Pub Date : 2026-02-11DOI: 10.3389/fmars.2026.1728376
Hoon Mo Koo, Inho Yang, Jinsoon Park, Yong-Woo Lee, Yong Hwa Oh
Physicochemical and biological parameters (temperature, salinity, pH, dissolved inorganic nutrients, and chlorophyll-a) were analyzed to evaluate the effects of precipitation variability associated with climate change on the water quality in the Nakdong River Estuary, South Korea. Multi-year monitoring data (2016–2021) were collected seasonally (February, May, August, and November) throughout the study period. Extreme rainfall events caused pronounced estuarine freshening (salinity < 1) and sharply enhanced riverine nutrient fluxes, with wet-to-dry season increases of 4–70 times for dissolved inorganic nitrogen, 4–36 times for phosphorus, and 9–740 times for silicate, showing strong positive correlations with precipitation (r² = 0.76–0.82, p < 0.001). Time-series and self-organizing map classifications revealed estuarine that the water quality was strongly controlled by seasonal precipitation and river discharge, whereas offshore waters exhibited weaker but detectable responses. Notably, extreme rainfall events altered the chlorophyll-a distribution, suppressing phytoplankton accumulation in the estuary because of dilution and flushing, while enhancing chlorophyll-a concentrations in offshore waters through nutrient-enriched river plume dispersion. These results demonstrated that extreme rainfall driven by climate change can enhance the terrestrial nutrient input into coastal waters, thereby increasing the potential for eutrophication and harmful algal blooms.
{"title":"Impacts of precipitation variability on water quality in the Nakdong River Estuary: multi-year (2016–2021) data analysis","authors":"Hoon Mo Koo, Inho Yang, Jinsoon Park, Yong-Woo Lee, Yong Hwa Oh","doi":"10.3389/fmars.2026.1728376","DOIUrl":"https://doi.org/10.3389/fmars.2026.1728376","url":null,"abstract":"Physicochemical and biological parameters (temperature, salinity, pH, dissolved inorganic nutrients, and chlorophyll-a) were analyzed to evaluate the effects of precipitation variability associated with climate change on the water quality in the Nakdong River Estuary, South Korea. Multi-year monitoring data (2016–2021) were collected seasonally (February, May, August, and November) throughout the study period. Extreme rainfall events caused pronounced estuarine freshening (salinity &lt; 1) and sharply enhanced riverine nutrient fluxes, with wet-to-dry season increases of 4–70 times for dissolved inorganic nitrogen, 4–36 times for phosphorus, and 9–740 times for silicate, showing strong positive correlations with precipitation (r² = 0.76–0.82, p &lt; 0.001). Time-series and self-organizing map classifications revealed estuarine that the water quality was strongly controlled by seasonal precipitation and river discharge, whereas offshore waters exhibited weaker but detectable responses. Notably, extreme rainfall events altered the chlorophyll-a distribution, suppressing phytoplankton accumulation in the estuary because of dilution and flushing, while enhancing chlorophyll-a concentrations in offshore waters through nutrient-enriched river plume dispersion. These results demonstrated that extreme rainfall driven by climate change can enhance the terrestrial nutrient input into coastal waters, thereby increasing the potential for eutrophication and harmful algal blooms.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"6 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153434","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 : 2026-02-10DOI: 10.3389/fmars.2026.1782614
JinYang Zhang, Yang Huang, JiaYu Yang, KaiYu Deng, HaiXiang Li, DunQiu Wang, YuFeng Xu, Kun Dong
Rivers serve as critical conduits for transporting pollutants and nutrients to coastal zones, directly influencing coastal ecosystem functions and marine environmental health. Understanding spatiotemporal variations and driving mechanisms of river water quality is therefore critical for effective watershed management and coastal zone protection. This study analyzed water quality data from three monitoring sections (Suqiao, Xialiang Village, and Longxi) along the Luoqing River in Guilin, China, collected during January 2023–March 2025. Seven conventional parameters—water temperature, pH, dissolved oxygen (DO), permanganate index (COD Mn ), total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH 3 -N)—were evaluated using Spearman correlation analysis, principal component analysis (PCA), and machine learning models (CatBoost, Random Forest, and XGBoost). The results showed pronounced monthly variability but relatively stable interannual patterns, indicating dominant control by seasonal hydrological and biogeochemical processes. Spatial differences were evident, with downstream sections exhibiting higher pollution levels and more complex parameter interactions, reflecting intensified anthropogenic influences. PCA extracted two principal components explaining over 70% of the total variance: PC1 associated with nutrient and organic pollution (TN, TP, NH 3 -N, COD Mn ) and PC2 representing physicochemical conditions (pH and DO). A Composite Pollution Index (CPI) was constructed based on NH 3 -N, TN, TP and COD Mn to characterize overall pollution levels. Machine learning models achieved high predictive performance for the CPI (R 2 ≈ 0.994). The shapley Additive Explanations (SHAP) and partial dependence analyses identified TN as the primary controlling factor, with synergistic enhancement between TN and COD Mn under high nitrogen conditions. Overall, Luoqing River water quality is characterized by a nitrogen-centered pollution structure, providing a scientific basis for targeted watershed management and coastal ecosystem protection.
{"title":"Machine learning-based correlation analysis of conventional water quality parameters and composite pollution index in the Luoqing river of the South China Sea Coastal Zone","authors":"JinYang Zhang, Yang Huang, JiaYu Yang, KaiYu Deng, HaiXiang Li, DunQiu Wang, YuFeng Xu, Kun Dong","doi":"10.3389/fmars.2026.1782614","DOIUrl":"https://doi.org/10.3389/fmars.2026.1782614","url":null,"abstract":"Rivers serve as critical conduits for transporting pollutants and nutrients to coastal zones, directly influencing coastal ecosystem functions and marine environmental health. Understanding spatiotemporal variations and driving mechanisms of river water quality is therefore critical for effective watershed management and coastal zone protection. This study analyzed water quality data from three monitoring sections (Suqiao, Xialiang Village, and Longxi) along the Luoqing River in Guilin, China, collected during January 2023–March 2025. Seven conventional parameters—water temperature, pH, dissolved oxygen (DO), permanganate index (COD <jats:sub>Mn</jats:sub> ), total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH <jats:sub>3</jats:sub> -N)—were evaluated using Spearman correlation analysis, principal component analysis (PCA), and machine learning models (CatBoost, Random Forest, and XGBoost). The results showed pronounced monthly variability but relatively stable interannual patterns, indicating dominant control by seasonal hydrological and biogeochemical processes. Spatial differences were evident, with downstream sections exhibiting higher pollution levels and more complex parameter interactions, reflecting intensified anthropogenic influences. PCA extracted two principal components explaining over 70% of the total variance: PC1 associated with nutrient and organic pollution (TN, TP, NH <jats:sub>3</jats:sub> -N, COD <jats:sub>Mn</jats:sub> ) and PC2 representing physicochemical conditions (pH and DO). A Composite Pollution Index (CPI) was constructed based on NH <jats:sub>3</jats:sub> -N, TN, TP and COD <jats:sub>Mn</jats:sub> to characterize overall pollution levels. Machine learning models achieved high predictive performance for the CPI (R <jats:sup>2</jats:sup> ≈ 0.994). The shapley Additive Explanations (SHAP) and partial dependence analyses identified TN as the primary controlling factor, with synergistic enhancement between TN and COD <jats:sub>Mn</jats:sub> under high nitrogen conditions. Overall, Luoqing River water quality is characterized by a nitrogen-centered pollution structure, providing a scientific basis for targeted watershed management and coastal ecosystem protection.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"14 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153440","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 : 2026-02-10DOI: 10.3389/fmars.2026.1744499
Xuancheng Liu, Junhua Huang, Zhengyi Fu, Jie Chang, Zhenhua Ma
This study aimed to examine the physiological responses of juvenile yellowfin tuna ( Thunnus albacares ) to short-term cold stress by comparing oxidative stress, metabolic regulation, and immune-related transcriptional responses in red and white muscles under two low-temperature conditions (24 °C and 18 °C) and a control temperature (30 °C). Juvenile tuna were exposed to these temperature conditions for 36 h, and muscle samples were collected at multiple time points to assess enzyme activities, biochemical indicators, and gene expression. Antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), exhibited a biphasic response, characterized by an initial upregulation at 18 °C after 12 h followed by a decline under prolonged cold exposure. Elevated malondialdehyde (MDA) levels in the red muscle at 24 h indicated enhanced lipid peroxidation and oxidative stress. At 36 h, increased activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and acid phosphatase (ACP) in the red muscle reflected altered metabolic status and enhanced involvement of amino acid-related processes, whereas reduced lactate dehydrogenase (LDH) activity suggested suppression of anaerobic metabolic capacity under prolonged cold stress. Gene expression analysis revealed tissue-specific responses: the red muscle showed a pronounced and sustained induction of hspa1b and acadm , while the white muscle exhibited a faster but less persistent transcriptional response. In addition, the immune-related gene irf3 was downregulated in the red muscle but transiently upregulated in the white muscle. Overall, red muscle displayed slower yet more sustained regulation, whereas white muscle responded more rapidly but exhibited greater sensitivity to cold-induced biochemical perturbations. These findings highlight time- and tissue-specific mechanisms underlying tuna muscle responses to cold stress and provide insights relevant to adaptive management strategies for pelagic fish under climate change scenarios.
{"title":"Short-term cold stress effects on antioxidant, metabolic, and immune responses in the red and white muscles of juvenile yellowfin tuna (Thunnus albacares)","authors":"Xuancheng Liu, Junhua Huang, Zhengyi Fu, Jie Chang, Zhenhua Ma","doi":"10.3389/fmars.2026.1744499","DOIUrl":"https://doi.org/10.3389/fmars.2026.1744499","url":null,"abstract":"This study aimed to examine the physiological responses of juvenile yellowfin tuna ( <jats:italic>Thunnus albacares</jats:italic> ) to short-term cold stress by comparing oxidative stress, metabolic regulation, and immune-related transcriptional responses in red and white muscles under two low-temperature conditions (24 °C and 18 °C) and a control temperature (30 °C). Juvenile tuna were exposed to these temperature conditions for 36 h, and muscle samples were collected at multiple time points to assess enzyme activities, biochemical indicators, and gene expression. Antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), exhibited a biphasic response, characterized by an initial upregulation at 18 °C after 12 h followed by a decline under prolonged cold exposure. Elevated malondialdehyde (MDA) levels in the red muscle at 24 h indicated enhanced lipid peroxidation and oxidative stress. At 36 h, increased activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and acid phosphatase (ACP) in the red muscle reflected altered metabolic status and enhanced involvement of amino acid-related processes, whereas reduced lactate dehydrogenase (LDH) activity suggested suppression of anaerobic metabolic capacity under prolonged cold stress. Gene expression analysis revealed tissue-specific responses: the red muscle showed a pronounced and sustained induction of <jats:italic>hspa1b</jats:italic> and <jats:italic>acadm</jats:italic> , while the white muscle exhibited a faster but less persistent transcriptional response. In addition, the immune-related gene <jats:italic>irf3</jats:italic> was downregulated in the red muscle but transiently upregulated in the white muscle. Overall, red muscle displayed slower yet more sustained regulation, whereas white muscle responded more rapidly but exhibited greater sensitivity to cold-induced biochemical perturbations. These findings highlight time- and tissue-specific mechanisms underlying tuna muscle responses to cold stress and provide insights relevant to adaptive management strategies for pelagic fish under climate change scenarios.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"59 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153574","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 : 2026-02-10DOI: 10.3389/fmars.2026.1771231
Shuwen Wang, Zikang Zhang, Yang Shi, Xiujun Sun, Ying Zhou, Yihang Shu, Fan Yang, Hongzhe Zhu, Kunde Yang
Formed by humidity stratification in the marine atmospheric boundary layer, evaporation ducts serve as critical natural channels for maritime over-the-horizon (OTH) wireless communication. Their unique structure effectively confines electromagnetic (EM) wave propagation, substantially enhancing the link stability and transmission quality of long-range maritime communication while exerting notable impact on OTH EM wave propagation. Tropical cyclones profoundly alter near-surface meteorological conditions and disrupt the distribution uniformity of evaporation ducts, directly inducing fluctuations in communication link path loss (PL), intensified signal attenuation, and even short-term outages, severely impairing maritime broadband communication. However, direct and mobile observations of evaporation ducts within typhoon interiors remain limited. This study investigated the evolution of evaporation duct height (EDH) during Typhoon Koinu (202314) through analysis of 108 hours of continuous observations by three clustered wave gliders. One glider traversed the typhoon eye, while the other two monitored regions of high wind speed (WS). The maximum recorded WS reached 26.5 m/s, accompanied by EDH of 11.9 m, whereas within the eye region, WS was 4.36 m/s with EDH of 5.7 m. The presence of the typhoon’s eye caused a 6.2-m reduction in EDH. Relative humidity (RH) fluctuated from 70% to 95% before the typhoon’s arrival and remained at around 90% during the typhoon’s passage. Correlation analysis indicated that RH was the dominant factor influencing EDH before the typhoon’s arrival, showing negative correlation (Spearman correlation coefficient: −0.83). In contrast, WS was the main driver of EDH variation during the typhoon’s passage, exhibiting strong positive correlation (Spearman correlation coefficient: 0.82). Sensitivity analysis confirmed that the inhibitory effect of elevated RH outweighed the contribution of high WS to EDH enhancement, leading to lower EDH values during the passage of the typhoon than in the pre-typhoon period. Analysis of the spatial distribution of EM wave propagation indicated that the low EDH induced by low WS in the typhoon’s eye caused PL that was 24 dB greater than under high-WS scenarios; overall, the presence of the typhoon’s eye caused greater PL.
{"title":"Continuous observation of evaporation ducts in Super Typhoon Koinu (202314) using clustered wave gliders: mechanisms and maritime communication implications","authors":"Shuwen Wang, Zikang Zhang, Yang Shi, Xiujun Sun, Ying Zhou, Yihang Shu, Fan Yang, Hongzhe Zhu, Kunde Yang","doi":"10.3389/fmars.2026.1771231","DOIUrl":"https://doi.org/10.3389/fmars.2026.1771231","url":null,"abstract":"Formed by humidity stratification in the marine atmospheric boundary layer, evaporation ducts serve as critical natural channels for maritime over-the-horizon (OTH) wireless communication. Their unique structure effectively confines electromagnetic (EM) wave propagation, substantially enhancing the link stability and transmission quality of long-range maritime communication while exerting notable impact on OTH EM wave propagation. Tropical cyclones profoundly alter near-surface meteorological conditions and disrupt the distribution uniformity of evaporation ducts, directly inducing fluctuations in communication link path loss (PL), intensified signal attenuation, and even short-term outages, severely impairing maritime broadband communication. However, direct and mobile observations of evaporation ducts within typhoon interiors remain limited. This study investigated the evolution of evaporation duct height (EDH) during Typhoon Koinu (202314) through analysis of 108 hours of continuous observations by three clustered wave gliders. One glider traversed the typhoon eye, while the other two monitored regions of high wind speed (WS). The maximum recorded WS reached 26.5 m/s, accompanied by EDH of 11.9 m, whereas within the eye region, WS was 4.36 m/s with EDH of 5.7 m. The presence of the typhoon’s eye caused a 6.2-m reduction in EDH. Relative humidity (RH) fluctuated from 70% to 95% before the typhoon’s arrival and remained at around 90% during the typhoon’s passage. Correlation analysis indicated that RH was the dominant factor influencing EDH before the typhoon’s arrival, showing negative correlation (Spearman correlation coefficient: −0.83). In contrast, WS was the main driver of EDH variation during the typhoon’s passage, exhibiting strong positive correlation (Spearman correlation coefficient: 0.82). Sensitivity analysis confirmed that the inhibitory effect of elevated RH outweighed the contribution of high WS to EDH enhancement, leading to lower EDH values during the passage of the typhoon than in the pre-typhoon period. Analysis of the spatial distribution of EM wave propagation indicated that the low EDH induced by low WS in the typhoon’s eye caused PL that was 24 dB greater than under high-WS scenarios; overall, the presence of the typhoon’s eye caused greater PL.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"317 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153438","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 : 2026-02-10DOI: 10.3389/fmars.2026.1737002
Belén Martín Míguez, Emma Heslop, Narissa Bax, Lisandro Benedetti-Cecchi, Gabrielle Canonico, Kim Currie, Karen Evans, Albert S. Fischer, Véronique Garçon, Maria Hood, Johannes Karstensen, Ana Lara-López, David Legler, Frank E. Muller-Karger, Balakrishnan Nair Thayannur Mullachery, Lina Mtwana Nordlund, Artur P. Palacz, Joanna Post, Samantha E. Simmons, Sabrina Speich, Laura Stukonytė, Adrienne J. Sutton, Toste Tanhua, Maciej Telszewski, Karina von Schuckmann, Anya M. Waite, Weidong Yu
The need for ocean information has never been greater. From climate change to food security and extreme events, we need to understand the role of the ocean and better predict change and impact. This is only possible with the sustained collection of a key set of ocean observations. The Global Ocean Observing System (GOOS) coordinates international efforts to collect these Essential Ocean Variables (EOVs), which span physics, biogeochemistry, biology and ecosystem realms. Guided by three expert panels, these EOVs are used to define the needs and design of a sustained, fit for purpose global ocean observing system, aimed at maximizing investments in observing infrastructure. As the GOOS EOVs are increasingly used, it has become important to discuss and refine the understanding of this framework, to ensure that the right balance is struck between their essential nature and the need to expand to new domains and integrate with key global policies. In this paper we provide a description of the EOV framework, discuss some of the challenges in implementing it, and identify a set of recommendations for GOOS and the ocean observing community to take forward. These recommendations include increasing the transparency of the EOV adoption process, and the need to periodically assess the EOVs in consultation with observing communities and with the entities managing other global essential variable frameworks in cross cutting realms such as climate and biodiversity. This will contribute to building a useful and responsive global ocean observing system that delivers the observations required to meet societal needs.
{"title":"GOOS Essential Ocean Variables: the backbone of a sustained and evolving global ocean observing system","authors":"Belén Martín Míguez, Emma Heslop, Narissa Bax, Lisandro Benedetti-Cecchi, Gabrielle Canonico, Kim Currie, Karen Evans, Albert S. Fischer, Véronique Garçon, Maria Hood, Johannes Karstensen, Ana Lara-López, David Legler, Frank E. Muller-Karger, Balakrishnan Nair Thayannur Mullachery, Lina Mtwana Nordlund, Artur P. Palacz, Joanna Post, Samantha E. Simmons, Sabrina Speich, Laura Stukonytė, Adrienne J. Sutton, Toste Tanhua, Maciej Telszewski, Karina von Schuckmann, Anya M. Waite, Weidong Yu","doi":"10.3389/fmars.2026.1737002","DOIUrl":"https://doi.org/10.3389/fmars.2026.1737002","url":null,"abstract":"The need for ocean information has never been greater. From climate change to food security and extreme events, we need to understand the role of the ocean and better predict change and impact. This is only possible with the sustained collection of a key set of ocean observations. The Global Ocean Observing System (GOOS) coordinates international efforts to collect these Essential Ocean Variables (EOVs), which span physics, biogeochemistry, biology and ecosystem realms. Guided by three expert panels, these EOVs are used to define the needs and design of a sustained, fit for purpose global ocean observing system, aimed at maximizing investments in observing infrastructure. As the GOOS EOVs are increasingly used, it has become important to discuss and refine the understanding of this framework, to ensure that the right balance is struck between their essential nature and the need to expand to new domains and integrate with key global policies. In this paper we provide a description of the EOV framework, discuss some of the challenges in implementing it, and identify a set of recommendations for GOOS and the ocean observing community to take forward. These recommendations include increasing the transparency of the EOV adoption process, and the need to periodically assess the EOVs in consultation with observing communities and with the entities managing other global essential variable frameworks in cross cutting realms such as climate and biodiversity. This will contribute to building a useful and responsive global ocean observing system that delivers the observations required to meet societal needs.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"13 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153437","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 : 2026-02-09DOI: 10.3389/fmars.2026.1761703
Kristina M. Barclay, Helen J. Gurney-Smith, Mohamed Ahmed, James R. Christian, Frédéric Cyr, Patrick J. Duke, Brent G. T. Else, Iria Gimenez, Martine Lizotte, M. Catherine Reader, Myron Roth, Krysten Rutherford, Michel Starr, Nadja S. Steiner, Jessie Turner, David L. VanderZwaag, Wiley Evans
Ocean acidification (OA) generally receives far less consideration than other climate stressors and related hazards, such as global warming and extreme weather events. Canada is uniquely vulnerable to OA given its extensive coastal oceans, the oceanographic processes in its three basins, accelerated warming and sea-ice melt, and extensive coastal communities and maritime economic sectors. Canada’s coastline is also home to extensive and diverse First Nations peoples with distinct histories, rights, title, laws, governance and whose traditions and cultures are extrinsically linked to the sea. However, there are currently very limited pathways to support OA action, mitigation, and/or adaptation in Canada, particularly at the policy level. Here, we present a first synthesis of the current state of OA knowledge across Canada's Pacific, Arctic, and Atlantic regions, including monitoring, modelling, biological responses, socioeconomic and policy perspectives, and examples of existing OA actions and efforts at local and provincial levels. We also suggest a step-wise pathway for actions to enhance the coordinated filling of OA knowledge gaps and integration of OA knowledge into decision-making frameworks. The goals of these recommendations are to improve our ability to respond to OA in Canada, and minimize risks to coastal marine environments and ecosystems, vulnerable sectors, and communities.
{"title":"Ocean acidification in Canada: the current state of knowledge and pathways for action","authors":"Kristina M. Barclay, Helen J. Gurney-Smith, Mohamed Ahmed, James R. Christian, Frédéric Cyr, Patrick J. Duke, Brent G. T. Else, Iria Gimenez, Martine Lizotte, M. Catherine Reader, Myron Roth, Krysten Rutherford, Michel Starr, Nadja S. Steiner, Jessie Turner, David L. VanderZwaag, Wiley Evans","doi":"10.3389/fmars.2026.1761703","DOIUrl":"https://doi.org/10.3389/fmars.2026.1761703","url":null,"abstract":"Ocean acidification (OA) generally receives far less consideration than other climate stressors and related hazards, such as global warming and extreme weather events. Canada is uniquely vulnerable to OA given its extensive coastal oceans, the oceanographic processes in its three basins, accelerated warming and sea-ice melt, and extensive coastal communities and maritime economic sectors. Canada’s coastline is also home to extensive and diverse First Nations peoples with distinct histories, rights, title, laws, governance and whose traditions and cultures are extrinsically linked to the sea. However, there are currently very limited pathways to support OA action, mitigation, and/or adaptation in Canada, particularly at the policy level. Here, we present a first synthesis of the current state of OA knowledge across Canada's Pacific, Arctic, and Atlantic regions, including monitoring, modelling, biological responses, socioeconomic and policy perspectives, and examples of existing OA actions and efforts at local and provincial levels. We also suggest a step-wise pathway for actions to enhance the coordinated filling of OA knowledge gaps and integration of OA knowledge into decision-making frameworks. The goals of these recommendations are to improve our ability to respond to OA in Canada, and minimize risks to coastal marine environments and ecosystems, vulnerable sectors, and communities.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"35 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146101","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 : 2026-02-09DOI: 10.3389/fmars.2026.1733628
Min Wang, Shijun Zhang, M. Jahanzeb Butt, Khadija Zulfiqar
Recently, international judicial forums have issued landmark advisory opinions on the subject of the ocean–climate nexus. The opinions are based on the recognition of the interconnection between the United Nations Framework Convention on Climate Change (UNFCCC) and the United Nations Convention on the Law of the Sea (UNCLOS). All judicial forums stated that Small Island Developing States (SIDS) are a distinct focus due to their disproportionate vulnerability to climate change, as reported by the Intergovernmental Panel on Climate Change (IPCC). According to the opinions, SIDS could become uninhabitable in the coming years, necessitating urgent global climate action. The United Nations (UN) has acknowledged the unique challenges of SIDS through various resolutions, which emphasise the need for climate justice and adherence to the 1.5 C climate target. Sustainable Development Goal 14 (SDG 14) brought attention to the direct impacts of climate change on oceans and the issues faced by SIDS. This paper reviews the historical and legal developments necessary for the sustainable development of SIDS, emphasising the nexus between climate change, ocean governance, and human rights. It highlights the potential for further advocacy and the interconnected nature of SDG 14 with judicial opinions.
{"title":"Advisory opinion of the ITLOS on climate change and International Law on the Request of Small Island Developing States (SIDS): a Sustainable Development Goal - 14 (SDG 14) perspective","authors":"Min Wang, Shijun Zhang, M. Jahanzeb Butt, Khadija Zulfiqar","doi":"10.3389/fmars.2026.1733628","DOIUrl":"https://doi.org/10.3389/fmars.2026.1733628","url":null,"abstract":"Recently, international judicial forums have issued landmark advisory opinions on the subject of the ocean–climate nexus. The opinions are based on the recognition of the interconnection between the United Nations Framework Convention on Climate Change (UNFCCC) and the United Nations Convention on the Law of the Sea (UNCLOS). All judicial forums stated that Small Island Developing States (SIDS) are a distinct focus due to their disproportionate vulnerability to climate change, as reported by the Intergovernmental Panel on Climate Change (IPCC). According to the opinions, SIDS could become uninhabitable in the coming years, necessitating urgent global climate action. The United Nations (UN) has acknowledged the unique challenges of SIDS through various resolutions, which emphasise the need for climate justice and adherence to the 1.5 C climate target. Sustainable Development Goal 14 (SDG 14) brought attention to the direct impacts of climate change on oceans and the issues faced by SIDS. This paper reviews the historical and legal developments necessary for the sustainable development of SIDS, emphasising the nexus between climate change, ocean governance, and human rights. It highlights the potential for further advocacy and the interconnected nature of SDG 14 with judicial opinions.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"314 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146100","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}
Introduction The microbiome is crucial for the health and resilience of marine species; however, in most cases its complexity and host-specific dynamics remain poorly understood. Methods This study provides a multi-year and multi-seasonal analysis of eukaryotic and prokaryotic microbiomes in three ecologically important bivalves - mussels ( Mytilus galloprovincialis ), clams ( Ruditapes philippinarum ), and cockles ( Cerastoderma edule ) – coexisting within the same coastal ecosystem in the Rı́a of Vigo (NW Spain). Results High-throughput sequencing of the V9 region of 18S rRNA and the V4 region of 16S rRNA genes revealed distinct microbiomes for each bivalve species, demonstrating significant host specificity and a stable microbial composition across seasons. Prevalent eukaryotic parasites, including Mytilicola intestinalis in mussels and trematodes such as Bucephalus minimus in cockles, were identified. Perkinsus olseni and Marteilia cochilia , protozoans associated with bivalve mortality and ecosystem disruption under environmental stress, were also detected. Endozoicomonas and Vibrio dominated the prokaryotic communities of all the three bivalves; however, species-specific bacteriomes were observed due to the presence of other distinct taxa. A meta-analysis comparing bivalve and environmental microbiomes, revealed that despite the microbial diversity in the water column and sediment, each bivalve maintained its own stable and specific microbiome, exceeding the habitat effect. We identified Vibrio, Woeseia and Lutimonas as keystone genera that shape these microbiomes through both competitive and cooperative interactions. Functional predictions suggest that mutualistic relationships enhance host health through metabolic and defensive roles, including the biosynthesis of secondary metabolites. Conclusion These findings demonstrate that host identity is the primary determinant of bivalve microbiome composition, with different keystone taxa that could serve as biomarkers for ecosystem and health monitoring in Rı́a de Vigo.
微生物群对海洋物种的健康和复原力至关重要；然而，在大多数情况下，其复杂性和宿主特有的动态仍然知之甚少。本研究对三种生态上重要的双壳类——贻贝（Mytilus galloprovincialis）、蛤蜊（Ruditapes philippinarum）和蛤贝（Cerastoderma edule）——共存于西班牙西北部维哥河沿岸的同一生态系统中的真核和原核微生物群进行了多年和多季节的分析。结果对18S rRNA基因的V9区和16S rRNA基因的V4区进行高通量测序，发现不同双壳类动物的微生物组不同，具有明显的宿主特异性和不同季节稳定的微生物组成。发现了常见的真核寄生虫，包括贻贝中的肠密螺旋体和贝蛤中的小Bucephalus等吸虫。在环境胁迫下，还发现了与双壳类动物死亡和生态系统破坏相关的原生动物——奥氏珀金苏斯（Perkinsus olseni）和辣椒马提利亚（Marteilia cochilia）。三种双壳类动物的原核生物群落均以内生单胞菌和弧菌为主；然而，由于存在其他不同的分类群，因此观察到物种特异性细菌组。对双壳类与环境微生物组的meta分析表明，尽管水体和沉积物中的微生物多样性，但每种双壳类都保持了自己稳定和特定的微生物组，超过了栖息地效应。我们确定弧菌，Woeseia和Lutimonas是通过竞争和合作相互作用塑造这些微生物群的关键属。功能预测表明，互惠关系通过代谢和防御作用（包括次生代谢物的生物合成）增强宿主健康。结论宿主身份是双壳类微生物组成的主要决定因素，不同的关键类群可作为rbi - a de Vigo生态系统和健康监测的生物标志物。
{"title":"Unveiling the specific microbiome of bivalves: insights into host microbial dynamics and pathogen interactions in a shared environment","authors":"Miriam Muñoz-Martínez, Magalí Rey-Campos, Raquel Aranguren, Raquel Ríos-Castro, Beatriz Novoa, Antonio Figueras","doi":"10.3389/fmars.2026.1731630","DOIUrl":"https://doi.org/10.3389/fmars.2026.1731630","url":null,"abstract":"Introduction The microbiome is crucial for the health and resilience of marine species; however, in most cases its complexity and host-specific dynamics remain poorly understood. Methods This study provides a multi-year and multi-seasonal analysis of eukaryotic and prokaryotic microbiomes in three ecologically important bivalves - mussels ( <jats:italic>Mytilus galloprovincialis</jats:italic> ), clams ( <jats:italic>Ruditapes philippinarum</jats:italic> ), and cockles ( <jats:italic>Cerastoderma edule</jats:italic> ) – coexisting within the same coastal ecosystem in the Rı́a of Vigo (NW Spain). Results High-throughput sequencing of the V9 region of 18S rRNA and the V4 region of 16S rRNA genes revealed distinct microbiomes for each bivalve species, demonstrating significant host specificity and a stable microbial composition across seasons. Prevalent eukaryotic parasites, including <jats:italic>Mytilicola intestinalis</jats:italic> in mussels and trematodes such as <jats:italic>Bucephalus minimus</jats:italic> in cockles, were identified. <jats:italic>Perkinsus olseni</jats:italic> and <jats:italic>Marteilia cochilia</jats:italic> , protozoans associated with bivalve mortality and ecosystem disruption under environmental stress, were also detected. <jats:italic>Endozoicomonas</jats:italic> and <jats:italic>Vibrio</jats:italic> dominated the prokaryotic communities of all the three bivalves; however, species-specific bacteriomes were observed due to the presence of other distinct taxa. A meta-analysis comparing bivalve and environmental microbiomes, revealed that despite the microbial diversity in the water column and sediment, each bivalve maintained its own stable and specific microbiome, exceeding the habitat effect. We identified <jats:italic>Vibrio, Woeseia</jats:italic> and <jats:italic>Lutimonas</jats:italic> as keystone genera that shape these microbiomes through both competitive and cooperative interactions. Functional predictions suggest that mutualistic relationships enhance host health through metabolic and defensive roles, including the biosynthesis of secondary metabolites. Conclusion These findings demonstrate that host identity is the primary determinant of bivalve microbiome composition, with different keystone taxa that could serve as biomarkers for ecosystem and health monitoring in Rı́a de Vigo.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"88 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146099","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 : 2026-02-09DOI: 10.3389/fmars.2025.1687771
Chen Li, Chengxi Yin, Pengcheng Wang
The development of marine fisheries is critical to China’s food security and national livelihoods, although many fishermen face limited income growth due to resource and operational constraints. Smart fishery technologies have the potential to transform production and increase fishermen’s income, yet their socio-economic impacts remain underexplored. Using panel data from China’s marine fisheries (2011–2023), this paper empirically examines the impact of fishery intelligence on fishermen’s income. The results show that fishery intelligence significantly increases income by promoting technological progress, improving talent quality, and enhancing ecological conditions. This positive effect is stronger in regions with higher levels of regional fisheries innovation. Heterogeneity analysis indicates that income growth is significant in southern regions, large-scale fisheries, and areas with high trade volumes, while it is insignificant in northern regions, small-scale operations, and areas with low trade volumes. These findings suggest that policymakers should prioritize smart fishery adoption, invest in training programs to enhance fishermen’s skills, support ecological management, and implement region-specific interventions to promote high-quality development in marine fisheries.
{"title":"Promoting or inhibiting? The impact of smart fishery on fishermen’s income in China’s marine fisheries","authors":"Chen Li, Chengxi Yin, Pengcheng Wang","doi":"10.3389/fmars.2025.1687771","DOIUrl":"https://doi.org/10.3389/fmars.2025.1687771","url":null,"abstract":"The development of marine fisheries is critical to China’s food security and national livelihoods, although many fishermen face limited income growth due to resource and operational constraints. Smart fishery technologies have the potential to transform production and increase fishermen’s income, yet their socio-economic impacts remain underexplored. Using panel data from China’s marine fisheries (2011–2023), this paper empirically examines the impact of fishery intelligence on fishermen’s income. The results show that fishery intelligence significantly increases income by promoting technological progress, improving talent quality, and enhancing ecological conditions. This positive effect is stronger in regions with higher levels of regional fisheries innovation. Heterogeneity analysis indicates that income growth is significant in southern regions, large-scale fisheries, and areas with high trade volumes, while it is insignificant in northern regions, small-scale operations, and areas with low trade volumes. These findings suggest that policymakers should prioritize smart fishery adoption, invest in training programs to enhance fishermen’s skills, support ecological management, and implement region-specific interventions to promote high-quality development in marine fisheries.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"60 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146104","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 : 2026-02-06DOI: 10.3389/fmars.2026.1752067
Lara Maleen Beckmann, Lova Eveborn, Ellen Kenchington, Rhian G. Waller
The Corner Rise Seamounts (CRS), located in an area beyond national jurisdiction (ABNJ), are recognized biodiversity hotspots protected from bottom-contact fishing by the Northwest Atlantic Fisheries Organization (NAFO). These seamounts are registered as an Other Effective Area-Based Conservation Measure. The Western Central Atlantic Fisheries Commission (WECAFC) has also recommended protection for the southern CRS. While Vulnerable Marine Ecosystem (VME) indicators like corals and sponges are known to occur here, the environmental drivers of their distribution and the status of structure-forming VME habitats remain poorly characterized. We analyzed high-resolution remotely-operated vehicle video from NOAA’s 2021 Okeanos Explorer expedition across eight CRS (940-4,189 m depth). Coral and sponge community composition was assessed using multivariate analysis, and VMEs were identified using internationally recognized spatial criteria. Community structure was primarily driven by depth-related oceanographic gradients, with secondary longitudinal zonation. Assemblages formed three distinct clusters on the seamounts: (1) upper-mid bathyal sites (900-1,900 m) influenced by upper intermediate North Atlantic waters; (2) lower bathyal sites (2,000-2,600 m) associated with Labrador Sea Water; and (3) an abyssal site on Rockaway Seamount (~4,100 m) under Denmark Strait Overflow Water influence. Six habitats down to 2,495 m depth met VME indicator density thresholds for significant concentrations. Our results demonstrate that depth and water mass structure are key drivers of coral and sponge biogeography on the CRS. VME identification provides scientific support for maintaining existing NAFO and WECAFC closures. With NAFO protections due for review in 2027, these findings offer timely evidence to inform conservation and management decisions for CRS and similar ABNJ seamount ecosystems.
{"title":"Hotspots beyond borders: quantitative assessment of Vulnerable Marine Ecosystems on the Corner Rise seamounts with implications for conservation planning","authors":"Lara Maleen Beckmann, Lova Eveborn, Ellen Kenchington, Rhian G. Waller","doi":"10.3389/fmars.2026.1752067","DOIUrl":"https://doi.org/10.3389/fmars.2026.1752067","url":null,"abstract":"The Corner Rise Seamounts (CRS), located in an area beyond national jurisdiction (ABNJ), are recognized biodiversity hotspots protected from bottom-contact fishing by the Northwest Atlantic Fisheries Organization (NAFO). These seamounts are registered as an Other Effective Area-Based Conservation Measure. The Western Central Atlantic Fisheries Commission (WECAFC) has also recommended protection for the southern CRS. While Vulnerable Marine Ecosystem (VME) indicators like corals and sponges are known to occur here, the environmental drivers of their distribution and the status of structure-forming VME habitats remain poorly characterized. We analyzed high-resolution remotely-operated vehicle video from NOAA’s 2021 Okeanos Explorer expedition across eight CRS (940-4,189 m depth). Coral and sponge community composition was assessed using multivariate analysis, and VMEs were identified using internationally recognized spatial criteria. Community structure was primarily driven by depth-related oceanographic gradients, with secondary longitudinal zonation. Assemblages formed three distinct clusters on the seamounts: (1) upper-mid bathyal sites (900-1,900 m) influenced by upper intermediate North Atlantic waters; (2) lower bathyal sites (2,000-2,600 m) associated with Labrador Sea Water; and (3) an abyssal site on Rockaway Seamount (~4,100 m) under Denmark Strait Overflow Water influence. Six habitats down to 2,495 m depth met VME indicator density thresholds for significant concentrations. Our results demonstrate that depth and water mass structure are key drivers of coral and sponge biogeography on the CRS. VME identification provides scientific support for maintaining existing NAFO and WECAFC closures. With NAFO protections due for review in 2027, these findings offer timely evidence to inform conservation and management decisions for CRS and similar ABNJ seamount ecosystems.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"87 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121858","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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