Pub Date : 2026-03-19DOI: 10.3389/fmars.2026.1765872
Anthony W. J. Bicknell, Samuel Gierhart, Mario Lambrette, Matthew J. Witt
Offshore wind turbine fixed-bottom foundations provide artificial hard substrate through the water column that encourages marine flora and fauna to colonise and aggregate around the introduced structures, a well-documented phenomenon known as the ‘artificial reef effect’. The cumulative impact thousands of turbine foundations at multiple offshore sites have on local and regional marine species populations and communities is not fully understood. Knowledge of the extent and magnitude of the reefing effect at a fine scale (single turbines) is a prerequisite to making broader-scale (single or multiple wind farms) predictions of population level and ecosystem changes caused by presence of offshore wind farms. The influence of fine-scale distance (<250 m) to turbine jacket foundations on abundance, biomass and size of demersal fishes was assessed at a northern latitude wind farm. Abundance and biomass of all demersal fishes, flatfish Pleuronectiformes spp. and haddock Melanogrammus aeglefinus were found to have a significant negative relationship with increasing distance from foundations. Haddock were found to aggregate closer to the structures, yet all statistical models predicted a similar magnitude of increase for each group of between ~1.5 and 1.6 times more individuals and biomass at 30 m from the foundations compared to 240 m. The results illustrate that fine-scale proximity to offshore wind fixed foundations has considerable effects on the presence of some demersal fish species. The cumulative or wider ecosystem consequences of these effects are not known, but the further evidence for localised reefing effects can be of strategic interest for optimizing future wind farm project design, included implementation of nature-inclusive measures that could help meet future marine net gain aspirations.
{"title":"Fine-scale proximity to offshore wind turbine foundations increases biomass of demersal fish species","authors":"Anthony W. J. Bicknell, Samuel Gierhart, Mario Lambrette, Matthew J. Witt","doi":"10.3389/fmars.2026.1765872","DOIUrl":"https://doi.org/10.3389/fmars.2026.1765872","url":null,"abstract":"Offshore wind turbine fixed-bottom foundations provide artificial hard substrate through the water column that encourages marine flora and fauna to colonise and aggregate around the introduced structures, a well-documented phenomenon known as the ‘artificial reef effect’. The cumulative impact thousands of turbine foundations at multiple offshore sites have on local and regional marine species populations and communities is not fully understood. Knowledge of the extent and magnitude of the reefing effect at a fine scale (single turbines) is a prerequisite to making broader-scale (single or multiple wind farms) predictions of population level and ecosystem changes caused by presence of offshore wind farms. The influence of fine-scale distance (&lt;250 m) to turbine jacket foundations on abundance, biomass and size of demersal fishes was assessed at a northern latitude wind farm. Abundance and biomass of all demersal fishes, flatfish Pleuronectiformes spp. and haddock <jats:italic>Melanogrammus aeglefinus</jats:italic> were found to have a significant negative relationship with increasing distance from foundations. Haddock were found to aggregate closer to the structures, yet all statistical models predicted a similar magnitude of increase for each group of between ~1.5 and 1.6 times more individuals and biomass at 30 m from the foundations compared to 240 m. The results illustrate that fine-scale proximity to offshore wind fixed foundations has considerable effects on the presence of some demersal fish species. The cumulative or wider ecosystem consequences of these effects are not known, but the further evidence for localised reefing effects can be of strategic interest for optimizing future wind farm project design, included implementation of nature-inclusive measures that could help meet future marine net gain aspirations.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"7 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147492753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-19DOI: 10.3389/fmars.2026.1720284
Alena Wachmann, Alejandra Mora-Soto, Jennifer Yakimishyn, Krista Bohlen, Emily Fulton, Maycira Costa
Canopy-forming kelps, bull kelp ( Nereocystis luetkeana ) and giant kelp ( Macrocystis tenuifolia ), form dynamic underwater forests that underpin coastal biodiversity, fisheries, and human well-being. Yet, their persistence under accelerating ocean warming and intensifying marine heatwaves remains poorly understood, particularly at regional scales. We integrate nearly 170 years of evidence, including data from British Admiralty charts (1858–1956) and 10-m Sentinel-2 imagery (2020–2023) to map modern kelp distribution and centennial persistence across 5,600 km of the West Coast of Vancouver Island (WCVI), British Columbia, Canada, partitioned into four ecoregions. Kelp forests in cooler, high-energy ecoregions, containing 97.5% of modern canopy area, remained highly persistent (~88%) over the past century, suggesting the presence of climatic refugia. By contrast, the warmer and more sheltered ecoregion exhibited markedly lower persistence (52%), which was associated with elevated spring and summer sea surface temperatures. These results demonstrate the importance of century-scale baselines for distinguishing natural variability from climate-driven change and identify spatial refugia as priority areas for conservation and restoration within British Columbia’s and First Nations’ marine protection and climate adaptation strategies.
{"title":"Centennial persistence of kelp forests on the West Coast of Vancouver Island, Canada","authors":"Alena Wachmann, Alejandra Mora-Soto, Jennifer Yakimishyn, Krista Bohlen, Emily Fulton, Maycira Costa","doi":"10.3389/fmars.2026.1720284","DOIUrl":"https://doi.org/10.3389/fmars.2026.1720284","url":null,"abstract":"Canopy-forming kelps, bull kelp ( <jats:italic>Nereocystis luetkeana</jats:italic> ) and giant kelp ( <jats:italic>Macrocystis tenuifolia</jats:italic> ), form dynamic underwater forests that underpin coastal biodiversity, fisheries, and human well-being. Yet, their persistence under accelerating ocean warming and intensifying marine heatwaves remains poorly understood, particularly at regional scales. We integrate nearly 170 years of evidence, including data from British Admiralty charts (1858–1956) and 10-m Sentinel-2 imagery (2020–2023) to map modern kelp distribution and centennial persistence across 5,600 km of the West Coast of Vancouver Island (WCVI), British Columbia, Canada, partitioned into four ecoregions. Kelp forests in cooler, high-energy ecoregions, containing 97.5% of modern canopy area, remained highly persistent (~88%) over the past century, suggesting the presence of climatic refugia. By contrast, the warmer and more sheltered ecoregion exhibited markedly lower persistence (52%), which was associated with elevated spring and summer sea surface temperatures. These results demonstrate the importance of century-scale baselines for distinguishing natural variability from climate-driven change and identify spatial refugia as priority areas for conservation and restoration within British Columbia’s and First Nations’ marine protection and climate adaptation strategies.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"94 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147492749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-19DOI: 10.3389/fmars.2026.1797207
Cristina Munari, Michele Mistri
This review synthesizes current knowledge on the sea walnut Mnemiopsis leidyi , focusing on its potential as an emerging source of bioactive compounds rather than solely as a marine invader. The Ponto–Mediterranean expansion of the species and its ecological impacts are briefly outlined to provide context on the origin and magnitude of available biomass. Particular emphasis is placed on biological traits, physiological plasticity, and environmental tolerance that enable recurrent production of large gelatinous stocks. Recent evidence indicates substantial biochemical diversity, including antibiofilm and antimicrobial peptides, photoproteins, and a largely unexplored immune-associated molecular space with potential biotechnological and pharmaceutical relevance. These characteristics position M. leidyi as a promising candidate for biorefinery approaches aimed at extracting high-value molecules from low-cost marine biomass. However, pronounced spatial and temporal variability, together with the inherent unpredictability of natural blooms, represents a major bottleneck for reliable biomass supply and industrial exploitation. Addressing this constraint will require complementary strategies to stabilize production and improve process scalability. By integrating ecological context with biochemical and applied perspectives, this review identifies key challenges, knowledge gaps, and future directions for the sustainable valorization of gelatinous marine biomass and its derived biomolecular resources.
{"title":"The sea walnut Mnemiopsis leidyi: from ecological nuisance to potential biological resource","authors":"Cristina Munari, Michele Mistri","doi":"10.3389/fmars.2026.1797207","DOIUrl":"https://doi.org/10.3389/fmars.2026.1797207","url":null,"abstract":"This review synthesizes current knowledge on the sea walnut <jats:italic>Mnemiopsis leidyi</jats:italic> , focusing on its potential as an emerging source of bioactive compounds rather than solely as a marine invader. The Ponto–Mediterranean expansion of the species and its ecological impacts are briefly outlined to provide context on the origin and magnitude of available biomass. Particular emphasis is placed on biological traits, physiological plasticity, and environmental tolerance that enable recurrent production of large gelatinous stocks. Recent evidence indicates substantial biochemical diversity, including antibiofilm and antimicrobial peptides, photoproteins, and a largely unexplored immune-associated molecular space with potential biotechnological and pharmaceutical relevance. These characteristics position <jats:italic>M. leidyi</jats:italic> as a promising candidate for biorefinery approaches aimed at extracting high-value molecules from low-cost marine biomass. However, pronounced spatial and temporal variability, together with the inherent unpredictability of natural blooms, represents a major bottleneck for reliable biomass supply and industrial exploitation. Addressing this constraint will require complementary strategies to stabilize production and improve process scalability. By integrating ecological context with biochemical and applied perspectives, this review identifies key challenges, knowledge gaps, and future directions for the sustainable valorization of gelatinous marine biomass and its derived biomolecular resources.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"14 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147492751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-18DOI: 10.3389/fmars.2026.1725777
Douglas M. Scheidt, Jane A. Provancha, Eric D. Stolen, David R. Breininger, Resa A. Cancro, Russell H. Lowers, Eric A. Reyier, Bonnie J. Ahr
Florida manatees ( Trichechus manatus latirostris ) are challenged by human alteration of landscapes and waterways. Coastal eutrophication has increased the frequency and intensity of Indian River Lagoon (IRL) algal blooms, promoting seagrass die-offs in areas that once consistently provided manatee forage. For decades the densest aggregations of manatees in Florida, outside of warm-water sites in winter, occurred in the northern Banana River (NBR) at Kennedy Space Center. Historically, the nearby Mosquito Lagoon (ML) had low numbers. Beginning in 2011, several catastrophic algal blooms caused the die-off of nearly 60% of the areal extent of all IRL seagrasses. Most severe impacts were in the Indian River and Banana River with lesser impacts in ML. This study evaluated several decades of manatee aerial survey data using statistical models to identify the environmental and temporal factors influencing manatee abundance, behavior and habitat use in the NBR (1990–2024) and ML (2016–2024). Using a Bayesian hierarchical model, we evaluated how manatee counts were affected by season, water clarity, and coastwide trends in manatee population size. Manatee abundance was evaluated across four distinct IRL seagrass Die-Off periods: Pre-Die-Off, Initial Die-Off (2011-2015), Secondary Die-Off (2016-2022), and Post-Die-Off (2023-2024). NBR manatee abundance increased well into the Initial Die-Off and then declined sharply until reaching historic lows in 2019. Beginning in 2016, only the ML maintained high seagrass coverage and a notable surge in manatee counts indicated aggregations shifted to ML. The Boosted Regression Tree Analysis top two predictors of abundance were seagrass Die-Offs periods and season. Optimized Hotspot Analysis of NBR manatee spatial distribution was compared to seagrass distribution and revealed that during the Pre-Die-Off, manatee hotspots occurred along deep-water resting areas adjacent to seagrass. Starting in the Initial Die-Off, manatee hotspots shifted toward ever shallower waters presumably to access the receding seagrass beds. The proportion of calves observed also declined dramatically after the Initial Die-Off period. These findings demonstrate that manatees aggregate in traditional areas with extreme fidelity but need to shift to “other pastures” during localized seagrass die-offs. Future shifts from habitat degradation will require best practices and adaptive management to safeguard manatees.
{"title":"A multi-decadal aerial survey reveals patterns in manatee abundance and response to seagrass die-offs","authors":"Douglas M. Scheidt, Jane A. Provancha, Eric D. Stolen, David R. Breininger, Resa A. Cancro, Russell H. Lowers, Eric A. Reyier, Bonnie J. Ahr","doi":"10.3389/fmars.2026.1725777","DOIUrl":"https://doi.org/10.3389/fmars.2026.1725777","url":null,"abstract":"Florida manatees ( <jats:italic>Trichechus manatus latirostris</jats:italic> ) are challenged by human alteration of landscapes and waterways. Coastal eutrophication has increased the frequency and intensity of Indian River Lagoon (IRL) algal blooms, promoting seagrass die-offs in areas that once consistently provided manatee forage. For decades the densest aggregations of manatees in Florida, outside of warm-water sites in winter, occurred in the northern Banana River (NBR) at Kennedy Space Center. Historically, the nearby Mosquito Lagoon (ML) had low numbers. Beginning in 2011, several catastrophic algal blooms caused the die-off of nearly 60% of the areal extent of all IRL seagrasses. Most severe impacts were in the Indian River and Banana River with lesser impacts in ML. This study evaluated several decades of manatee aerial survey data using statistical models to identify the environmental and temporal factors influencing manatee abundance, behavior and habitat use in the NBR (1990–2024) and ML (2016–2024). Using a Bayesian hierarchical model, we evaluated how manatee counts were affected by season, water clarity, and coastwide trends in manatee population size. Manatee abundance was evaluated across four distinct IRL seagrass Die-Off periods: Pre-Die-Off, Initial Die-Off (2011-2015), Secondary Die-Off (2016-2022), and Post-Die-Off (2023-2024). NBR manatee abundance increased well into the Initial Die-Off and then declined sharply until reaching historic lows in 2019. Beginning in 2016, only the ML maintained high seagrass coverage and a notable surge in manatee counts indicated aggregations shifted to ML. The Boosted Regression Tree Analysis top two predictors of abundance were seagrass Die-Offs periods and season. Optimized Hotspot Analysis of NBR manatee spatial distribution was compared to seagrass distribution and revealed that during the Pre-Die-Off, manatee hotspots occurred along deep-water resting areas adjacent to seagrass. Starting in the Initial Die-Off, manatee hotspots shifted toward ever shallower waters presumably to access the receding seagrass beds. The proportion of calves observed also declined dramatically after the Initial Die-Off period. These findings demonstrate that manatees aggregate in traditional areas with extreme fidelity but need to shift to “other pastures” during localized seagrass die-offs. Future shifts from habitat degradation will require best practices and adaptive management to safeguard manatees.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"46 23 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147492801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-17DOI: 10.3389/fmars.2026.1743589
Taavi Liblik, Fred Buschmann
The Baltic Sea observing system combines ship-based, autonomous, and remote-sensing components, yet major observational gaps persist in the shallow and dynamic coastal zone. Here, we present the first evaluation of a micro-autonomous underwater vehicle (micro-AUV) for high-resolution mapping of the Baltic Sea water column and assess its potential integration into regional coastal observing systems. Eleven missions were conducted in 2025 across three contrasting environments—the shallow estuarine Bay of Matsalu, the Suur Strait, and the coastal slope of the Baltic Proper—covering depths from 1 to over 100 m. The micro-AUV operated reliably under diverse hydrographic conditions, capturing fine-scale frontal, submesoscale, and benthic-layer structures, as well as a dual upwelling cell. Comparisons with reference profiles confirmed the high accuracy of temperature and salinity measurements, and strong correlations for chlorophyll-a fluorescence and turbidity. The vehicle’s endurance (up to 40 km or ~7 h at 1.5 m s −1 ) enables efficient mesoscale surveys, while its maneuverability allows operation in very shallow or complex coastal areas where gliders and floats cannot be used. The results demonstrate that micro-AUVs can fill a critical observational gap between ship-based surveys, gliders, FerryBoxes, and coastal stations by extending coastal observations offshore and resolving vertical structures inaccessible to remote sensing. Despite limitations in endurance and communication range, micro-AUVs represent a promising, cost-efficient addition to integrated coastal observing systems, supporting targeted process studies and rapid-response missions in dynamic environments such as the Baltic Sea.
波罗的海观测系统结合了船基、自主和遥感组件，但主要的观测空白仍然存在于浅海和动态沿海区。在这里，我们首次对用于波罗的海水柱高分辨率测绘的微型自主水下航行器（micro-AUV）进行了评估，并评估了其整合到区域沿海观测系统的潜力。2025年，在三个截然不同的环境中进行了11次任务——马萨卢浅水河口湾、苏尔海峡和波罗的海沿岸斜坡——覆盖深度从1米到100多米。该微型auv在不同的水文条件下可靠地工作，捕获了精细尺度的锋面、亚中尺度和底层结构，以及双上升流单元。与参考剖面的比较证实了温度和盐度测量的高准确性，以及叶绿素-a荧光和浊度的强相关性。车辆的续航力（在1.5 m s - 1下可达40公里或~7小时）能够进行有效的中尺度调查，同时其机动性允许在非常浅或复杂的沿海地区操作，这些地区不能使用滑翔机和浮子。结果表明，微型auv可以通过将沿海观测扩展到近海并解析遥感无法获得的垂直结构，填补船载调查、滑翔机、FerryBoxes和海岸站之间的关键观测空白。尽管在续航能力和通信范围方面存在局限性，但微型auv代表了综合海岸观测系统的一个有前途的、经济高效的补充，支持波罗的海等动态环境中有针对性的过程研究和快速响应任务。
{"title":"Application of a small AUV for mapping water column properties in the Baltic Sea","authors":"Taavi Liblik, Fred Buschmann","doi":"10.3389/fmars.2026.1743589","DOIUrl":"https://doi.org/10.3389/fmars.2026.1743589","url":null,"abstract":"The Baltic Sea observing system combines ship-based, autonomous, and remote-sensing components, yet major observational gaps persist in the shallow and dynamic coastal zone. Here, we present the first evaluation of a micro-autonomous underwater vehicle (micro-AUV) for high-resolution mapping of the Baltic Sea water column and assess its potential integration into regional coastal observing systems. Eleven missions were conducted in 2025 across three contrasting environments—the shallow estuarine Bay of Matsalu, the Suur Strait, and the coastal slope of the Baltic Proper—covering depths from 1 to over 100 m. The micro-AUV operated reliably under diverse hydrographic conditions, capturing fine-scale frontal, submesoscale, and benthic-layer structures, as well as a dual upwelling cell. Comparisons with reference profiles confirmed the high accuracy of temperature and salinity measurements, and strong correlations for chlorophyll-a fluorescence and turbidity. The vehicle’s endurance (up to 40 km or ~7 h at 1.5 m s <jats:sup>−1</jats:sup> ) enables efficient mesoscale surveys, while its maneuverability allows operation in very shallow or complex coastal areas where gliders and floats cannot be used. The results demonstrate that micro-AUVs can fill a critical observational gap between ship-based surveys, gliders, FerryBoxes, and coastal stations by extending coastal observations offshore and resolving vertical structures inaccessible to remote sensing. Despite limitations in endurance and communication range, micro-AUVs represent a promising, cost-efficient addition to integrated coastal observing systems, supporting targeted process studies and rapid-response missions in dynamic environments such as the Baltic Sea.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"11 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-17DOI: 10.3389/fmars.2026.1789035
Rui Guo, Meng Ye
After substantial progress in emission reductions and water quality improvement, semi-enclosed seas often enter a post-remediation governance phase characterized by trade-offs among oligotrophication risks, ecosystem productivity, and fisheries livelihoods. However, how this shift is explicitly articulated and institutionally organized in policy language remains insufficiently supported by verifiable textual evidence. Using Japan’s Seto Inland Sea as a case, this study constructs a corpus of 41 statutory policy documents and traces long-term changes in policy discourse across three governance periods. Methodologically, this study applies a complementary text-as-data evidence strategy: word frequency analysis to identify period-specific core vocabulary and its shifts; paragraph-based co-occurrence networks weighted by the Jaccard coefficient to reveal concept couplings and issue modules; Kruskal-type multidimensional scaling to map the continuous semantic space and detect semantic neighborhoods and transition zones. Results indicate that the corpus consistently focuses on environmental conservation and is organized around an administrative action logic oriented to planning and the implementation of measures. Period 1 is dominated by legal-article structure and procedural vocabulary such as permission and notification, translating pollution control into verifiable statutory requirements and vertically coordinated enforcement arrangements. Period 2 retains the primacy of water quality regulation while strengthening performance-oriented narratives around total load control, load reduction, and target attainment, and integrating eutrophication risks, habitat restoration, watershed coordination, and infrastructure governance into a unified policy framework. Period 3 marks a structural turn: nutrient-salt governance shifts from one-way reduction to an appropriateness-oriented approach, and the discourse becomes tightly coupled with monitoring and effectiveness verification. This study clarifies the institutional mechanisms underpinning the shift from a clean sea to a clean and abundant sea and offers transferable institutional and methodological implications for other enclosed or semi-enclosed seas seeking to balance rule certainty with adaptive flexibility in the post-eutrophication stage.
{"title":"From pollution control to adaptive governance: evidence from text-as-data analysis of statutory discourse in Japan’s Seto Inland Sea","authors":"Rui Guo, Meng Ye","doi":"10.3389/fmars.2026.1789035","DOIUrl":"https://doi.org/10.3389/fmars.2026.1789035","url":null,"abstract":"After substantial progress in emission reductions and water quality improvement, semi-enclosed seas often enter a post-remediation governance phase characterized by trade-offs among oligotrophication risks, ecosystem productivity, and fisheries livelihoods. However, how this shift is explicitly articulated and institutionally organized in policy language remains insufficiently supported by verifiable textual evidence. Using Japan’s Seto Inland Sea as a case, this study constructs a corpus of 41 statutory policy documents and traces long-term changes in policy discourse across three governance periods. Methodologically, this study applies a complementary text-as-data evidence strategy: word frequency analysis to identify period-specific core vocabulary and its shifts; paragraph-based co-occurrence networks weighted by the Jaccard coefficient to reveal concept couplings and issue modules; Kruskal-type multidimensional scaling to map the continuous semantic space and detect semantic neighborhoods and transition zones. Results indicate that the corpus consistently focuses on environmental conservation and is organized around an administrative action logic oriented to planning and the implementation of measures. Period 1 is dominated by legal-article structure and procedural vocabulary such as permission and notification, translating pollution control into verifiable statutory requirements and vertically coordinated enforcement arrangements. Period 2 retains the primacy of water quality regulation while strengthening performance-oriented narratives around total load control, load reduction, and target attainment, and integrating eutrophication risks, habitat restoration, watershed coordination, and infrastructure governance into a unified policy framework. Period 3 marks a structural turn: nutrient-salt governance shifts from one-way reduction to an appropriateness-oriented approach, and the discourse becomes tightly coupled with monitoring and effectiveness verification. This study clarifies the institutional mechanisms underpinning the shift from a clean sea to a clean and abundant sea and offers transferable institutional and methodological implications for other enclosed or semi-enclosed seas seeking to balance rule certainty with adaptive flexibility in the post-eutrophication stage.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"8 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-17DOI: 10.3389/fmars.2026.1788001
Louis Criqui, Céline Guéguen
The molecular composition of copper(II)-binding organic ligands isolated via immobilized metal affinity chromatography (IMAC) and solid-phase extraction (SPE-PPL) was investigated across distinct oceanic regions using trapped ion mobility spectrometry time-of-flight mass spectrometry (Tims-TOF). Significant differences in molecular composition were observed between high-nutrient, low-chlorophyll (HNLC; northeastern Pacific and southern Atlantic Oceans) and non-HNLC regions (Arctic Ocean). Non-HNLC samples exhibited higher mass-to-charge (m/z) values, elevated abundances of CAS-like and lignin-like compounds, and lower weighted CCS and H/C ratios, indicating greater aromaticity and a predominance of allochthonous organic ligands. The IMAC-SPE Cu(II)-binding ligand pools in the northeastern Pacific and southern Atlantic Oceans (HNLC regions) shared over 25% more compounds than those in the non-HNLC Arctic Ocean. Among the 17 compounds detected in all samples, carbazomycin A was identified with high confidence, marking its first detection in marine waters. Empirical CCS–m/z relationships revealed that IMAC-SPE Cu(II)-binding ligands exhibited strong, consistent correlations within the same molecular groups (carbohydrate-, CAS-, and lignin-like). The persistence of these relationships regardless of sample location and depth suggests that the ion mobility signatures are broadly conserved. Such consistency underscores the robustness of CCS–m/z trends, while also highlighting how molecular class exerts a stronger influence on IMAC-SPE Cu(II)-binding behavior than environmental origin. These findings underscore the importance of regional variability in IMAC-SPE Cu(II)-binding organic ligand composition and its implications for Cu bioavailability, toxicity, and global biogeochemical cycling in marine ecosystems.
{"title":"Spatial comparison of the molecular composition of copper-binding organic ligands isolated by Cu(II)-IMAC-SPE and detected by Tims-TOF MS","authors":"Louis Criqui, Céline Guéguen","doi":"10.3389/fmars.2026.1788001","DOIUrl":"https://doi.org/10.3389/fmars.2026.1788001","url":null,"abstract":"The molecular composition of copper(II)-binding organic ligands isolated via immobilized metal affinity chromatography (IMAC) and solid-phase extraction (SPE-PPL) was investigated across distinct oceanic regions using trapped ion mobility spectrometry time-of-flight mass spectrometry (Tims-TOF). Significant differences in molecular composition were observed between high-nutrient, low-chlorophyll (HNLC; northeastern Pacific and southern Atlantic Oceans) and non-HNLC regions (Arctic Ocean). Non-HNLC samples exhibited higher mass-to-charge (m/z) values, elevated abundances of CAS-like and lignin-like compounds, and lower weighted CCS and H/C ratios, indicating greater aromaticity and a predominance of allochthonous organic ligands. The IMAC-SPE Cu(II)-binding ligand pools in the northeastern Pacific and southern Atlantic Oceans (HNLC regions) shared over 25% more compounds than those in the non-HNLC Arctic Ocean. Among the 17 compounds detected in all samples, carbazomycin A was identified with high confidence, marking its first detection in marine waters. Empirical CCS–m/z relationships revealed that IMAC-SPE Cu(II)-binding ligands exhibited strong, consistent correlations within the same molecular groups (carbohydrate-, CAS-, and lignin-like). The persistence of these relationships regardless of sample location and depth suggests that the ion mobility signatures are broadly conserved. Such consistency underscores the robustness of CCS–m/z trends, while also highlighting how molecular class exerts a stronger influence on IMAC-SPE Cu(II)-binding behavior than environmental origin. These findings underscore the importance of regional variability in IMAC-SPE Cu(II)-binding organic ligand composition and its implications for Cu bioavailability, toxicity, and global biogeochemical cycling in marine ecosystems.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"57 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine fish communities in coastal systems are increasingly shaped by environmental gradients associated with anthropogenic pressures and climate variability, yet how these factors influence community assembly and functional traits remain poorly understood. In this study, environmental DNA (eDNA) metabarcoding using the 12S MiFish primer with 33 water samples was integrated with taxonomic and functional diversity analyses, co-occurrence network analysis, the neutral community model, hierarchical modeling of species communities, and single-trait-based community-weighted means to investigate fish communities in the Taiwan Strait (TWS). This interdisciplinary approach provides both a unique perspective and a comprehensive framework for fish biodiversity assessment. Fish communities exhibited high modularity and weak interspecific interactions, with an uneven distribution of species within functional space, indicating elevated ecological vulnerability. Community assembly was jointly governed by stochastic and deterministic processes, with NO₂⁻ identified as a significant environmental driver shaping fish community assembly. Notably, fish communities in the inshore and principal axis regions exhibited higher clustering coefficient but lower network modularity compared to other regions. Hierarchical modeling of species communities and community-weighted means further indicated clear distributional and trait differences among fish from the estuarine to offshore areas, consistent with species-specific responses to environmental gradients from inshore to offshore areas. Overall, TWS fish communities are dominated by species with very small and small body-length traits, while reef-associated fishes are mainly concentrated in inshore and midshore regions. Fish community assembly and functional traits in TWS exhibited systematic variation along the offshore distance gradient and were jointly modulated by key environmental factors.
{"title":"Integrating eDNA metabarcoding and functional trait analysis to uncover fish community structure and assembly mechanism in the Taiwan strait","authors":"Weiyi He, Hao Huang, Lei Wang, Danyun Ou, Jiaqiao Wang, Runze Han, Yanxu Zhang, Jinli Qiu, Weiwen Li, Kar-Hoe Loh, Sze-Wan Poong","doi":"10.3389/fmars.2026.1761251","DOIUrl":"https://doi.org/10.3389/fmars.2026.1761251","url":null,"abstract":"Marine fish communities in coastal systems are increasingly shaped by environmental gradients associated with anthropogenic pressures and climate variability, yet how these factors influence community assembly and functional traits remain poorly understood. In this study, environmental DNA (eDNA) metabarcoding using the 12S MiFish primer with 33 water samples was integrated with taxonomic and functional diversity analyses, co-occurrence network analysis, the neutral community model, hierarchical modeling of species communities, and single-trait-based community-weighted means to investigate fish communities in the Taiwan Strait (TWS). This interdisciplinary approach provides both a unique perspective and a comprehensive framework for fish biodiversity assessment. Fish communities exhibited high modularity and weak interspecific interactions, with an uneven distribution of species within functional space, indicating elevated ecological vulnerability. Community assembly was jointly governed by stochastic and deterministic processes, with NO₂⁻ identified as a significant environmental driver shaping fish community assembly. Notably, fish communities in the inshore and principal axis regions exhibited higher clustering coefficient but lower network modularity compared to other regions. Hierarchical modeling of species communities and community-weighted means further indicated clear distributional and trait differences among fish from the estuarine to offshore areas, consistent with species-specific responses to environmental gradients from inshore to offshore areas. Overall, TWS fish communities are dominated by species with very small and small body-length traits, while reef-associated fishes are mainly concentrated in inshore and midshore regions. Fish community assembly and functional traits in TWS exhibited systematic variation along the offshore distance gradient and were jointly modulated by key environmental factors.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"33 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Estuaries are vital socio-ecological systems that support biodiversity, provide nursery habitats, and deliver essential ecosystem services for human well-being. This study focuses on highly impacted estuarine systems affected by chronic wastewater inputs at selected Eastern Cape estuaries in South Africa. The study assesses the temporal and spatial variation patterns of pollutant loads on societal impacts and the influence of inter- and intra-annual flow variability in the estuaries. A mixed-method approach integrated laboratory analyses, field surveys, and a rare seven-year longitudinal dataset (2017–2021) of quarterly monitored physico-chemical and Potentially Toxic Element (PTEs) parameters from six estuaries: Swartkops, Qholora, Mtimubu, Mnyameni, Kowie, and Buffalo. Spatiotemporal analyses and Bayesian Hierarchical Models (BHMs) were applied to investigate ecological–socioeconomic interactions and support adaptive management. Dominant variables influencing estuarine dynamics included salinity (0.80), temperature (0.74), chromium (0.72), nickel (0.72), lead (–0.70), and oxidation–reduction potential (–0.63), reflecting the link between salinity and metal contamination, which is influenced by mixing processes and redox conditions. Increasing temperature and declining nutrient loads were especially evident in the Kowie and Buffalo estuaries. The BHMs achieved strong predictive performance (r = 0.75). Findings underscore the importance of integrated spatial planning and adaptive management strategies to strengthen estuarine resilience. The study provides a critical baseline for future monitoring and restoration, with implications for water governance, environmental policy, and climate adaptation in water-stressed regions such as South Africa and the broader Global South.
{"title":"Flow regime variability and wastewater pollution in estuarine systems: a longitudinal assessment of ecological and societal impacts in South Africa’s Eastern Cape","authors":"Mzolisi Tungwana, Oseni Taiwo Amoo, Lee-Ann Sade Modley","doi":"10.3389/fmars.2026.1734808","DOIUrl":"https://doi.org/10.3389/fmars.2026.1734808","url":null,"abstract":"Estuaries are vital socio-ecological systems that support biodiversity, provide nursery habitats, and deliver essential ecosystem services for human well-being. This study focuses on highly impacted estuarine systems affected by chronic wastewater inputs at selected Eastern Cape estuaries in South Africa. The study assesses the temporal and spatial variation patterns of pollutant loads on societal impacts and the influence of inter- and intra-annual flow variability in the estuaries. A mixed-method approach integrated laboratory analyses, field surveys, and a rare seven-year longitudinal dataset (2017–2021) of quarterly monitored physico-chemical and Potentially Toxic Element (PTEs) parameters from six estuaries: Swartkops, Qholora, Mtimubu, Mnyameni, Kowie, and Buffalo. Spatiotemporal analyses and Bayesian Hierarchical Models (BHMs) were applied to investigate ecological–socioeconomic interactions and support adaptive management. Dominant variables influencing estuarine dynamics included salinity (0.80), temperature (0.74), chromium (0.72), nickel (0.72), lead (–0.70), and oxidation–reduction potential (–0.63), reflecting the link between salinity and metal contamination, which is influenced by mixing processes and redox conditions. Increasing temperature and declining nutrient loads were especially evident in the Kowie and Buffalo estuaries. The BHMs achieved strong predictive performance (r = 0.75). Findings underscore the importance of integrated spatial planning and adaptive management strategies to strengthen estuarine resilience. The study provides a critical baseline for future monitoring and restoration, with implications for water governance, environmental policy, and climate adaptation in water-stressed regions such as South Africa and the broader Global South.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"114 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-16DOI: 10.3389/fmars.2026.1789125
Dongren Li, Guoye Zhao, Xiaohe Lai, Yan Su, Chuan Li, Xiudong Xie
Understanding how turbidity in river-delta estuaries responds to short-term atmospheric variability is central to navigation, water quality, and ecosystem risk assessments. A widespread working assumption in many impact and hazard frameworks is that forcing–response mappings are approximately stationary: similar atmospheric forcing should, on average, yield comparable turbidity responses. Here we test this assumption for the Minjiang River Estuary (SE China) using a monthly Sentinel−2 record spanning January 2017–November 2025, quantifying turbidity variability with two complementary satellite proxies: (i) the areal fraction of persistently high turbidity (Afrac) and (ii) an intensity metric based on the upper tail of turbidity within the region of interest (Ip90). Breakpoint analysis identifies three regimes: R1 (Jan 2017–Sep 2022; n=67 months), an intermediate baseline state; R2 (Oct 2022–Feb 2024; n=17), an amplified and more variable state; and R3 (Mar 2024–Nov 2025; n=21), a suppressed state with markedly reduced variance. Critically, coastal pressure anomalies during R2 and R3 are statistically indistinguishable (Mann–Whitney p=0.7027; Cliff’s δ=0.076), yet turbidity anomalies collapse from elevated values in R2 (frac′ 0.301 ± 0.247) to near−zero in R3 (−0.011 ± 0.079), implying a regime-dependent change in response gain rather than weakened forcing. Phase−space diagnostics further reveal hysteresis, consistent with history dependence and sediment “memory” in the resuspendable bed supply. Together, these results provide satellite evidence that estuarine turbidity sensitivity can reorganize abruptly, challenging stationary assumptions commonly used in delta risk assessment and motivating monitoring approaches that track both external forcing and internal state variables.
{"title":"When strong forcing fails to raise turbidity: a regime-based diagnosis of state dependence in the Minjiang River Estuary from Sentinel−2 (2017–2025)","authors":"Dongren Li, Guoye Zhao, Xiaohe Lai, Yan Su, Chuan Li, Xiudong Xie","doi":"10.3389/fmars.2026.1789125","DOIUrl":"https://doi.org/10.3389/fmars.2026.1789125","url":null,"abstract":"Understanding how turbidity in river-delta estuaries responds to short-term atmospheric variability is central to navigation, water quality, and ecosystem risk assessments. A widespread working assumption in many impact and hazard frameworks is that forcing–response mappings are approximately stationary: similar atmospheric forcing should, on average, yield comparable turbidity responses. Here we test this assumption for the Minjiang River Estuary (SE China) using a monthly Sentinel−2 record spanning January 2017–November 2025, quantifying turbidity variability with two complementary satellite proxies: (i) the areal fraction of persistently high turbidity (Afrac) and (ii) an intensity metric based on the upper tail of turbidity within the region of interest (Ip90). Breakpoint analysis identifies three regimes: R1 (Jan 2017–Sep 2022; n=67 months), an intermediate baseline state; R2 (Oct 2022–Feb 2024; n=17), an amplified and more variable state; and R3 (Mar 2024–Nov 2025; n=21), a suppressed state with markedly reduced variance. Critically, coastal pressure anomalies during R2 and R3 are statistically indistinguishable (Mann–Whitney p=0.7027; Cliff’s δ=0.076), yet turbidity anomalies collapse from elevated values in R2 (frac′ 0.301 ± 0.247) to near−zero in R3 (−0.011 ± 0.079), implying a regime-dependent change in response gain rather than weakened forcing. Phase−space diagnostics further reveal hysteresis, consistent with history dependence and sediment “memory” in the resuspendable bed supply. Together, these results provide satellite evidence that estuarine turbidity sensitivity can reorganize abruptly, challenging stationary assumptions commonly used in delta risk assessment and motivating monitoring approaches that track both external forcing and internal state variables.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"409 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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