Pub Date : 2026-03-01Epub Date: 2025-12-29DOI: 10.1016/j.marpolbul.2025.119121
Isabela Figueiredo Fraga, Rebeca Dias de Souza Coutinho, Pedro Magno Vilar de Araújo, Otto Bismarck Fazzano Gadig, Marcelo Vianna, Rachel Ann Hauser-Davis
Sharks are key components of marine ecosystem services, contributing to nutrient transport, regulating lower trophic level populations, and serving as important fishery resources for human communities. While overfishing remains the most harmful threat to shark populations, chemical contamination is a growing concern, with the potential to disrupt the morphological development of exposed individuals. Studies on fluctuating asymmetry in elasmobranchs are still extremely scarce, and none have associated this condition to metal and metalloid contamination, either total or subcellular. In this sense, five bilateral cephalofoil parameters of hammerhead sharks from Rio de Janeiro and São Paulo were measured and correlated with total metal and metalloid concentrations detected in the ampullae of Lorenzini, eyes, muscle, and brain, as well as with subcellular metallothionein-bound metals, in a novel approach, to assess fluctuating asymmetry. The correlations observed between total and subcellular metals and metalloids and fluctuating asymmetry indices determined herein for the first time suggest that metal exposure may impair the symmetrical development of these animals. However, it is important to note that certain methodological limitations, such as the use of soft structures susceptible to deformation, may compromise measurement reliability. Future studies are paramount to assess these potential morphological outcomes of metal contamination in these elasmobranch species.
{"title":"Total and subcellular metals are associated with fluctuating asymmetry in Sphyrna lewini and Sphyrna zygaena (Elasmobranchii: Sphyrnidae).","authors":"Isabela Figueiredo Fraga, Rebeca Dias de Souza Coutinho, Pedro Magno Vilar de Araújo, Otto Bismarck Fazzano Gadig, Marcelo Vianna, Rachel Ann Hauser-Davis","doi":"10.1016/j.marpolbul.2025.119121","DOIUrl":"10.1016/j.marpolbul.2025.119121","url":null,"abstract":"<p><p>Sharks are key components of marine ecosystem services, contributing to nutrient transport, regulating lower trophic level populations, and serving as important fishery resources for human communities. While overfishing remains the most harmful threat to shark populations, chemical contamination is a growing concern, with the potential to disrupt the morphological development of exposed individuals. Studies on fluctuating asymmetry in elasmobranchs are still extremely scarce, and none have associated this condition to metal and metalloid contamination, either total or subcellular. In this sense, five bilateral cephalofoil parameters of hammerhead sharks from Rio de Janeiro and São Paulo were measured and correlated with total metal and metalloid concentrations detected in the ampullae of Lorenzini, eyes, muscle, and brain, as well as with subcellular metallothionein-bound metals, in a novel approach, to assess fluctuating asymmetry. The correlations observed between total and subcellular metals and metalloids and fluctuating asymmetry indices determined herein for the first time suggest that metal exposure may impair the symmetrical development of these animals. However, it is important to note that certain methodological limitations, such as the use of soft structures susceptible to deformation, may compromise measurement reliability. Future studies are paramount to assess these potential morphological outcomes of metal contamination in these elasmobranch species.</p>","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"224 ","pages":"119121"},"PeriodicalIF":4.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145863312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
As an artificial radionuclide with unique source identification characteristics, 236U serves as a crucial tool for tracing the migration processes of radioactive substances in the marine environment. To address the unclear issues regarding the distribution, retention mechanisms, and sources of 236U in the sediments of the Beibu Gulf, this study analyzed 33 surface sediment samples from the region, aiming to clarify the aforementioned key characteristics and provide basic data support for regional radioactive environment research. The results revealed that the 236U atomic concentration ranged from 1.21 × 106 to 6.80 × 107 atoms/g (mean: 1.27 × 107 atoms/g), with the 236U/238U atomic ratio ranging from 3.30 × 10−10 to 3.62 × 10−8 (mean: 0.557 × 10−8). Spatially, the distribution exhibited a pattern of elevated levels in the north and diminished levels in the south, with higher concentrations near estuaries and lower values in open sea areas. Based on an average 236U/239Pu ratio of 0.203, it is inferred that the 236U in the sediments of the Beibu Gulf primarily originated from global atmospheric nuclear test fallout, subject to local modulation by terrestrial inputs, and influenced by the combined effects of redox conditions and hydrodynamic factors.
{"title":"Distribution characteristics and retention mechanisms of 236U in sediments of the Beibu Gulf","authors":"Zhiyi Tu, Xiaolei Zhao, Lin Liu, Xianghao Luo, Yukun Li, Guodong Yu, Manqing Liu, Kaixing Guo, Chunping Huang, Jianhui Lai, Deyu Wang, Huijuan Wang, Yongjing Guan","doi":"10.1016/j.marpolbul.2026.119430","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119430","url":null,"abstract":"As an artificial radionuclide with unique source identification characteristics, <ce:sup loc=\"post\">236</ce:sup>U serves as a crucial tool for tracing the migration processes of radioactive substances in the marine environment. To address the unclear issues regarding the distribution, retention mechanisms, and sources of <ce:sup loc=\"post\">236</ce:sup>U in the sediments of the Beibu Gulf, this study analyzed 33 surface sediment samples from the region, aiming to clarify the aforementioned key characteristics and provide basic data support for regional radioactive environment research. The results revealed that the <ce:sup loc=\"post\">236</ce:sup>U atomic concentration ranged from 1.21 × 10<ce:sup loc=\"post\">6</ce:sup> to 6.80 × 10<ce:sup loc=\"post\">7</ce:sup> atoms/g (mean: 1.27 × 10<ce:sup loc=\"post\">7</ce:sup> atoms/g), with the <ce:sup loc=\"post\">236</ce:sup>U/<ce:sup loc=\"post\">238</ce:sup>U atomic ratio ranging from 3.30 × 10<ce:sup loc=\"post\">−10</ce:sup> to 3.62 × 10<ce:sup loc=\"post\">−8</ce:sup> (mean: 0.557 × 10<ce:sup loc=\"post\">−8</ce:sup>). Spatially, the distribution exhibited a pattern of elevated levels in the north and diminished levels in the south, with higher concentrations near estuaries and lower values in open sea areas. Based on an average <ce:sup loc=\"post\">236</ce:sup>U/<ce:sup loc=\"post\">239</ce:sup>Pu ratio of 0.203, it is inferred that the <ce:sup loc=\"post\">236</ce:sup>U in the sediments of the Beibu Gulf primarily originated from global atmospheric nuclear test fallout, subject to local modulation by terrestrial inputs, and influenced by the combined effects of redox conditions and hydrodynamic factors.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"43 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-17DOI: 10.1016/j.marpolbul.2026.119423
Francesca Biandolino, Amalia Amato, Maria Costantini, Luisa Albarano, Loredana Manfra, Giovanni Libralato, Valerio Zupo, Ermelinda Prato
This study compared the effects of microplastics (MPs) originating from a fossil-based polymer (polypropylene, PP) and a bioplastic (polylactic acid, PLA) on the amphipod Gammarus aequicauda. Microplastics (38–220 μm) derived from commercial disposable products were used to evaluate acute toxicity, yielding 96-h LC₅₀ values of >100 mg/L for PLA and 34.71 mg/L for PP. Both MP types were further tested under sub-lethal conditions (5 mg/L) over a 60-day exposure period to assess impacts on growth and reproduction. Chronic exposure resulted in a significant reduction in growth in both PLA- and PP-treated groups beginning at day 45, with PP-exposed individuals also showing the lowest survival rates. Additionally, PLA and PP exposure prolonged embryonic development compared with controls. Reproductive impairment was most pronounced in the PP treatment, which exhibited significant decreases in the number of ovigerous females and in total offspring, alongside an increase in aborted eggs.
{"title":"Polylactic acid versus polypropylene microplastics: ecotoxicological effects on Gammarus aequicauda using a multi-level approach","authors":"Francesca Biandolino, Amalia Amato, Maria Costantini, Luisa Albarano, Loredana Manfra, Giovanni Libralato, Valerio Zupo, Ermelinda Prato","doi":"10.1016/j.marpolbul.2026.119423","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119423","url":null,"abstract":"This study compared the effects of microplastics (MPs) originating from a fossil-based polymer (polypropylene, PP) and a bioplastic (polylactic acid, PLA) on the amphipod <ce:italic>Gammarus aequicauda</ce:italic>. Microplastics (38–220 μm) derived from commercial disposable products were used to evaluate acute toxicity, yielding 96-h LC₅₀ values of >100 mg/L for PLA and 34.71 mg/L for PP. Both MP types were further tested under sub-lethal conditions (5 mg/L) over a 60-day exposure period to assess impacts on growth and reproduction. Chronic exposure resulted in a significant reduction in growth in both PLA- and PP-treated groups beginning at day 45, with PP-exposed individuals also showing the lowest survival rates. Additionally, PLA and PP exposure prolonged embryonic development compared with controls. Reproductive impairment was most pronounced in the PP treatment, which exhibited significant decreases in the number of ovigerous females and in total offspring, alongside an increase in aborted eggs.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"325 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-17DOI: 10.1016/j.marpolbul.2026.119426
Angela Popławska, Patryk Kurek, Marta Staniszewska, Iga Nehring, Bożena Graca, Agata Rychter, Leszek Łęczyński, Magdalena Bełdowska
Polymetallic iron-manganese (Fe-Mn) nodules from the Baltic Sea are increasingly seen as a valuable source of rare earth elements (REE) and technology-critical elements (TCE). However, no prior studies have examined their potential to accumulate toxic organic pollutants, which may affect REE recovery processes. Here, we report the first detection of endocrine-disrupting phenol derivatives: bisphenol A, 4-nonylphenol, and 4-tert-octylphenol as well as microplastic particles in Fe-Mn nodules from the Polish Exclusive Economic Zone. Phenol derivatives concentrations were 5–151 times higher in nodules than in sediments below. We identified 27 microplastic particles, dominated by industrial polymers such as neoprene and chlorosulfonated polyethylene. Our results show that Fe-Mn nodules can function not only as geochemical resources but also as sinks for organic pollutants. With increasing interest in nodule exploitation, recovery methods should be adapted to minimize phenol derivatives and microplastic release into the environment and reduce human exposure.
{"title":"Accumulation of phenol derivatives and microplastic in ferromanganese nodules (Fe-Mn) from Polish Exclusive Economic Zone – preliminary studies","authors":"Angela Popławska, Patryk Kurek, Marta Staniszewska, Iga Nehring, Bożena Graca, Agata Rychter, Leszek Łęczyński, Magdalena Bełdowska","doi":"10.1016/j.marpolbul.2026.119426","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119426","url":null,"abstract":"Polymetallic iron-manganese (Fe-Mn) nodules from the Baltic Sea are increasingly seen as a valuable source of rare earth elements (REE) and technology-critical elements (TCE). However, no prior studies have examined their potential to accumulate toxic organic pollutants, which may affect REE recovery processes. Here, we report the first detection of endocrine-disrupting phenol derivatives: bisphenol A, 4-nonylphenol, and 4-tert-octylphenol as well as microplastic particles in Fe-Mn nodules from the Polish Exclusive Economic Zone. Phenol derivatives concentrations were 5–151 times higher in nodules than in sediments below. We identified 27 microplastic particles, dominated by industrial polymers such as neoprene and chlorosulfonated polyethylene. Our results show that Fe-Mn nodules can function not only as geochemical resources but also as sinks for organic pollutants. With increasing interest in nodule exploitation, recovery methods should be adapted to minimize phenol derivatives and microplastic release into the environment and reduce human exposure.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"7 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-17DOI: 10.1016/j.marpolbul.2026.119422
Zhuorong Du, Zhenzhen Li, Xuanqi Chen, Mei Liu, Lijuan Feng, Qian Li, Zhi Chen, Qingguo Chen
Phosphate-solubilizing bacteria (PSB) are well-known for their ability to convert nonbioavailable phosphates into bioavailable forms, however, research on PSB that possess both phosphate solubilization and crude oil degradation capabilities in marine environments has not yet been explored, and the role of these bacteria in microbial remediation of petroleum contamination in seawater needs be investigated. In this study, laboratory simulated marine oil spill bioremediation experiment was carried out to explore the role of PSB with crude oil degradation capabilities (A strain of PSB-1 used in this study) in petroleum hydrocarbon degradation by indigenous microorganisms in marine environment. It was found that PSB-1 significantly enhanced crude oil removal, with a degradation efficiency of 60% achieved after 30 days at a crude oil concentration of 1 g/L, Concurrently, the concentration of soluble phosphate in seawater increased to 47.36 mg/L, reflecting a 170% increase compared to the control. Metagenomic analysis further indicated that the phosphate-solubilizing activity of PSB-1 not only augmented phosphate availability but also stimulated the growth and succession of indigenous hydrocarbon-degrading microorganisms, thereby altering the microbial community structure and improving overall degradation capacity. These findings highlight the ecological significance of PSB-1 in facilitating crude oil biodegradation in marine environments and offer novel insights into bioremediation strategies for crude oil-contaminated seawater.
{"title":"Laboratory-scale simulation study on the bioremediation of marine oil pollution by phosphate-solubilizing bacteria Bacillus subtilis PSB-1","authors":"Zhuorong Du, Zhenzhen Li, Xuanqi Chen, Mei Liu, Lijuan Feng, Qian Li, Zhi Chen, Qingguo Chen","doi":"10.1016/j.marpolbul.2026.119422","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119422","url":null,"abstract":"Phosphate-solubilizing bacteria (PSB) are well-known for their ability to convert nonbioavailable phosphates into bioavailable forms, however, research on PSB that possess both phosphate solubilization and crude oil degradation capabilities in marine environments has not yet been explored, and the role of these bacteria in microbial remediation of petroleum contamination in seawater needs be investigated. In this study, laboratory simulated marine oil spill bioremediation experiment was carried out to explore the role of PSB with crude oil degradation capabilities (A strain of PSB-1 used in this study) in petroleum hydrocarbon degradation by indigenous microorganisms in marine environment. It was found that PSB-1 significantly enhanced crude oil removal, with a degradation efficiency of 60% achieved after 30 days at a crude oil concentration of 1 g/L, Concurrently, the concentration of soluble phosphate in seawater increased to 47.36 mg/L, reflecting a 170% increase compared to the control. Metagenomic analysis further indicated that the phosphate-solubilizing activity of PSB-1 not only augmented phosphate availability but also stimulated the growth and succession of indigenous hydrocarbon-degrading microorganisms, thereby altering the microbial community structure and improving overall degradation capacity. These findings highlight the ecological significance of PSB-1 in facilitating crude oil biodegradation in marine environments and offer novel insights into bioremediation strategies for crude oil-contaminated seawater.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"32 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-16DOI: 10.1016/j.marpolbul.2026.119425
Victor Vasques Ribeiro, Ítalo Braga Castro
Barnacles are filter-feeders of promising performance as sentinels of microplastic contamination, yet their use remains limited. Here, we synthesize field-based evidence on microplastic in barnacles worldwide, proposing analytical standardization to enable their use in environmental monitoring. Fourteen field studies across seven countries reveal pronounced spatiotemporal variability. Fibers and fragments dominated, with polyethylene and cellophane as the prevalent polymers, reflecting distinct regional contamination profiles. Barnacles consistently reflected environmental microplastic conditions, capturing both elevated and low contamination regimes. Reaching 184.1 particles g−1, Japan and Iran are potential hotspots. However, a global overview of barnacle-based assessments remains limited due to analytical heterogeneity and geographical monitoring gaps. Key methodological priorities for future research include standardizing rigorous quality control, biometrics, digestion, filtration, and multi-matrix integration. Barnacles may be robust sentinels, capable of enhancing the spatiotemporal and ecological representativeness of global microplastic monitoring frameworks.
{"title":"Barnacles as emerging sentinels of microplastic contamination: A global synthesis and analytical framing","authors":"Victor Vasques Ribeiro, Ítalo Braga Castro","doi":"10.1016/j.marpolbul.2026.119425","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119425","url":null,"abstract":"Barnacles are filter-feeders of promising performance as sentinels of microplastic contamination, yet their use remains limited. Here, we synthesize field-based evidence on microplastic in barnacles worldwide, proposing analytical standardization to enable their use in environmental monitoring. Fourteen field studies across seven countries reveal pronounced spatiotemporal variability. Fibers and fragments dominated, with polyethylene and cellophane as the prevalent polymers, reflecting distinct regional contamination profiles. Barnacles consistently reflected environmental microplastic conditions, capturing both elevated and low contamination regimes. Reaching 184.1 particles g<ce:sup loc=\"post\">−1</ce:sup>, Japan and Iran are potential hotspots. However, a global overview of barnacle-based assessments remains limited due to analytical heterogeneity and geographical monitoring gaps. Key methodological priorities for future research include standardizing rigorous quality control, biometrics, digestion, filtration, and multi-matrix integration. Barnacles may be robust sentinels, capable of enhancing the spatiotemporal and ecological representativeness of global microplastic monitoring frameworks.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"2 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-16DOI: 10.1016/j.marpolbul.2026.119397
Ping Wang, Zheng-Xin Hu, Yu Xin, Bing-Han Li, Lu Han, Shu-Hang Dong, Chun-Ying Liu, Tao Liu, Jing-Wen Hu, Jiang-Chen Gong, Gui-Peng Yang
Macroalgae aquaculture plays a crucial role in carbon sequestration and mitigating coastal eutrophication, yet its impacts on carbon and sulfur cycling during the harvesting process is still poorly understood. Here, the effects of the harvesting on the carbonate system and biogenic sulfur release were examined in November, corresponding to the Laminaria japonica – Gracilariopsis lemaneiformis rotational aquaculture zones in Sansha Bay, China, in 2022. Our findings indicate that the significant release of dissolved organic carbon after harvesting occurred alongside the remineralization of organic carbon, making the aquaculture area act as a net atmospheric CO₂ source during the observation period. The average sea-to-air flux was 6.48 mmol m−2 d−1, which was 14.43 to 34.71 times higher than adjacent non-cultivated waters. Concurrently, the sinking macroalgal debris promoted dimethylsulphoniopropionate production in the bottom layers, elevating biogenic sulfur concentrations in the aquaculture area. In contrast, in-situ mesocosm cultivation showed that fresh G. lemaneiformis was mainly characterized by photosynthetic carbon fixation and sulfur release. The main difference is that the mesocosm system was production-dominated, controlled by photosynthetic carbon fixation and biogenic sulfur release from fresh macroalgae, whereas the field system was primarily dominated by debris input and organic carbon remineralization, which regulated carbon and sulfur cycling. These findings highlight the role of macroalgae in the carbon and sulfur cycle at harvest and highlight the need for optimized management strategies to more accurately assess the long-term impacts of macroalgae cultivation on the water carbon and sulfur cycle and its climate change.
{"title":"Impact of macroalgae farming on the carbonate system and biogenic sulfur dynamics in Sansha Bay, China","authors":"Ping Wang, Zheng-Xin Hu, Yu Xin, Bing-Han Li, Lu Han, Shu-Hang Dong, Chun-Ying Liu, Tao Liu, Jing-Wen Hu, Jiang-Chen Gong, Gui-Peng Yang","doi":"10.1016/j.marpolbul.2026.119397","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119397","url":null,"abstract":"Macroalgae aquaculture plays a crucial role in carbon sequestration and mitigating coastal eutrophication, yet its impacts on carbon and sulfur cycling during the harvesting process is still poorly understood. Here, the effects of the harvesting on the carbonate system and biogenic sulfur release were examined in November, corresponding to the <ce:italic>Laminaria japonica</ce:italic> – <ce:italic>Gracilariopsis lemaneiformis</ce:italic> rotational aquaculture zones in Sansha Bay, China, in 2022. Our findings indicate that the significant release of dissolved organic carbon after harvesting occurred alongside the remineralization of organic carbon, making the aquaculture area act as a net atmospheric CO₂ source during the observation period. The average sea-to-air flux was 6.48 mmol m<ce:sup loc=\"post\">−2</ce:sup> d<ce:sup loc=\"post\">−1</ce:sup>, which was 14.43 to 34.71 times higher than adjacent non-cultivated waters. Concurrently, the sinking macroalgal debris promoted dimethylsulphoniopropionate production in the bottom layers, elevating biogenic sulfur concentrations in the aquaculture area. In contrast, in-situ mesocosm cultivation showed that fresh <ce:italic>G. lemaneiformis</ce:italic> was mainly characterized by photosynthetic carbon fixation and sulfur release. The main difference is that the mesocosm system was production-dominated, controlled by photosynthetic carbon fixation and biogenic sulfur release from fresh macroalgae, whereas the field system was primarily dominated by debris input and organic carbon remineralization, which regulated carbon and sulfur cycling. These findings highlight the role of macroalgae in the carbon and sulfur cycle at harvest and highlight the need for optimized management strategies to more accurately assess the long-term impacts of macroalgae cultivation on the water carbon and sulfur cycle and its climate change.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"37 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-16DOI: 10.1016/j.marpolbul.2026.119384
Mahmoud Elmezain, Atif Sultan, Mobeen Ur Rehman, Sultan Alshehhi, Maryam R. Al Shehhi, Irfan Hussain
Coral reefs are among the most diverse and productive marine ecosystems, providing food security and livelihoods for millions of people, especially in coastal and rural areas where small-scale reef fisheries are a main source of fish. Rising sea temperatures and pollution are causing widespread bleaching, driven by the loss of algal symbionts, and accelerating reef degradation. Underwater imaging paired with color-based health charts provides a non-invasive method for monitoring bleaching. However, current approaches require extensive manual annotation and are limited by underwater image noise such as blur and color casts. Existing AI-based monitoring approaches are often semi-autonomous and lack fine-grained bleaching localization capabilities. In this paper, we propose Coral Color-Reference Chart Automation (Coral-CRCA), a multi-stage algorithm that replicates the visual assessment process used by marine biologists to fully automate coral bleaching evaluation with color-reference charts. Initially, the pipeline incorporates a preprocessing image denoising module to improve robustness to underwater image distortions. The method then segments the coral region, isolates chart quadrants, and assigns each coral pixel to the closest reference grade by color similarity, generating pixel-level bleaching visualizations and reporting bleaching percentage. We evaluate each stage of the pipeline through comparative analyses and assess the complete system on 3400 expert-annotated, field-collected coral images from the Arabian/Persian Gulf. The method achieves a mean absolute error (MAE) of 19.17% in bleaching percentage estimation and a binary classification accuracy (bleached/healthy) of 96.12%, matching expert-level performance on this dataset. The source codes are available on this link https://github.com/MahmoudElMezain/Coral-CRCA_Color-Reference-Chart-Automation-Algorithm
{"title":"Coral-CRCA: A Color-Reference Chart Automation algorithm for coral bleaching visualization and severity assessment","authors":"Mahmoud Elmezain, Atif Sultan, Mobeen Ur Rehman, Sultan Alshehhi, Maryam R. Al Shehhi, Irfan Hussain","doi":"10.1016/j.marpolbul.2026.119384","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119384","url":null,"abstract":"Coral reefs are among the most diverse and productive marine ecosystems, providing food security and livelihoods for millions of people, especially in coastal and rural areas where small-scale reef fisheries are a main source of fish. Rising sea temperatures and pollution are causing widespread bleaching, driven by the loss of algal symbionts, and accelerating reef degradation. Underwater imaging paired with color-based health charts provides a non-invasive method for monitoring bleaching. However, current approaches require extensive manual annotation and are limited by underwater image noise such as blur and color casts. Existing AI-based monitoring approaches are often semi-autonomous and lack fine-grained bleaching localization capabilities. In this paper, we propose Coral Color-Reference Chart Automation (Coral-CRCA), a multi-stage algorithm that replicates the visual assessment process used by marine biologists to fully automate coral bleaching evaluation with color-reference charts. Initially, the pipeline incorporates a preprocessing image denoising module to improve robustness to underwater image distortions. The method then segments the coral region, isolates chart quadrants, and assigns each coral pixel to the closest reference grade by color similarity, generating pixel-level bleaching visualizations and reporting bleaching percentage. We evaluate each stage of the pipeline through comparative analyses and assess the complete system on 3400 expert-annotated, field-collected coral images from the Arabian/Persian Gulf. The method achieves a mean absolute error (MAE) of 19.17% in bleaching percentage estimation and a binary classification accuracy (bleached/healthy) of 96.12%, matching expert-level performance on this dataset. The source codes are available on this link <ce:inter-ref xlink:href=\"https://github.com/MahmoudElMezain/Coral-CRCA_Color-Reference-Chart-Automation-Algorithm\" xlink:type=\"simple\">https://github.com/MahmoudElMezain/Coral-CRCA_Color-Reference-Chart-Automation-Algorithm</ce:inter-ref>","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"18 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
This study investigates four classes of persistent organic pollutants, specifically PCDD/Fs, PBDD/Fs, dl-PCBs, and PBDEs in 20 sediment samples collected from Daya Bay. All target compounds were extracted and analyzed via GC-HRMS. Source identification was performed using PCA and PMF on congener concentration data, supplemented by comprehensive information on pollution sources within and around Daya Bay. The results reveal PCDD/F concentrations were notably high, primarily deriving from the historical application of sodium pentachlorophenol in the surrounding area to control the snail oncomelania. In contrast, PBDD/Fs were detected at relatively low concentrations, with multiple distinct sources identified: thermal and combustion processes, atmospheric photochemical degradation of PBDEs, and potential biosynthesis of tetra- and penta-PBDDs by marine algae. dl-PCBs were present at low concentrations, attributed to thermal processes involving commercial PCB-containing products. PBDEs concentrations showed substantial variability, linked to commercial formulations of penta-BDE, octa-BDE, and deca-BDE. TOC and PAHs in sediments were determined. The correlation analysis of target pollutants, PAHs and TOC concentrations in sediments shows PCDD/Fs closely associated with TOC, and PAHs well interrelated with PCBs, supporting above source interpretations. The total toxic equivalent concentrations of PCDD/Fs, PBDD/Fs, and dl-PCBs were generally below the thresholds associated with high risk to mammals, as defined by the U.S.EPA. For PBDEs, all sampling sites exhibited low to moderate ecological risk. To our knowledge, this study is the first comprehensive report on the concentrations of PCDD/Fs, PBDD/Fs, and dl-PCBs in Daya Bay sediments, providing valuable insights for the environmental management and protection of Daya Bay.
{"title":"Characterization and source apportionment of halogenated organic pollutants in sediments from the Daya Bay, South China Sea","authors":"Ren-Jie Shang, Jian-Fang Hu, Ming-Yang Liu, Yao Xiao, Yi-Ting Zeng, Li-Tian Huang, Ping-An Peng","doi":"10.1016/j.marpolbul.2026.119343","DOIUrl":"https://doi.org/10.1016/j.marpolbul.2026.119343","url":null,"abstract":"This study investigates four classes of persistent organic pollutants, specifically PCDD/Fs, PBDD/Fs, dl-PCBs, and PBDEs in 20 sediment samples collected from Daya Bay. All target compounds were extracted and analyzed via GC-HRMS. Source identification was performed using PCA and PMF on congener concentration data, supplemented by comprehensive information on pollution sources within and around Daya Bay. The results reveal PCDD/F concentrations were notably high, primarily deriving from the historical application of sodium pentachlorophenol in the surrounding area to control the snail oncomelania. In contrast, PBDD/Fs were detected at relatively low concentrations, with multiple distinct sources identified: thermal and combustion processes, atmospheric photochemical degradation of PBDEs, and potential biosynthesis of tetra- and penta-PBDDs by marine algae. dl-PCBs were present at low concentrations, attributed to thermal processes involving commercial PCB-containing products. PBDEs concentrations showed substantial variability, linked to commercial formulations of penta-BDE, octa-BDE, and deca-BDE. TOC and PAHs in sediments were determined. The correlation analysis of target pollutants, PAHs and TOC concentrations in sediments shows PCDD/Fs closely associated with TOC, and PAHs well interrelated with PCBs, supporting above source interpretations. The total toxic equivalent concentrations of PCDD/Fs, PBDD/Fs, and dl-PCBs were generally below the thresholds associated with high risk to mammals, as defined by the U.S.EPA. For PBDEs, all sampling sites exhibited low to moderate ecological risk. To our knowledge, this study is the first comprehensive report on the concentrations of PCDD/Fs, PBDD/Fs, and dl-PCBs in Daya Bay sediments, providing valuable insights for the environmental management and protection of Daya Bay.","PeriodicalId":18215,"journal":{"name":"Marine pollution bulletin","volume":"180 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146210329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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