenic impacts. During the 3-year period (2022–2024), a complex assessment of coral reef status and a number of stressful factors has been performed on 17 reef sites in the coastal waters of the province. The mean coral cover was 27.4 % ± SD 26.8 %; coral taxa with stress-tolerant and weedy life strategies made the largest contributions to the composition of local coral communities. Only 5 of 17 sites revealed relatively high cover (>50 %), and only 7 sites had a coral genus richness > 10. More than half of the sites (9) revealed a high proportion of coral rubble (>20 %) as an obvious sign of reef decline. The phase shift from the dominance of stony corals to the dominance of macroalgae or non-skeleton cnidarians (soft coral Clavularia sp. and corallimorpharians Rhodactis spp.) was observed at 7 sites. Five stressful environmental factors stipulating reef decline were distinguished: 1) impact of annual cyclones; 2) anthropogenic reinforcement of sedimentation and eutrophication; 3) overfishing; 4) repetitive crown-of-thorns starfish outbreaks; and 5) sea surface temperature anomalies (the latter is mitigated by seasonal upwelling). Of the 17 reef sites, 2 with high resilience potential were recommended marine-protected areas. The management of other sites should be improved to increase reef resilience and biodiversity conservation.
{"title":"Ecological status and resilience of coral reefs in South-Central Vietnam (Khanh Hoa Province) in the third decade of the 21st century","authors":"Konstantin S. Tkachenko , Vu Viet Dung , Vo Thi Ha","doi":"10.1016/j.rsma.2025.104074","DOIUrl":"10.1016/j.rsma.2025.104074","url":null,"abstract":"<div><div>Khanh Hoa Province of South-Central Vietnam has extended coastline with many bays, coves and islands, which historically formed favorable conditions for the development of coral reefs in the South China Sea. The area is characterized by a high diversity of reef-building corals (more than 350 species). However, since the beginning of the 2000s, local coral communities have been in a state of increasing decline resulting from the enhancement of stressful natural and anthropogenic impacts. During the 3-year period (2022–2024), a complex assessment of coral reef status and a number of stressful factors has been performed on 17 reef sites in the coastal waters of the province. The mean coral cover was 27.4 % ± SD 26.8 %; coral taxa with stress-tolerant and weedy life strategies made the largest contributions to the composition of local coral communities. Only 5 of 17 sites revealed relatively high cover (>50 %), and only 7 sites had a coral genus richness > 10. More than half of the sites (9) revealed a high proportion of coral rubble (>20 %) as an obvious sign of reef decline. The phase shift from the dominance of stony corals to the dominance of macroalgae or non-skeleton cnidarians (soft coral <em>Clavularia</em> sp. and corallimorpharians <em>Rhodactis</em> spp.) was observed at 7 sites. Five stressful environmental factors stipulating reef decline were distinguished: 1) impact of annual cyclones; 2) anthropogenic reinforcement of sedimentation and eutrophication; 3) overfishing; 4) repetitive crown-of-thorns starfish outbreaks; and 5) sea surface temperature anomalies (the latter is mitigated by seasonal upwelling). Of the 17 reef sites, 2 with high resilience potential were recommended marine-protected areas. The management of other sites should be improved to increase reef resilience and biodiversity conservation.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104074"},"PeriodicalIF":2.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.rsma.2025.104065
Geomol George , Anusuya S.
Precise binary image segmentation in underwater environments is crucial for marine biology and underwater robotics applications, as fluctuations in lighting, water conditions, and object appearance provide substantial difficulties. To tackle these problems, this research presents PDBU-Net, an innovative deep-learning framework specifically created to improve the extraction of features and the accuracy of segmentation for binary images captured underwater. PDBU-Net incorporates a progressive feature extraction methodology into a strong deep neural network structure, resulting in significant enhancements in segmentation performance compared to current methods. PDBU-Net was tested extensively and achieved an average Intersection over Union (IoU) of 90.39% and an F-score of 94.94%. The model achieved precision and recall rates of 94.55% and 95.39% respectively, along with an overall accuracy of 95.66%. The results validate the efficacy of PDBU-Net in precisely detecting objects in a wide range of underwater photos, showcasing its successful implementation in real underwater analysis and robotics.
{"title":"Advancing underwater binary image segmentation with PDBU-Net: A progressive approach to feature extraction and accuracy improvement","authors":"Geomol George , Anusuya S.","doi":"10.1016/j.rsma.2025.104065","DOIUrl":"10.1016/j.rsma.2025.104065","url":null,"abstract":"<div><div>Precise binary image segmentation in underwater environments is crucial for marine biology and underwater robotics applications, as fluctuations in lighting, water conditions, and object appearance provide substantial difficulties. To tackle these problems, this research presents PDBU-Net, an innovative deep-learning framework specifically created to improve the extraction of features and the accuracy of segmentation for binary images captured underwater. PDBU-Net incorporates a progressive feature extraction methodology into a strong deep neural network structure, resulting in significant enhancements in segmentation performance compared to current methods. PDBU-Net was tested extensively and achieved an average Intersection over Union (IoU) of 90.39% and an F-score of 94.94%. The model achieved precision and recall rates of 94.55% and 95.39% respectively, along with an overall accuracy of 95.66%. The results validate the efficacy of PDBU-Net in precisely detecting objects in a wide range of underwater photos, showcasing its successful implementation in real underwater analysis and robotics.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104065"},"PeriodicalIF":2.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The “IMO 2020 sulphur limit” is an important means to promote sulfur emission reduction in shipping, and the real oil inspection report is the basis for the realization of the IMO 2020, however, shipping companies and third-party fuel testing agencies conspire to falsify the oil inspection report. Therefore, this paper establishes a three-party game model between shipping companies, third-party fuel testing agencies and maritime management agencies based on prospect theory to study rent-seeking behaviour. On this basis, this model conducts a systematic analysis of the strategy selection and conditions for evolutionary stability among the three parties, and elucidates the underlying principles driving the evolutionary trends of each entity within the shipping system. Finally, a simulation analysis is conducted based on a real-world case of a ship's fuel sulfur emissions exceeding the standard to make suggestions for the maritime management agencies. The results show that:1) When shipping companies and maritime regulatory authorities exhibit a heightened awareness of risk aversion, they are inclined to refrain from adopting strategies that could entail potential risks, even if such strategies may yield substantial short-term gains.2) The price differential between high-sulfur and low-sulfur fuels constitutes a critical determinant influencing the decision-making processes of shipping companies. Additionally, factors such as the potential loss of corporate reputation, the likelihood of crew members actively reporting violations, and the implementation of a punitive feedback mechanism influence the degree to which shipping companies adhere to standardized operational practices.3) Testing cost represents a pivotal factor influencing the operations of third-party testing institutions.4) The choice of Maritime management agency is related to the cost of strict regulation, the fines by higher governmental authorities and environmental governance cost, and these factors exhibit distinct thresholds.
{"title":"Rent-seeking behavior of ship sulfur emission detection based on evolutionary game theory","authors":"Jing Liang , Liang Dong , Yuhang Che , Yu Tang , Yuying Dou","doi":"10.1016/j.rsma.2025.104060","DOIUrl":"10.1016/j.rsma.2025.104060","url":null,"abstract":"<div><div>The “IMO 2020 sulphur limit” is an important means to promote sulfur emission reduction in shipping, and the real oil inspection report is the basis for the realization of the IMO 2020, however, shipping companies and third-party fuel testing agencies conspire to falsify the oil inspection report. Therefore, this paper establishes a three-party game model between shipping companies, third-party fuel testing agencies and maritime management agencies based on prospect theory to study rent-seeking behaviour. On this basis, this model conducts a systematic analysis of the strategy selection and conditions for evolutionary stability among the three parties, and elucidates the underlying principles driving the evolutionary trends of each entity within the shipping system. Finally, a simulation analysis is conducted based on a real-world case of a ship's fuel sulfur emissions exceeding the standard to make suggestions for the maritime management agencies. The results show that:1) When shipping companies and maritime regulatory authorities exhibit a heightened awareness of risk aversion, they are inclined to refrain from adopting strategies that could entail potential risks, even if such strategies may yield substantial short-term gains.2) The price differential between high-sulfur and low-sulfur fuels constitutes a critical determinant influencing the decision-making processes of shipping companies. Additionally, factors such as the potential loss of corporate reputation, the likelihood of crew members actively reporting violations, and the implementation of a punitive feedback mechanism influence the degree to which shipping companies adhere to standardized operational practices.3) Testing cost represents a pivotal factor influencing the operations of third-party testing institutions.4) The choice of Maritime management agency is related to the cost of strict regulation, the fines by higher governmental authorities and environmental governance cost, and these factors exhibit distinct thresholds.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104060"},"PeriodicalIF":2.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, trace metal levels of seagrass (Cymodocea rotundata) were used as bioindicators to investigate the variability of trace metals in a remote atoll (Dongsha) on the continental slope of the South China Sea. Seagrass samples were collected (bi)weekly from December 2014 to March 2016, and water and sediment samples were also collected several times during the period. To assess the temporal variability of trace metals in this region, which is influenced by different monsoon-bearing atmospheric sources, especially anthropogenic ones, the concentrations of trace metals (Cd, Cu, Ni and Zn) in all three types of samples were determined. Among the different media, sediment and seagrass showed similar spatial variability in trace metal content. Water samples showed no discernible spatial or temporal trend for the particular elements. Our results showed that trace metal concentrations in seagrass collected during the northeast monsoon season (winter-spring) were on average 52 % higher for Cd, 28 % for Cu, and 17 % for Zn than those collected during the southwest monsoon season (summer-autumn). These results are consistent with atmospheric trace metal concentrations obtained during parts of the same study period. This implies that trace metal content in seagrass is not only influenced by local sources, but may also serve as an indication of atmospheric trace metal sources transported to the offshore Dongsha Atoll in the South China Sea.
{"title":"Seasonal variability of trace metal accumulation in seagrass (Cymodocea rotundata) at the Dongsha Atoll, South China Sea","authors":"Kuo-Tung Jiann , Heng-Yin Hsu , Chung-Hsin Yuan , Keryea Soong","doi":"10.1016/j.rsma.2025.104071","DOIUrl":"10.1016/j.rsma.2025.104071","url":null,"abstract":"<div><div>In this study, trace metal levels of seagrass (<em>Cymodocea rotundata</em>) were used as bioindicators to investigate the variability of trace metals in a remote atoll (Dongsha) on the continental slope of the South China Sea. Seagrass samples were collected (bi)weekly from December 2014 to March 2016, and water and sediment samples were also collected several times during the period. To assess the temporal variability of trace metals in this region, which is influenced by different monsoon-bearing atmospheric sources, especially anthropogenic ones, the concentrations of trace metals (Cd, Cu, Ni and Zn) in all three types of samples were determined. Among the different media, sediment and seagrass showed similar spatial variability in trace metal content. Water samples showed no discernible spatial or temporal trend for the particular elements. Our results showed that trace metal concentrations in seagrass collected during the northeast monsoon season (winter-spring) were on average 52 % higher for Cd, 28 % for Cu, and 17 % for Zn than those collected during the southwest monsoon season (summer-autumn). These results are consistent with atmospheric trace metal concentrations obtained during parts of the same study period. This implies that trace metal content in seagrass is not only influenced by local sources, but may also serve as an indication of atmospheric trace metal sources transported to the offshore Dongsha Atoll in the South China Sea.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104071"},"PeriodicalIF":2.1,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.rsma.2025.104067
Md. Maheen Mahmud Bappy , Md. Mofizur Rahman , Md. Tareque Bhuiyan , Mohammad Mahbubur Rahman , Partho Banik , As-Ad Ujjaman Nur , Jimmy Yu , Takaomi Arai , Bilal Ahamad Paray , Norhayati Ngah , M. Belal Hossain
Understanding microplastics (MPs) pollution and its associated risks in bathing beaches, particularly those characterized by heavy commercial trading, is essential for the protection of marine ecosystems and human health. Despite the global concern regarding MPs, contamination levels along the Bangladesh coast, especially on popular bathing beaches, remain largely unexplored. This study aimed to investigate the levels, characteristics, and associated risks of MPs at Patenga and Parki beaches along the Bay of Bengal coast. The results revealed that MPs concentrations ranged from 305.56 to 116.67 MPs/m³ at Patenga and from 250.00 to 83.33 MPs/m³ at Parki Beach, indicating significant differences in contamination levels between the two sites. The predominant characteristics of the MPs included violet coloration, fibrous structures, and sizes measuring less than 0.5 mm, with identified polymers such as PET, PP, PS, ABS, PE, and Nylon. The pollution load indexes (PLI) for both beaches exceeded 1, highlighting substantial risks to the marine ecosystem. The Coefficient of Microplastic Impact (CMPI) indicated varying degrees of impact, ranging from severe to minimal, while the polymeric risk evaluation (Hi) suggested considerable risks, particularly at Patenga. Furthermore, the MPs pollution risk index (PRI) values indicated a higher threat level at Patenga (HPatenga = 7.9) compared to Parki (HParki = 1.9). The Microplastics Pollution Index (MPPI) further indicated a significant abundance of microplastics, with Patenga exhibiting higher levels than Parki. These findings led to the development of a conceptual model illustrating the sources and transport pathways of MPs, underscoring the urgent need for effective management strategies to mitigate MPs pollution and safeguard public health on these bathing beaches.
{"title":"Contamination, potential sources, and risk assessment of microplastics in surface waters of two public bathing beaches along the Northern Bay of Bengal","authors":"Md. Maheen Mahmud Bappy , Md. Mofizur Rahman , Md. Tareque Bhuiyan , Mohammad Mahbubur Rahman , Partho Banik , As-Ad Ujjaman Nur , Jimmy Yu , Takaomi Arai , Bilal Ahamad Paray , Norhayati Ngah , M. Belal Hossain","doi":"10.1016/j.rsma.2025.104067","DOIUrl":"10.1016/j.rsma.2025.104067","url":null,"abstract":"<div><div>Understanding microplastics (MPs) pollution and its associated risks in bathing beaches, particularly those characterized by heavy commercial trading, is essential for the protection of marine ecosystems and human health. Despite the global concern regarding MPs, contamination levels along the Bangladesh coast, especially on popular bathing beaches, remain largely unexplored. This study aimed to investigate the levels, characteristics, and associated risks of MPs at Patenga and Parki beaches along the Bay of Bengal coast. The results revealed that MPs concentrations ranged from 305.56 to 116.67 MPs/m³ at Patenga and from 250.00 to 83.33 MPs/m³ at Parki Beach, indicating significant differences in contamination levels between the two sites. The predominant characteristics of the MPs included violet coloration, fibrous structures, and sizes measuring less than 0.5 mm, with identified polymers such as PET, PP, PS, ABS, PE, and Nylon. The pollution load indexes (PLI) for both beaches exceeded 1, highlighting substantial risks to the marine ecosystem. The Coefficient of Microplastic Impact (CMPI) indicated varying degrees of impact, ranging from severe to minimal, while the polymeric risk evaluation (Hi) suggested considerable risks, particularly at Patenga. Furthermore, the MPs pollution risk index (PRI) values indicated a higher threat level at Patenga (H<sub>Patenga</sub> = 7.9) compared to Parki (H<sub>Parki</sub> = 1.9). The Microplastics Pollution Index (MPPI) further indicated a significant abundance of microplastics, with Patenga exhibiting higher levels than Parki. These findings led to the development of a conceptual model illustrating the sources and transport pathways of MPs, underscoring the urgent need for effective management strategies to mitigate MPs pollution and safeguard public health on these bathing beaches.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104067"},"PeriodicalIF":2.1,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.rsma.2025.104062
Yanjie Zhou, Xueqian Wang, Chenglin Hu, Tao Li
Inland ports are important facilities for transferring cargo to the seaport along the New Maritime Silk Road. Inland port ranking will affect the port development decisions. This paper explores the inland port ranking along the Yangtze River considering the port efficiency. Firstly, we adopt the Data Envelopment Analysis (DEA) method to calculate the port efficiency, which is considered one of the seventeen indicators for inland port ranking. Secondly, Analytic Hierarchy Process (AHP) and the entropy method are used to calculate the subjective and objective weights of the indicators for determining their relative importance. Finally, the technique for order preference by similarity to ideal solution (TOPSIS) method is developed to calculate the inland port ranking. This paper did a case study by adopting five major inland ports along the Yangtze River, which are Wuhan, Jiujiang, Yueyang, Yichang, Huangshi, and Jingzhou ports. The evaluation results were analyzed in depth to identify each port's strengths and weaknesses. Based on these analyses, solutions and recommendations are proposed for ports with purely technical inefficiencies, input redundancy and output shortfall, as well as management insights for sustainable port development.
{"title":"Inland port ranking analysis considering port efficiency for sustainable port development: A case study","authors":"Yanjie Zhou, Xueqian Wang, Chenglin Hu, Tao Li","doi":"10.1016/j.rsma.2025.104062","DOIUrl":"10.1016/j.rsma.2025.104062","url":null,"abstract":"<div><div>Inland ports are important facilities for transferring cargo to the seaport along the New Maritime Silk Road. Inland port ranking will affect the port development decisions. This paper explores the inland port ranking along the Yangtze River considering the port efficiency. Firstly, we adopt the Data Envelopment Analysis (DEA) method to calculate the port efficiency, which is considered one of the seventeen indicators for inland port ranking. Secondly, Analytic Hierarchy Process (AHP) and the entropy method are used to calculate the subjective and objective weights of the indicators for determining their relative importance. Finally, the technique for order preference by similarity to ideal solution (TOPSIS) method is developed to calculate the inland port ranking. This paper did a case study by adopting five major inland ports along the Yangtze River, which are Wuhan, Jiujiang, Yueyang, Yichang, Huangshi, and Jingzhou ports. The evaluation results were analyzed in depth to identify each port's strengths and weaknesses. Based on these analyses, solutions and recommendations are proposed for ports with purely technical inefficiencies, input redundancy and output shortfall, as well as management insights for sustainable port development.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104062"},"PeriodicalIF":2.1,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1016/j.rsma.2025.104064
Maigualida Ricoy Martínez , Katrina Anne de Rozario , Mislina Mustafa , Maisarah Mohd Ali Ridza , Sharnietha Ratnam , Bernard Cazelles
Sea turtles play critical roles in marine ecosystems, yet they face numerous threats, not only of anthropogenic origin but also those exacerbated by environmental changes. This study investigates the impacts of both local and global climatic forcing on green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtle populations in Malaysia. Using 17 years of nesting data from Tioman Island, we examined nesting abundance, spatial distribution, temporal trends, and egg abundance in relation to local climatic conditions (temperature and precipitation) and global climatic conditions (El Niño Southern Oscillation – ENSO), through Wavelet Analysis. Our study demonstrates that both local and global climate variables significantly influence turtle egg abundance, with local factors driving short-term seasonal variability and global factors like ENSO affecting long-term multiannual cycles. Additionally, we found that warmer temperatures during El Niño events negatively impact green turtles egg abundance 2 years and a half later but positively impact hawksbill turtles 2 years post–event. These contrasting responses emphasize species-specific reproductive adaptations to climatic variability. Understanding these dynamics is critical for developing adaptive conservation strategies that mitigate the effects of climate change and promote sustainable population management for both species.
{"title":"Multiscale climate forcing on green and hawksbill turtle nesting dynamics in Malaysia","authors":"Maigualida Ricoy Martínez , Katrina Anne de Rozario , Mislina Mustafa , Maisarah Mohd Ali Ridza , Sharnietha Ratnam , Bernard Cazelles","doi":"10.1016/j.rsma.2025.104064","DOIUrl":"10.1016/j.rsma.2025.104064","url":null,"abstract":"<div><div>Sea turtles play critical roles in marine ecosystems, yet they face numerous threats, not only of anthropogenic origin but also those exacerbated by environmental changes. This study investigates the impacts of both local and global climatic forcing on green (<em>Chelonia mydas</em>) and hawksbill (<em>Eretmochelys imbricata</em>) turtle populations in Malaysia. Using 17 years of nesting data from Tioman Island, we examined nesting abundance, spatial distribution, temporal trends, and egg abundance in relation to local climatic conditions (temperature and precipitation) and global climatic conditions (El Niño Southern Oscillation – ENSO), through Wavelet Analysis. Our study demonstrates that both local and global climate variables significantly influence turtle egg abundance, with local factors driving short-term seasonal variability and global factors like ENSO affecting long-term multiannual cycles. Additionally, we found that warmer temperatures during El Niño events negatively impact green turtles egg abundance 2 years and a half later but positively impact hawksbill turtles 2 years post–event. These contrasting responses emphasize species-specific reproductive adaptations to climatic variability. Understanding these dynamics is critical for developing adaptive conservation strategies that mitigate the effects of climate change and promote sustainable population management for both species.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"83 ","pages":"Article 104064"},"PeriodicalIF":2.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号