Pub Date : 2025-01-22DOI: 10.3389/fmars.2024.1521036
Sung-Uk An, Kyung-Tae Kim, Sung-Han Kim, Ju-Wook Baek, Hyun-Jeong Jeong, Chul-In Sun, Jin Young Choi, Sokjin Hong, Dae In Lee, Jae Seong Lee
The mineralization of organic matter at the sediment plays a crucial role in ecosystem functioning by facilitating the biogeochemical cycling of carbon and nutrients. This process not only supports nutrient availability for primary production but also regulates the long-term storage of carbon within sediments. To understand the biogeochemical processes associated with organic matter mineralization and nutrient regeneration, we estimated total and diffusive sediment oxygen uptake rates, benthic nutrient fluxes, and organic carbon (OC) budgets at four sites in the semi-enclosed Jinhae Bay (JB). The total oxygen uptake (TOU) rates ranged from 38.4 to 49.6 mmol O2 m–2 d–1, and diffusive oxygen uptake (DOU) rates ranged from 12.3 ± 1.8 to 15.1 ± 1.4 mmol O2 m–2 d–1. The average ratio of TOU : DOU ranged from 3.12 to 3.28 over JB, which suggests significant benthic faunal activities in JB sediments. The vertical flux of organic carbon ranged from 45.5 ± 7.0 to 93.0 ± 25.3 mmol C m-2 d–1, and mainly consisted of biodeposits associated with aquaculture activities. The burial flux into the sediment ranged from 3.96 ± 1.00 to 7.17 ± 1.64 mmol C m–2 d–1, and burial efficiencies were 4.25 to 15.8%, which indicated that deposited organic carbon was either mineralized in surface sediment before burial or laterally transferred by resuspension. The benthic nutrient fluxes at four sites ranged from 1.50 to 2.07 mmol m–2 d–1 for nitrogen, from 0.02 to 0.05 mmol m–2 d–1 for phosphate, and from 6.72 to 9.11 mmol m–2 d–1 for silicate. The benthic nitrogen and phosphate fluxes accounted for 82.1 to 149% and 23.1 to 57.6%, respectively, of the required levels for primary production in the water column. Our results suggest that OC oxidation in the JB sediment may significantly contribute to the biogeochemical OC cycles and tight benthic–pelagic coupling associated with nutrient regeneration.
{"title":"Biogeochemical cycling of sedimentary organic carbon and benthic nutrient fluxes in the semi-enclosed Jinhae Bay, Korea: insights into benthic-pelagic coupling","authors":"Sung-Uk An, Kyung-Tae Kim, Sung-Han Kim, Ju-Wook Baek, Hyun-Jeong Jeong, Chul-In Sun, Jin Young Choi, Sokjin Hong, Dae In Lee, Jae Seong Lee","doi":"10.3389/fmars.2024.1521036","DOIUrl":"https://doi.org/10.3389/fmars.2024.1521036","url":null,"abstract":"The mineralization of organic matter at the sediment plays a crucial role in ecosystem functioning by facilitating the biogeochemical cycling of carbon and nutrients. This process not only supports nutrient availability for primary production but also regulates the long-term storage of carbon within sediments. To understand the biogeochemical processes associated with organic matter mineralization and nutrient regeneration, we estimated total and diffusive sediment oxygen uptake rates, benthic nutrient fluxes, and organic carbon (OC) budgets at four sites in the semi-enclosed Jinhae Bay (JB). The total oxygen uptake (TOU) rates ranged from 38.4 to 49.6 mmol O<jats:sub>2</jats:sub> m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup>, and diffusive oxygen uptake (DOU) rates ranged from 12.3 ± 1.8 to 15.1 ± 1.4 mmol O<jats:sub>2</jats:sub> m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup>. The average ratio of TOU : DOU ranged from 3.12 to 3.28 over JB, which suggests significant benthic faunal activities in JB sediments. The vertical flux of organic carbon ranged from 45.5 ± 7.0 to 93.0 ± 25.3 mmol C m<jats:sup>-2</jats:sup> d<jats:sup>–1</jats:sup>, and mainly consisted of biodeposits associated with aquaculture activities. The burial flux into the sediment ranged from 3.96 ± 1.00 to 7.17 ± 1.64 mmol C m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup>, and burial efficiencies were 4.25 to 15.8%, which indicated that deposited organic carbon was either mineralized in surface sediment before burial or laterally transferred by resuspension. The benthic nutrient fluxes at four sites ranged from 1.50 to 2.07 mmol m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup> for nitrogen, from 0.02 to 0.05 mmol m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup> for phosphate, and from 6.72 to 9.11 mmol m<jats:sup>–2</jats:sup> d<jats:sup>–1</jats:sup> for silicate. The benthic nitrogen and phosphate fluxes accounted for 82.1 to 149% and 23.1 to 57.6%, respectively, of the required levels for primary production in the water column. Our results suggest that OC oxidation in the JB sediment may significantly contribute to the biogeochemical OC cycles and tight benthic–pelagic coupling associated with nutrient regeneration.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"33 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020253","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 : 2025-01-22DOI: 10.3389/fmars.2024.1523111
Wenlong Xu, Shuibo Hu, Alex Hayward, Zuomin Wang, Shuaiwei Liu
Understanding the variability of bio-optical properties in coastal seas is essential to assessing the impact of natural and anthropogenic activities on the quality of the coastal environments and their resources. This study investigated the vertical distribution of bio-optical properties and their potential driving forces in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) using a bio-optical dataset collected during the winter dry season. The hydrographic and biogeochemical properties observed across the GBA exhibited significant spatial variability, allowing the classification of the waters into three distinct regions: estuarine diluted water (EDW), Guangdong coastal current water (GCCW), and dense shelf water (DSW). Our findings show that EDW exhibited beam attenuation and optical backscatter coefficients an order of magnitude greater compared to the other two regions, which was attributed to factors such as higher concentrations of suspended particulate matter and organic material from estuarine sources. In contrast, the GCCW was characterized by lower salinity, temperature, and suspended particulate matter and displayed reduced turbidity near the coast, whereas nutrient-rich GCCW waters transported to the mid-shelf region supported increased phytoplankton biomass and a greater abundance of micro-phytoplankton. By exploring the bio-optical characteristics and their underlying processes in the GBA, this study enhances our understanding of the complex dynamics shaping the optical properties of coastal waters in this heavily urbanized region.
{"title":"Physical drivers of bio-optical properties in the Guangdong-Hong Kong-Macao Greater Bay Area during the winter dry season","authors":"Wenlong Xu, Shuibo Hu, Alex Hayward, Zuomin Wang, Shuaiwei Liu","doi":"10.3389/fmars.2024.1523111","DOIUrl":"https://doi.org/10.3389/fmars.2024.1523111","url":null,"abstract":"Understanding the variability of bio-optical properties in coastal seas is essential to assessing the impact of natural and anthropogenic activities on the quality of the coastal environments and their resources. This study investigated the vertical distribution of bio-optical properties and their potential driving forces in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) using a bio-optical dataset collected during the winter dry season. The hydrographic and biogeochemical properties observed across the GBA exhibited significant spatial variability, allowing the classification of the waters into three distinct regions: estuarine diluted water (EDW), Guangdong coastal current water (GCCW), and dense shelf water (DSW). Our findings show that EDW exhibited beam attenuation and optical backscatter coefficients an order of magnitude greater compared to the other two regions, which was attributed to factors such as higher concentrations of suspended particulate matter and organic material from estuarine sources. In contrast, the GCCW was characterized by lower salinity, temperature, and suspended particulate matter and displayed reduced turbidity near the coast, whereas nutrient-rich GCCW waters transported to the mid-shelf region supported increased phytoplankton biomass and a greater abundance of micro-phytoplankton. By exploring the bio-optical characteristics and their underlying processes in the GBA, this study enhances our understanding of the complex dynamics shaping the optical properties of coastal waters in this heavily urbanized region.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"84 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020203","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 : 2025-01-22DOI: 10.3389/fmars.2024.1451997
Man Liang, Annie Foppert, Karen J. Westwood, Sophie Bestley
In the Indian sector of the Southern Ocean, 80°E marks an important transition in ocean circulation between the greater Prydz Bay gyre to the west and the Australian Antarctic gyre to the east. Here, the submarine Kerguelen Plateau impedes the eastward flow of the Antarctic Circumpolar Current (ACC), topographically steering the flow. Enhanced biological productivity associated with the southern plateau supports an important marine ecosystem with many foraging marine predators. We collate ship-based hydrographic data on the vertical structure of the upper water column near 80°E from eight voyages spanning 1994 to 2021, from 58°S towards the Antarctic continent. The study aims to investigate the mixed layer oceanography, the implications for nutrient supply from deep to near-surface waters, and associated biological production. Our results show that the major oceanographic fronts are constrained within the narrow Princess Elizabeth Trough, between the southern Kerguelen Plateau and the Antarctic slope. Therefore, the Southern Boundary and the Southern ACC Front (SACCF) are often co-located, albeit with some interannual variability, with the location of the SACCF ranging from roughly 63°S to 65°S. The average depth of the seasonal mixed layer ranges from 34-49 m, typically deepening from south to north, in association with longer time since sea-ice melt. Below the mixed layer, Winter Water (WW) characteristics also vary across the observed latitudinal range; typically the temperature and thickness of the WW layer are inversely related, with warmer WW layers being thinner. Subsurface nitrate concentrations range from 20-40 µM, while silicate concentrations reach 100 µM. Nutrient drawdown is calculated based on mean concentrations in the mixed layer and WW layer, with drawdown values at individual stations reaching nearly 12 µM and 60 µM for nitrate and silicate, respectively, and a positive correlation between the two. Nutrient drawdown was higher in association with longer time since sea-ice melt and with thinner WW layers, while higher nitrate-based production was associated with deeper mixed layers. Observed relationships between upper water column characteristics and biological processes are discussed in terms of likely nutrient supply mechanisms and seasonal patterns of utilization.
{"title":"Observed upper-ocean structure and seasonal production in the southern Kerguelen Plateau region, 1994-2021","authors":"Man Liang, Annie Foppert, Karen J. Westwood, Sophie Bestley","doi":"10.3389/fmars.2024.1451997","DOIUrl":"https://doi.org/10.3389/fmars.2024.1451997","url":null,"abstract":"In the Indian sector of the Southern Ocean, 80°E marks an important transition in ocean circulation between the greater Prydz Bay gyre to the west and the Australian Antarctic gyre to the east. Here, the submarine Kerguelen Plateau impedes the eastward flow of the Antarctic Circumpolar Current (ACC), topographically steering the flow. Enhanced biological productivity associated with the southern plateau supports an important marine ecosystem with many foraging marine predators. We collate ship-based hydrographic data on the vertical structure of the upper water column near 80°E from eight voyages spanning 1994 to 2021, from 58°S towards the Antarctic continent. The study aims to investigate the mixed layer oceanography, the implications for nutrient supply from deep to near-surface waters, and associated biological production. Our results show that the major oceanographic fronts are constrained within the narrow Princess Elizabeth Trough, between the southern Kerguelen Plateau and the Antarctic slope. Therefore, the Southern Boundary and the Southern ACC Front (SACCF) are often co-located, albeit with some interannual variability, with the location of the SACCF ranging from roughly 63°S to 65°S. The average depth of the seasonal mixed layer ranges from 34-49 m, typically deepening from south to north, in association with longer time since sea-ice melt. Below the mixed layer, Winter Water (WW) characteristics also vary across the observed latitudinal range; typically the temperature and thickness of the WW layer are inversely related, with warmer WW layers being thinner. Subsurface nitrate concentrations range from 20-40 µM, while silicate concentrations reach 100 µM. Nutrient drawdown is calculated based on mean concentrations in the mixed layer and WW layer, with drawdown values at individual stations reaching nearly 12 µM and 60 µM for nitrate and silicate, respectively, and a positive correlation between the two. Nutrient drawdown was higher in association with longer time since sea-ice melt and with thinner WW layers, while higher nitrate-based production was associated with deeper mixed layers. Observed relationships between upper water column characteristics and biological processes are discussed in terms of likely nutrient supply mechanisms and seasonal patterns of utilization.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"74 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020202","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 : 2025-01-22DOI: 10.3389/fmars.2024.1462326
James T. McArdle, Julie S. Barber, Sarah K. Grossman, Lindy L. Hunter
Overexploitation and degradation of water quality nearly depleted Olympia oyster stocks in Puget Sound, Washington, USA by the early 1900s. With an intended goal of creating self-sustaining Olympia oyster populations in a target region in Puget Sound, the Swinomish Indian Tribal Community began reestablishing Olympia oysters at two different sites, Kiket and Lone Tree, from 2015-2017. One of our primary objectives was to quantify the biological successes or failures of our reestablished populations. Our results provide a guide for the evolution of project-specific, evidence-based restoration plans that could allow for further use of adaptive management and conservation aquaculture. Following the creation of experimental plots and restoration beds across two sites using 735 m² of shell habitat, including 245 m² of seeded cultch, we measured temporal change in oyster length and density as proxies for growth, recruitment, and survival. Significant growth was observed each year in each lagoon. Despite the known presence of brooding oysters and competent larvae in the region, we found no evidence of recruitment at either site through six years of monitoring. Survival decreased significantly each year and at each site. Thus, while we quantify evidence of growth and reproduction, we are not meeting the success metrics of recruitment or survival therefore hindering the chances of long-term success. We hypothesize that our restoration efforts are hampered by the relatively small population size within our restored areas, insufficient amounts of appropriate surrounding habitat, and lower water residence time. Our study suggests managers need to consistently monitor restoration projects due to site-specific differences and to determine if local failure is a possibility. Low survival and recruitment do not necessitate termination of projects. However, these measurements do suggest that projects like ours need to consider expanding use of conservation aquaculture as a tool or employing adaptive management by developing and implementing novel strategies to increase naturally-occurring adult populations and available habitat.
{"title":"Planning for success but facing uncertainty: lessons learned from a native oyster, Ostrea lurida, restoration project in the Salish Sea","authors":"James T. McArdle, Julie S. Barber, Sarah K. Grossman, Lindy L. Hunter","doi":"10.3389/fmars.2024.1462326","DOIUrl":"https://doi.org/10.3389/fmars.2024.1462326","url":null,"abstract":"Overexploitation and degradation of water quality nearly depleted Olympia oyster stocks in Puget Sound, Washington, USA by the early 1900s. With an intended goal of creating self-sustaining Olympia oyster populations in a target region in Puget Sound, the Swinomish Indian Tribal Community began reestablishing Olympia oysters at two different sites, Kiket and Lone Tree, from 2015-2017. One of our primary objectives was to quantify the biological successes or failures of our reestablished populations. Our results provide a guide for the evolution of project-specific, evidence-based restoration plans that could allow for further use of adaptive management and conservation aquaculture. Following the creation of experimental plots and restoration beds across two sites using 735 m² of shell habitat, including 245 m² of seeded cultch, we measured temporal change in oyster length and density as proxies for growth, recruitment, and survival. Significant growth was observed each year in each lagoon. Despite the known presence of brooding oysters and competent larvae in the region, we found no evidence of recruitment at either site through six years of monitoring. Survival decreased significantly each year and at each site. Thus, while we quantify evidence of growth and reproduction, we are not meeting the success metrics of recruitment or survival therefore hindering the chances of long-term success. We hypothesize that our restoration efforts are hampered by the relatively small population size within our restored areas, insufficient amounts of appropriate surrounding habitat, and lower water residence time. Our study suggests managers need to consistently monitor restoration projects due to site-specific differences and to determine if local failure is a possibility. Low survival and recruitment do not necessitate termination of projects. However, these measurements do suggest that projects like ours need to consider expanding use of conservation aquaculture as a tool or employing adaptive management by developing and implementing novel strategies to increase naturally-occurring adult populations and available habitat.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"8 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020205","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}
Intelligent ship monitoring technology, driven by its exceptional data fitting ability, has emerged as a crucial component within the field of intelligent maritime perception. However, existing deep learning-based ship monitoring studies primarily focus on minimizing the discrepancy between predicted and true labels during model training. This approach, unfortunately, restricts the model to learning only from labeled ship samples within the training set, limiting its capacity to recognize new and unseen ship categories. To address this challenge and enhance the model’s generalization ability and adaptability, a novel framework is presented, termed MultiAngle Metric Networks. The proposed framework incorporates ResNet as its foundation. By employing a novel multi-scale loss function and a new similarity measure, the framework effectively learns ship patterns by minimizing sample distances within the same category and maximizing distances between samples of different categories. The experimental results indicate that the proposed framework achieves the highest level of ship monitoring accuracy when evaluated on three distinct ship monitoring datasets. Even in the case of unfamiliar ships, where the detection performance of conventional models significantly deteriorates, the framework maintains stable and efficient detection capabilities. These experimental results highlight the framework’s ability to effectively generalize its understanding beyond the training samples and adapt to real-world scenarios.
{"title":"Addressing unfamiliar ship type recognition in real-scenario vessel monitoring: a multi-angle metric networks framework","authors":"Jiahua Sun, Jiawen Li, Ronghui Li, Langtao Wu, Liang Cao, Molin Sun","doi":"10.3389/fmars.2024.1516586","DOIUrl":"https://doi.org/10.3389/fmars.2024.1516586","url":null,"abstract":"Intelligent ship monitoring technology, driven by its exceptional data fitting ability, has emerged as a crucial component within the field of intelligent maritime perception. However, existing deep learning-based ship monitoring studies primarily focus on minimizing the discrepancy between predicted and true labels during model training. This approach, unfortunately, restricts the model to learning only from labeled ship samples within the training set, limiting its capacity to recognize new and unseen ship categories. To address this challenge and enhance the model’s generalization ability and adaptability, a novel framework is presented, termed MultiAngle Metric Networks. The proposed framework incorporates ResNet as its foundation. By employing a novel multi-scale loss function and a new similarity measure, the framework effectively learns ship patterns by minimizing sample distances within the same category and maximizing distances between samples of different categories. The experimental results indicate that the proposed framework achieves the highest level of ship monitoring accuracy when evaluated on three distinct ship monitoring datasets. Even in the case of unfamiliar ships, where the detection performance of conventional models significantly deteriorates, the framework maintains stable and efficient detection capabilities. These experimental results highlight the framework’s ability to effectively generalize its understanding beyond the training samples and adapt to real-world scenarios.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"12 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020207","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 : 2025-01-21DOI: 10.3389/fmars.2024.1509455
Gabriel Dax Anderson
Coral reefs are experiencing more intense and frequent disturbances induced by climate change, such as cyclones and bleaching events. This necessitates a better understanding of the ongoing environmental conditions that stress these systems and the subsequent arc of longer-term reef responses to these stressful conditions. From March of 2014 to May of 2017, the Lizard Island reefs in the northern region of the Great Barrier Reef experienced four consecutive annual disturbances; Cyclone Ita in 2014, Cyclone Nathan in 2015, and two massive bleaching events in 2016 and 2017. Between the concentrated patches of physical damage from the cyclones and the uniform impact of the bleaching events, these reefs were devastated, with none of the eight study sites harboring more than 20% live coral cover by May of 2017. In November of 2023, after six years of relatively calmer conditions with no conspicuous region-wide, large-scale disturbances, I documented the extant coral community on eight previously-monitored reefs around Lizard Island. All reefs showed significant (p = 0.0054, F = 3.46, df = 47) improvement from their 2017 immediate post-disturbance degradation. Living coral at my study sites had recovered to between 18.4 ± 0.6 (mean ± 1 SE) to 59.9 ± 5.3% of the reef area per site by 2023, with many sites towards the higher end of that range. Recovery of coral extent appeared to follow a north-south trend in which more Trade Wind-sheltered northerly sites had generally greater recovery and higher live coral cover compared to more exposed southern sites, which experienced significantly less coral recovery. Fast-growing Acroporid corals drove the recovery of coral extent in these more northern sites. While family richness across all sites improved by 2023 (4.0 ± 0.1; grand mean ± 1 se), Lizard Island reefs have yet to reach their pre-disturbance diversity (4.8 ± 0.6 in 2014). Future annual surveys of the study sites as well as others surveyed in 2017 may better clarify the relationship between reef location and the rate of recovery of coral cover post-disturbance.
{"title":"Recovery of coral cover at Lizard island Australia 6 years post-disturbance","authors":"Gabriel Dax Anderson","doi":"10.3389/fmars.2024.1509455","DOIUrl":"https://doi.org/10.3389/fmars.2024.1509455","url":null,"abstract":"Coral reefs are experiencing more intense and frequent disturbances induced by climate change, such as cyclones and bleaching events. This necessitates a better understanding of the ongoing environmental conditions that stress these systems and the subsequent arc of longer-term reef responses to these stressful conditions. From March of 2014 to May of 2017, the Lizard Island reefs in the northern region of the Great Barrier Reef experienced four consecutive annual disturbances; Cyclone Ita in 2014, Cyclone Nathan in 2015, and two massive bleaching events in 2016 and 2017. Between the concentrated patches of physical damage from the cyclones and the uniform impact of the bleaching events, these reefs were devastated, with none of the eight study sites harboring more than 20% live coral cover by May of 2017. In November of 2023, after six years of relatively calmer conditions with no conspicuous region-wide, large-scale disturbances, I documented the extant coral community on eight previously-monitored reefs around Lizard Island. All reefs showed significant (<jats:italic>p</jats:italic> = 0.0054, F = 3.46, df = 47) improvement from their 2017 immediate post-disturbance degradation. Living coral at my study sites had recovered to between 18.4 ± 0.6 (mean ± 1 SE) to 59.9 ± 5.3% of the reef area per site by 2023, with many sites towards the higher end of that range. Recovery of coral extent appeared to follow a north-south trend in which more Trade Wind-sheltered northerly sites had generally greater recovery and higher live coral cover compared to more exposed southern sites, which experienced significantly less coral recovery. Fast-growing Acroporid corals drove the recovery of coral extent in these more northern sites. While family richness across all sites improved by 2023 (4.0 ± 0.1; grand mean ± 1 se), Lizard Island reefs have yet to reach their pre-disturbance diversity (4.8 ± 0.6 in 2014). Future annual surveys of the study sites as well as others surveyed in 2017 may better clarify the relationship between reef location and the rate of recovery of coral cover post-disturbance.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"33 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992339","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 : 2025-01-21DOI: 10.3389/fmars.2024.1529684
Bin Wang, Jingjing Li, Mingzhi Zhang, Anqi Li, Zhentao Song, Zhen He, Ruiqi Zhang, Tong Hao, Jinsheng Sun
IntroductionThe molting processes are crucial for the survival and development of crustaceans. Eriocheir sinensis demonstrates representative discontinuous growth during molting, while muscle is the most obvious tissue exhibiting this property. However, the signal regulation mechanisms involved in muscle during molting remain unexplored.MethodsIn this work, a comprehensive analysis of the gene expressions in E. sinensis muscle between post-molt and inter-molt stages were performed by integrating the ATAC-seq and RNA-seq techniques.ResultsThe integration analysis identified 446 up-regulated and 21 down-regulated genes in the two stages. GO enrichment analysis revealed that the up-regulated genes are largely associated with protein phosphorylation and phosphorus metabolism, while the down-regulated genes are mainly involved in DNA metabolism, transcription, cell adhesion, and G protein-coupled receptor (GPCR) signaling pathway. In all the enriched signaling pathways, GPCR signaling pathway includes the most differentially expressed genes (8 genes), which underlines its importance in the signal transduction from the post-molt stage to the inter-molt stage. Further protein structure analysis and RT-qPCR validation confirmed five GPCR genes related to molting process, in which four genes (GRM7, FMRFaR, mth2, gpr161) are active during the post-molt stage and one gene (moody) functions during the inter-molt stage.DiscussionThese findings highlight the key regulatory proteins and pathways involved in E. sinensis muscle during molting and also offer foundational data for studying the mechanisms of molting and discontinuous growth in crustaceans.
{"title":"Integration of ATAC-seq and RNA-seq reveals signal regulation during post-molt and inter-molt stages in muscle of Eriocheir sinensis","authors":"Bin Wang, Jingjing Li, Mingzhi Zhang, Anqi Li, Zhentao Song, Zhen He, Ruiqi Zhang, Tong Hao, Jinsheng Sun","doi":"10.3389/fmars.2024.1529684","DOIUrl":"https://doi.org/10.3389/fmars.2024.1529684","url":null,"abstract":"IntroductionThe molting processes are crucial for the survival and development of crustaceans. <jats:italic>Eriocheir sinensis</jats:italic> demonstrates representative discontinuous growth during molting, while muscle is the most obvious tissue exhibiting this property. However, the signal regulation mechanisms involved in muscle during molting remain unexplored.MethodsIn this work, a comprehensive analysis of the gene expressions in E. sinensis muscle between post-molt and inter-molt stages were performed by integrating the ATAC-seq and RNA-seq techniques.ResultsThe integration analysis identified 446 up-regulated and 21 down-regulated genes in the two stages. GO enrichment analysis revealed that the up-regulated genes are largely associated with protein phosphorylation and phosphorus metabolism, while the down-regulated genes are mainly involved in DNA metabolism, transcription, cell adhesion, and G protein-coupled receptor (GPCR) signaling pathway. In all the enriched signaling pathways, GPCR signaling pathway includes the most differentially expressed genes (8 genes), which underlines its importance in the signal transduction from the post-molt stage to the inter-molt stage. Further protein structure analysis and RT-qPCR validation confirmed five GPCR genes related to molting process, in which four genes (<jats:italic>GRM7, FMRFaR, mth2, gpr161</jats:italic>) are active during the post-molt stage and one gene (<jats:italic>moody</jats:italic>) functions during the inter-molt stage.DiscussionThese findings highlight the key regulatory proteins and pathways involved in <jats:italic>E. sinensis</jats:italic> muscle during molting and also offer foundational data for studying the mechanisms of molting and discontinuous growth in crustaceans.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"13 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142991599","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 : 2025-01-21DOI: 10.3389/fmars.2024.1456505
Marta Peña Fernández, Josh Williams, Janina V. Büscher, J. Murray Roberts, Sebastian J. Hennige, Uwe Wolfram
The structural complexity of cold-water corals is threatened by ocean acidification. Increased porosity and thinning in structurally critical parts of the reef framework may lead to rapid physical collapse on an ecosystem scale, reducing their potential for biodiversity support. Understanding the structural-mechanical relationships of reef-forming corals is important to enable the use of in silico mechanical models as predictive tools that allow us to determine risk and timescales of reef collapse. Here, we analyze morphological variations of the branching architecture of the cold-water coral species Lophelia pertusa to advance mechanical in silico models based on their skeletal structure. We identified a critical size of five interbranch lengths that allows using homogenized finite element models to analyze mechanical competence. At smaller length scales, mechanical surrogate models need to explicitly account for the statistical morphological differences in the skeletal structure. We showed large morphological variations between fragments of L. pertusa colonies and branches, as well as dead and live skeletal fragments which are driven by growth and adaptation to environmental stressors, with no clear branching-specific patterns. Future in silico mechanical models should statistically model these variations to be used as monitoring tools for predicting risk of cold-water coral reefs crumbling.
{"title":"Morphological analysis of cold-water coral skeletons for evaluating in silico mechanical models of reef-scale crumbling","authors":"Marta Peña Fernández, Josh Williams, Janina V. Büscher, J. Murray Roberts, Sebastian J. Hennige, Uwe Wolfram","doi":"10.3389/fmars.2024.1456505","DOIUrl":"https://doi.org/10.3389/fmars.2024.1456505","url":null,"abstract":"The structural complexity of cold-water corals is threatened by ocean acidification. Increased porosity and thinning in structurally critical parts of the reef framework may lead to rapid physical collapse on an ecosystem scale, reducing their potential for biodiversity support. Understanding the structural-mechanical relationships of reef-forming corals is important to enable the use of <jats:italic>in silico</jats:italic> mechanical models as predictive tools that allow us to determine risk and timescales of reef collapse. Here, we analyze morphological variations of the branching architecture of the cold-water coral species <jats:italic>Lophelia pertusa</jats:italic> to advance mechanical <jats:italic>in silico</jats:italic> models based on their skeletal structure. We identified a critical size of five interbranch lengths that allows using homogenized finite element models to analyze mechanical competence. At smaller length scales, mechanical surrogate models need to explicitly account for the statistical morphological differences in the skeletal structure. We showed large morphological variations between fragments of <jats:italic>L. pertusa</jats:italic> colonies and branches, as well as <jats:italic>dead</jats:italic> and <jats:italic>live</jats:italic> skeletal fragments which are driven by growth and adaptation to environmental stressors, with no clear branching-specific patterns. Future <jats:italic>in silico</jats:italic> mechanical models should statistically model these variations to be used as monitoring tools for predicting risk of cold-water coral reefs crumbling.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"20 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992335","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 : 2025-01-21DOI: 10.3389/fmars.2024.1536363
Dan Liu, Ling Ke, Zhe Zeng, Shuo Zhang, Shanwei Liu
Sea fog is a severe marine environmental disaster that significantly threatens the safety of maritime transportation. It is a major environmental factor contributing to ship collisions. The Himawari-8 satellite’s remote sensing capabilities effectively bridge the spatial and temporal gaps in data from traditional meteorological stations for sea fog detection. Therefore, the study of the influence of sea fog on ship collisions becomes feasible and is highly significant. To investigate the spatial and temporal effects of sea fog on vessel near-miss collisions, this paper proposes a general-purpose framework for analyzing the spatial and temporal correlations between satellite-derived large-scale sea fog using a machine learning model and the near-miss collisions detected by the automatic identification system through the Vessel Conflict Ranking Operator. First, sea fog-sensitive bands from the Himawari-8 satellite, combined with the Normalized Difference Snow Index (NDSI), are chosen as features, and an SVM model is employed for sea fog detection. Second, the geographically weighted regression model investigates spatial variations in the correlation between sea fog and near-miss collisions. Third, we perform the analysis for monthly time series data to investigate the within-year seasonal dynamics and fluctuations. The proposed framework is implemented in a case study using the Bohai Sea as an example. It shows that in large harbor areas with high ship density (such as Tangshan Port and Tianjin Port), sea fog contributes significantly to near-miss collisions, with local regression coefficients greater than 0.4. While its impact is less severe in the central Bohai Sea due to the open waters. Temporally, the contribution of sea fog to near-miss collisions is more pronounced in fall and winter, while it is lowest in summer. This study sheds light on how the spatial and temporal patterns of sea fog, derived from satellite remote sensing data, contribute to the risk of near-miss collisions, which may help in navigational decisions to reduce the risk of ship collisions.
{"title":"Machine learning-based analysis of sea fog’s spatial and temporal impact on near-miss ship collisions using remote sensing and AIS data","authors":"Dan Liu, Ling Ke, Zhe Zeng, Shuo Zhang, Shanwei Liu","doi":"10.3389/fmars.2024.1536363","DOIUrl":"https://doi.org/10.3389/fmars.2024.1536363","url":null,"abstract":"Sea fog is a severe marine environmental disaster that significantly threatens the safety of maritime transportation. It is a major environmental factor contributing to ship collisions. The Himawari-8 satellite’s remote sensing capabilities effectively bridge the spatial and temporal gaps in data from traditional meteorological stations for sea fog detection. Therefore, the study of the influence of sea fog on ship collisions becomes feasible and is highly significant. To investigate the spatial and temporal effects of sea fog on vessel near-miss collisions, this paper proposes a general-purpose framework for analyzing the spatial and temporal correlations between satellite-derived large-scale sea fog using a machine learning model and the near-miss collisions detected by the automatic identification system through the Vessel Conflict Ranking Operator. First, sea fog-sensitive bands from the Himawari-8 satellite, combined with the Normalized Difference Snow Index (NDSI), are chosen as features, and an SVM model is employed for sea fog detection. Second, the geographically weighted regression model investigates spatial variations in the correlation between sea fog and near-miss collisions. Third, we perform the analysis for monthly time series data to investigate the within-year seasonal dynamics and fluctuations. The proposed framework is implemented in a case study using the Bohai Sea as an example. It shows that in large harbor areas with high ship density (such as Tangshan Port and Tianjin Port), sea fog contributes significantly to near-miss collisions, with local regression coefficients greater than 0.4. While its impact is less severe in the central Bohai Sea due to the open waters. Temporally, the contribution of sea fog to near-miss collisions is more pronounced in fall and winter, while it is lowest in summer. This study sheds light on how the spatial and temporal patterns of sea fog, derived from satellite remote sensing data, contribute to the risk of near-miss collisions, which may help in navigational decisions to reduce the risk of ship collisions.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"22 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992338","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 : 2025-01-21DOI: 10.3389/fmars.2024.1538136
Chengqian Pan, Syed Shams ul Hassan, Ishaq Muhammad, Huizi Jin
The microbial diversity in oceans is considerable, widely distributed in seawater, marine sediments, and marine organisms. Compared with terrestrial resources in traditional natural product research, the living environments of marine microorganisms are starkly different. The drastic differences in survival conditions, such as high salinity, oligotrophic conditions, lack of light, and limited oxygen, determine that microorganisms exhibit distinctive characteristics in metabolism, survival modes, and adaptive mechanisms. These factors contribute to significant distinctions in secondary metabolic pathways and enzymatic reaction mechanisms between marine and terrestrial microorganisms. In this review, we summarized a total of 72 novel natural products with antibacterial activity, published in 2024, which are derived from marine-derived fungi. These products (polyketides, alkaloids, terpenoids, and peptides) are emphasized in terms of their structures and biological activities. This article aims to provide useful information for the research and development of novel antibiotics.
{"title":"Marine fungi as a goldmine for novel antibiotics: a 2024 perspective","authors":"Chengqian Pan, Syed Shams ul Hassan, Ishaq Muhammad, Huizi Jin","doi":"10.3389/fmars.2024.1538136","DOIUrl":"https://doi.org/10.3389/fmars.2024.1538136","url":null,"abstract":"The microbial diversity in oceans is considerable, widely distributed in seawater, marine sediments, and marine organisms. Compared with terrestrial resources in traditional natural product research, the living environments of marine microorganisms are starkly different. The drastic differences in survival conditions, such as high salinity, oligotrophic conditions, lack of light, and limited oxygen, determine that microorganisms exhibit distinctive characteristics in metabolism, survival modes, and adaptive mechanisms. These factors contribute to significant distinctions in secondary metabolic pathways and enzymatic reaction mechanisms between marine and terrestrial microorganisms. In this review, we summarized a total of 72 novel natural products with antibacterial activity, published in 2024, which are derived from marine-derived fungi. These products (polyketides, alkaloids, terpenoids, and peptides) are emphasized in terms of their structures and biological activities. This article aims to provide useful information for the research and development of novel antibiotics.","PeriodicalId":12479,"journal":{"name":"Frontiers in Marine Science","volume":"11 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992340","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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