Pub Date : 2026-02-02DOI: 10.3389/fmars.2026.1572290
Hope Hunter, Chidong Zhang, Dongxiao Zhang, Hannah M. Horowitz
Air-sea fluxes have rarely or never been estimated from in situ observations in many parts of the global oceans, especially in the Arctic, despite their critical roles in weather and climate. In consequence, their reproductions by numerical models have seldomly been validated against observations. In this study, observations from Saildrone Explorer uncrewed surface vehicles are used to validate surface sensible and latent heat fluxes from GFS deterministic forecasts and GEFS ensemble forecasts in the Arctic during May – October 2019. The most striking result from this study is the low biases in sea surface temperature (SST) in the initial conditions of both the deterministic and ensemble forecasts. Excessively cold predictions of SST lead to reversed signs in air-sea differences in temperature and humidity in comparison to the observations. Consequently, surface sensible and latent heat fluxes in the forecast can be negative (from air into the water), while observed fluxes are positive. The larger SST biases at the initial time og the GEFS ensemble forecasts is the main reason for their underperformance in comparison to the GFS deterministic forecasts. The results clearly demonstrate the vital step of improving forecasts in the Arctic is to prepare for accurate initial conditions of SST.
{"title":"Validation of forecasted surface sensible and latent heat fluxes by GFS and GEFS against saildrone observations in the Arctic","authors":"Hope Hunter, Chidong Zhang, Dongxiao Zhang, Hannah M. Horowitz","doi":"10.3389/fmars.2026.1572290","DOIUrl":"https://doi.org/10.3389/fmars.2026.1572290","url":null,"abstract":"Air-sea fluxes have rarely or never been estimated from <jats:italic>in situ</jats:italic> observations in many parts of the global oceans, especially in the Arctic, despite their critical roles in weather and climate. In consequence, their reproductions by numerical models have seldomly been validated against observations. In this study, observations from Saildrone Explorer uncrewed surface vehicles are used to validate surface sensible and latent heat fluxes from GFS deterministic forecasts and GEFS ensemble forecasts in the Arctic during May – October 2019. The most striking result from this study is the low biases in sea surface temperature (SST) in the initial conditions of both the deterministic and ensemble forecasts. Excessively cold predictions of SST lead to reversed signs in air-sea differences in temperature and humidity in comparison to the observations. Consequently, surface sensible and latent heat fluxes in the forecast can be negative (from air into the water), while observed fluxes are positive. The larger SST biases at the initial time og the GEFS ensemble forecasts is the main reason for their underperformance in comparison to the GFS deterministic forecasts. The results clearly demonstrate the vital step of improving forecasts in the Arctic is to prepare for accurate initial conditions of SST.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"396 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101377","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 : 2026-02-02DOI: 10.3389/fmars.2025.1666791
Sivakamavalli Jeyachandran, Mohammed Aman
In this review, the potentials of jellyfish-based plastics as an alternative to conventional plastics are looked at principally regarding their use at sea. The collagen and additional biopolymers extracted from jellyfish have distinct physical and chemical properties i.e., biodegradability, toughness, and can blend with the environment, which enables it to manufacture green material to substitute the plastic fillers found in the ocean. In the review, what is known about jellyfish biomolecules is summarized, their properties studied, and how these biomolecules are subjected to biodegradation in marine ecosystems, as well as their use to package, create fishing gear, marine sensors, and agrochemical release controls in aquaculture, is discussed. The effect of environmental factors on the degradation, useful life cycle and large-scale production and regulation challenges are also examined. This review applies the concepts of material science, marine biotechnology, and environmental policies to suggest significant research gaps, as well as describe potential new concepts that can support the application of jellyfish-derived bioplastics to create marine and environmental sustainability.
{"title":"Jellyfish-derived bioplastics: properties, degradation, and marine applications","authors":"Sivakamavalli Jeyachandran, Mohammed Aman","doi":"10.3389/fmars.2025.1666791","DOIUrl":"https://doi.org/10.3389/fmars.2025.1666791","url":null,"abstract":"In this review, the potentials of jellyfish-based plastics as an alternative to conventional plastics are looked at principally regarding their use at sea. The collagen and additional biopolymers extracted from jellyfish have distinct physical and chemical properties i.e., biodegradability, toughness, and can blend with the environment, which enables it to manufacture green material to substitute the plastic fillers found in the ocean. In the review, what is known about jellyfish biomolecules is summarized, their properties studied, and how these biomolecules are subjected to biodegradation in marine ecosystems, as well as their use to package, create fishing gear, marine sensors, and agrochemical release controls in aquaculture, is discussed. The effect of environmental factors on the degradation, useful life cycle and large-scale production and regulation challenges are also examined. This review applies the concepts of material science, marine biotechnology, and environmental policies to suggest significant research gaps, as well as describe potential new concepts that can support the application of jellyfish-derived bioplastics to create marine and environmental sustainability.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"96 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101446","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 : 2026-02-02DOI: 10.3389/fmars.2026.1752602
Yihan Wang
Focusing water waves is a potential technology improving the power generation of wave energy converters. Two semi-ellipsoidal reflectors, including long-axis opening and short-axis opening, were adopted to investigate the water-wave focusing effects. A 3D numerical wave tank was built and solved using the computational fluid dynamics (CFD) method. First, the wave fields around the reflectors against different wave periods were calculated. Furthermore, the wave elevation at monitoring locations of the reflectors against different wave steepness was investigated. Results demonstrate that the number of focusing points of the long-axis opening is more than that of the short-axis opening for short wave periods. The locations of focusing points move with the change of wave periods. However, for long wave periods, the waves can be focused over a large area in front of the reflector. The wave height at the focusing area overall becomes smaller with the increase in the wave periods. Additionally, the wave steepness has insignificant effects on the dimensionless wave height.
{"title":"Water-waves focusing by an elliptical reflector","authors":"Yihan Wang","doi":"10.3389/fmars.2026.1752602","DOIUrl":"https://doi.org/10.3389/fmars.2026.1752602","url":null,"abstract":"Focusing water waves is a potential technology improving the power generation of wave energy converters. Two semi-ellipsoidal reflectors, including long-axis opening and short-axis opening, were adopted to investigate the water-wave focusing effects. A 3D numerical wave tank was built and solved using the computational fluid dynamics (CFD) method. First, the wave fields around the reflectors against different wave periods were calculated. Furthermore, the wave elevation at monitoring locations of the reflectors against different wave steepness was investigated. Results demonstrate that the number of focusing points of the long-axis opening is more than that of the short-axis opening for short wave periods. The locations of focusing points move with the change of wave periods. However, for long wave periods, the waves can be focused over a large area in front of the reflector. The wave height at the focusing area overall becomes smaller with the increase in the wave periods. Additionally, the wave steepness has insignificant effects on the dimensionless wave height.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"41 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101449","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 : 2026-01-30DOI: 10.3389/fmars.2026.1771442
Qiang Song, Jiasheng Wang, Thomas J. Algeo, Liyuan Xu, Can Chen, Zhou Wang, Cong Cheng, Kunlong Geng, Qing Li
Framboidal pyrite, a common form of authigenic pyrite in marine sediments, forms through the co-precipitation of equant, equidimensional microcrystals that can effectively sequester trace elements. Nevertheless, the relationships among key attributes of framboids (i.e., framboid size, microcrystal dimensions, and number of microcrystals) and the detailed mechanisms of trace−element enrichment within framboids are not yet well understood. To address this gap, we present a dataset encompassing framboid key attributes, sulfur isotopes, and trace−element (Ni, Mo) concentrations from two gas−hydrate−bearing drillsites (GMGS4−SC−W02B and GMGS4−SC−W03B) in the Shenhu area, Pearl River Mouth Basin, South China Sea. In this methane−seep−influenced setting, framboid size is primarily controlled by microcrystal diameter and secondarily by microcrystal abundance. Nickel enrichment in framboidal pyrite follows a two−stage mechanism. Initially, Ni is taken up into FeS precursors before being incorporated into pyrite via isomorphous substitution on {111} microcrystal surfaces during framboid growth. This results in a strong positive correlation with microcrystal size (R² = 0.73, p < 0.001) rather than with their number (R 2 = 0.18, p = 0.02). In contrast, Mo content shows positive correlations with both framboid size and microcrystal abundance (R² = 0.66, p < 0.01 and R² = 0.42, p = 0.01, respectively), consistent with its incorporation as nano−inclusions or nanoparticles within the pyrite lattice. The enrichment of both elements initiates from the strong adsorption capacity of iron monosulfide precursors. In methane release environments, enhanced anaerobic oxidation of methane facilitates the conversion of molybdate to particle-reactive thiomolybdates, which are effectively captured by growing pyrite framboids. Nickel, on the other hand, benefits from the increase in microcrystalline surface area during growth, where it replaces exposed Fe 2+ through isomorphic substitution, leading to enrichment on microcrystal surfaces. This study advances the mechanistic understanding of trace−element incorporation in framboidal pyrite, and these findings strengthen the reliability of nickel and molybdenum as robust proxies for reconstructing paleoenvironmental conditions and paleo-methane release activity.
{"title":"Ni and Mo enrichment mechanisms in framboidal pyrite during methane-release events (Baiyun Sag, South China Sea)","authors":"Qiang Song, Jiasheng Wang, Thomas J. Algeo, Liyuan Xu, Can Chen, Zhou Wang, Cong Cheng, Kunlong Geng, Qing Li","doi":"10.3389/fmars.2026.1771442","DOIUrl":"https://doi.org/10.3389/fmars.2026.1771442","url":null,"abstract":"Framboidal pyrite, a common form of authigenic pyrite in marine sediments, forms through the co-precipitation of equant, equidimensional microcrystals that can effectively sequester trace elements. Nevertheless, the relationships among key attributes of framboids (i.e., framboid size, microcrystal dimensions, and number of microcrystals) and the detailed mechanisms of trace−element enrichment within framboids are not yet well understood. To address this gap, we present a dataset encompassing framboid key attributes, sulfur isotopes, and trace−element (Ni, Mo) concentrations from two gas−hydrate−bearing drillsites (GMGS4−SC−W02B and GMGS4−SC−W03B) in the Shenhu area, Pearl River Mouth Basin, South China Sea. In this methane−seep−influenced setting, framboid size is primarily controlled by microcrystal diameter and secondarily by microcrystal abundance. Nickel enrichment in framboidal pyrite follows a two−stage mechanism. Initially, Ni is taken up into FeS precursors before being incorporated into pyrite via isomorphous substitution on {111} microcrystal surfaces during framboid growth. This results in a strong positive correlation with microcrystal size (R² = 0.73, <jats:italic>p</jats:italic> &lt; 0.001) rather than with their number (R <jats:sup>2</jats:sup> = 0.18, <jats:italic>p</jats:italic> = 0.02). In contrast, Mo content shows positive correlations with both framboid size and microcrystal abundance (R² = 0.66, <jats:italic>p</jats:italic> &lt; 0.01 and R² = 0.42, <jats:italic>p</jats:italic> = 0.01, respectively), consistent with its incorporation as nano−inclusions or nanoparticles within the pyrite lattice. The enrichment of both elements initiates from the strong adsorption capacity of iron monosulfide precursors. In methane release environments, enhanced anaerobic oxidation of methane facilitates the conversion of molybdate to particle-reactive thiomolybdates, which are effectively captured by growing pyrite framboids. Nickel, on the other hand, benefits from the increase in microcrystalline surface area during growth, where it replaces exposed Fe <jats:sup>2+</jats:sup> through isomorphic substitution, leading to enrichment on microcrystal surfaces. This study advances the mechanistic understanding of trace−element incorporation in framboidal pyrite, and these findings strengthen the reliability of nickel and molybdenum as robust proxies for reconstructing paleoenvironmental conditions and paleo-methane release activity.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"67 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095963","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 : 2026-01-30DOI: 10.3389/fmars.2026.1735326
Abdulkarim K. Alhowaish
Introduction The blue economy has emerged as a strategic framework for aligning marine-based economic development with environmental sustainability and social equity. Empirical evidence from arid and industrialized coastal regions, however, remains limited. Methods This study employs a convergent mixed-methods design using a structured questionnaire administered to 404 stakeholders across the Eastern Province coastline of Saudi Arabia, complemented by qualitative open-ended responses. Quantitative analyses included descriptive statistics, exploratory factor analysis, and regression modeling, while qualitative data were thematically analyzed. Results Results indicate strong stakeholder support for blue economy development, particularly in fisheries, aquaculture, tourism, and logistics. Two core dimensions, perceived opportunities and perceived constraints, significantly influence stakeholder support. Institutional fragmentation, environmental degradation, and weak regulatory enforcement emerged as key barriers. Discussion Findings reveal a dual governance dynamic characterized by high economic optimism alongside institutional and environmental concerns. Strengthening coordination, participation, and regulatory enforcement is essential for sustainable blue economy governance in arid coastal regions.
{"title":"Governing the blue economy in arid coastal regions: opportunities, constraints, and stakeholder perspectives from the Eastern Province coast of Saudi Arabia","authors":"Abdulkarim K. Alhowaish","doi":"10.3389/fmars.2026.1735326","DOIUrl":"https://doi.org/10.3389/fmars.2026.1735326","url":null,"abstract":"Introduction The blue economy has emerged as a strategic framework for aligning marine-based economic development with environmental sustainability and social equity. Empirical evidence from arid and industrialized coastal regions, however, remains limited. Methods This study employs a convergent mixed-methods design using a structured questionnaire administered to 404 stakeholders across the Eastern Province coastline of Saudi Arabia, complemented by qualitative open-ended responses. Quantitative analyses included descriptive statistics, exploratory factor analysis, and regression modeling, while qualitative data were thematically analyzed. Results Results indicate strong stakeholder support for blue economy development, particularly in fisheries, aquaculture, tourism, and logistics. Two core dimensions, perceived opportunities and perceived constraints, significantly influence stakeholder support. Institutional fragmentation, environmental degradation, and weak regulatory enforcement emerged as key barriers. Discussion Findings reveal a dual governance dynamic characterized by high economic optimism alongside institutional and environmental concerns. Strengthening coordination, participation, and regulatory enforcement is essential for sustainable blue economy governance in arid coastal regions.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"290 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095969","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 : 2026-01-30DOI: 10.3389/fmars.2026.1746235
Øystein Langangen, Stein Kaartvedt, Ketil Hylland, Joël M. Durant
Coastal fish populations in temperate regions increasingly experience environmental pressures and dramatic decreases in stock size. Currently, there are serious concerns about the status of the Atlantic cod ( Gadus morhua ) in the Oslofjord region, a 120-km inlet in southeastern Norway. Given the recent political debate, the large public interest, and the recent decision to close large areas in the Oslofjord to all fishing, the scarcity of quantitative estimates on cod biomass in the region presents an acute challenge. Typically, the state of the cod in the Oslofjord has been assessed by the analysis of juvenile fish datasets. However, scientific surveys targeting adult life stages are limited, and abundance and biomass estimates are based on relatively short time series and with limited spatial coverage. Here, we demonstrate how commercial landings data can be used to describe a recent decline in catch per unit effort in the region, a proxy related to biomass. These results are highly topical and can serve as a baseline for further investigations on the reasons for the collapse of the cod population. While our results demonstrate the value of the large commercial dataset, the introduction of conservation actions calls for alternative and more comprehensive monitoring in the area for documenting a potential future recovery. Our results highlight research and data needs associated with current efforts to improve the status of fish stocks in general, and the Atlantic cod in the Oslofjord in particular.
{"title":"The collapse of Atlantic cod in the Oslofjord","authors":"Øystein Langangen, Stein Kaartvedt, Ketil Hylland, Joël M. Durant","doi":"10.3389/fmars.2026.1746235","DOIUrl":"https://doi.org/10.3389/fmars.2026.1746235","url":null,"abstract":"Coastal fish populations in temperate regions increasingly experience environmental pressures and dramatic decreases in stock size. Currently, there are serious concerns about the status of the Atlantic cod ( <jats:italic>Gadus morhua</jats:italic> ) in the Oslofjord region, a 120-km inlet in southeastern Norway. Given the recent political debate, the large public interest, and the recent decision to close large areas in the Oslofjord to all fishing, the scarcity of quantitative estimates on cod biomass in the region presents an acute challenge. Typically, the state of the cod in the Oslofjord has been assessed by the analysis of juvenile fish datasets. However, scientific surveys targeting adult life stages are limited, and abundance and biomass estimates are based on relatively short time series and with limited spatial coverage. Here, we demonstrate how commercial landings data can be used to describe a recent decline in catch per unit effort in the region, a proxy related to biomass. These results are highly topical and can serve as a baseline for further investigations on the reasons for the collapse of the cod population. While our results demonstrate the value of the large commercial dataset, the introduction of conservation actions calls for alternative and more comprehensive monitoring in the area for documenting a potential future recovery. Our results highlight research and data needs associated with current efforts to improve the status of fish stocks in general, and the Atlantic cod in the Oslofjord in particular.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"58 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095961","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 : 2026-01-30DOI: 10.3389/fmars.2026.1685780
Konstantinos Touloumis, Athanassios C. Tsikliras, Donna Dimarchopoulou
Overfishing remains widespread in European seas, and the 2020 sustainability objectives under the Common Fisheries Policy (CFP) have not been fully met, leaving many stocks outside safe biological limits. At the same time, management must also ensure economic viability for fishing fleets, highlighting the need to quantify trade-offs between stock recovery and fleet profitability. Building on previous research, we assess 220 fish and invertebrate stocks across eight ecoregions, providing higher spatial resolution than previous analyses. Using a surplus-production framework, we model biomass and profitability trajectories under alternative exploitation scenarios. Results show that reducing fishing mortality to moderate exploitation patterns produces the most robust improvements in profitability across regions, while also supporting biomass rebuilding. However, the magnitude and timing of these effects vary geographically: northeast Atlantic regions start from higher baseline stock status but exhibit more modest marginal gains, whereas Mediterranean and Black Sea regions, despite poorer initial conditions, display stronger rebuilding potential and larger relative improvements once fishing pressure is reduced, with pronounced heterogeneity among subregions. These findings suggest that moderate exploitation reductions can yield long-term economic gains, though transitional costs and ecosystem constraints may limit near-term feasibility. Our results have direct relevance for region-specific European Union (EU) management, indicating where existing multiannual plans may require complementary measures to align biological sustainability with fleet profitability. We conclude that spatially resolved bioeconomic assessments can inform adaptive management and support progress toward both ecological and socioeconomic objectives under the CFP and associated frameworks.
{"title":"Revisiting rebuilding options of European fisheries","authors":"Konstantinos Touloumis, Athanassios C. Tsikliras, Donna Dimarchopoulou","doi":"10.3389/fmars.2026.1685780","DOIUrl":"https://doi.org/10.3389/fmars.2026.1685780","url":null,"abstract":"Overfishing remains widespread in European seas, and the 2020 sustainability objectives under the Common Fisheries Policy (CFP) have not been fully met, leaving many stocks outside safe biological limits. At the same time, management must also ensure economic viability for fishing fleets, highlighting the need to quantify trade-offs between stock recovery and fleet profitability. Building on previous research, we assess 220 fish and invertebrate stocks across eight ecoregions, providing higher spatial resolution than previous analyses. Using a surplus-production framework, we model biomass and profitability trajectories under alternative exploitation scenarios. Results show that reducing fishing mortality to moderate exploitation patterns produces the most robust improvements in profitability across regions, while also supporting biomass rebuilding. However, the magnitude and timing of these effects vary geographically: northeast Atlantic regions start from higher baseline stock status but exhibit more modest marginal gains, whereas Mediterranean and Black Sea regions, despite poorer initial conditions, display stronger rebuilding potential and larger relative improvements once fishing pressure is reduced, with pronounced heterogeneity among subregions. These findings suggest that moderate exploitation reductions can yield long-term economic gains, though transitional costs and ecosystem constraints may limit near-term feasibility. Our results have direct relevance for region-specific European Union (EU) management, indicating where existing multiannual plans may require complementary measures to align biological sustainability with fleet profitability. We conclude that spatially resolved bioeconomic assessments can inform adaptive management and support progress toward both ecological and socioeconomic objectives under the CFP and associated frameworks.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"16 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095962","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 : 2026-01-30DOI: 10.3389/fmars.2025.1677103
Ariell Friedman, Jacquomo Monk, Oscar Pizarro, Dhugal Lindsay, Elizabeth Oh, Blair Thornton, Andrew Carroll, Rachel Przeslawski, Stefan Williams
The rapid growth of marine imaging has outpaced our ability to efficiently analyse the imagery, creating challenges in data management, collaboration, and standardisation. This paper presents Squidle+, a web-based, collaborative platform for the end-to-end management, delivery, discovery, and annotation of marine imagery. Squidle+ provides a centralised portal and annotation repository while linking to imagery hosted on pre-existing cloud storage, eliminating data transfer and duplication. The system features a user-friendly interface with map-based exploration tools, advanced annotation workflows, and integrated analytics through a comprehensive API back-end. Collaboration is managed through user groups with granular permissions, while integrated QA/QC tools enable cross-validation between human annotators and Machine Learning (ML) algorithms. A key innovation is a framework to translate between multiple standardised or user-defined annotation vocabularies. This gives users the flexibility to construct data sets that target specific scientific questions and facilitates data reuse, cross-project syntheses, large-scale ML training, and broad summaries that can be fed into national-level reporting. Squidle+ has been developed in close collaboration with an active user community and currently contains datasets from several platforms and operators around the world. It is currently the largest known repository of openly accessible georeferenced marine images with associated annotations. Squidle+ streamlines complex workflows and significantly enhances the Findability, Accessibility, Interoperability, and Reusability (FAIR) of marine image data.
{"title":"Squidle+: a collaborative platform to manage, discover and annotate marine imagery","authors":"Ariell Friedman, Jacquomo Monk, Oscar Pizarro, Dhugal Lindsay, Elizabeth Oh, Blair Thornton, Andrew Carroll, Rachel Przeslawski, Stefan Williams","doi":"10.3389/fmars.2025.1677103","DOIUrl":"https://doi.org/10.3389/fmars.2025.1677103","url":null,"abstract":"The rapid growth of marine imaging has outpaced our ability to efficiently analyse the imagery, creating challenges in data management, collaboration, and standardisation. This paper presents Squidle+, a web-based, collaborative platform for the end-to-end management, delivery, discovery, and annotation of marine imagery. Squidle+ provides a centralised portal and annotation repository while linking to imagery hosted on pre-existing cloud storage, eliminating data transfer and duplication. The system features a user-friendly interface with map-based exploration tools, advanced annotation workflows, and integrated analytics through a comprehensive API back-end. Collaboration is managed through user groups with granular permissions, while integrated QA/QC tools enable cross-validation between human annotators and Machine Learning (ML) algorithms. A key innovation is a framework to translate between multiple standardised or user-defined annotation vocabularies. This gives users the flexibility to construct data sets that target specific scientific questions and facilitates data reuse, cross-project syntheses, large-scale ML training, and broad summaries that can be fed into national-level reporting. Squidle+ has been developed in close collaboration with an active user community and currently contains datasets from several platforms and operators around the world. It is currently the largest known repository of openly accessible georeferenced marine images with associated annotations. Squidle+ streamlines complex workflows and significantly enhances the Findability, Accessibility, Interoperability, and Reusability (FAIR) of marine image data.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"23 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095966","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 : 2026-01-30DOI: 10.3389/fmars.2026.1756144
Seong In Na, Hye Jin Seo, Se Hyeon Jang
Stratified marine systems are often characterized by a deep chlorophyll maximum (DCM); however, the taxonomic and functional dynamics of protist assemblages within this layer remain poorly understood. We integrated microscopy, pigment-based CHEMTAX analysis, 18S rRNA metabarcoding, and metatranscriptomics to compare protist communities in the surface and DCM layers of the northeastern East China Sea. Microscopy and pigment data revealed higher cell abundances, increased chlorophyll- a levels, and distinct pigment signatures at the DCM, particularly for haptophytes, chlorophytes, and pelagophytes. Amplicon sequencing revealed increased representation of chlorophyte and Syndiniales at depth, whereas metatranscriptomic profiles showed elevated transcriptional activity in diatoms, dinoflagellates, and chlorophytes. Functional gene analyses revealed DCM-specific upregulation of photosystem I subunits, light-harvesting complex proteins, and nitrogen assimilation pathways, indicating photoacclimation and nutrient exploitation under low-light, nutrient-rich conditions. Syndiniales were abundant in DNA-based data but mostly transcriptionally inactive, suggesting dormancy or parasitic stages, while diatoms exhibited high transcriptional activity despite low DNA abundance. These findings indicate a clear decoupling between taxonomic presence and metabolic activity, emphasizing that ecological roles cannot be inferred from abundance alone. Our findings identify the DCM as a biogeochemical hotspot shaped by taxon-specific metabolic strategies and vertical niche partitioning, underscoring the key role of protists in sustaining productivity and carbon cycling in stratified ocean ecosystems.
{"title":"Integrative insights into marine protist assemblages between surface and deep chlorophyll maximum","authors":"Seong In Na, Hye Jin Seo, Se Hyeon Jang","doi":"10.3389/fmars.2026.1756144","DOIUrl":"https://doi.org/10.3389/fmars.2026.1756144","url":null,"abstract":"Stratified marine systems are often characterized by a deep chlorophyll maximum (DCM); however, the taxonomic and functional dynamics of protist assemblages within this layer remain poorly understood. We integrated microscopy, pigment-based CHEMTAX analysis, 18S rRNA metabarcoding, and metatranscriptomics to compare protist communities in the surface and DCM layers of the northeastern East China Sea. Microscopy and pigment data revealed higher cell abundances, increased chlorophyll- <jats:italic>a</jats:italic> levels, and distinct pigment signatures at the DCM, particularly for haptophytes, chlorophytes, and pelagophytes. Amplicon sequencing revealed increased representation of chlorophyte and Syndiniales at depth, whereas metatranscriptomic profiles showed elevated transcriptional activity in diatoms, dinoflagellates, and chlorophytes. Functional gene analyses revealed DCM-specific upregulation of photosystem I subunits, light-harvesting complex proteins, and nitrogen assimilation pathways, indicating photoacclimation and nutrient exploitation under low-light, nutrient-rich conditions. Syndiniales were abundant in DNA-based data but mostly transcriptionally inactive, suggesting dormancy or parasitic stages, while diatoms exhibited high transcriptional activity despite low DNA abundance. These findings indicate a clear decoupling between taxonomic presence and metabolic activity, emphasizing that ecological roles cannot be inferred from abundance alone. Our findings identify the DCM as a biogeochemical hotspot shaped by taxon-specific metabolic strategies and vertical niche partitioning, underscoring the key role of protists in sustaining productivity and carbon cycling in stratified ocean ecosystems.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"88 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095967","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}
Rhizostomeae (Scyphozoa) jellyfishes are widespread in neritic waters and include species of commercial importance in Asia. This group comprises jellyfish taxa that host endosymbiotic dinoflagellates of the family Symbiodiniaceae, which provide autotrophic benefits. Despite their value, limited molecular data for Japanese rhizostome taxa has hinder accurate taxonomic classification and interpretation of novel traits. This study combines molecular methods to provide the most complete understanding of molecular phylogenetic relations of Rhizostomeae jellyfishes while assessing the number of Symbiodiniaceae taxa that can be hosted in each species at the medusa level through a new method developed herein for tandem amplification of symbionts and host, validated with microscopy. We also evaluate which rhizostomes produce cassiosomes and whether Symbiodiniaceae are found in the core. Phylogenetic analysis of host mitochondrial (16S rRNA, COI) and nuclear (28S) gene regions of 18 medusae from five genera revealed: (1) Mastigias in Japanese waters corresponds to M. albipunctata ; (2) Cassiopea from Kagoshima likely represents an undescribed species, though Cassiopea xamachana may have been introduced; (3) Two cepheid species - Cephea cephea and Netrostoma setouchianum - occur in Japan; (4) Rhopilema esculentum , a commonly harvested species, is endemic to western Japan. Symbiotic Symbiodiniaceae ITS2 analysis identified three dominant genera ( Symbiodinium , Cladocopium , and Durusdinium ). More than one genus among these was found to be hosted in samples of the genera Mastigias and Cassiopea , indicating plasticity in symbiont association at both the taxon and individual medusa level. Microscopy confirmed cassiosome production exclusively in species examined of the suborder Kolpophorae: Cassiopea sp., N. setouchianum , and M. albipunctata , though absent in a juvenile M. albipunctata sample. Conversely, R. esculentum hosts Symbiodiniaceae but appears to lack the ability to produce cassiosomes. Overall, findings support the distinctive evolution of Symbiodiniaceae–Rhizostomeae symbiosis, the monophyly of the suborder Kolpophorae, and the synapomorphy of cassiosome production in Kolpophorae with onset likely influenced by developmental stage. Broader taxon sampling, especially within Dactyliophorae, will provide further clues on the functional evolution and cellular organization underlying photoendosymbiosis and cassiosome production in these medusozoans.
{"title":"A comparative molecular study of rhizostome jellyfishes (Cnidaria, Scyphozoa, Rhizostomeae) from Japan reveals variability in Symbiodiniaceae taxon associations and cassiosome production","authors":"Kei Chloe Tan, Mitsuko Chikuchishin, Shuhei Ikeda, Ryota Tamada, Kazuya Okuizumi, Goh Nishitani, Minoru Ikeda, Cheryl Lewis Ames","doi":"10.3389/fmars.2025.1679299","DOIUrl":"https://doi.org/10.3389/fmars.2025.1679299","url":null,"abstract":"Rhizostomeae (Scyphozoa) jellyfishes are widespread in neritic waters and include species of commercial importance in Asia. This group comprises jellyfish taxa that host endosymbiotic dinoflagellates of the family Symbiodiniaceae, which provide autotrophic benefits. Despite their value, limited molecular data for Japanese rhizostome taxa has hinder accurate taxonomic classification and interpretation of novel traits. This study combines molecular methods to provide the most complete understanding of molecular phylogenetic relations of Rhizostomeae jellyfishes while assessing the number of Symbiodiniaceae taxa that can be hosted in each species at the medusa level through a new method developed herein for tandem amplification of symbionts and host, validated with microscopy. We also evaluate which rhizostomes produce cassiosomes and whether Symbiodiniaceae are found in the core. Phylogenetic analysis of host mitochondrial (16S rRNA, COI) and nuclear (28S) gene regions of 18 medusae from five genera revealed: (1) <jats:italic>Mastigias</jats:italic> in Japanese waters corresponds to <jats:italic>M. albipunctata</jats:italic> ; (2) <jats:italic>Cassiopea</jats:italic> from Kagoshima likely represents an undescribed species, though <jats:italic>Cassiopea xamachana</jats:italic> may have been introduced; (3) Two cepheid species - <jats:italic>Cephea cephea</jats:italic> and <jats:italic>Netrostoma setouchianum</jats:italic> - occur in Japan; (4) <jats:italic>Rhopilema esculentum</jats:italic> , a commonly harvested species, is endemic to western Japan. Symbiotic Symbiodiniaceae ITS2 analysis identified three dominant genera ( <jats:italic>Symbiodinium</jats:italic> , <jats:italic>Cladocopium</jats:italic> , and <jats:italic>Durusdinium</jats:italic> ). More than one genus among these was found to be hosted in samples of the genera <jats:italic>Mastigias</jats:italic> and <jats:italic>Cassiopea</jats:italic> , indicating plasticity in symbiont association at both the taxon and individual medusa level. Microscopy confirmed cassiosome production exclusively in species examined of the suborder Kolpophorae: <jats:italic>Cassiopea</jats:italic> sp., <jats:italic>N. setouchianum</jats:italic> , and <jats:italic>M. albipunctata</jats:italic> , though absent in a juvenile <jats:italic>M. albipunctata</jats:italic> sample. Conversely, <jats:italic>R. esculentum</jats:italic> hosts Symbiodiniaceae but appears to lack the ability to produce cassiosomes. Overall, findings support the distinctive evolution of Symbiodiniaceae–Rhizostomeae symbiosis, the monophyly of the suborder Kolpophorae, and the synapomorphy of cassiosome production in Kolpophorae with onset likely influenced by developmental stage. Broader taxon sampling, especially within Dactyliophorae, will provide further clues on the functional evolution and cellular organization underlying photoendosymbiosis and cassiosome production in these medusozoans.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"30 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095964","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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