Pub Date : 2026-03-01Epub Date: 2026-02-08DOI: 10.1016/j.rsma.2026.104848
Dongliang Wang , Wendi Zheng , Yupeng Liu , Lei Zhang , Shilin Tang
Oceanic fronts, characterized by sharp horizontal gradients in multiple oceanic properties such as temperature, salinity, and density, are widely recognized as ecological hotspots that enhance prey availability and attract higher trophic organisms. However, their quantitative impacts on fisheries in the northern South China Sea (NSCS) remain insufficiently understood. Here, we integrated nighttime light remote sensing data (2013–2022) with frontal indices (frontal frequency, distance, and intensity) to investigate the spatial and temporal associations between lit fishing activities and oceanic fronts. Results revealed that fishing effort was highly unevenly distributed and strongly aggregated along frontal zones. The Taiwan Shoal Front (TSF) and coastal upwelling fronts (UF) exhibited the strongest coupling with fisheries, while the Guangdong Coastal Front (GCF) showed offshore-biased aggregation and the South China Sea Slope Front (SCSSF) exerted weaker effects. Generalized Additive Models (GAMs) indicated that frontal distance was the most influential predictor, underscoring the importance of proximity to fronts. These findings highlight the critical ecological role of oceanic fronts in shaping fishing hotspots and provide empirical support for incorporating frontal dynamics into ecosystem-based fisheries management in the NSCS.
{"title":"Quantifying the influence of oceanic fronts on lit fishing activity in the northern South China Sea","authors":"Dongliang Wang , Wendi Zheng , Yupeng Liu , Lei Zhang , Shilin Tang","doi":"10.1016/j.rsma.2026.104848","DOIUrl":"10.1016/j.rsma.2026.104848","url":null,"abstract":"<div><div>Oceanic fronts, characterized by sharp horizontal gradients in multiple oceanic properties such as temperature, salinity, and density, are widely recognized as ecological hotspots that enhance prey availability and attract higher trophic organisms. However, their quantitative impacts on fisheries in the northern South China Sea (NSCS) remain insufficiently understood. Here, we integrated nighttime light remote sensing data (2013–2022) with frontal indices (frontal frequency, distance, and intensity) to investigate the spatial and temporal associations between lit fishing activities and oceanic fronts. Results revealed that fishing effort was highly unevenly distributed and strongly aggregated along frontal zones. The Taiwan Shoal Front (TSF) and coastal upwelling fronts (UF) exhibited the strongest coupling with fisheries, while the Guangdong Coastal Front (GCF) showed offshore-biased aggregation and the South China Sea Slope Front (SCSSF) exerted weaker effects. Generalized Additive Models (GAMs) indicated that frontal distance was the most influential predictor, underscoring the importance of proximity to fronts. These findings highlight the critical ecological role of oceanic fronts in shaping fishing hotspots and provide empirical support for incorporating frontal dynamics into ecosystem-based fisheries management in the NSCS.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104848"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422279","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 : 2026-03-01Epub Date: 2026-02-19DOI: 10.1016/j.rsma.2026.104865
Xiaojuan Song , Xingyu Wei , Xiangxing Ji , Xin Wang , Chongzheng Zhai , Guang Yang , Zhihua Feng , Xinran He
Microplastics (MPs) are emerging as a global pollutant due to their persistence and resistance to degradation. Coastal bays play vital ecological and socio-economic roles, yet their weak tidal dynamics and limited water exchange make them especially susceptible to MPs pollution. However, understanding of the spatio-temporal dynamics of MPs in semi-enclosed bays remains limited compared to open coastal systems in China. This study selected Haizhou Bay for a three-year investigation. Results revealed significant variability in surface water MPs: aquaculture areas (e.g., H2: 10.72 ± 0.68 items/m³) had significantly higher MPs abundance than nearshore (e.g., H3: 0.66 ± 0.06 items/m³) and offshore waters (e.g., H4: 0.34 ± 0.06 items/m³), mainly due to aging plastic aquaculture equipment. From 2023–2024, total MPs at H2 decreased by 33.2 % (7.44–4.97 items/m³), while PS proportion dropped from 85.5 % to 56.8 %, coinciding with local management actions like ecological buoy promotion. However, smaller particles (< 1000 µm) increased at multiple sites (e.g., from 40.6 % to 56.7 % at H1), indicating ongoing fragmentation. Nearshore MP responses (e.g., H6) lagged behind aquaculture zones (e.g., H2), while offshore areas showed gradual accumulation, reflecting hydrodynamic influences. These findings quantify pollution disparities among functional zones, elucidate anthropogenic and management impacts, and support targeted strategies for semi-enclosed bays.
{"title":"Spatiotemporal variations and sources of microplastics in surface water of Haizhou Bay, China: Insights from a three-year study","authors":"Xiaojuan Song , Xingyu Wei , Xiangxing Ji , Xin Wang , Chongzheng Zhai , Guang Yang , Zhihua Feng , Xinran He","doi":"10.1016/j.rsma.2026.104865","DOIUrl":"10.1016/j.rsma.2026.104865","url":null,"abstract":"<div><div>Microplastics (MPs) are emerging as a global pollutant due to their persistence and resistance to degradation. Coastal bays play vital ecological and socio-economic roles, yet their weak tidal dynamics and limited water exchange make them especially susceptible to MPs pollution. However, understanding of the spatio-temporal dynamics of MPs in semi-enclosed bays remains limited compared to open coastal systems in China. This study selected Haizhou Bay for a three-year investigation. Results revealed significant variability in surface water MPs: aquaculture areas (e.g., H2: 10.72 ± 0.68 items/m³) had significantly higher MPs abundance than nearshore (e.g., H3: 0.66 ± 0.06 items/m³) and offshore waters (e.g., H4: 0.34 ± 0.06 items/m³), mainly due to aging plastic aquaculture equipment. From 2023–2024, total MPs at H2 decreased by 33.2 % (7.44–4.97 items/m³), while PS proportion dropped from 85.5 % to 56.8 %, coinciding with local management actions like ecological buoy promotion. However, smaller particles (< 1000 µm) increased at multiple sites (e.g., from 40.6 % to 56.7 % at H1), indicating ongoing fragmentation. Nearshore MP responses (e.g., H6) lagged behind aquaculture zones (e.g., H2), while offshore areas showed gradual accumulation, reflecting hydrodynamic influences. These findings quantify pollution disparities among functional zones, elucidate anthropogenic and management impacts, and support targeted strategies for semi-enclosed bays.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104865"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422962","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 : 2026-03-01Epub Date: 2026-01-26DOI: 10.1016/j.rsma.2026.104803
Aline S. Martinez , Rosana M. Rocha , Ronaldo A. Christofoletti , Leandro M. Vieira , Ulisses S. Pinheiro , Maria Angélica Haddad , Igor E.G. Pinheiro , Franciane M. Pellizzari , Lumi Haraguchi , André Pardal
The construction and deployment of artificial structures (AS) in the marine environment is rapidly expanding worldwide with urban sprawl. AS cause biodiversity loss, facilitate bioinvasion, and affect species connectivity. The capacity of natural ecosystems to sustain biodiversity and deliver goods and services relies on the effective management of human activities in a sustainable manner. This is particularly worrying for developing nations, where coastal urbanisation is pacing faster whilst local human communities rely on fisheries and tourism. The aim of this review was to synthesize current knowledge on the ecological role of artificial structures on marine and estuarine biota in Brazil, considering both their positive and negative ecological effects. Based on 124 peer-reviewed studies, we show that research is spatially fragmented and largely focused on artificial reefs and fish ecology. Fish abundance was often greater around AS compared to sedimentary natural habitats. Over 40 % of the studies were descriptive, focused on the distribution of species or bioinvasion. Of 1017 species recorded on AS, 71 were exotic (all benthic invertebrates), mostly ascidians and bryozoans. Managerial strategies would benefit from quantitative comparative research between AS and natural habitats, focused on different taxonomic groups other than ichthyofauna, using variables that reflect ecosystem functions. Enhancing local biodiversity and improving ecosystem functioning in urbanized areas may be achieved from nature-based solutions research, such as marine eco-engineering. Finally, understanding long term impacts of AS, their role in spreading exotic and cryptogenic species, and the extent of sea-land modification by AS is a further urgent knowledge demand for sustainable urban planning and coastal management.
{"title":"Ecological role of artificial structures on marine and estuarine biota in Brazil: Current knowledge and implications for management","authors":"Aline S. Martinez , Rosana M. Rocha , Ronaldo A. Christofoletti , Leandro M. Vieira , Ulisses S. Pinheiro , Maria Angélica Haddad , Igor E.G. Pinheiro , Franciane M. Pellizzari , Lumi Haraguchi , André Pardal","doi":"10.1016/j.rsma.2026.104803","DOIUrl":"10.1016/j.rsma.2026.104803","url":null,"abstract":"<div><div>The construction and deployment of artificial structures (AS) in the marine environment is rapidly expanding worldwide with urban sprawl. AS cause biodiversity loss, facilitate bioinvasion, and affect species connectivity. The capacity of natural ecosystems to sustain biodiversity and deliver goods and services relies on the effective management of human activities in a sustainable manner. This is particularly worrying for developing nations, where coastal urbanisation is pacing faster whilst local human communities rely on fisheries and tourism. The aim of this review was to synthesize current knowledge on the ecological role of artificial structures on marine and estuarine biota in Brazil, considering both their positive and negative ecological effects. Based on 124 peer-reviewed studies, we show that research is spatially fragmented and largely focused on artificial reefs and fish ecology. Fish abundance was often greater around AS compared to sedimentary natural habitats. Over 40 % of the studies were descriptive, focused on the distribution of species or bioinvasion. Of 1017 species recorded on AS, 71 were exotic (all benthic invertebrates), mostly ascidians and bryozoans. Managerial strategies would benefit from quantitative comparative research between AS and natural habitats, focused on different taxonomic groups other than ichthyofauna, using variables that reflect ecosystem functions. Enhancing local biodiversity and improving ecosystem functioning in urbanized areas may be achieved from nature-based solutions research, such as marine eco-engineering. Finally, understanding long term impacts of AS, their role in spreading exotic and cryptogenic species, and the extent of sea-land modification by AS is a further urgent knowledge demand for sustainable urban planning and coastal management.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104803"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090453","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 : 2026-03-01Epub Date: 2026-01-27DOI: 10.1016/j.rsma.2026.104810
Aminu Ibrahim , Azimah Ismail , Hafizan Juahir , Hajjar Hartini Wan Jusoh
This study investigated the concentration, spatial distribution, and sources of polycyclic aromatic hydrocarbons (PAHs) in selected coastal zones of Malaysia. Total PAH concentrations ranged from 256 to 2176.1 ng/L, with a mean value of 1374 ng/L, indicating notable spatial variability across the study area. Chemometric techniques were applied to interpret pollution patterns and contamination levels. Cluster analysis classified the sampling sites into three distinct groups representing moderate, high, and high–moderate contamination levels. Discriminant analysis achieved a classification accuracy of 89.4 %, identifying naphthalene, acenaphthene, chrysene, and dibenzo[a,h]anthracene as the most influential compounds distinguishing between groups. Source apportionment indicated that PAHs in the study area predominantly originated from vehicular emissions, biomass (wood) combustion, and petroleum-related activities. The integration of chemometric approaches provided robust insights into contamination trends and pollutant sources, demonstrating their effectiveness for interpreting complex environmental datasets. These findings highlight the importance of multivariate statistical tools in improving environmental monitoring, risk assessment, and management strategies aimed at protecting coastal water quality
{"title":"Chemometric techniques for distribution and source identification of PAHs in selected coastal zones of Malaysia","authors":"Aminu Ibrahim , Azimah Ismail , Hafizan Juahir , Hajjar Hartini Wan Jusoh","doi":"10.1016/j.rsma.2026.104810","DOIUrl":"10.1016/j.rsma.2026.104810","url":null,"abstract":"<div><div>This study investigated the concentration, spatial distribution, and sources of polycyclic aromatic hydrocarbons (PAHs) in selected coastal zones of Malaysia. Total PAH concentrations ranged from 256 to 2176.1 ng/L, with a mean value of 1374 ng/L, indicating notable spatial variability across the study area. Chemometric techniques were applied to interpret pollution patterns and contamination levels. Cluster analysis classified the sampling sites into three distinct groups representing moderate, high, and high–moderate contamination levels. Discriminant analysis achieved a classification accuracy of 89.4 %, identifying naphthalene, acenaphthene, chrysene, and dibenzo[<em>a</em>,<em>h</em>]anthracene as the most influential compounds distinguishing between groups. Source apportionment indicated that PAHs in the study area predominantly originated from vehicular emissions, biomass (wood) combustion, and petroleum-related activities. The integration of chemometric approaches provided robust insights into contamination trends and pollutant sources, demonstrating their effectiveness for interpreting complex environmental datasets. These findings highlight the importance of multivariate statistical tools in improving environmental monitoring, risk assessment, and management strategies aimed at protecting coastal water quality</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104810"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191218","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 : 2026-03-01Epub Date: 2026-02-04DOI: 10.1016/j.rsma.2026.104835
Yanxia Li , Yang Li , Ziyang Zhang , Min Xu
Tidal flats are dynamic coastal systems whose stability relies on continuous sediment supply, yet sediment provenance in the central Jiangsu tidal flats remains poorly constrained, especially under reduced fluvial input and complex tidal forcing. This study aimed to quantify sediment sources, grain-size distributions, and their elevation-dependent patterns across these tidal flats. Surface sediments were collected from 12 transects in 2023 and analyzed using grain-size measurements, geochemical fingerprinting, and quantitative mixing models (FingerPro), incorporating a normalized tidal elevation framework to account for cross-shore and latitudinal variations. The main findings are: (1) The North Jiangsu Radial Sand Ridges (NJRSR) are the dominant sediment source, contributing ∼50 % of surface sediments, followed by the Old Yellow River Delta (∼26 %) and the Yangtze River (∼24 %), highlighting the overlooked but critical role of NJRSR in maintaining the sediment budget. (2) Grain size decreases with increasing tidal elevation, from a wide range (20–120 μm) at low-tide levels to finer, more homogeneous sediments at high-tide flats, reflecting hydrodynamic sorting and shoreline erosion patterns. (3) Mean grain size increases offshore, closely corresponding to NJRSR contributions, supporting the use of sediment texture as a proxy for provenance, although tracer elements were decoupled from grain-size variations due to dynamic redistribution. (4) Integrating elevation-dependent grain-size patterns with geochemical tracers provides a robust framework for interpreting sedimentary processes and source contributions. These results advance understanding of sediment dynamics, tidal flat evolution, and coastal resilience, offering methodological and conceptual insights applicable to other large tidal flat systems worldwide.
{"title":"Tracing sediment provenance in Central Jiangsu tidal flat: Quantitative analysis of grain size and geochemical elements","authors":"Yanxia Li , Yang Li , Ziyang Zhang , Min Xu","doi":"10.1016/j.rsma.2026.104835","DOIUrl":"10.1016/j.rsma.2026.104835","url":null,"abstract":"<div><div>Tidal flats are dynamic coastal systems whose stability relies on continuous sediment supply, yet sediment provenance in the central Jiangsu tidal flats remains poorly constrained, especially under reduced fluvial input and complex tidal forcing. This study aimed to quantify sediment sources, grain-size distributions, and their elevation-dependent patterns across these tidal flats. Surface sediments were collected from 12 transects in 2023 and analyzed using grain-size measurements, geochemical fingerprinting, and quantitative mixing models (FingerPro), incorporating a normalized tidal elevation framework to account for cross-shore and latitudinal variations. The main findings are: (1) The North Jiangsu Radial Sand Ridges (NJRSR) are the dominant sediment source, contributing ∼50 % of surface sediments, followed by the Old Yellow River Delta (∼26 %) and the Yangtze River (∼24 %), highlighting the overlooked but critical role of NJRSR in maintaining the sediment budget. (2) Grain size decreases with increasing tidal elevation, from a wide range (20–120 μm) at low-tide levels to finer, more homogeneous sediments at high-tide flats, reflecting hydrodynamic sorting and shoreline erosion patterns. (3) Mean grain size increases offshore, closely corresponding to NJRSR contributions, supporting the use of sediment texture as a proxy for provenance, although tracer elements were decoupled from grain-size variations due to dynamic redistribution. (4) Integrating elevation-dependent grain-size patterns with geochemical tracers provides a robust framework for interpreting sedimentary processes and source contributions. These results advance understanding of sediment dynamics, tidal flat evolution, and coastal resilience, offering methodological and conceptual insights applicable to other large tidal flat systems worldwide.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104835"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191159","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 : 2026-03-01Epub Date: 2026-02-05DOI: 10.1016/j.rsma.2026.104839
Rajapakshalage Thashikala Nethmini , Qing He , Gonglingxia Jiang , Qinghua Hou , Qingxiang Chen , Xiaolei Li , Ke Dong , Lingling Xie , Nan Li
Ocean fronts represent dynamic physical boundaries with steep environmental gradients that promote ecological niche differentiation and influence microbial diversity. However, their contribution to governing microbial diversity and distribution at finer spatial scales remains unclear. In this study, we investigated the microbial diversity and seasonal distribution patterns across thermal, salinity, and chlorophyll-a ocean fronts within the semi-enclosed basin of Beibu gulf, China. Our findings reveal that ocean fronts did not function as ecological boundaries facilitating niche partitioning of microbial assemblages within Beibu gulf. Hierarchical clustering showed no spatial alignment between microbial community distribution and frontal zones, and both linear and non-linear regression analyses found no significant correlations between front intensities and microbial alpha diversity. Instead, nutrients consistently emerged as the primary determinant of microbial distribution, substantially exceeding the influence of water properties and ocean fronts, with nitrogen compounds and phosphate identified as key drivers of bacterial and fungal diversity patterns. Our findings indicate that nutrient-mediated biogeochemical processes, rather than physical oceanic fronts, predominantly regulate microbial community structure in marginal seas and highlights the significance of nutrient dynamics for microbial distribution mechanisms and diversity maintenance in fine-scale marine systems.
{"title":"Nutritional regimes transcend hydrographic boundaries: Determinants of microbial diversity across frontal systems at fine scale","authors":"Rajapakshalage Thashikala Nethmini , Qing He , Gonglingxia Jiang , Qinghua Hou , Qingxiang Chen , Xiaolei Li , Ke Dong , Lingling Xie , Nan Li","doi":"10.1016/j.rsma.2026.104839","DOIUrl":"10.1016/j.rsma.2026.104839","url":null,"abstract":"<div><div>Ocean fronts represent dynamic physical boundaries with steep environmental gradients that promote ecological niche differentiation and influence microbial diversity. However, their contribution to governing microbial diversity and distribution at finer spatial scales remains unclear. In this study, we investigated the microbial diversity and seasonal distribution patterns across thermal, salinity, and chlorophyll-a ocean fronts within the semi-enclosed basin of Beibu gulf, China. Our findings reveal that ocean fronts did not function as ecological boundaries facilitating niche partitioning of microbial assemblages within Beibu gulf. Hierarchical clustering showed no spatial alignment between microbial community distribution and frontal zones, and both linear and non-linear regression analyses found no significant correlations between front intensities and microbial alpha diversity. Instead, nutrients consistently emerged as the primary determinant of microbial distribution, substantially exceeding the influence of water properties and ocean fronts, with nitrogen compounds and phosphate identified as key drivers of bacterial and fungal diversity patterns. Our findings indicate that nutrient-mediated biogeochemical processes, rather than physical oceanic fronts, predominantly regulate microbial community structure in marginal seas and highlights the significance of nutrient dynamics for microbial distribution mechanisms and diversity maintenance in fine-scale marine systems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104839"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191161","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 : 2026-03-01Epub Date: 2026-01-28DOI: 10.1016/j.rsma.2026.104820
Tasrina Rabia Choudhury , M. Abbas Alam , Foyez Jalal Uddin , Syed Riad , Sheikh Fahim Faysal Sowrav , M. Safiur Rahman , A.M. Sarwaruddin Chowdhury
Due to the persistence and non-biodegradable nature of heavy metals, human anthropogenic activities have made heavy metal a particular threat. In this study, heavy metals in sediment have been determined to assess the environmental pollution level of the southeast coastal and riverine zone of Bangladesh. Elevated concentrations of Ag, Cd, Hg, As, and Se in sediments are primarily associated with specific industrial activities, including shipbreaking yards, metal processing and electroplating industries (Ag, Cd), tanneries and dyeing industries (Cr, Cd), paint manufacturing and battery-related activities (Pb, Hg), and untreated urban and industrial effluents (As, Se). These findings indicate that localized industrial practices, rather than generalized waste disposal alone, play a dominant role in shaping sediment contamination patterns in the study area. 14 sampling sites from Karnaphuli river sites where heavy industries are placed and 10 sampling sites each from Patenga sea beach and Sandwip Island for sediment (0–5 cm) have been selected. Sediment pollution level has been evaluated by Pollution load index (PLI), Enrichment factor (EF), Geo-accumulation index (Igeo), potential ecological risk index (RI) and inter element correlation analysis. The results have showed that sediment is highly polluted with Ag and moderately polluted with Cd, Hg, As, Se. For non-carcinogenic health risk assessment, Health hazard (HI) has been measured based on adult person standard. Non-carcinogenic health risk assessment based on sediment ingestion and dermal exposure pathways indicated HI values exceeding unity for adults in selected industrial locations. The result also showed that pollution is occurring in some highly risked areas named as Ichanagar, Banglabazar ghat, Sadarghat, Laldair chair, Mahesh khal Satgola, South Salimpur union, Zaobagan and Golden Beach. This study identifies the types of industries responsible for the pollution and suggests several remedies to mitigate pollution levels.
{"title":"Assessment of heavy metal pollution and ecological risk in sediments from the Southeast coastal and riverine zones of Bangladesh","authors":"Tasrina Rabia Choudhury , M. Abbas Alam , Foyez Jalal Uddin , Syed Riad , Sheikh Fahim Faysal Sowrav , M. Safiur Rahman , A.M. Sarwaruddin Chowdhury","doi":"10.1016/j.rsma.2026.104820","DOIUrl":"10.1016/j.rsma.2026.104820","url":null,"abstract":"<div><div>Due to the persistence and non-biodegradable nature of heavy metals, human anthropogenic activities have made heavy metal a particular threat. In this study, heavy metals in sediment have been determined to assess the environmental pollution level of the southeast coastal and riverine zone of Bangladesh. Elevated concentrations of Ag, Cd, Hg, As, and Se in sediments are primarily associated with specific industrial activities, including shipbreaking yards, metal processing and electroplating industries (Ag, Cd), tanneries and dyeing industries (Cr, Cd), paint manufacturing and battery-related activities (Pb, Hg), and untreated urban and industrial effluents (As, Se). These findings indicate that localized industrial practices, rather than generalized waste disposal alone, play a dominant role in shaping sediment contamination patterns in the study area. 14 sampling sites from Karnaphuli river sites where heavy industries are placed and 10 sampling sites each from Patenga sea beach and Sandwip Island for sediment (0–5 cm) have been selected. Sediment pollution level has been evaluated by Pollution load index (PLI), Enrichment factor (EF), Geo-accumulation index (Igeo), potential ecological risk index (RI) and inter element correlation analysis. The results have showed that sediment is highly polluted with Ag and moderately polluted with Cd, Hg, As, Se. For non-carcinogenic health risk assessment, Health hazard (HI) has been measured based on adult person standard. Non-carcinogenic health risk assessment based on sediment ingestion and dermal exposure pathways indicated HI values exceeding unity for adults in selected industrial locations. The result also showed that pollution is occurring in some highly risked areas named as Ichanagar, Banglabazar ghat, Sadarghat, Laldair chair, Mahesh khal Satgola, South Salimpur union, Zaobagan and Golden Beach. This study identifies the types of industries responsible for the pollution and suggests several remedies to mitigate pollution levels.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104820"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191135","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 : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.rsma.2026.104822
Hai Li , Fang Yang , Xiang Zhang , Yuzhuo Liao , Yuan Li , Puqing Song , Shigang Liu , Longshan Lin
The identification of ecological corridors is crucial for mitigating habitat fragmentation and conserving biodiversity. This study pioneered the use of environmental DNA (eDNA) metabarcoding to identify potential fish ecological corridors in Xiamen Bay, a subtropical semi-enclosed bay in Southeast China, addressing the challenge of delineating marine corridors for mobile species. We collected surface and bottom water samples from 29 sites across 10 transects during winter and summer of 2021. eDNA metabarcoding of the 12S rRNA gene (MiFish-U) revealed distinct seasonal shifts in fish community composition, with 46 and 112 species detected in winter and summer, respectively. The communities were predominantly composed of warm-water and temperate species, with a significant proportion of migratory taxa. Alpha and beta diversity analyses confirmed significant seasonal variations in community structure. Spatial analysis of habitat nodes identified ecological corridors with clear seasonal dynamics. In winter, a primary corridor connected the estuary to the western waters and Tong'an Bay, while a secondary corridor linked the Jiulong River Estuary to the southern waters of Xiamen Island. During summer, both corridors extended eastward, with the primary corridor reaching through the waters around Dadeng Island to the eastern waters and the secondary corridor expanding to the eastern waters of Xiamen Island. These corridors likely facilitate various critical ecological processes. Our findings demonstrate that eDNA metabarcoding is a powerful, spatially explicit tool for identifying ecological corridors in complex marine environments, offering a novel and efficient approach to inform marine spatial planning and conservation strategies.
{"title":"Delineating fish ecological corridors in a subtropical bay using eDNA metabarcoding: A case study from Xiamen Bay, China","authors":"Hai Li , Fang Yang , Xiang Zhang , Yuzhuo Liao , Yuan Li , Puqing Song , Shigang Liu , Longshan Lin","doi":"10.1016/j.rsma.2026.104822","DOIUrl":"10.1016/j.rsma.2026.104822","url":null,"abstract":"<div><div>The identification of ecological corridors is crucial for mitigating habitat fragmentation and conserving biodiversity. This study pioneered the use of environmental DNA (eDNA) metabarcoding to identify potential fish ecological corridors in Xiamen Bay, a subtropical semi-enclosed bay in Southeast China, addressing the challenge of delineating marine corridors for mobile species. We collected surface and bottom water samples from 29 sites across 10 transects during winter and summer of 2021. eDNA metabarcoding of the 12S rRNA gene (MiFish-U) revealed distinct seasonal shifts in fish community composition, with 46 and 112 species detected in winter and summer, respectively. The communities were predominantly composed of warm-water and temperate species, with a significant proportion of migratory taxa. Alpha and beta diversity analyses confirmed significant seasonal variations in community structure. Spatial analysis of habitat nodes identified ecological corridors with clear seasonal dynamics. In winter, a primary corridor connected the estuary to the western waters and Tong'an Bay, while a secondary corridor linked the Jiulong River Estuary to the southern waters of Xiamen Island. During summer, both corridors extended eastward, with the primary corridor reaching through the waters around Dadeng Island to the eastern waters and the secondary corridor expanding to the eastern waters of Xiamen Island. These corridors likely facilitate various critical ecological processes. Our findings demonstrate that eDNA metabarcoding is a powerful, spatially explicit tool for identifying ecological corridors in complex marine environments, offering a novel and efficient approach to inform marine spatial planning and conservation strategies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104822"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191287","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}
Yellowfin tuna (Thunnus albacares) is a highly migratory species of considerable ecological and economic importance, particularly for fisheries in the Pacific and Indian Ocean regions. Over the past six decades, global catches have significantly declined due to the combined impacts of climate change and shifting oceanographic conditions, which alter the species’ spatial and temporal habitat dynamics. This review compiles research from 1963 to 2023 across key regions, including the Western Pacific, Indian Ocean, and Southeast Asian seas, to examine the main environmental factors influencing yellowfin tuna distribution, such as sea surface temperature (SST), chlorophyll-a concentration, salinity, and sea surface height (SSH). Optimal habitats occur at SSTs of 23.4–30.42 °C in tropical waters and 19.53–25.41 °C in subtropical regions. Oceanographic phenomena such as upwelling, fronts, and eddies enhance nutrient availability and prey aggregation, attracting tuna to productive zones. Climate variability, particularly El Niño and La Niña events, also affects migration patterns and catch fluctuations. El Niño phenomena frequently result in higher fish catches due to increased nutrient availability, whereas La Niña conditions generally decrease catches by altering the locations of suitable habitats. These changes pose serious challenges to the sustainability of tropical fisheries, especially within the Exclusive Economic Zones (EEZs) of countries in subtropical regions. Advances in remote sensing and machine learning now offer promising tools for predicting habitat shifts and supporting adaptive fisheries management. Understanding the complex interactions between oceanographic parameters and climate variability is essential for developing sustainable tuna conservation strategies in the face of environmental change.
{"title":"A review of yellowfin tuna ecology in a changing ocean: Synthesis of habitat dynamics, oceanographic influences, and climate impacts (1963–2023)","authors":"Siti Khadijah Srioktoviana , Mukti Zainuddin , Rachmat Hidayat , Alfira Yuniar , Aisjah Farhum , Safruddin , Muzzneena Ahmad Mustapha , Andi Risda Fitrianti Abudarda , Muhammad Ridwan","doi":"10.1016/j.rsma.2026.104830","DOIUrl":"10.1016/j.rsma.2026.104830","url":null,"abstract":"<div><div>Yellowfin tuna (<em>Thunnus albacares</em>) is a highly migratory species of considerable ecological and economic importance, particularly for fisheries in the Pacific and Indian Ocean regions. Over the past six decades, global catches have significantly declined due to the combined impacts of climate change and shifting oceanographic conditions, which alter the species’ spatial and temporal habitat dynamics. This review compiles research from 1963 to 2023 across key regions, including the Western Pacific, Indian Ocean, and Southeast Asian seas, to examine the main environmental factors influencing yellowfin tuna distribution, such as sea surface temperature (SST), chlorophyll-a concentration, salinity, and sea surface height (SSH). Optimal habitats occur at SSTs of 23.4–30.42 °C in tropical waters and 19.53–25.41 °C in subtropical regions. Oceanographic phenomena such as upwelling, fronts, and eddies enhance nutrient availability and prey aggregation, attracting tuna to productive zones. Climate variability, particularly El Niño and La Niña events, also affects migration patterns and catch fluctuations. El Niño phenomena frequently result in higher fish catches due to increased nutrient availability, whereas La Niña conditions generally decrease catches by altering the locations of suitable habitats. These changes pose serious challenges to the sustainability of tropical fisheries, especially within the Exclusive Economic Zones (EEZs) of countries in subtropical regions. Advances in remote sensing and machine learning now offer promising tools for predicting habitat shifts and supporting adaptive fisheries management. Understanding the complex interactions between oceanographic parameters and climate variability is essential for developing sustainable tuna conservation strategies in the face of environmental change.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104830"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191288","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 : 2026-03-01Epub Date: 2026-01-31DOI: 10.1016/j.rsma.2026.104824
Elena G. Panina , Alexey V. Smirnov , Elena Rybakova , Jean-François Hamel , Annie Mercier , Antonina Kremenetskaia
A new holothuroid, Psolus comanchei sp. nov., is described from methane seeps on the Koryak slope and non-vent (background) communities of the Piip Volcano in the bathyal western Bering Sea. The new species differs by lacking ossicles in the sole skin and presenting mushroom-cap-shaped ossicles on the test, tentacles and tube feet. Molecular analyses (COI, 16S) confirm P. comanchei sp. nov. is distinct from congeners but closely related to North Pacific, Arctic, and Atlantic species (P. eximius, P. chitonoides, P. fabricii, P. peronii and P. phantapus) and an unidentified Psolus sp. from the Emperor Seamount Chain. COI data also confirm its presence in the East Pacific. Our phylogeny challenges the monophyly of Psolus, revealing at least two polyphyletic lineages. The close relationships among North Pacific, amphiboreal, and boreal-Arctic species suggest a North Pacific origin for this clade. Although common near seeps, P. comanchei sp. nov. is not obligate to reducing environments.
在白令海西部深海区Piip火山Koryak斜坡和非喷口（背景）群落的甲烷渗漏中，描述了一种新的holothroid， Psolus comanchei sp. nov.。新物种的不同之处在于脚底皮肤上没有小骨，而在脚上有蘑菇帽状的小骨，触角和管状脚。分子分析（COI, 16S）证实P. comanchei sp. 11 .与同系物不同，但与北太平洋，北极和大西洋的物种（P. eximius， P. chitonoides， P. fabricii， P. peronii和P. phantapus）和来自皇帝海山链的未识别的Psolus sp.密切相关。COI数据也证实了它在东太平洋的存在。我们的系统发育挑战了Psolus的单系性，揭示了至少两个多系谱系。北太平洋、两栖动物和北方-北极物种之间的密切关系表明，这一进化支起源于北太平洋。虽然常见的近渗漏，P. comanchei sp. 11 .没有义务减少环境。
{"title":"A new species of Psolus (Dendrochirotida: Holothuroidea) from methane seeps and non-chemosynthetic environments of the bathyal western Bering Sea with notes on phylogeny and geography of the genus","authors":"Elena G. Panina , Alexey V. Smirnov , Elena Rybakova , Jean-François Hamel , Annie Mercier , Antonina Kremenetskaia","doi":"10.1016/j.rsma.2026.104824","DOIUrl":"10.1016/j.rsma.2026.104824","url":null,"abstract":"<div><div>A new holothuroid, <em>Psolus comanchei</em> sp. nov., is described from methane seeps on the Koryak slope and non-vent (background) communities of the Piip Volcano in the bathyal western Bering Sea. The new species differs by lacking ossicles in the sole skin and presenting mushroom-cap-shaped ossicles on the test, tentacles and tube feet. Molecular analyses (<em>COI</em>, <em>16S</em>) confirm <em>P. comanchei</em> sp. nov. is distinct from congeners but closely related to North Pacific, Arctic, and Atlantic species (<em>P. eximius, P. chitonoides, P. fabricii, P. peronii</em> and <em>P. phantapus</em>) and an unidentified <em>Psolus</em> sp. from the Emperor Seamount Chain. <em>COI</em> data also confirm its presence in the East Pacific. Our phylogeny challenges the monophyly of <em>Psolus</em>, revealing at least two polyphyletic lineages. The close relationships among North Pacific, amphiboreal, and boreal-Arctic species suggest a North Pacific origin for this clade. Although common near seeps, <em>P. comanchei</em> sp. nov. is not obligate to reducing environments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104824"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191286","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}
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