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To investigate the differences in wave attenuation characteristics among rigid, flexible, and rigid-flexible composite vegetation under regular waves, a series of physical model tests were conducted in a laboratory flume. The wave attenuation effects of these three vegetation types were quantitatively analyzed, and the relationships between the drag coefficient (CD) and Reynolds number (Re), Keulegan–Carpenter number (KC), and Ursell number (Ur)—were determined. Results show that all three configurations induce a progressive along-flume reduction in wave height. Increasing incident wave period or vegetation submergence ratio consistently weakens wave dissipation for all vegetation types. The response to wave height differs by configuration: dissipation by rigid vegetation increases markedly and continuously with wave height, whereas flexible vegetation exhibits a nonlinear behavior, strengthening at first and then weakening as wave height further increases. The rigid–flexible combined configuration integrates these advantages and also shows enhanced dissipation with increasing wave height. Moreover, CD for the three vegetation types can be represented using a unified theoretical expression; the primary distinction among configurations is the value of the influence factor γ, which accounts for the effect of vegetation swaying on wave-height attenuation. Statistically significant dependencies of CD on Re, KC, and Ur are observed and can be parameterized by a unified empirical formulation. These results provide a theoretical basis and design reference for optimizing vegetation configurations in coastal ecological protection and restoration engineering.
To investigate the differences in wave attenuation characteristics among rigid, flexible, and rigid-flexible composite vegetation under regular waves, a series of physical model tests were conducted in a laboratory flume. The wave attenuation effects of these three vegetation types were quantitatively analyzed, and the relationships between the drag coefficient (CD) and Reynolds number (Re), Keulegan–Carpenter number (KC), and Ursell number (Ur)—were determined. Results show that all three configurations induce a progressive along-flume reduction in wave height. Increasing incident wave period or vegetation submergence ratio consistently weakens wave dissipation for all vegetation types. The response to wave height differs by configuration: dissipation by rigid vegetation increases markedly and continuously with wave height, whereas flexible vegetation exhibits a nonlinear behavior, strengthening at first and then weakening as wave height further increases. The rigid–flexible combined configuration integrates these advantages and also shows enhanced dissipation with increasing wave height. Moreover, CD for the three vegetation types can be represented using a unified theoretical expression; the primary distinction among configurations is the value of the influence factor γ, which accounts for the effect of vegetation swaying on wave-height attenuation. Statistically significant dependencies of CD on Re, KC, and Ur are observed and can be parameterized by a unified empirical formulation. These results provide a theoretical basis and design reference for optimizing vegetation configurations in coastal ecological protection and restoration engineering.
, Available online , doi: 10.12284/hyxb20260000
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Developing plans for marine protected areas and predicting future changes in marine ecosystems require improved understanding of the response of marine lower trophic levels to environmental changes. For this purpose, numerical models are useful tools while they require continual improvement because of the inclusion of multiple parameters. This study focuses on development and evaluation of a high-resolution three-dimensional coupled ocean, sea-ice and ecosystem model for the Ross Sea (abbr. ROSE). Based on learnings from reviewing the previously developed marine ecosystem models covering the Ross Sea, ROSE is developed using version 3.6 of the Nucleus for European Modeling of the Ocean, version 3 of the Louvain-la-Neuve Sea Ice Model, and the Pelagic Interactions Scheme for Carbon and Ecosystem Study (volume 2). A series tuning of the parameters related to ice dynamics has been carried out. The results suggest that tuning the ice-ocean drag coefficient leads to improved simulation of the coastal polynya, which is a distinct feature in the Ross Sea. A decade-long hindcast simulation, covering 2010–2020, is achieved. The simulated space-time variations of sea ice, ocean hydrography, dissolved iron and Chl-a concentrations are evaluated against available observations and previously published results. The evaluation results suggest that ROSE possesses reasonable skills in reproducing the known features of the above state variables and thus can be further applied to study the mechanism driving recent environmental changes and the response of lower trophic levels in the Ross Sea ecosystem.
Developing plans for marine protected areas and predicting future changes in marine ecosystems require improved understanding of the response of marine lower trophic levels to environmental changes. For this purpose, numerical models are useful tools while they require continual improvement because of the inclusion of multiple parameters. This study focuses on development and evaluation of a high-resolution three-dimensional coupled ocean, sea-ice and ecosystem model for the Ross Sea (abbr. ROSE). Based on learnings from reviewing the previously developed marine ecosystem models covering the Ross Sea, ROSE is developed using version 3.6 of the Nucleus for European Modeling of the Ocean, version 3 of the Louvain-la-Neuve Sea Ice Model, and the Pelagic Interactions Scheme for Carbon and Ecosystem Study (volume 2). A series tuning of the parameters related to ice dynamics has been carried out. The results suggest that tuning the ice-ocean drag coefficient leads to improved simulation of the coastal polynya, which is a distinct feature in the Ross Sea. A decade-long hindcast simulation, covering 2010–2020, is achieved. The simulated space-time variations of sea ice, ocean hydrography, dissolved iron and Chl-a concentrations are evaluated against available observations and previously published results. The evaluation results suggest that ROSE possesses reasonable skills in reproducing the known features of the above state variables and thus can be further applied to study the mechanism driving recent environmental changes and the response of lower trophic levels in the Ross Sea ecosystem.
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Infragravity waves (with periods of 25−250 s) are critical components of nearshore hydrodynamic processes and have significant influence on coastal geomorphological evolution and engineering safety. Based on the conservation equations of mass, momentum, and energy, this paper systematically reviews the latest research progress on the generation mechanisms and evolution characteristics of infragravity waves. Regarding generation mechanisms, the review elaborates on four primary mechanisms: bound long waves, moving breakpoint forcing, bore merging, and wind gusts. Particular attention is given to the theoretical development from the classical equilibrium solution to non-equilibrium solutions for bound long waves, along with the recently proposed unified Green's function approach. In terms of propagation and evolution, the phase variation and energy transfer, nonlinear shoaling, nearshore dissipation, and shoreline reflection of infragravity waves on sloping beaches are introduced. Then, the amplification of infragravity waves over offshore raised topographies and coral reefs is also examined. The article further points out the inherent randomness present during the evolution of infragravity waves. Finally, future research directions are outlined, providing a theoretical reference for further study and application in terms of infragravity waves.
Infragravity waves (with periods of 25−250 s) are critical components of nearshore hydrodynamic processes and have significant influence on coastal geomorphological evolution and engineering safety. Based on the conservation equations of mass, momentum, and energy, this paper systematically reviews the latest research progress on the generation mechanisms and evolution characteristics of infragravity waves. Regarding generation mechanisms, the review elaborates on four primary mechanisms: bound long waves, moving breakpoint forcing, bore merging, and wind gusts. Particular attention is given to the theoretical development from the classical equilibrium solution to non-equilibrium solutions for bound long waves, along with the recently proposed unified Green's function approach. In terms of propagation and evolution, the phase variation and energy transfer, nonlinear shoaling, nearshore dissipation, and shoreline reflection of infragravity waves on sloping beaches are introduced. Then, the amplification of infragravity waves over offshore raised topographies and coral reefs is also examined. The article further points out the inherent randomness present during the evolution of infragravity waves. Finally, future research directions are outlined, providing a theoretical reference for further study and application in terms of infragravity waves.
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Toxic algal species pose significant threats to ecological environmental safety and human health. Azadinium dexteroporum, one of the main producers of azaspiracid toxins, remains poorly studied in China, and its distribution in Chinese coastal waters is still unclear. In this study, environmental DNA (eDNA) methods were used to obtain occurrence records of A. dexteroporum in Chinese coastal areas. Using the 2050s and 2100s as future projection periods, the Maximum Entropy (MaxEnt)model was applied to simulate the potential suitable habitats of this species under current and three future climate scenarios (SSP126, SSP245, and SSP585). The results indicated that nitrate concentration, silicate concentration, and sea surface temperature were the primary environmental factors influencing the distribution of A. dexteroporum. Under current conditions, the suitable habitat area was estimated to be 63.71 × 104 km2, mainly concentrated in the northern South China Sea. With climate change, the potential suitable area of A. dexteroporum is projected to shrink, decreasing to 5.58×104 km2～32.21×104 km2 by the 2100s. The spatial distribution pattern of suitable habitats shows an overall “southward contraction and northward expansion” trend: the extensive suitable areas in the South China Sea are expected to disappear, while new suitable areas may emerge in the Yellow and Bohai Seas. The centroid of suitable habitats is projected to shift up to 1,439 km, migrating from the northern South China Sea to north of the Yangtze River estuary. These findings provide important scientific insights for the ecological risk monitoring, forecasting, and management of harmful dinoflagellates.
Toxic algal species pose significant threats to ecological environmental safety and human health. Azadinium dexteroporum, one of the main producers of azaspiracid toxins, remains poorly studied in China, and its distribution in Chinese coastal waters is still unclear. In this study, environmental DNA (eDNA) methods were used to obtain occurrence records of A. dexteroporum in Chinese coastal areas. Using the 2050s and 2100s as future projection periods, the Maximum Entropy (MaxEnt)model was applied to simulate the potential suitable habitats of this species under current and three future climate scenarios (SSP126, SSP245, and SSP585). The results indicated that nitrate concentration, silicate concentration, and sea surface temperature were the primary environmental factors influencing the distribution of A. dexteroporum. Under current conditions, the suitable habitat area was estimated to be 63.71 × 104 km2, mainly concentrated in the northern South China Sea. With climate change, the potential suitable area of A. dexteroporum is projected to shrink, decreasing to 5.58×104 km2～32.21×104 km2 by the 2100s. The spatial distribution pattern of suitable habitats shows an overall “southward contraction and northward expansion” trend: the extensive suitable areas in the South China Sea are expected to disappear, while new suitable areas may emerge in the Yellow and Bohai Seas. The centroid of suitable habitats is projected to shift up to 1,439 km, migrating from the northern South China Sea to north of the Yangtze River estuary. These findings provide important scientific insights for the ecological risk monitoring, forecasting, and management of harmful dinoflagellates.
, Available online , doi: 10.12284/hyxb20260001
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In order to study the biological characteristics of Rhopilema esculentum and its environmental influencing factors, this study analyzed the biological characteristics of R.esculentum in different years according to the monitoring data of R. esculentum resources in Shengsi sea area of Hangzhou Bay from June to July 2022 to 2024, and explored the relationship between the umbrella diameter, body weight and environmental influencing factors of R. esculentum by GAM model. The results showed that there were significant differences between umbrella diameter and body weight of R.esculentum before the special fishing permits during the summer fishing moratorium, and the growth rate of R. esculentum body weight showed different growth trends at different growth stages. The results of the GAM showed that umbrella diameter and body weight of R. esculentum increased gradually with the increase of sea surface temperature from 21.18 ℃ to 26.81 ℃. Sea surface salinity has a significant effect on the growth of R. esculentum umbrella diameter. In the salinity range of 9.3～25.2, the umbrella diameter of R. esculentum increases, and the optimum salinity is 17.7～22.7. In the interaction between sea surface temperature and salinity, the high value area of umbrella diameter and the middle value area of body weight of R. esculentum are in the range of sea surface temperature 24～26.3 ℃ and sea surface salinity 15～22. There were significant differences in umbrella diameter and body weight among years after the special fishing permits during the summer fishing moratorium. Comprehensive analysis showed that the growth of umbrella diameter and body weight of R. esculentum was affected by sea surface temperature and salinity, and the initial fishing time could be determined based on the level of sea surface temperature.
In order to study the biological characteristics of Rhopilema esculentum and its environmental influencing factors, this study analyzed the biological characteristics of R.esculentum in different years according to the monitoring data of R. esculentum resources in Shengsi sea area of Hangzhou Bay from June to July 2022 to 2024, and explored the relationship between the umbrella diameter, body weight and environmental influencing factors of R. esculentum by GAM model. The results showed that there were significant differences between umbrella diameter and body weight of R.esculentum before the special fishing permits during the summer fishing moratorium, and the growth rate of R. esculentum body weight showed different growth trends at different growth stages. The results of the GAM showed that umbrella diameter and body weight of R. esculentum increased gradually with the increase of sea surface temperature from 21.18 ℃ to 26.81 ℃. Sea surface salinity has a significant effect on the growth of R. esculentum umbrella diameter. In the salinity range of 9.3～25.2, the umbrella diameter of R. esculentum increases, and the optimum salinity is 17.7～22.7. In the interaction between sea surface temperature and salinity, the high value area of umbrella diameter and the middle value area of body weight of R. esculentum are in the range of sea surface temperature 24～26.3 ℃ and sea surface salinity 15～22. There were significant differences in umbrella diameter and body weight among years after the special fishing permits during the summer fishing moratorium. Comprehensive analysis showed that the growth of umbrella diameter and body weight of R. esculentum was affected by sea surface temperature and salinity, and the initial fishing time could be determined based on the level of sea surface temperature.
, Available online , doi: 10.12284/hyxb2025142
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To investigate the resource utilization and interspecific relationships of macrobenthic fauna in the rocky intertidal zones of Zhejiang Province, surveys were conducted at 10 rocky intertidal sites from March 2024 to April 2025. The index of relative importance (IRI), niche breadth (Bi), niche overlap (Oik), variance ratio (VR), chi-square test, association coefficient (AC), percentage of co-occurrence (PC), Spearman rank correlation, and redundancy analysis (RDA) were applied to analyze the ecological niches, interspecific associations, and relationships between dominant species and environmental factors. The results showed: (1) the rocky intertidal zones of Zhejiang host a rich diversity of species, with 17 dominant species identified (IRI > 100); (2) Thais clavigera and Nodilittorina exigua had wide niche breadths and were classified as wide niche breadth species, while Chthamalus challengeri and Crassostrea angulata were narrow niche breadth species. (3) significant niche overlap was observed among T. clavigera, Littorina brevicula, Thais luteostoma, and Notoacmea schrenckii, indicating intense resource competition; (4) salinity and chl a were key factors influencing species abundance, and a significant negative correlation was found between salinity and chl a. (5) the community structure of macrobenthos in the rocky intertidal zones appeared to be loosely organized and compositionally unstable, suggesting that it may currently be in a stage of successional recovery.
To investigate the resource utilization and interspecific relationships of macrobenthic fauna in the rocky intertidal zones of Zhejiang Province, surveys were conducted at 10 rocky intertidal sites from March 2024 to April 2025. The index of relative importance (IRI), niche breadth (Bi), niche overlap (Oik), variance ratio (VR), chi-square test, association coefficient (AC), percentage of co-occurrence (PC), Spearman rank correlation, and redundancy analysis (RDA) were applied to analyze the ecological niches, interspecific associations, and relationships between dominant species and environmental factors. The results showed: (1) the rocky intertidal zones of Zhejiang host a rich diversity of species, with 17 dominant species identified (IRI > 100); (2) Thais clavigera and Nodilittorina exigua had wide niche breadths and were classified as wide niche breadth species, while Chthamalus challengeri and Crassostrea angulata were narrow niche breadth species. (3) significant niche overlap was observed among T. clavigera, Littorina brevicula, Thais luteostoma, and Notoacmea schrenckii, indicating intense resource competition; (4) salinity and chl a were key factors influencing species abundance, and a significant negative correlation was found between salinity and chl a. (5) the community structure of macrobenthos in the rocky intertidal zones appeared to be loosely organized and compositionally unstable, suggesting that it may currently be in a stage of successional recovery.
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Abstract:
China’s marine waters support abundant sea cucumber resources, with 138 species recorded across 7 orders, 16 families and 61 genera, including 39 species of major nutritional and economic value. These species are widely distributed across tropical, subtropical, and temperate waters, where they play essential roles in maintaining benthic ecological processes, regulating sediment structure, and supporting the development of marine ranching systems. At present, research on sea cucumbers in China has largely focused on aquaculture techniques and the bioactive properties of functional compounds, whereas fundamental studies on taxonomy and systematics remain comparatively limited. Since the establishment of the sea cucumber classification system in the 19th century, taxonomic methodologies have undergone a profound shift from traditional morphology-based approaches to modern molecular systematics. Traditional taxonomy relies primarily on external morphology and ossicle characteristics, with as many as 25 recognized ossicle types. However, the complexity of ossicle structures, the pronounced morphological polymorphism, and the high interspecific similarity and substantial intraspecific variation collectively hinder precise identification of closely related taxa and individuals at different life-history stages when using morphology alone.In recent years, the widespread application of molecular barcoding techniques such as COI and 16S rRNA, together with the rapid development of mitogenomic and whole-genome phylogenetic approaches, has significantly improved the accuracy of species identification and phylogenetic reconstruction. Despite these advances, several challenges persist, including insufficient deep-sea and South China Sea sampling, incomplete specimen coverage, limited molecular datasets, and inconsistent identification standards. Future research should strengthen systematic sampling and long-term monitoring in key marine regions, establish an integrative taxonomic framework combining traditional morphological traits, ossicle microstructure, and multi-gene molecular data, and promote the adoption of environmental DNA (eDNA) non-invasive sampling and AI-assisted digital imaging platforms. The establishment of standardized genetic and morphological databases, together with a national DNA barcode library, will provide essential technical support for rapid species identification and sustainable resource management. This study comprehensively reviews the species diversity patterns and taxonomic progress of Chinese sea cucumbers, identifies the current challenges in holothurian taxonomy, and proposes future directions toward a robust classification framework that underpins biodiversity conservation, ecological restoration, and the sustainable utilization of sea cucumber resources.
China’s marine waters support abundant sea cucumber resources, with 138 species recorded across 7 orders, 16 families and 61 genera, including 39 species of major nutritional and economic value. These species are widely distributed across tropical, subtropical, and temperate waters, where they play essential roles in maintaining benthic ecological processes, regulating sediment structure, and supporting the development of marine ranching systems. At present, research on sea cucumbers in China has largely focused on aquaculture techniques and the bioactive properties of functional compounds, whereas fundamental studies on taxonomy and systematics remain comparatively limited. Since the establishment of the sea cucumber classification system in the 19th century, taxonomic methodologies have undergone a profound shift from traditional morphology-based approaches to modern molecular systematics. Traditional taxonomy relies primarily on external morphology and ossicle characteristics, with as many as 25 recognized ossicle types. However, the complexity of ossicle structures, the pronounced morphological polymorphism, and the high interspecific similarity and substantial intraspecific variation collectively hinder precise identification of closely related taxa and individuals at different life-history stages when using morphology alone.In recent years, the widespread application of molecular barcoding techniques such as COI and 16S rRNA, together with the rapid development of mitogenomic and whole-genome phylogenetic approaches, has significantly improved the accuracy of species identification and phylogenetic reconstruction. Despite these advances, several challenges persist, including insufficient deep-sea and South China Sea sampling, incomplete specimen coverage, limited molecular datasets, and inconsistent identification standards. Future research should strengthen systematic sampling and long-term monitoring in key marine regions, establish an integrative taxonomic framework combining traditional morphological traits, ossicle microstructure, and multi-gene molecular data, and promote the adoption of environmental DNA (eDNA) non-invasive sampling and AI-assisted digital imaging platforms. The establishment of standardized genetic and morphological databases, together with a national DNA barcode library, will provide essential technical support for rapid species identification and sustainable resource management. This study comprehensively reviews the species diversity patterns and taxonomic progress of Chinese sea cucumbers, identifies the current challenges in holothurian taxonomy, and proposes future directions toward a robust classification framework that underpins biodiversity conservation, ecological restoration, and the sustainable utilization of sea cucumber resources.
, Available online , doi: 10.12284/hyxb202500-1
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In this study, two fibroblast growth factor (FGF) genes, named as PdFGF1 and PdFGF17, were identified and cloned from the coral Pocillopora damicornis. Sequence analysis showed that PdFGF1 and PdFGF17 encode 195 and 149 amino acids, respectively. Both contain a signal peptide and a typical FGF domain, with characteristic β–sheets and η–loops in their topological structures. The FGF family in higher animals can be divided into seven subfamilies (FGF1, FGF4, FGF7, FGF8, FGF9, FGF11, and FGF19). Multiple sequence alignment and phylogenetic analysis revealed that PdFGF1 belongs to the FGF1 subfamily, sharing 30.15% sequence identity with HsFGF1 (Homo sapiens), whereas PdFGF17 clusters with the FGF8 subfamily, sharing 29.36% identity with HsFGF17. To further elucidate their biological roles, transcriptomic analysis was performed on P. damicornis under heat stress induced polyp bailout. The results showed that the expression levels of FGF family genes (PdFGF1, PdFGF2, PdFGF9, PdFGF17, PdFGF18, PdFGFR1, PdFGFR2, PdFGFR3 and PdFGFR4) were significantly upregulated during the detachment process. Moreover, the FGF signaling pathway was found to activate the downstream Ras/MAPK cascade, thereby regulating cytoskeletal remodeling and cell adhesion. Gene co-expression network analysis using Cytoscape further revealed significant co-expression relationships between FGF genes and extracellular matrix (ECM) degrading genes in the coenosarc tissue, including ADAMTSs, COL21A1, CTSZ, and P4HA. Collectively, these findings suggest that heat stress activates the FGF signaling pathway in P. damicornis, promoting ECM degradation and ultimately mediating coenosarc dissociation and polyp bailout.
In this study, two fibroblast growth factor (FGF) genes, named as PdFGF1 and PdFGF17, were identified and cloned from the coral Pocillopora damicornis. Sequence analysis showed that PdFGF1 and PdFGF17 encode 195 and 149 amino acids, respectively. Both contain a signal peptide and a typical FGF domain, with characteristic β–sheets and η–loops in their topological structures. The FGF family in higher animals can be divided into seven subfamilies (FGF1, FGF4, FGF7, FGF8, FGF9, FGF11, and FGF19). Multiple sequence alignment and phylogenetic analysis revealed that PdFGF1 belongs to the FGF1 subfamily, sharing 30.15% sequence identity with HsFGF1 (Homo sapiens), whereas PdFGF17 clusters with the FGF8 subfamily, sharing 29.36% identity with HsFGF17. To further elucidate their biological roles, transcriptomic analysis was performed on P. damicornis under heat stress induced polyp bailout. The results showed that the expression levels of FGF family genes (PdFGF1, PdFGF2, PdFGF9, PdFGF17, PdFGF18, PdFGFR1, PdFGFR2, PdFGFR3 and PdFGFR4) were significantly upregulated during the detachment process. Moreover, the FGF signaling pathway was found to activate the downstream Ras/MAPK cascade, thereby regulating cytoskeletal remodeling and cell adhesion. Gene co-expression network analysis using Cytoscape further revealed significant co-expression relationships between FGF genes and extracellular matrix (ECM) degrading genes in the coenosarc tissue, including ADAMTSs, COL21A1, CTSZ, and P4HA. Collectively, these findings suggest that heat stress activates the FGF signaling pathway in P. damicornis, promoting ECM degradation and ultimately mediating coenosarc dissociation and polyp bailout.
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Gross Oxygen production (GOP) in the surface ocean is a key indicator for evaluating the intensity of phytoplankton photosynthesis and the efficiency of marine biological carbon sequestration. However, photosynthesis and respiration occur simultaneously. It is very difficult to distinguish the total photosynthetic O2 production from respiration O2 consumption. Therefore, in situ measurement of marine GOP is extremely challenging. The triple oxygen isotope anomaly (17Δ) of dissolved oxygen does not change with respiration, providing a new isotopic indicator for evaluating marine GOP. Due to the extremely low natural abundance of 17O and its susceptibility to mass interference from N2, high precision measurement for triple oxygen isotopes (δ18O, 17Δ) of O2 is very difficult. In this study, we developed a high-vacuum pretreatment system and a gas chromatographic purification line. We successfully separated N2 from O2 and Ar for dissolved gases. By precisely controlling the temperature and collection time, we ensured 100% collection of O2 and avoided oxygen isotopic fractionation from purification. Based on this method, the observed long-term external precision of the air standard was ± 2.6 per meg for 17Δ. Then, we analyzed the triple oxygen isotopic compositions of 5 dissolved gas samples collected in Prydz Bay, Southern Ocean, in January 2021. The mean 17Δ value of dissolved oxygen in the mixed layer was 66 per meg, corresponding to an average GOP of 181 mmol O2 m−2 day−1. Our observation is consistent with the relatively low GOP of the high-latitude Southern Ocean during summer. The high-precision analytical method for triple oxygen isotopes of O2 in this study demonstrates great potential for applications in marine GOP research and also provides valuable support for atmospheric and ice core trapped gas studies.
Gross Oxygen production (GOP) in the surface ocean is a key indicator for evaluating the intensity of phytoplankton photosynthesis and the efficiency of marine biological carbon sequestration. However, photosynthesis and respiration occur simultaneously. It is very difficult to distinguish the total photosynthetic O2 production from respiration O2 consumption. Therefore, in situ measurement of marine GOP is extremely challenging. The triple oxygen isotope anomaly (17Δ) of dissolved oxygen does not change with respiration, providing a new isotopic indicator for evaluating marine GOP. Due to the extremely low natural abundance of 17O and its susceptibility to mass interference from N2, high precision measurement for triple oxygen isotopes (δ18O, 17Δ) of O2 is very difficult. In this study, we developed a high-vacuum pretreatment system and a gas chromatographic purification line. We successfully separated N2 from O2 and Ar for dissolved gases. By precisely controlling the temperature and collection time, we ensured 100% collection of O2 and avoided oxygen isotopic fractionation from purification. Based on this method, the observed long-term external precision of the air standard was ± 2.6 per meg for 17Δ. Then, we analyzed the triple oxygen isotopic compositions of 5 dissolved gas samples collected in Prydz Bay, Southern Ocean, in January 2021. The mean 17Δ value of dissolved oxygen in the mixed layer was 66 per meg, corresponding to an average GOP of 181 mmol O2 m−2 day−1. Our observation is consistent with the relatively low GOP of the high-latitude Southern Ocean during summer. The high-precision analytical method for triple oxygen isotopes of O2 in this study demonstrates great potential for applications in marine GOP research and also provides valuable support for atmospheric and ice core trapped gas studies.
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Mangrove ecosystems play a pivotal role in sustaining coastal ecological stability. However, under the compounded influences of climate change and human disturbance, these ecosystems are experiencing severe degradation. Artificial afforestation has emerged as the predominant restoration strategy. This study focuses on young mangrove plantations along the Guangxi coastline, investigating the ecological strategy differences among various species within these artificial plantations. Utilizing plant functional traits and the CSR (Competitor, Stress-tolerator, Ruderal) strategy theory, the study explores the relationships between functional traits, CSR strategies, and the driving factors behind these ecological patterns. The findings reveal that: (1) There are significant variations in CSR strategies among different species. Aegiceras corniculatum and Kandelia obovata predominantly exhibit the S strategy, Bruguiera gymnorrhiza is more inclined towards the C strategy, while Avicennia marina demonstrates a relatively balanced distribution across the CSR spectrum. (2) A significant correlation exists between CSR strategies and functional trait indicators. Specifically, the C strategy shows a significant positive correlation with chlorophyll content and tree height increment, and a significant negative correlation with leaf phosphorus content. The S strategy is significantly negatively correlated with tree height increment. The R strategy exhibits significant positive correlations with chlorophyll content and tree height increment, and significant negative correlations with leaf nitrogen content and leaf phosphorus content. (3) Flood time and depth are identified as key environmental factors driving the variation in CSR strategies within the young mangrove plantations. This study substantiates the applicability of CSR theory in intertidal artificial mangrove ecosystems, elucidating the mechanistic connections between plant adaptive strategies and ecological niche occupation. The results provide both theoretical insights and practical guidance for optimizing species selection and enhancing the efficiency of mangrove ecosystem restoration.
Mangrove ecosystems play a pivotal role in sustaining coastal ecological stability. However, under the compounded influences of climate change and human disturbance, these ecosystems are experiencing severe degradation. Artificial afforestation has emerged as the predominant restoration strategy. This study focuses on young mangrove plantations along the Guangxi coastline, investigating the ecological strategy differences among various species within these artificial plantations. Utilizing plant functional traits and the CSR (Competitor, Stress-tolerator, Ruderal) strategy theory, the study explores the relationships between functional traits, CSR strategies, and the driving factors behind these ecological patterns. The findings reveal that: (1) There are significant variations in CSR strategies among different species. Aegiceras corniculatum and Kandelia obovata predominantly exhibit the S strategy, Bruguiera gymnorrhiza is more inclined towards the C strategy, while Avicennia marina demonstrates a relatively balanced distribution across the CSR spectrum. (2) A significant correlation exists between CSR strategies and functional trait indicators. Specifically, the C strategy shows a significant positive correlation with chlorophyll content and tree height increment, and a significant negative correlation with leaf phosphorus content. The S strategy is significantly negatively correlated with tree height increment. The R strategy exhibits significant positive correlations with chlorophyll content and tree height increment, and significant negative correlations with leaf nitrogen content and leaf phosphorus content. (3) Flood time and depth are identified as key environmental factors driving the variation in CSR strategies within the young mangrove plantations. This study substantiates the applicability of CSR theory in intertidal artificial mangrove ecosystems, elucidating the mechanistic connections between plant adaptive strategies and ecological niche occupation. The results provide both theoretical insights and practical guidance for optimizing species selection and enhancing the efficiency of mangrove ecosystem restoration.
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Eodemus subtilis is an intertidal to shallow-water crab species belonging to the family Portunidae (Order: Decapoda), primarily distributed along the southeastern coastal waters of China. In this study, we conducted a comprehensive characterization of its mitochondrial genome using high-throughput sequencing and bioinformatic analyses. The complete mitochondrial genome of E. subtilis is 15,878 bp in length and comprises 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and one non-coding control region. Notably, 24 of these genes are encoded on the heavy strand (H-strand). The mitochondrial genome exhibits a strong A+T bias (69.81%), with negative AT-skew (-0.021) and GC-skew (-0.233). Analysis of relative synonymous codon usage (RSCU) revealed that the codons UCU (Ser2) and UUA (Leu2) are highly frequent, with preferred codons predominantly ending in A/T. The gene arrangement in E. subtilis is highly conserved, maintaining the ancestral gene order typical of Brachyura crabs, with no observed rearrangements. Selection pressure analysis (Ka/Ks) of the 13 PCGs across Portunidae crabs indicated that 11 genes (excluding COIII and ND1) underwent purifying selection. Phylogenetic and divergence time estimation analyses demonstrated that E. subtilis forms a clade with Monomia gladiator, with an estimated divergence time of approximately 44.34 million years ago (Mya). These findings provide significant new insights into the evolutionary history and molecular adaptations of E. subtilis within Portunidae, as well as into the evolutionary relationships of Portunidae within Brachyura.
Eodemus subtilis is an intertidal to shallow-water crab species belonging to the family Portunidae (Order: Decapoda), primarily distributed along the southeastern coastal waters of China. In this study, we conducted a comprehensive characterization of its mitochondrial genome using high-throughput sequencing and bioinformatic analyses. The complete mitochondrial genome of E. subtilis is 15,878 bp in length and comprises 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and one non-coding control region. Notably, 24 of these genes are encoded on the heavy strand (H-strand). The mitochondrial genome exhibits a strong A+T bias (69.81%), with negative AT-skew (-0.021) and GC-skew (-0.233). Analysis of relative synonymous codon usage (RSCU) revealed that the codons UCU (Ser2) and UUA (Leu2) are highly frequent, with preferred codons predominantly ending in A/T. The gene arrangement in E. subtilis is highly conserved, maintaining the ancestral gene order typical of Brachyura crabs, with no observed rearrangements. Selection pressure analysis (Ka/Ks) of the 13 PCGs across Portunidae crabs indicated that 11 genes (excluding COIII and ND1) underwent purifying selection. Phylogenetic and divergence time estimation analyses demonstrated that E. subtilis forms a clade with Monomia gladiator, with an estimated divergence time of approximately 44.34 million years ago (Mya). These findings provide significant new insights into the evolutionary history and molecular adaptations of E. subtilis within Portunidae, as well as into the evolutionary relationships of Portunidae within Brachyura.
, Available online , doi: 10.12284/hyxb2025006
Abstract:
Studying the occurrence and dynamics of microplastics on coastal beaches is crucial for the integrated management of coastal zones and the assessment of ecological risks. Previous research has highlighted that physical processes play a pivotal role in influencing the occurrences of microplastic on coastal beaches. However, the impact of extreme meteorological events such as typhoons on the distribution of microplastic pollution has yet to be explored. This study conducted field fixed-plot experiments on the coastal beaches of Xiamen City before and after Typhoon "Haikui" to analyze the variations in the abundance, composition, and diversity of microplastic on beaches. The results showed that the abundance of microplastics on the beaches in Xiamen City before Typhoon Haikui was (251.5 ± 27.9) n/kg, and this value significantly decreased to (127.0 ± 18.8) n/kg post-typhoon. Before and after the typhoon, the composition of microplastics on the beaches showed distinct variations, with the abundance of microplastics of different shapes and sizes responding differently to the typhoon. In particular, the abundance of smaller particles (<500 μm) significantly decreased, while the proportion of fibrous particles increased. Moreover, the typhoon event led to a general decrease in the Shannon-Wiener diversity index, while an increase in the Pielou’s evenness index. The impact of typhoons on the distribution of microplastics on beaches arises from the complex coupling of multiple dynamic physical processes in extreme weather, and it is also closely related to factors such as the location and substrate conditions of the coasts. To achieve simulation and prediction of the dynamics of microplastic pollution during typhoon processes, systematic and comprehensive research on the relevant mechanisms is still required in the future.
Studying the occurrence and dynamics of microplastics on coastal beaches is crucial for the integrated management of coastal zones and the assessment of ecological risks. Previous research has highlighted that physical processes play a pivotal role in influencing the occurrences of microplastic on coastal beaches. However, the impact of extreme meteorological events such as typhoons on the distribution of microplastic pollution has yet to be explored. This study conducted field fixed-plot experiments on the coastal beaches of Xiamen City before and after Typhoon "Haikui" to analyze the variations in the abundance, composition, and diversity of microplastic on beaches. The results showed that the abundance of microplastics on the beaches in Xiamen City before Typhoon Haikui was (251.5 ± 27.9) n/kg, and this value significantly decreased to (127.0 ± 18.8) n/kg post-typhoon. Before and after the typhoon, the composition of microplastics on the beaches showed distinct variations, with the abundance of microplastics of different shapes and sizes responding differently to the typhoon. In particular, the abundance of smaller particles (<500 μm) significantly decreased, while the proportion of fibrous particles increased. Moreover, the typhoon event led to a general decrease in the Shannon-Wiener diversity index, while an increase in the Pielou’s evenness index. The impact of typhoons on the distribution of microplastics on beaches arises from the complex coupling of multiple dynamic physical processes in extreme weather, and it is also closely related to factors such as the location and substrate conditions of the coasts. To achieve simulation and prediction of the dynamics of microplastic pollution during typhoon processes, systematic and comprehensive research on the relevant mechanisms is still required in the future.
, Available online
Abstract:
This study focuses on the physical process of a sea fog event during Typhoon Lekima in the Northern Yellow Sea by using observation data, reanalysis data and backward trajectory model. The analysis indicates that the typhoon circulation was the decisive factor determining whether fog formed offshore and developed inland. The warm and humid southerlies from the south Yellow Sea condensed into fog on the colder sea surface besides the typhoon center, which not only provided sufficient moisture for the formation and development of the sea fog but also formed a significant inversion layer over the fog area with the downdraft in the center of the typhoon. The "stable up and turbulent down" structure in the atmospheric boundary layer improved the development of sea fog on the coast and inland area. However, the horizontal wind steering and the strengthening wind speed behind the typhoon strengthened the wind shear in the atmospheric boundary layer, resulting in the enhanced turbulent mixing and the decrease of the stability in the bottom atmospheric boundary layer, which was the main cause of the fog dissipation.
This study focuses on the physical process of a sea fog event during Typhoon Lekima in the Northern Yellow Sea by using observation data, reanalysis data and backward trajectory model. The analysis indicates that the typhoon circulation was the decisive factor determining whether fog formed offshore and developed inland. The warm and humid southerlies from the south Yellow Sea condensed into fog on the colder sea surface besides the typhoon center, which not only provided sufficient moisture for the formation and development of the sea fog but also formed a significant inversion layer over the fog area with the downdraft in the center of the typhoon. The "stable up and turbulent down" structure in the atmospheric boundary layer improved the development of sea fog on the coast and inland area. However, the horizontal wind steering and the strengthening wind speed behind the typhoon strengthened the wind shear in the atmospheric boundary layer, resulting in the enhanced turbulent mixing and the decrease of the stability in the bottom atmospheric boundary layer, which was the main cause of the fog dissipation.
, Available online
Abstract:
The possibility of the Indonesian submarine wreck on 20 April 2021 was analyzed based on satellite remote sensing observation and numerical simulation. The results indicate that large-amplitude oceanic internal waves, estimated to be approximately 50 m using satellite images, originate from the Lombok Strait. They are widely distributed to the north of the Bali Island and are suggested to cause an abrupt sinking of the Indonesian submarine.
The possibility of the Indonesian submarine wreck on 20 April 2021 was analyzed based on satellite remote sensing observation and numerical simulation. The results indicate that large-amplitude oceanic internal waves, estimated to be approximately 50 m using satellite images, originate from the Lombok Strait. They are widely distributed to the north of the Bali Island and are suggested to cause an abrupt sinking of the Indonesian submarine.
, Available online
Abstract:
Abstract：The potential fish production was controlled largely by ocean primary production (OPP) and there were a lot of research findings of estimating fish production by using OPP in China. The relationships between the biomass of fishery stock and OPP were often complicated by the varieties of trophic control in the ecosystem. In this paper, we examined the relationship between biomass of chub mackerel (Scomber japonicus) and net primary production (NPP) and discussed mechanism of trophic control in the ecosystem of chub mackerel fishing ground in south East China Sea by using catch and effort data from the large purse sense of China fishery and NPP derived from remote sensing. The results showed there was a significant non-linear relationship between NPP and standardized CPUE (Catch Per Unit Effort) (P<0.05) instead of the linear trend. The non-linear relationship could be described by a reversed parabolic curve, which meant the biomass of chub mackerel increased with NPP and then decreased when the NPP exceeded a point. The results implied there were other trophic controls in addition to bottom-up control occurred in the ecosystem in south East China Sea. We speculated the change of abundance of the key species at intermediate trophic levels or/and interspecific competitions contribute to the relationship.
Abstract：The potential fish production was controlled largely by ocean primary production (OPP) and there were a lot of research findings of estimating fish production by using OPP in China. The relationships between the biomass of fishery stock and OPP were often complicated by the varieties of trophic control in the ecosystem. In this paper, we examined the relationship between biomass of chub mackerel (Scomber japonicus) and net primary production (NPP) and discussed mechanism of trophic control in the ecosystem of chub mackerel fishing ground in south East China Sea by using catch and effort data from the large purse sense of China fishery and NPP derived from remote sensing. The results showed there was a significant non-linear relationship between NPP and standardized CPUE (Catch Per Unit Effort) (P<0.05) instead of the linear trend. The non-linear relationship could be described by a reversed parabolic curve, which meant the biomass of chub mackerel increased with NPP and then decreased when the NPP exceeded a point. The results implied there were other trophic controls in addition to bottom-up control occurred in the ecosystem in south East China Sea. We speculated the change of abundance of the key species at intermediate trophic levels or/and interspecific competitions contribute to the relationship.
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