{"title":"Control factors and contamination assessment of organic matter in Korean coastal sediments","authors":"Junsik Woo , Teaha Kim , Hyojin Lee , Mansik Choi","doi":"10.1016/j.rsma.2025.104343","DOIUrl":"10.1016/j.rsma.2025.104343","url":null,"abstract":"<div><div>Using data from the Korea National Marine Ecosystem Monitoring Program (2017–2022), this study investigates the spatiotemporal distribution of organic matter across five ecoregions designated by the Marine Environment Management Act. Three analytical approaches were applied to identify key factors influencing organic matter distribution: (1) correlation with sediment particle surface area and clay content, (2) characterization of organic matter sources, and (3) evaluation of sedimentary productivity. Background concentrations were established for each ecoregion, reflecting their unique sedimentary characteristics. Based on these baselines, contamination trends were found to be decreasing in the Central West Sea and Western South Sea, while increasing in the East Sea, Korea Strait, and Jeju Sea. Despite certain methodological limitations in defining background concentrations and contamination thresholds, this study provides valuable insights into the drivers of organic matter contamination and offers essential baseline data for future environmental assessments and coastal management strategies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104343"},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653737","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}
{"title":"Thresholds of visible light detection in hawksbill turtle (Eretmochelys imbricata) hatchlings","authors":"Robert T. Gammariello , Stephen G. Dunbar","doi":"10.1016/j.rsma.2025.104337","DOIUrl":"10.1016/j.rsma.2025.104337","url":null,"abstract":"<div><div>Light is the primary environmental cue that hatchling sea turtles use to find the ocean post-emergence from the nest. The process of seafinding is interrupted by any form of light stronger than natural, ambient light. Three of the seven species of sea turtles have been investigated to determine their thresholds of detection for various wavelengths of light across the visible spectrum to help reduce hatchling misorientation. Hawksbill turtles, however, have not yet been investigated, and their general preference for nesting under vegetation, rather than on open sand, justifies the hypothesis that their vision may be more sensitive to lower light intensities than other species. Using a Y-maze choice experiment, we discerned the detection threshold for hawksbill hatchlings for visible light of 415, 470, 535, 555, 590, 601, and 660 nm. Hawksbills were most sensitive to light of 555 nm, least sensitive to light of 660 nm, and exhibited detection thresholds that are intermediate compared to previously studied species of sea turtles. Our results may be critical for informing changes in beachfront lighting, as we illustrate that even at very low intensities, light across the visible spectrum may still attract and misorient hawksbill hatchlings.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104337"},"PeriodicalIF":2.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604661","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}
Cheng-Rui Yan , Li-Sha Hu , Xiao-Min Zhang , Shao-Wen Li , Fan Li , Yun-Wei Dong
{"title":"Water-sediment regulation drives multi-taxon biodiversity and ecological network dynamics in the Yellow River Estuary","authors":"Cheng-Rui Yan , Li-Sha Hu , Xiao-Min Zhang , Shao-Wen Li , Fan Li , Yun-Wei Dong","doi":"10.1016/j.rsma.2025.104336","DOIUrl":"10.1016/j.rsma.2025.104336","url":null,"abstract":"<div><div>The Yellow River's high sediment load requires the Water-Sediment Regulation Scheme (WSRS) to manage sediment and water flow, leading to significant environmental changes and changes in biodiversity in the Yellow River Estuary (YRE). The present study used an environmental DNA approach to assess changes in biodiversity and community structure of invertebrates and fish in the YRE during WSRS. A total of 301 invertebrate species were identified using COI, and invertebrate communities remained stable from July to August 2022. Fish diversity declined significantly, with 14 detected species. Community stability analysis based COI revealed increased average degree and strong connections in invertebrates but reduced modularity in August, while the co-occurrence networks shifted from multiple modules (July) to a single dominant structure (August). Dominant species <em>S. crassa</em> abundance significantly declined from 24 % in July to 7 % in August (<em>p</em> < 0.05), but functioned as a bridging species in the invertebrate taxa. Redundancy analysis revealed significant shifts in invertebrate taxa between July and August (<em>p</em> = 0.001), driven by temperature, pH, dissolved oxygen, nitrate nitrogen, and ammonia nitrogen. Fish species were mainly influenced by suspended solids and phosphate. The results show that environmental factors have varying effects on different biological taxa in YRE. This study helps to better understand the impact of water-sediment regulation on the ecological structure and provides new insights for future ecological management in the YRE.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104336"},"PeriodicalIF":2.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144581128","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}
{"title":"Variability of mesoscale eddies and their kinetic energy in the Bay of Bengal using a high-resolution ocean model","authors":"Navin Chandra , Vimlesh Pant","doi":"10.1016/j.rsma.2025.104329","DOIUrl":"10.1016/j.rsma.2025.104329","url":null,"abstract":"<div><div>Oceanic eddies significantly contribute to the mixing of tracers such as temperature, salinity, and nutrients. Eddies are crucial to energy transfer and ocean circulation. The Bay of Bengal (BoB) is a naturally suitable location for intense eddy activity because of its distinct geographical and meteorological characteristics. Using a high-resolution regional ocean model, the mesoscale eddies in the BoB were detected, and their variability was examined in the current study. The model results show good agreement with the available observations. Both geometrical and dynamical approaches are used to identify and track the eddies, which aids in the removal of the frontal jets. The seasonal distribution of eddies, their spatial features, and propagation pathways are investigated. Following the identification and separation of the cyclonic eddy (CE) from the anticyclonic eddy (AE), the kinetic energy of each individual eddy is computed. In the western BoB, the variability of the East India Coastal Current (EICC) dictates eddy generation. The river discharge and bathymetry play a crucial role in determining eddy formation and its features in the northern BoB. Throughout the year, the radius of AEs is greater than that of CEs, reaching its maximum during the pre-monsoon (MAM) season. Compared to CEs, there is a stronger correlation between the size and energy of AEs. Eddie's share of the BoB's overall kinetic energy fluctuates from 7.2 % in March to 19.1 % in November. The seasonal contribution of eddies to the eddy kinetic energy (EKE) of the BoB is discussed, along with the varying strength and direction of winds and surface currents.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104329"},"PeriodicalIF":2.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144596023","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}
Tamires Matos-Barbosa , Rafael André Lourenço , Joao Bosco Gusmao , Arlene Bispo dos Santos Nossol , Tatiane Combi
{"title":"Acute and chronic sources of polycyclic aromatic hydrocarbons (PAHs) in coastal sediments impacted by the 2019–2020 oil spill in NE Brazil","authors":"Tamires Matos-Barbosa , Rafael André Lourenço , Joao Bosco Gusmao , Arlene Bispo dos Santos Nossol , Tatiane Combi","doi":"10.1016/j.rsma.2025.104330","DOIUrl":"10.1016/j.rsma.2025.104330","url":null,"abstract":"<div><div>The 2019–2020 oil spill off the Brazilian coast represents one of the largest environmental disasters in the South Atlantic, impacting diverse ecosystems and vulnerable communities. This study investigates the occurrence, levels, composition, and potential ecological risks of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of mangroves affected by the spill along the coast of Bahia, NE Brazil. Fifty-one samples were collected across seven sites, including oil-impacted areas, a control site, and a chronically contaminated area, during three campaigns conducted 12, 18, and 24 months after the spill. Total PAH concentrations (∑16 PAHs) ranged from 39.1 to 595.4 ng g⁻¹ and fell within low to moderate contamination levels. Despite a general decreasing trend over time, spatial and temporal patterns were inconsistent, and PAH distributions appeared to be influenced by both the oil spill and local anthropogenic inputs. Higher alkyl-PAHs/parent-PAHs ratios in Siribinha and Boipeba suggest a long-term influence of petrogenic sources linked to the oil spill, while elevated PAHs in the São Paulo River reflect chronic industrial and urban pollution. Diagnostic ratios and compositional profiles confirmed mixed pyrogenic and petrogenic signatures across sites. Although mean sediment quality guideline quotients indicated low ecotoxicological risk overall, exceedances of threshold values for acenaphthylene and phenanthrene at some sites, particularly those inhabited by traditional communities, highlight the importance of continued monitoring. This study provides the first spatially and temporally resolved assessment of PAH contamination in mangrove sediments following the 2019–2020 oil spill, contributing to a broader understanding of both acute and chronic hydrocarbon impacts in tropical coastal ecosystems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104330"},"PeriodicalIF":2.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580786","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}
Jian-Yu Dong , Kunlong Qiu , Hongbin Zeng , Gorka Bidegain , Gang Hou , Ning Chen , Xuefeng Wang
{"title":"Macrobenthos communities and ecological quality assessment in the subtropical estuary: Insights for management of marine protected area","authors":"Jian-Yu Dong , Kunlong Qiu , Hongbin Zeng , Gorka Bidegain , Gang Hou , Ning Chen , Xuefeng Wang","doi":"10.1016/j.rsma.2025.104331","DOIUrl":"10.1016/j.rsma.2025.104331","url":null,"abstract":"<div><div>The marine protected area in the Jianjiang River Estuary was established in 2011; however, subsequent research on the ecological health of the estuarine biological community has been lacking, making it difficult to scientifically evaluate or inform the management of the reserve. In this study, we assessed the composition and diversity of macrobenthic communities at ten different sites in the Jianjiang River estuary reserve in both Spring and Autumn and used three biotic indices to evaluate the ecological quality status (EcoQs) across the reserve. We identified 58 macrobenthic taxa, of which the largest proportion were Mollusca (48.28 %), followed by Annelida (27.59 %) and Arthropoda (18.97 %). Macrobenthic abundance and biomass varied among sites and seasons, and community composition was driven by different environmental variables in Spring and Autumn. With respect to our three indices of ecological quality, abundance-biomass comparison (ABC) curve analysis and the associated <em>W</em>-statistics indicated that macrobenthic communities in the reserve were undisturbed in the Spring but disturbed in Autumn. The AZTI marine biotic index (AMBI) indicated that most sites have high or good EcoQs, with higher EcoQs in the Spring, and the multivariate AMBI (M-AMBI) index similarly suggested that the average EcoQs were good in Spring but only moderate in Autumn. We suspect that the consistently lower EcoQs in Autumn across all sites were largely due to a 1-in-10-year flood discharge that occurred during our sampling year and disturbed sites near the river outflow. Overall, our results point towards specific, scientifically informed suggestions for future management of the Jianjiang River estuary reserve.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104331"},"PeriodicalIF":2.1,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144587843","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}
{"title":"The robotic revolution in biofouling management: Disruption, adaptation, and the future of antifouling industries","authors":"Heting Hong , Chengyi Luo , Guoping Hong","doi":"10.1016/j.rsma.2025.104328","DOIUrl":"10.1016/j.rsma.2025.104328","url":null,"abstract":"<div><div>The emergence of underwater cleaning robots (UCRs) is transforming antifouling strategies from static, chemical-dependent paradigms to dynamic, service-oriented ecosystems. This paper argues that UCRs are not merely technological innovations but systemic disruptors that threaten legacy coating industries while enabling new models of ecological stewardship and service-based biofouling management. Through an analysis of market trends, ethical trade-offs, and evolving hybrid technologies, this study identifies governance measures necessary to ensure that UCR benefits—ecological, economic, and social—are equitably distributed. These include dynamic fouling indices, decentralized cooperative ownership, and epistemic justice frameworks that incorporate Indigenous and artisanal knowledge into robotic governance. The paper advocates for a transition toward adaptive, antifragile systems rooted in co-evolution rather than suppression, and calls for proactive public-sector engagement to steward this shift.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104328"},"PeriodicalIF":2.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580785","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}
Zhijun Yao , Guanjun Li , Shichao Yang , Guoru Huang
{"title":"Historical and future projected regional sea levels in the Pearl River Delta, South China","authors":"Zhijun Yao , Guanjun Li , Shichao Yang , Guoru Huang","doi":"10.1016/j.rsma.2025.104324","DOIUrl":"10.1016/j.rsma.2025.104324","url":null,"abstract":"<div><div>Due to the particularity of its location, coastal areas are not only affected by climate change and urbanization, but also affected by the downstream boundary jacking caused by sea level rise, which further expands the flood disaster. Therefore, it is necessary to analyze historical sea levels and predict future regional sea levels in order to prevent or mitigate flood disasters in coastal areas. This study used tidal station data from the Pearl River Delta (PRD) and mathematical statistics to analyze historical sea levels and establish a model to predict future sea level rise in the PRD. The results showed a significant increase in sea levels in the PRD, but the rate of increase was lower in the Pearl River estuary than at other stations. A substantial change in the sea level trend occurred in the 1990s due to urbanization in the PRD. The rate of sea level change was, on average, 3.4 cm/10a higher during the urbanization period than during the entire study period. The periods of sea levels change in the PRD were 4–7, 10–15, 18, and 22–29 years. Sea level fluctuations were predicted to be higher in the future. Different global climate models provided different results of sea level rise, but the values increased with an increase in the scenario level. The sea level will rise by 22.4 (24.0) cm, 31.0 (47.4) cm, 39.1 (73.5) cm, and 45.8 (94.4) cm in the near (long) future under the SSP126, SSP245, SSP370, and SSP585 scenarios, respectively.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104324"},"PeriodicalIF":2.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144587869","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}
{"title":"Presence, risk assessment, and priority pollutants determination of antifouling paint biocides in Istanbul Beylikduzu Marina, Sea of Marmara, Türkiye","authors":"Nagihan Ersoy Korkmaz , Abdullah Aksu , Tuğba Tomalak , Başak Savun , Timuçin Kapudan , Cem Gazi̇oğlu , Nuray Çağlar Balkıs","doi":"10.1016/j.rsma.2025.104326","DOIUrl":"10.1016/j.rsma.2025.104326","url":null,"abstract":"<div><div>Antifouling chemicals are mainly used on water-contact surfaces to prevent biofouling formation on ships or submarine hulls. This study focuses on examining the presence of antifouling paint biocides (Irgarol 1051, chlorothalonil, and dichlofluanid) in the seawater of Beylikduzu Marina, Istanbul, and includes an assessment of their environmental risks. Surface seawater samples were collected from six stations around the marina in the spring, summer, autumn, and winter of 2023. The collected water samples were processed using both liquid-liquid extraction and stir bar sorptive extraction methods, and analyses were carried out using gas chromatography-mass spectrometry. Wilcoxon and Bland-Altman tests confirmed the higher efficiency of stir bar sorptive extraction. The highest concentrations of chlorothalonil, dichlofluanid, and Irgarol 1051 were determined as <MDL, 0.16 µg/L, and 0.24 µg/L, respectively, by liquid-liquid extraction method, while the highest concentrations of these compounds were measured as 0.5 µg/L, 0.81 µg/L, and 1.57 µg/L, respectively, by magnetic stir bar extraction method. One-way analysis of variance (ANOVA) showed no significant seasonal variation in biocide concentrations, while regression analysis suggested a limited influence of water quality parameters, particularly for Irgarol 1051. Hierarchical cluster analysis grouped stations based on biocide concentrations, linking M2-M3 to boat mooring, M5-M4 to restricted circulation, M1 to maintenance, and M6 to external influences, emphasizing the role of anthropogenic and hydrodynamic factors in biocide distribution. The risk assessment indicates that the examined antifouling biocides may pose a threat to aquatic life. Irgarol 1051, in particular, requires attention due to its significant risk quotients.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104326"},"PeriodicalIF":2.1,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580787","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}
{"title":"An overview on microplastic pollution in the Black Sea coastal waters of Türkiye","authors":"Özlem TUNÇ DEDE , Yalçın TEPE","doi":"10.1016/j.rsma.2025.104319","DOIUrl":"10.1016/j.rsma.2025.104319","url":null,"abstract":"<div><div>Besides its strategic importance, the Black Sea is a unique basin in terms of biodiversity, fishing and natural resources for the countries on its coasts such as Bulgaria, Georgia, Moldova, Romania, Russia and Ukraine, as well as for Turkiye. The total coastline of the Black Sea is 4.869 km, of which 3.456 km are the coasts of Ukraine (1.756 km, 36.1 %) and Turkey (1.700 km, 34.9 %). This unique marine basin is under intense pollution threat due to the discharge of freshwater, sediment and nutrients from the rivers of all surrounding countries, as well as numerous pollutants, including microplastics. Microplastics, which are among the emerging pollutants originating from terrestrial runoff, industrial discharge and marine activities, adversely affect the aquatic ecosystem and pose a risk to public health. Ingestion by marine organisms can lead to bioaccumulation and biodiversity reduction. This review critically assesses the presence of microplastics in water, sediments and marine organisms along the Black Sea coast of Turkiye. A total of 45 conducted studies were examined within this review, and 87 % of them were reported from the eastern Black Sea. The results revealed that MPs pollution is more intense in the eastern Black Sea and MP type, polymer and color were found to be dominant with fiber (57.8 %), PET (43.4 %) and white (50 %) respectively. However, being the largest closed sea in the world, the Black Sea is the discharge point of many pollutants from different countries, therefore it is very important to investigate the presence of MPs along the entire Black Sea coast in order to protect and maintain marine ecosystems, to establish the necessary legislation and protection strategies and to take measures to reduce the level of pollution.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"89 ","pages":"Article 104319"},"PeriodicalIF":2.1,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557026","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}