Pub Date : 2025-02-21DOI: 10.3389/fmars.2025.1465125
Natalia Yingling, Karen E. Selph, Moira Décima, Karl A. Safi, Andrés Gutiérrez-Rodríguez, Christian K. Fender, Michael R. Stukel
Phytoplankton community structure is crucial to pelagic food webs and biogeochemical processes. Understanding size-based biomass distribution and carbon dynamics is essential for assessing their contributions to oceanic carbon cycling. This study quantifies plankton carbon (C) based size spectra, community composition, living to total particulate organic carbon (POC) and C:Chlorophyll a (C:Chla) ratios across biogeographical provinces in the Pacific sector of the Southern Ocean near the Subtropical Front (Chatham Rise, Aotearoa-New Zealand). We analyzed phytoplankton community composition using epifluorescence microscopy and flow cytometry, while quantifying size-fractionated Chl-a and POC to estimate normalized biomass, abundance size spectra, and C:Chla ratios. On average, subtropical-influenced waters had lower macronutrients, higher total Chla (1.1 ± 0.2 μg Chla L-1) and were dominated by nanoplankton, which accounted for 45% of the total plankton community (35.2 ± 4.6 μg C L-1). In contrast, picoplankton dominated plankton communities within the subantarctic-influenced and accounted for 35% of the total plankton community (18.5 ± 0.9 μg C L-1) in these water with higher macronutrient concentrations and lower total Chla concentrations (0.32 ± 0.06 μg Chla L-1). Subantarctic-influenced regions had steeper (more negative) slopes for the normalized biomass size spectrum (average = -1.00) compared to subtropical-influenced waters (average = -0.78) indicating greater relative dominance of small taxa. The subantarctic-influenced region had ~2-fold higher surface average C:Chla ratios compared to the subtropical-influenced region with picoplankton consistently having lower C:Chla ratios, due to low Chla values, than larger nano- or microplankton. Live plankton carbon contributed a median of 67% of total particulate organic carbon in the euphotic zone (non-living detritus comprises the remaining ~1/3), which is indicative of substantial primary production and rapid recycling by a strong microbial loop. Our study provides important insights into phytoplankton community structure, biomass distribution and their contribution to carbon sequestration in this region, highlighting the important roles of nanoplankton in subtropical productive waters and picoplankton in offshore subantarctic waters as well as a strong variation of C:Chla across different phytoplankton size classes.
{"title":"Investigating plankton size spectra, biomass, abundance, and community composition in the Subtropical Convergence Front in the Southern Ocean","authors":"Natalia Yingling, Karen E. Selph, Moira Décima, Karl A. Safi, Andrés Gutiérrez-Rodríguez, Christian K. Fender, Michael R. Stukel","doi":"10.3389/fmars.2025.1465125","DOIUrl":"https://doi.org/10.3389/fmars.2025.1465125","url":null,"abstract":"Phytoplankton community structure is crucial to pelagic food webs and biogeochemical processes. Understanding size-based biomass distribution and carbon dynamics is essential for assessing their contributions to oceanic carbon cycling. This study quantifies plankton carbon (C) based size spectra, community composition, living to total particulate organic carbon (POC) and C:Chlorophyll <jats:italic>a</jats:italic> (C:Chl<jats:italic>a</jats:italic>) ratios across biogeographical provinces in the Pacific sector of the Southern Ocean near the Subtropical Front (Chatham Rise, Aotearoa-New Zealand). We analyzed phytoplankton community composition using epifluorescence microscopy and flow cytometry, while quantifying size-fractionated Chl-<jats:italic>a</jats:italic> and POC to estimate normalized biomass, abundance size spectra, and C:Chl<jats:italic>a</jats:italic> ratios. On average, subtropical-influenced waters had lower macronutrients, higher total Chl<jats:italic>a</jats:italic> (1.1 ± 0.2 μg Chl<jats:italic>a</jats:italic> L<jats:sup>-1</jats:sup>) and were dominated by nanoplankton, which accounted for 45% of the total plankton community (35.2 ± 4.6 μg C L<jats:sup>-1</jats:sup>). In contrast, picoplankton dominated plankton communities within the subantarctic-influenced and accounted for 35% of the total plankton community (18.5 ± 0.9 μg C L<jats:sup>-1</jats:sup>) in these water with higher macronutrient concentrations and lower total Chl<jats:italic>a</jats:italic> concentrations (0.32 ± 0.06 μg Chl<jats:italic>a</jats:italic> L<jats:sup>-1</jats:sup>). Subantarctic-influenced regions had steeper (more negative) slopes for the normalized biomass size spectrum (average = -1.00) compared to subtropical-influenced waters (average = -0.78) indicating greater relative dominance of small taxa. The subantarctic-influenced region had ~2-fold higher surface average C:Chl<jats:italic>a</jats:italic> ratios compared to the subtropical-influenced region with picoplankton consistently having lower C:Chl<jats:italic>a</jats:italic> ratios, due to low Chl<jats:italic>a</jats:italic> values, than larger nano- or microplankton. Live plankton carbon contributed a median of 67% of total particulate organic carbon in the euphotic zone (non-living detritus comprises the remaining ~1/3), which is indicative of substantial primary production and rapid recycling by a strong microbial loop. Our study provides important insights into phytoplankton community structure, biomass distribution and their contribution to carbon sequestration in this region, highlighting the important roles of nanoplankton in subtropical productive waters and picoplankton in offshore subantarctic waters as well as a strong variation of C:Chl<jats:italic>a</jats:italic> across different phytoplankton size classes.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"128 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470645","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 : 2025-02-21DOI: 10.3389/fmars.2025.1531684
Jagoba Lupiola, Javier F. Bárcena, Javier García-Alba, Andrés García
The environmental variability of rivers and tides create complex mixing patterns, which modulate the estuarine ecosystem services. Therefore, a thorough understanding of these systems is vital, not only for their protection but also for their recovery. This study first applies a method to analyze the different mechanisms driving the mixing and stratification of the water column in Suances estuary, a small estuary with large intertidal zones, by using numerical modeling to calculate the potential energy anomaly (ϕ) and its derivative (ϕt). Numerical results show that Suances estuary presents an ellipse of mixing and stratification variability driven by, firstly, the river flow (seasonal cycle – monthly time scale), secondly, the tidal phase (ebb-flood cycle – diurnal time scale) and, lastly, the tidal magnitude (spring-neap cycle – fortnightly time scale). Furthermore, these results explicitly highlight how the driving mechanisms can vary for the same estuary geometry at different locations due to diurnal, fortnightly and seasonal changes in forcing. The predominant driving mechanisms in Suances estuary are straining (S) tending to stratify the estuary, river and tide advection (A) tending to mix it and non-linear straining (N), caused by contributions from intertidal areas that favor mixing or stratification according to the tidal cycles. Additionally, a threshold was found between the potential energy anomaly and the depth of the water column, confirming that there are limiting values of the potential energy anomaly depending on the depth that can develop in the estuary. This is especially significant in small and shallow estuaries, since maximum values of the potential energy anomaly will be obtained as a function of depth.
{"title":"Characteristics and driving mechanisms of mixing and stratification in Suances estuary using the potential energy anomaly budget equation","authors":"Jagoba Lupiola, Javier F. Bárcena, Javier García-Alba, Andrés García","doi":"10.3389/fmars.2025.1531684","DOIUrl":"https://doi.org/10.3389/fmars.2025.1531684","url":null,"abstract":"The environmental variability of rivers and tides create complex mixing patterns, which modulate the estuarine ecosystem services. Therefore, a thorough understanding of these systems is vital, not only for their protection but also for their recovery. This study first applies a method to analyze the different mechanisms driving the mixing and stratification of the water column in Suances estuary, a small estuary with large intertidal zones, by using numerical modeling to calculate the potential energy anomaly (ϕ) and its derivative (<jats:italic>ϕ<jats:sub>t</jats:sub></jats:italic>). Numerical results show that Suances estuary presents an ellipse of mixing and stratification variability driven by, firstly, the river flow (seasonal cycle – monthly time scale), secondly, the tidal phase (ebb-flood cycle – diurnal time scale) and, lastly, the tidal magnitude (spring-neap cycle – fortnightly time scale). Furthermore, these results explicitly highlight how the driving mechanisms can vary for the same estuary geometry at different locations due to diurnal, fortnightly and seasonal changes in forcing. The predominant driving mechanisms in Suances estuary are straining (S) tending to stratify the estuary, river and tide advection (A) tending to mix it and non-linear straining (N), caused by contributions from intertidal areas that favor mixing or stratification according to the tidal cycles. Additionally, a threshold was found between the potential energy anomaly and the depth of the water column, confirming that there are limiting values of the potential energy anomaly depending on the depth that can develop in the estuary. This is especially significant in small and shallow estuaries, since maximum values of the potential energy anomaly will be obtained as a function of depth.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"26 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470503","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}
IntroductionLand resources play a vital role in national economic and social development. Hainan Province faces the challenge of balancing land use with conservation while striving to develop a high-quality free trade port. This study aims to analyze land use changes and their driving factors to support sustainable land use policies.MethodsThis study utilised the GlobeLand30 dataset, along with data on temperature, precipitation, the digital elevation model (DEM), slope, soil, gross domestic product (GDP), and population, to apply the Patch-generating Land Use Simulation (PLUS) model. This model was used to analyse land use changes on Hainan Island from 2000 to 2020, to investigate the relationship between land use change and its driving factors.Results(1) During 2000~2020, forests and cultivated land were the predominant land use type, while wetlands and artificial surfaces increased by two times, and bare land remained stable; (2) Temperature significantly influenced cultivated land, forests, and grasslands, while GDP and population growth impacted water bodies and artificial surfaces; (3) The predicted land use map for 2020 achieved high accuracy (Kappa = 0.85); (4) By 2040, forests and cultivated land are expected to remain dominant, with grasslands and artificial surfaces decreasing, while wetlands and bare land are projected to increase.DiscussionThe study highlights the complex interactions between land use and its driving factors in Hainan. The findings provide valuable insights for sustainable land use policy development, balancing economic growth with ecological conservation in the region.
{"title":"Land use change projection and driving factors exploration in Hainan Island based on the PLUS model","authors":"Jiahui Liu, Yaoqi Hou, Fangyi Li, Binbin Zheng, Zeheng Chen, Fa Zheng, Xiaohai Zhang, Rui Yu","doi":"10.3389/fmars.2025.1534508","DOIUrl":"https://doi.org/10.3389/fmars.2025.1534508","url":null,"abstract":"IntroductionLand resources play a vital role in national economic and social development. Hainan Province faces the challenge of balancing land use with conservation while striving to develop a high-quality free trade port. This study aims to analyze land use changes and their driving factors to support sustainable land use policies.MethodsThis study utilised the GlobeLand30 dataset, along with data on temperature, precipitation, the digital elevation model (DEM), slope, soil, gross domestic product (GDP), and population, to apply the Patch-generating Land Use Simulation (PLUS) model. This model was used to analyse land use changes on Hainan Island from 2000 to 2020, to investigate the relationship between land use change and its driving factors.Results(1) During 2000~2020, forests and cultivated land were the predominant land use type, while wetlands and artificial surfaces increased by two times, and bare land remained stable; (2) Temperature significantly influenced cultivated land, forests, and grasslands, while GDP and population growth impacted water bodies and artificial surfaces; (3) The predicted land use map for 2020 achieved high accuracy (Kappa = 0.85); (4) By 2040, forests and cultivated land are expected to remain dominant, with grasslands and artificial surfaces decreasing, while wetlands and bare land are projected to increase.DiscussionThe study highlights the complex interactions between land use and its driving factors in Hainan. The findings provide valuable insights for sustainable land use policy development, balancing economic growth with ecological conservation in the region.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"31 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470616","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 : 2025-02-21DOI: 10.3389/fmars.2025.1447316
Jan Tiede, Remo Cossu, Jan Visscher, Alistair Grinham, Torsten Schlurmann
Reynolds stresses and Turbulent Kinetic Energy (TKE) are instrumental in quantifying the turbulent dynamics that govern mixing and momentum transport in estuaries, factors crucial for understanding and managing estuarine circulation, water quality, and sediment transport. Employing Acoustic Doppler Current profilers, this study investigated hydrodynamics and turbulence in the Brisbane River, Australia. Measurements were conducted at two locations, covering the mouth and middle reach of the estuary. Of particular interest were flow reversals during flood flows, adding complexity to the turbulent dynamics. Reynolds stresses at site I were primarily generated by bed shear, while site II showed more complex stresses due to density differences and lateral circulations. At the river mouth, the mixed semidiurnal tidal regime led to a highly variable turbulent regime, with subsequent flood and ebb events exhibiting markedly different characteristics.
{"title":"Turbulence and mixing variability in a microtidal estuary subject to mixed semidiurnal tidal cycles","authors":"Jan Tiede, Remo Cossu, Jan Visscher, Alistair Grinham, Torsten Schlurmann","doi":"10.3389/fmars.2025.1447316","DOIUrl":"https://doi.org/10.3389/fmars.2025.1447316","url":null,"abstract":"Reynolds stresses and Turbulent Kinetic Energy (TKE) are instrumental in quantifying the turbulent dynamics that govern mixing and momentum transport in estuaries, factors crucial for understanding and managing estuarine circulation, water quality, and sediment transport. Employing Acoustic Doppler Current profilers, this study investigated hydrodynamics and turbulence in the Brisbane River, Australia. Measurements were conducted at two locations, covering the mouth and middle reach of the estuary. Of particular interest were flow reversals during flood flows, adding complexity to the turbulent dynamics. Reynolds stresses at site I were primarily generated by bed shear, while site II showed more complex stresses due to density differences and lateral circulations. At the river mouth, the mixed semidiurnal tidal regime led to a highly variable turbulent regime, with subsequent flood and ebb events exhibiting markedly different characteristics.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"65 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470588","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 : 2025-02-21DOI: 10.3389/fmars.2025.1503748
Liu Lina, Muhammad Murad Zaib Butt
International Fisheries Law (IFL) provides innovative approaches to fisheries governance at national levels. The emergence of Sustainable Development Goal 14 (SDG 14) is phenomenal for fisheries because it creates new means for implementing IFL. Under SDG 14, fisheries governance for sustainable fisheries has become a complex and challenging task for any state. Developing States like Pakistan are struggling to achieve SDG 14 with new approaches to fisheries governance. The current situation of fisheries governance in Pakistan motivated the content of this research paper. This research paper adopted the comprehensive literature review (CLR) methodology to analyse existing fisheries governance mechanisms in Pakistan. Besides CLR, the paper also analysed a ‘case study’ on fisheries governance of Pakistan entitled ‘National Policy and Strategy for Marine Fisheries. Furthermore, one hundred sixty-seven research articles and national and international legislation on fisheries governance from 2010 - 2023 are analysed. The results of the CLR methodology suggested that an extensive integrated mechanism under a comprehensive framework should be developed for fisheries governance. The framework forwarded a policy mechanism incorporating sustainable development goals with SDG 14 that should be implemented coherently for sustainable fisheries. The discussion followed the analysis and suggested that regional to local and bottom-up and top-down approaches in fisheries governance are required to address the challenges to sustainable fisheries in Pakistan. The conclusion of the discussion portrayed that future research related to fisheries governance in Pakistan shall be based on the practical implementation of SDG 14.
{"title":"Analysing Pakistan’s fisheries legislation and institutional framework: integrating Sustainable Development Goal 14 within the scope of International Fisheries Law","authors":"Liu Lina, Muhammad Murad Zaib Butt","doi":"10.3389/fmars.2025.1503748","DOIUrl":"https://doi.org/10.3389/fmars.2025.1503748","url":null,"abstract":"International Fisheries Law (IFL) provides innovative approaches to fisheries governance at national levels. The emergence of Sustainable Development Goal 14 (SDG 14) is phenomenal for fisheries because it creates new means for implementing IFL. Under SDG 14, fisheries governance for sustainable fisheries has become a complex and challenging task for any state. Developing States like Pakistan are struggling to achieve SDG 14 with new approaches to fisheries governance. The current situation of fisheries governance in Pakistan motivated the content of this research paper. This research paper adopted the comprehensive literature review (CLR) methodology to analyse existing fisheries governance mechanisms in Pakistan. Besides CLR, the paper also analysed a ‘case study’ on fisheries governance of Pakistan entitled ‘National Policy and Strategy for Marine Fisheries. Furthermore, one hundred sixty-seven research articles and national and international legislation on fisheries governance from 2010 - 2023 are analysed. The results of the CLR methodology suggested that an extensive integrated mechanism under a comprehensive framework should be developed for fisheries governance. The framework forwarded a policy mechanism incorporating sustainable development goals with SDG 14 that should be implemented coherently for sustainable fisheries. The discussion followed the analysis and suggested that regional to local and bottom-up and top-down approaches in fisheries governance are required to address the challenges to sustainable fisheries in Pakistan. The conclusion of the discussion portrayed that future research related to fisheries governance in Pakistan shall be based on the practical implementation of SDG 14.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"26 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470604","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 : 2025-02-21DOI: 10.3389/fmars.2025.1489091
Yitong Chen, Kaiyue Cheng
Arctic shipping is a significant source of greenhouse gas (GHG) emissions, including carbon dioxide and black carbon, which intensify climate risks in the region. While the International Maritime Organization (IMO) has established the International Code for Ships Operating in Polar Waters (Polar Code) to address environmental and safety concerns of polar navigation, it falls short in promoting the decarbonization of Arctic shipping. The collaboration between the IMO and the Arctic Council, along with the contributions of the Arctic Council’s task forces, is essential but requires further strengthening. In response to the climate crisis, the IMO has raised environmental standards, leading efforts to promote low-carbon growth in Arctic shipping through measures such as sulfur limits, heavy fuel oil bans, and reductions in black carbon emissions. Despite these initiatives, the governance of Arctic shipping decarbonization remains fragmented. To achieve meaningful decarbonization, the Polar Code must be strengthened and expanded into a unified regulatory framework. Additionally, enhanced collaboration between the IMO and the Arctic Council is crucial to maximize their collective impact. As a key player in Arctic shipping, China must strengthen compliance with international regulations through updated domestic legislation and Arctic policies. By actively engaging in multilateral mechanisms and developing a port state control inspection network, China can play a pivotal role in advancing Arctic shipping governance and IMO energy efficiency standards, contributing to a more coordinated and sustainable approach to the region’s environmental challenges and global maritime governance.
{"title":"Decarbonizing Arctic shipping: governance pathways and future directions","authors":"Yitong Chen, Kaiyue Cheng","doi":"10.3389/fmars.2025.1489091","DOIUrl":"https://doi.org/10.3389/fmars.2025.1489091","url":null,"abstract":"Arctic shipping is a significant source of greenhouse gas (GHG) emissions, including carbon dioxide and black carbon, which intensify climate risks in the region. While the International Maritime Organization (IMO) has established the International Code for Ships Operating in Polar Waters (Polar Code) to address environmental and safety concerns of polar navigation, it falls short in promoting the decarbonization of Arctic shipping. The collaboration between the IMO and the Arctic Council, along with the contributions of the Arctic Council’s task forces, is essential but requires further strengthening. In response to the climate crisis, the IMO has raised environmental standards, leading efforts to promote low-carbon growth in Arctic shipping through measures such as sulfur limits, heavy fuel oil bans, and reductions in black carbon emissions. Despite these initiatives, the governance of Arctic shipping decarbonization remains fragmented. To achieve meaningful decarbonization, the Polar Code must be strengthened and expanded into a unified regulatory framework. Additionally, enhanced collaboration between the IMO and the Arctic Council is crucial to maximize their collective impact. As a key player in Arctic shipping, China must strengthen compliance with international regulations through updated domestic legislation and Arctic policies. By actively engaging in multilateral mechanisms and developing a port state control inspection network, China can play a pivotal role in advancing Arctic shipping governance and IMO energy efficiency standards, contributing to a more coordinated and sustainable approach to the region’s environmental challenges and global maritime governance.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"14 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470618","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 : 2025-02-21DOI: 10.3389/fmars.2025.1449332
Kindrat Beregovyi, Jennifer A. Dijkstra, Thomas Butkiewicz
Advances in 3D scanning and reconstruction techniques, such as structure-from-motion, have resulted in an abundance of increasingly-detailed 3D habitat models. However, many existing methods for calculating structural complexity of these models use 2.5D techniques that fail to capture the details of truly 3D models with overlapping features. This paper presents novel algorithms that extend traditional rugosity metrics to generate multi-scale rugosity maps for complex 3D models. Models are repeatedly subdivided for local analysis using multiple 3D grids, which are jittered to smooth results and suppress extreme values from edge cases and poorly-fit reference planes. A rugosity-minimizing technique is introduced to find optimal reference planes for the arbitrary sections of the model within each grid cell. These algorithms are implemented in an open-source analysis software package, HabiCAT 3D (Habitat Complexity Analysis Tool), that calculates and visualizes high-quality 3D rugosity maps for large and complex models. It also extends fractal dimension and vector dispersion complexity metrics, and is used in this paper to evaluate and discuss the appropriateness of each metric to various coral reef datasets.
三维扫描和重建技术（如从运动中提取结构）的进步带来了大量越来越精细的三维生境模型。然而，现有的许多计算这些模型结构复杂性的方法使用的是 2.5D 技术，无法捕捉到具有重叠特征的真正 3D 模型的细节。本文提出了新颖的算法，扩展了传统的凹凸度量，为复杂的三维模型生成多尺度凹凸图。使用多个三维网格对模型进行重复细分，以进行局部分析，并对网格进行抖动以平滑结果，抑制边缘情况和拟合不良参考平面产生的极端值。此外，还引入了崎岖最小化技术，为每个网格单元内模型的任意部分找到最佳参考平面。这些算法在一个开源分析软件包 HabiCAT 3D （栖息地复杂性分析工具）中得以实现，该软件包可计算和可视化大型复杂模型的高质量三维崎岖度图。它还扩展了分形维度和矢量分散复杂性度量，并在本文中用于评估和讨论每种度量对各种珊瑚礁数据集的适用性。
{"title":"Calculating 3D rugosity maps for complex habitat scans","authors":"Kindrat Beregovyi, Jennifer A. Dijkstra, Thomas Butkiewicz","doi":"10.3389/fmars.2025.1449332","DOIUrl":"https://doi.org/10.3389/fmars.2025.1449332","url":null,"abstract":"Advances in 3D scanning and reconstruction techniques, such as structure-from-motion, have resulted in an abundance of increasingly-detailed 3D habitat models. However, many existing methods for calculating structural complexity of these models use 2.5D techniques that fail to capture the details of truly 3D models with overlapping features. This paper presents novel algorithms that extend traditional rugosity metrics to generate multi-scale rugosity maps for complex 3D models. Models are repeatedly subdivided for local analysis using multiple 3D grids, which are jittered to smooth results and suppress extreme values from edge cases and poorly-fit reference planes. A rugosity-minimizing technique is introduced to find optimal reference planes for the arbitrary sections of the model within each grid cell. These algorithms are implemented in an open-source analysis software package, HabiCAT 3D (Habitat Complexity Analysis Tool), that calculates and visualizes high-quality 3D rugosity maps for large and complex models. It also extends fractal dimension and vector dispersion complexity metrics, and is used in this paper to evaluate and discuss the appropriateness of each metric to various coral reef datasets.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"5 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470587","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 : 2025-02-21DOI: 10.3389/fmars.2025.1513013
Yiyang Tan, Yan Bai
Antarctic krill (Euphausia superba) is a key species that sustains the biodiversity of the Southern Ocean and is a protected and restricted fishing target in this region. Considering the significant impacts of climate change on the ecological environment of the Southern Ocean, it is critical to understand the long-term spatio-temporal habitat distribution of Antarctic krill. This study integrates remote sensing and reanalysis data with Antarctic krill survey records to evaluate krill habitat suitability in the Southern Ocean. A novel habitat suitability model was developed using phytoplankton phenology and sea ice dynamics as key timing parameters, employing the Categorical Boosting (CatBoost) algorithm. This is the first time interannual variation in krill habitat distribution, spanning over 20 years (1997–2019), has been analyzed in relation to environmental parameters. Results show that the ice-free period in the Amundsen Sea has extended annually, while phytoplankton blooms have occurred earlier, lasted longer, and exhibited increasing chlorophyll a concentration (CHL), particularly in coastal regions. Additionally, the CatBoost model outperformed traditional species distribution models (SDMs) in handling large-scale presence-absence data (GCV = 0.16), demonstrating that bloom peak CHL and sea ice retreat timing are more effective indicators of krill habitat suitability than single-time environmental parameters. Based on long-term changes in highly suitable habitat areas for Antarctic krill and synchronized trends with the Southern Annular Mode (SAM) index, the overall area of suitable habitat for Antarctic krill in the Prydz sector has declined, likely linked to surface cooling caused by climate change. In contrast, the coastal region of the Atlantic sector, particularly the Western Antarctic Peninsula, a rapid warming area, has experienced an increase in krill habitat suitability. However, habitat suitability in the Weddell Sea has shown a marked decrease. Although climate change has produced mixed effects on krill habitats due to the varying responses of krill different life stages to environmental parameters, this study overall highlights a degradation of krill habitat in the Southern Ocean over the past two decades. These findings provide new insights into Antarctic krill habitat modeling and offer a long-term perspective on the climate change impacts, emphasizing the need for future under-ice investigations.
{"title":"Antarctic krill habitat suitability variation in the Southern Ocean over 20 years","authors":"Yiyang Tan, Yan Bai","doi":"10.3389/fmars.2025.1513013","DOIUrl":"https://doi.org/10.3389/fmars.2025.1513013","url":null,"abstract":"Antarctic krill (<jats:italic>Euphausia superba</jats:italic>) is a key species that sustains the biodiversity of the Southern Ocean and is a protected and restricted fishing target in this region. Considering the significant impacts of climate change on the ecological environment of the Southern Ocean, it is critical to understand the long-term spatio-temporal habitat distribution of Antarctic krill. This study integrates remote sensing and reanalysis data with Antarctic krill survey records to evaluate krill habitat suitability in the Southern Ocean. A novel habitat suitability model was developed using phytoplankton phenology and sea ice dynamics as key timing parameters, employing the Categorical Boosting (CatBoost) algorithm. This is the first time interannual variation in krill habitat distribution, spanning over 20 years (1997–2019), has been analyzed in relation to environmental parameters. Results show that the ice-free period in the Amundsen Sea has extended annually, while phytoplankton blooms have occurred earlier, lasted longer, and exhibited increasing chlorophyll a concentration (CHL), particularly in coastal regions. Additionally, the CatBoost model outperformed traditional species distribution models (SDMs) in handling large-scale presence-absence data (GCV = 0.16), demonstrating that bloom peak CHL and sea ice retreat timing are more effective indicators of krill habitat suitability than single-time environmental parameters. Based on long-term changes in highly suitable habitat areas for Antarctic krill and synchronized trends with the Southern Annular Mode (SAM) index, the overall area of suitable habitat for Antarctic krill in the Prydz sector has declined, likely linked to surface cooling caused by climate change. In contrast, the coastal region of the Atlantic sector, particularly the Western Antarctic Peninsula, a rapid warming area, has experienced an increase in krill habitat suitability. However, habitat suitability in the Weddell Sea has shown a marked decrease. Although climate change has produced mixed effects on krill habitats due to the varying responses of krill different life stages to environmental parameters, this study overall highlights a degradation of krill habitat in the Southern Ocean over the past two decades. These findings provide new insights into Antarctic krill habitat modeling and offer a long-term perspective on the climate change impacts, emphasizing the need for future under-ice investigations.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"65 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470621","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 : 2025-02-21DOI: 10.3389/fmars.2025.1538734
Jian Xu, Guangpeng Feng, Yunzhi Yan
Nanoplastics (NPs) and copper (Cu) are increasingly released into aquatic environments, posing significant risks to aquatic organisms, including crabs. As the primary interface between the organism and the surrounding environment, gills are particularly susceptible to the impacts of NPs and Cu exposure. Investigating the toxicity of these pollutants, especially their combined effects, is crucial for assessing their environmental risks. This study evaluated the toxicity of NPs (0.4 mg/L), Cu²+ (0.1 mg/L), and the combination (NPs + Cu²+) on the gill tissues of Eriocheir sinensis, focusing on tissue morphology, metabolism, and immune functions. The results demonstrated that exposure to NPs, Cu²+ and NPs + Cu²+ caused structural damage to gill tissues and significantly elevated antioxidant parameters such as GSH-Px activity and GSH content, as well as immune parameters including ACP and AKP activity. Compared with the single exposure group, energy metabolism-related genes (TAT, TPI, HK) were down-regulated in the combined exposure group. Pathways associated with glutathione metabolism and cytochrome P450 were notably affected, and the combined exposure suppressed the expression of immune-related genes such as CYP450, GST, and UGT. In summary, we found an enhanced toxicological impact of NPs when combined with Cu2+. Thus, this study provides insights into the toxicological mechanisms of NPs and Cu²+ in aquatic organisms, highlighting their ecological risks to aquatic ecosystems.
{"title":"Effects of polystyrene nanoplastics and copper on gill tissue structure, metabolism, and immune function of the Chinese mitten crab (Eriocheir sinensis)","authors":"Jian Xu, Guangpeng Feng, Yunzhi Yan","doi":"10.3389/fmars.2025.1538734","DOIUrl":"https://doi.org/10.3389/fmars.2025.1538734","url":null,"abstract":"Nanoplastics (NPs) and copper (Cu) are increasingly released into aquatic environments, posing significant risks to aquatic organisms, including crabs. As the primary interface between the organism and the surrounding environment, gills are particularly susceptible to the impacts of NPs and Cu exposure. Investigating the toxicity of these pollutants, especially their combined effects, is crucial for assessing their environmental risks. This study evaluated the toxicity of NPs (0.4 mg/L), Cu²<jats:sup>+</jats:sup> (0.1 mg/L), and the combination (NPs + Cu²<jats:sup>+</jats:sup>) on the gill tissues of <jats:italic>Eriocheir sinensis</jats:italic>, focusing on tissue morphology, metabolism, and immune functions. The results demonstrated that exposure to NPs, Cu²<jats:sup>+</jats:sup> and NPs + Cu²<jats:sup>+</jats:sup> caused structural damage to gill tissues and significantly elevated antioxidant parameters such as GSH-Px activity and GSH content, as well as immune parameters including ACP and AKP activity. Compared with the single exposure group, energy metabolism-related genes (<jats:italic>TAT</jats:italic>, <jats:italic>TPI</jats:italic>, <jats:italic>HK</jats:italic>) were down-regulated in the combined exposure group. Pathways associated with glutathione metabolism and cytochrome P450 were notably affected, and the combined exposure suppressed the expression of immune-related genes such as <jats:italic>CYP450</jats:italic>, <jats:italic>GST</jats:italic>, and <jats:italic>UGT</jats:italic>. In summary, we found an enhanced toxicological impact of NPs when combined with Cu<jats:sup>2+</jats:sup>. Thus, this study provides insights into the toxicological mechanisms of NPs and Cu²<jats:sup>+</jats:sup> in aquatic organisms, highlighting their ecological risks to aquatic ecosystems.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"24 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470499","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 : 2025-02-21DOI: 10.3389/fmars.2025.1555994
Hairui Yu, Maida Mushtaq, Saira Razzaq, Umar Ali, Muhammad Khan, Abdur Rahman, Guobo Quan, Mehroze Fatima, Saima Naveed, Muhammad Hammad Zafar, Muhammad Aziz ur Rahman
The study aimed to evaluate the effects of dietary supplementation of selenium (Se), vitamin C, and vitamin E on growth performance, meat quality, and antioxidant status in Hypophthalmichthys molitrix juveniles. A total of 480 juveniles (mean weight: 20 ± 0.29 g) were randomly assigned to 24 aquaria (20 fish per 100 L), which were allocated to eight dietary treatments (three aquaria per treatment) following a completely randomized design. The dietary treatments included: (1) a basal diet without supplementation (Control), (2) selenium supplementation (S), (3) vitamin C supplementation (C), (4) vitamin E supplementation (E), (5) selenium and vitamin C supplementation (SC), (6) selenium and vitamin E supplementation (SE), (7) vitamin C and vitamin E supplementation (EC), and (8) selenium, vitamin C, and vitamin E supplementation (SCE). The supplementation levels were 0.9 mg/kg Se, 300 mg/kg vitamin C, and 100 mg/kg vitamin E, respectively. After a one-week acclimatization period, a 10-week growth trial was conducted. Fish fed the SCE diet exhibited significantly higher (p< 0.05) final weight gain, body length gain, body weight gain percentage, and specific growth rates compared to other treatments. Selenium concentrations in the kidney, liver, pancreas, and muscle were significantly higher (p< 0.05) in the SCE, SC, SE, and EC groups compared to the Control and single-supplement groups. Hematological parameters, including WBC, RBC, HGB, HCT, and MCHC, were significantly higher (p< 0.05) in the SCE group compared to all other groups. Similarly, serum activities of ALT, AST, and ALP were significantly lower (p< 0.05) in the SCE group than in other treatments, while blood glucose levels were unaffected (p > 0.05) by dietary treatments. Antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly enhanced (p< 0.05) in the whole body and muscle tissues of fish receiving Se, vitamin C, and E supplementation. Thiobarbituric acid reactive substances (TBARS) levels in muscle and serum were significantly higher (p< 0.05) in the Control group compared to all supplemented groups. The proximate composition of meat, including dry matter, fat, ash, and protein contents, was not significantly affected (p > 0.05) by the dietary treatments. In conclusion, dietary supplementation of selenium, vitamin C, and vitamin E significantly improved growth performance, selenium deposition in tissues, and antioxidant status of Hypophthalmichthys molitrix juveniles, without adversely affecting meat chemical composition.
该研究旨在评估膳食补充硒（Se）、维生素 C 和维生素 E 对鳙鱼幼鱼生长性能、肉质和抗氧化状态的影响。将 480 尾幼鱼（平均体重：20 ± 0.29 克）随机分配到 24 个水族箱中（每 100 升水族箱中有 20 尾鱼），并按照完全随机设计将其分配到 8 个饮食处理中（每个处理有 3 个水族箱）。饮食处理包括(1)不添加补充剂的基础日粮（对照组）；(2)硒补充剂（S）；(3)维生素 C 补充剂（C）；(4)维生素 E 补充剂（E）；(5)硒和维生素 C 补充剂（SC）；(6)硒和维生素 E 补充剂（SE）；(7)维生素 C 和维生素 E 补充剂（EC）；(8)硒、维生素 C 和维生素 E 补充剂（SCE）。补充量分别为 0.9 毫克/千克硒、300 毫克/千克维生素 C 和 100 毫克/千克维生素 E。经过一周的适应期后，进行了为期 10 周的生长试验。与其他处理相比，喂食 SCE 日粮的鱼的最终增重、体长、增重百分比和特定生长率都明显更高（p< 0.05）。与对照组和单一添加剂组相比，SCE、SC、SE 和 EC 组的肾脏、肝脏、胰腺和肌肉中的硒浓度明显更高（p< 0.05）。与所有其他组相比，SCE 组的血液学参数，包括白细胞、红细胞、血红蛋白、血细胞压积和 MCHC，均明显升高（p< 0.05）。同样，SCE 组的 ALT、AST 和 ALP 的血清活性也明显低于其他处理组（p< 0.05），而血糖水平则不受饮食处理的影响（p> 0.05）。补充 Se、维生素 C 和 E 的鱼类全身和肌肉组织中的超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT) 和谷胱甘肽过氧化物酶 (GPx) 等抗氧化酶活性显著提高（p< 0.05）。与所有补充组相比，对照组肌肉和血清中硫代巴比妥酸活性物质（TBARS）水平明显升高（p< 0.05）。肉的近似组成，包括干物质、脂肪、灰分和蛋白质含量，没有受到日粮处理的明显影响（p> 0.05）。总之，硒、维生素 C 和维生素 E 的膳食补充能明显改善鳙鱼幼鱼的生长性能、组织中的硒沉积和抗氧化状态，而不会对肉的化学成分产生不利影响。
{"title":"Effects of dietary organic selenium, vitamin C, and vitamin E supplementation on growth performance, serum biochemistry, and antioxidant status in juvenile Hypophthalmichthys molitrix","authors":"Hairui Yu, Maida Mushtaq, Saira Razzaq, Umar Ali, Muhammad Khan, Abdur Rahman, Guobo Quan, Mehroze Fatima, Saima Naveed, Muhammad Hammad Zafar, Muhammad Aziz ur Rahman","doi":"10.3389/fmars.2025.1555994","DOIUrl":"https://doi.org/10.3389/fmars.2025.1555994","url":null,"abstract":"The study aimed to evaluate the effects of dietary supplementation of selenium (Se), vitamin C, and vitamin E on growth performance, meat quality, and antioxidant status in <jats:italic>Hypophthalmichthys molitrix</jats:italic> juveniles. A total of 480 juveniles (mean weight: 20 ± 0.29 g) were randomly assigned to 24 aquaria (20 fish per 100 L), which were allocated to eight dietary treatments (three aquaria per treatment) following a completely randomized design. The dietary treatments included: (1) a basal diet without supplementation (Control), (2) selenium supplementation (S), (3) vitamin C supplementation (C), (4) vitamin E supplementation (E), (5) selenium and vitamin C supplementation (SC), (6) selenium and vitamin E supplementation (SE), (7) vitamin C and vitamin E supplementation (EC), and (8) selenium, vitamin C, and vitamin E supplementation (SCE). The supplementation levels were 0.9 mg/kg Se, 300 mg/kg vitamin C, and 100 mg/kg vitamin E, respectively. After a one-week acclimatization period, a 10-week growth trial was conducted. Fish fed the SCE diet exhibited significantly higher (p&lt; 0.05) final weight gain, body length gain, body weight gain percentage, and specific growth rates compared to other treatments. Selenium concentrations in the kidney, liver, pancreas, and muscle were significantly higher (p&lt; 0.05) in the SCE, SC, SE, and EC groups compared to the Control and single-supplement groups. Hematological parameters, including WBC, RBC, HGB, HCT, and MCHC, were significantly higher (p&lt; 0.05) in the SCE group compared to all other groups. Similarly, serum activities of ALT, AST, and ALP were significantly lower (p&lt; 0.05) in the SCE group than in other treatments, while blood glucose levels were unaffected (p &gt; 0.05) by dietary treatments. Antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly enhanced (p&lt; 0.05) in the whole body and muscle tissues of fish receiving Se, vitamin C, and E supplementation. Thiobarbituric acid reactive substances (TBARS) levels in muscle and serum were significantly higher (p&lt; 0.05) in the Control group compared to all supplemented groups. The proximate composition of meat, including dry matter, fat, ash, and protein contents, was not significantly affected (p &gt; 0.05) by the dietary treatments. In conclusion, dietary supplementation of selenium, vitamin C, and vitamin E significantly improved growth performance, selenium deposition in tissues, and antioxidant status of <jats:italic>Hypophthalmichthys molitrix</jats:italic> juveniles, without adversely affecting meat chemical composition.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"28 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470589","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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