Bathymetric measurement of shallow water is of fundamental importance to coastal environment research and resource management.However,there are still great challenges in estimating water depth using satellite observat...Bathymetric measurement of shallow water is of fundamental importance to coastal environment research and resource management.However,there are still great challenges in estimating water depth using satellite observations in turbid coastal waters.In this paper,we developed a physicsenhanced deep neural network to estimate bathymetry of highly turbid waters of the Changjiang(Yangtze)River estuary from dual-polarized synthetic aperture radar(SAR)images.Sentinel-1A/B SAR images with a spatial resolution of 20 m×22 m were collected and matched with water depth data from nautical charts during 2017-2023.For the input parameters of the model,in addition to the normalized radar backscatter cross section(NRCS)at single polarization and incidence angle,the impacts of both polarimetric characteristics and physical environmental factors on model performance were discussed in detail.Results of feature importance analysis and sensitivity experiments indicate that the polarization ratio and NRCS after removing the influence of background sea surface wind field make significant contributions to the bathymetry retrieval model.The root mean square error(RMSE)of SAR derived water depth decreases from 1.44 to 0.78 m within 0-30-m depth,and the mean relative error(MRE)is reduced from 15.6%to 8.6%.Compared with other machine learning models such as ResNet,XGBoost,and Random Forest,the MRE is reduced by 3.9%,5.7%,and 7.4%,respectively.The spatial distribution of SAR derived water depth also exhibits a high degree of consistency with observations,demonstrating the great potential of the model in estimating the depth of turbid shallow waters.展开更多
Retrogressive landslides in sensitive clays pose significant risks to nearby infrastructure,as natural toe erosion or localized disturbances can trigger progressive block failures.While prior studies have largely reli...Retrogressive landslides in sensitive clays pose significant risks to nearby infrastructure,as natural toe erosion or localized disturbances can trigger progressive block failures.While prior studies have largely relied on two-dimensional(2D)large-deformation analyses,such models overlook key three-dimensional(3D)failure mechanisms and variability effects.This study develops a 3D probabilistic framework by integrating the Coupled Eulerian–Lagrangian(CEL)method with random field theory to simulate retrogressive landslides in spatially variable clay.Using Monte Carlo simulations,we compare 2D and 3D random large-deformation models to evaluate failure modes,runout distances,sliding velocities,and influence zones.The 3D analyses captured more complex failure modes—such as lateral retrogression and asynchronous block mobilization across slope width.Additionally,the 3D analyses predict longer mean runout distances(13.76 vs.11.92 m),wider mean influence distance(11.35 vs.8.73 m),and higher mean sliding velocities(4.66 vs.3.94 m/s)than their 2D counterparts.Moreover,3D models exhibit lower coefficients of variation(e.g.,0.10 for runout distance)due to spatial averaging across slope width.Probabilistic hazard assessment shows that 2D models significantly underpredict near-field failure probabilities(e.g.,48.8%vs.89.9%at 12 m from the slope toe).These findings highlight the limitations of 2D analyses and the importance of multi-directional spatial variability for robust geohazard assessments.The proposed 3D framework enables more realistic prediction of landslide mobility and supports the design of safer,risk-informed infrastructure.展开更多
Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impac...Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.展开更多
Three-dimensional ocean subsurface temperature and salinity structures(OST/OSS)in the South China Sea(SCS)play crucial roles in oceanic climate research and disaster mitigation.Traditionally,real-time OST and OSS are ...Three-dimensional ocean subsurface temperature and salinity structures(OST/OSS)in the South China Sea(SCS)play crucial roles in oceanic climate research and disaster mitigation.Traditionally,real-time OST and OSS are mainly obtained through in-situ ocean observations and simulation by ocean circulation models,which are usually challenging and costly.Recently,dynamical,statistical,or machine learning models have been proposed to invert the OST/OSS from sea surface information;however,these models mainly focused on the inversion of monthly OST and OSS.To address this issue,we apply clustering algorithms and employ a stacking strategy to ensemble three models(XGBoost,Random Forest,and LightGBM)to invert the real-time OST/OSS based on satellite-derived data and the Argo dataset.Subsequently,a fusion of temperature and salinity is employed to reconstruct OST and OSS.In the validation dataset,the depth-averaged Correlation(Corr)of the estimated OST(OSS)is 0.919(0.83),and the average Root-Mean-Square Error(RMSE)is0.639°C(0.087 psu),with a depth-averaged coefficient of determination(R~2)of 0.84(0.68).Notably,at the thermocline where the base models exhibit their maximum error,the stacking-based fusion model exhibited significant performance enhancement,with a maximum enhancement in OST and OSS inversion exceeding 10%.We further found that the estimated OST and OSS exhibit good agreement with the HYbrid Coordinate Ocean Model(HYCOM)data and BOA_Argo dataset during the passage of a mesoscale eddy.This study shows that the proposed model can effectively invert the real-time OST and OSS,potentially enhancing the understanding of multi-scale oceanic processes in the SCS.展开更多
Bivalve mollusks represent a taxonomically and economically significant clade within Mollusca.However,the regulatory mechanisms governing their embryonic development remain poorly characterized.The dwarf surf clam(Mul...Bivalve mollusks represent a taxonomically and economically significant clade within Mollusca.However,the regulatory mechanisms governing their embryonic development remain poorly characterized.The dwarf surf clam(Mulinia lateralis),characterized by a short generation time and high fecundity,has recently gained recognition as an ideal model system for bivalve embryological research.This study explored the epigenetic mechanisms driving embryogenesis in M.lateralis,with a particular focus on the maternal-to-zygotic transition(MZT),by integrating chromatin-state profiling and transcriptomic analysis.For the first time in this species,CUT&Tag was employed to generate high-resolution landscapes of histone modifications H3K4me1,H3K4me3,H3K27me3,and H3K27ac across key developmental stages.The resulting data revealed extensive reprogramming of histone marks,indicating dynamic shifts in chromatin architecture during early embryonic development.Integration with transcriptomic data identified the timing of MZT in M.lateralis between the morula and gastrula stages and highlighted a suite of candidate genes essential for embryogenesis.These findings provide mechanistic insight into chromatin-mediated control of bivalve embryogenesis and establish M.lateralis as a robust platform for epigenomic research in marine invertebrates,with implications for functional gene studies and aquaculture advancement.展开更多
To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave att...To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave attenuation in random waves.First,the flow velocity distribution characteristic of the pitching flap at typical times was summarized.Then,the effects of random wave and flap parameters on the flap’s significant pitching angle amplitude θ_(s) and hydrodynamic coefficients were investigated.The results reveal that θ_(s) and wave reflection coefficient K_(r) values increase with increasing significant wave height Hs,random wave steepnessλs,and flap relative height.As Hs andλs increase,the wave transmission coefficient K_(t) increases while the wave dissipation coefficient K_(d) decreases.Additionally,K_(t) decreases with increasing flap relative height.With increasing equivalent damping coefficient ratio,θ_(s) and K_(t) decrease,while K_(r) and K_(d) increase.The relationships betweenλs and flap relative height on the one hand andθ_(s),K_(r),K_(t),and K_(d) in random waves on the other hand are compared to those in regular waves.Based on the equal incident wave energy and the equal incident wave energy flux,the pitching flap performs better in the wave attenuation capability under random waves than in regular waves.Finally,the dimensionless parameters with respect to random wave and flap were used to derive the K_(r) and K_(t) for-mulae,which were validated with the related data.展开更多
The silver-lipped pearl oyster(Pinctada maxima)is the largest and most commercially valuable pearl-producing oyster,renowned for its ability to generate large,lustrous pearls.This species is a sequential hermaphrodite...The silver-lipped pearl oyster(Pinctada maxima)is the largest and most commercially valuable pearl-producing oyster,renowned for its ability to generate large,lustrous pearls.This species is a sequential hermaphrodite,with pearl production displaying notable sexual dimorphism.Consequently,understanding the molecular mechanisms governing sex determination and differentiation is crucial for advancing breeding strategies in the pearl oyster industry.To elucidate these mechanisms,this study conducted integrative transcriptomic analyses of P.maxima gonadal tissues using isoform sequencing(Isoseq)and RNA sequencing(RNA-seq).Comparative analysis of ovarian and testicular tissues identified 2768 differentially expressed genes(DEGs).Gene coexpression network analysis delineated four key modules,including three sex-specific modules and one shared module.Key genes implicated in sex determination and maintenance were identified,including FOXL2,NANOS1,andβ-catenin,important for ovarian maintenance,and DMRT,SOX30,FEM1,and FOXJ1,crucial for testicular maintenance.These genes,widely studied in other taxa,were confirmed as hub genes in the sex-related modules of P.maxima.Interestingly,genes within the shared module were significantly enriched in the spliceosome pathway.Alternative splicing analysis highlighted its extensive role in gonadal tissues,with more pronounced activity observed in the testis compared to the ovary.Nearly half(47.83%,375)of the identified genes undergoing differential alternative splicing(DASGs)also exhibited differential transcript usage(DTUGs),while only 17%of DTUGs overlapped with DEGs.Genes associated with sex differentiation,such as DMRT,β-catenin,and U2AF2,displayed sex-specific and/or sex-biased isoforms.These findings offer novel insights into the molecular basis of sex differentiation in P.maxima,which could inform the development of targeted breeding strategies aimed at sex control,thereby enhancing pearl quality and yield in aquaculture.This study offers a robust molecular foundation for advancing breeding programs and optimizing production in the pearl oyster industry.展开更多
A polyketide synthase-nonribosomal peptide synthetase gene cluster twn in Talaromyces sp.HDN1820200 was activated by overexpression of the pathway-specific transcriptional factor TwnD.Large-scale fermentation and chem...A polyketide synthase-nonribosomal peptide synthetase gene cluster twn in Talaromyces sp.HDN1820200 was activated by overexpression of the pathway-specific transcriptional factor TwnD.Large-scale fermentation and chemical investigation of the mutant strain HDN1820200/TwnD led to the discovery of one new polyketide-amino acid conjugate,bipolamide C and one new polyketide compound,variotin A.The structures of the new compounds were determined by nuclear magnetic resonance(NMR)analysis,high-resolution electrospray ionization mass spectrometry,feeding experiments,NMR calculation and DP4^(+)analysis.This study revealed that the overexpression of the pathway-specific transcriptional factor represents a promising approach for the discovery of new natural products in fungi within specialized habitat.展开更多
Triploid oysters are widely cultured due to their superior growth compared to diploids.However,differences in tempera-ture-salinity adaptation between di-and triploid oysters remain inconclusive.This study compared th...Triploid oysters are widely cultured due to their superior growth compared to diploids.However,differences in tempera-ture-salinity adaptation between di-and triploid oysters remain inconclusive.This study compared the survival rates,antioxidant en-zyme activities,and gene expressions in di-and triploid Pacific oyster Crassostrea gigas cultured in different temperatures(17,20,23,26,and 29℃)and salinities(18,22,26,30,and 34).Results showed that the optimum survival condition for both di-and triploids is 23℃/30.At 23℃,triploids exhibited significantly higher superoxide dismutase activity and lower heat shock protein 70(Hsp70)expression than diploids.At 29℃,triploids exhibited significantly higher survival rates than diploids.Across varying tem-peratures,triploids demonstrated significantly higher survival rates and antioxidant enzyme activities,along with lower malondialdehyde(MDA)levels and Hsp70 expression compared to diploids.The overall results demonstrate that triploids have a more robust antioxidant ca-pacity,reduced oxidative damage,and lower mortality than diploids under temperature treatments.Additionally,at a salinity of 18,triploids showed significantly higher catalase(CAT)level than diploids.Across varying salinities,triploids maintained lower MDA levels.These results suggest that triploids possess a stronger antioxidant defense under salinity treatments.In conclusion,triploid C.gigas demonstrates superior adaptation to diverse temperature and salinity conditions over diploids and are recommended for culture to improve oyster production.展开更多
Crassostrea gigas is distinguished by its robust fertility,adaptability to various environmental conditions,and rich nutritional profile,which render it a cornerstone of the global shellfish market.Tetraploid oysters,...Crassostrea gigas is distinguished by its robust fertility,adaptability to various environmental conditions,and rich nutritional profile,which render it a cornerstone of the global shellfish market.Tetraploid oysters,in particular,is a pivotal role within the oyster industry,however,their growth and survival characteristics need to be improved.This study aimed to assess the viability of enhancing the growth and survival characteristics of tetraploid C.gigas through genetic selection.This was achieved by investigating the heritability and genetic correlation of growth and survival at various stages of C.gigas development.Genetic parameters were assessed based on in-group correlations in 28 full-sib families during the larval stage(days 3,8,13,18,and 23 after fertilization).The heritability of larval shell height and shell length ranged from 0.50 to 0.71 and 0.44 to 0.71,respectively,and varied with age.The heritability of larval survival was 0.40–0.64,indicating that it is viable to enhancelarval survival through selection.The genetic correlation between the growth traits of larvae at different ages was highly positive(0.959–0.999),indicating that the selection of a single growth trait could cause the positive response of other growth traits.However,the genetic correlation between larval survival and growth traits was low,showing a significant negative correlation(-0.198–-0.293)at day 23 of age,suggesting thatselecting for enhanced survival in tetraploid C.gigas may result in a detrimental impact on growth traits.The results are helpful for future researches to evaluate the genetic parameters related to growth and survival traits in juvenile and adult stages of the tetraploid family of C.gigas,which can provide further guidance for the selection of tetraploid C.gigas.展开更多
Tetraploid oysters frequently exhibit growth and survival rates inferior to diploid and triploid oysters.Tetraploid Pacific oysters(Crassostrea gigas)are pivotal as broodstock in the triploid C.gigas industry.However,...Tetraploid oysters frequently exhibit growth and survival rates inferior to diploid and triploid oysters.Tetraploid Pacific oysters(Crassostrea gigas)are pivotal as broodstock in the triploid C.gigas industry.However,the high mortality of tetraploid C.gigas has occurred in production practice with the increasing temperature.The transcriptional patterns of high temperature-susceptible and-tolerant tetraploid C.gigas were compared in response to prolonged thermal treatment.The H was defined as oysters that have not been thermally treated.The susceptible and tolerant oysters after thermal treatment were designed as TS and TH,respectively.The survival rate of tetraploid C.gigas was low(6.33%±2.87%)after thermal treatment.A total of 5147,5250,and 433 differentially expressed genes(DEGs)were detected in TS vs.TH,TS vs.H,and TH vs.H groups,respectively.Functional enrichment analysis indicated that DEGs were notably enriched in various pathways,including the NF-kappa B signaling pathway,apoptosis,TNF signaling pathway,and arginine and proline metabolism,across both TS vs.TH and TS vs.H groups.Among the DEGs under thermal treatment in susceptible oysters,the translation regulation genes like eIF2a kinase 1,eIF2a kinase 3,MKNK1,and ATF-4 exhibited differential expressions.Susceptible oysters displayed a higher number of differentially expressed IAP genes compared to tolerant oysters,while the expression pattern of HSP genes differed between susceptible and tolerant oysters.This study underscores the contrasting response of susceptible and tolerant tetraploid C.gigas to thermal treatment,suggesting that high temperature-susceptible tetraploid C.gigas may be more responsive to rapid alterations in immune response and apoptosis compared to high temperature-tolerant tetraploid C.gigas.It is necessary to improve the high temperature tolerance of tetraploid C.gigas by selective breeding to promote the development of the triploid industry.展开更多
Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurna...Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurnal and semidiurnal tidal constituents.We integrated the development technique of the Technical University of Denmark(DTU10)model and calculated the residual tides using the intermediary FES2012 model.We utilized all available Topex/Poseidon,Jason-1,Ocean Surface Topography Mission(OSTM)/Jason-2 primary and tandem missions to develop the new model.To reduce the discrepancies between the model and in situ measurements estimated S2 tide constituent,the ERA-Interim model was selected for dry tropospheric correction of altimetry data.The newly developed model with an improved spatial resolution from 1/8°×1/8°to 1/16°×1/16°was assessed and compared against contemporary global ocean tide models using in situ measurements in coastal regions,continental shelf waters,marginal seas,and deep waters.The results demonstrate improvements in shallow waters and coastal regions,particularly in representative coastal re-gions such as the Northwest European Shelf and East Asian Marginal Seas.Moreover,the model performs well in simulating S_(2) and K_(2) tides with root mean square differences of 0.355 and 0.234 cm,respectively,against in situ measurements in deep waters world-wide.Compared with that of DTU10,the root sum square of the new model for the eight main tidal constituents decrease by 8.4%to 0.997 cm.展开更多
Capsaicin-containing polymer materials with functional structure were successfully prepared by simple free radical poly-merization of capsaicin functional monomers(Poly(AMTHBA-co-NVP))with 1-vinyl-2-pyrrolidone.Compar...Capsaicin-containing polymer materials with functional structure were successfully prepared by simple free radical poly-merization of capsaicin functional monomers(Poly(AMTHBA-co-NVP))with 1-vinyl-2-pyrrolidone.Compared with pure capsaicin polymer,the adsorption content of the obtained Poly(AMTHBA-co-NVP)increased by more than 3 times,which has huge potential research value.The composition and morphology of Poly(AMTHBA-co-NVP)before and after adsorption were analyzed using XRD,FT-IR,XPS,SEM and TEM.The mechanism of the adsorption process was summarized,through the study of the optimal molar ratio of reactants,acid-base environment,adsorption model fitting,characterization data results,and pollutant competition experiments.The following conclusions can be drawn:1)The pseudo-second-order kinetic model better matches the adsorption kinetics of partial Cr(VI).2)Part of the restored Cr(III)is trapped by specific groups on Poly(AMTHBA-co-NVP)and part of the Cr(III)is released back into solution.3)The adsorption mechanism includes ion exchange,coordination and chemical bonding.4)The highest adsorp-tion capacity of the polymeric material was up to 370.59 mg/g when the molar ratio of reactants was AMTHBA:NVP=2:8.This work not only provides ideas for the synthesis of capsaicin structural and functional polymers,but also provides inspiration for wastewater treatment measures.展开更多
All maritime industries are plagued by marine biofouling pollution,which causes large economic and environmental costs.Therefore,there is an urgent need for ecofriendly alternatives that can effectively reduce the neg...All maritime industries are plagued by marine biofouling pollution,which causes large economic and environmental costs.Therefore,there is an urgent need for ecofriendly alternatives that can effectively reduce the negative consequences of biofouling pollution.This study aimed to produce novel capsaicin-inspired amide derivatives(CIADs)with multifunctional antifouling features by introducing amide compounds to aromatic compounds via a Friedel-Crafts alkylation reaction.The structure of the CIADs was characterized using FTIR,1H NMR,13C NMR,and HRMS,and the comprehensive antifouling capacity was determined by thermal stability,anti-ultraviolet,antibacterial,anti-algal,and marine field experiments.CIADs showed good thermal stability and did not show obvious weight loss before 226°C.2,4-dihydroxy-3,5-diphenylimidemet-hylbenzophenone(DDB)had an excellent ultraviolet absorption effect,which was even better than that of 2-hydroxy-4-(octyloxy)benzophenone.The antibacterial and anti-algal rates of N-(2,4-dimethyl-3-chloro-5-benzamide-methyl-6-hydroxybenzyl)benzamide(NDCBHB)were more than 99.5%and 64.0%,respectively,and the surface of antifouling coating with NDCBHB(NDCBHB-AC)was covered with only a small amount of sludge and biofilm,its antifouling effect was better than that of chlorothalonil.The above work provides a reference for preparing green and multifunctional antifouling agents.展开更多
1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against thi...1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against this strategic backdrop,deep-sea mineral and energy resources are increasingly viewed as essential supplements to terrestrial supply bottlenecks and as strategic safeguards for the future low-carbon economy.The international seabed forms a vast strategic resource of global significance,offering great potential to support energy transition and security.Therefore,under sound scientific evaluation and strict regulation,prudent development of this resource should serve both economic needs and the broader goals of sustainable energy transformation[1].展开更多
High-accuracy Sea level prediction is important for understanding marine environments and climate change.In this work,a deep convolutional neural network(CNN)combined with attention mechanism(ADNN)is established for s...High-accuracy Sea level prediction is important for understanding marine environments and climate change.In this work,a deep convolutional neural network(CNN)combined with attention mechanism(ADNN)is established for sea level anomaly(SLA)prediction from historical satellite observations.Multi-year(1998-2020)radar altimetry observed SLA pattern samples in the South China Sea are used for model training and testing.Compared with existing deep learning models such as CNN and convolutional long short-term memory(ConvLSTM)network,ADNN demonstrates the highest accuracies of 94.0%,91.1%,88.4%and 86.2%for 1-d,3-d,5-d and 7-d SLA field predictions,with regional average root mean square errors(RMSE)of 0.27 cm,0.51 cm,0.80 cm and 1.09 cm,respectively.The integration of CNN and attention mechanism significantly improves the model performance,especially in estimating short-term sea level changes,with a 74.7%reduction in the RMSE for 1-d predictions compared to the baseline CNN model.Comparative experiments also show that the ADNN model performs well when the input data contains a certain degree of noise.Moreover,a multivariate ADNN(M-ADNN)model is designed to investigate the impacts of environmental variables such as sea surface temperature(SST)and wind on SLA prediction.The model yields a slightly higher accuracy but the results are quite similar to those of the ADNN model.The findings suggest that,although SST or wind can affect sea level changes,the ADNN model demonstrates the ability to identify and learn sufficient information about sea level changes solely from satellite altimetry measurements of SLA,especially for relatively long-term(≥5 d)predictions.This eliminates the need for additional input parameter data,thereby improving the SLA prediction efficiency.展开更多
This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physic...This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physical processes including eddy dynamics and Kuroshio intrusions.Our observations revealed a significant reorganization in phytoplankton community structure,with the harmful algal bloom(HAB)—forming dinoflagellate Scrippsiella acuminata now dominating euphotic zone assemblages,followed by Nitzschia spp.The pronounced shift toward HAB species dominance elevates ecological risks associated with dinoflagellate blooms,while the concurrent decline in diatom abundance may indicate reduced marine primary productivity.Phytoplankton communities displayed clear spatial segregation,characterized by cyanobacterial dominance in Kuroshio intrusion zones,preferential distribution of dinoflagellates in warm eddy regions,and diatom prevalence in cold eddy systems and deep-current environments.Phytoplankton community composition showed distinct spatial patterns,driven primarily by temperature and nutrient gradients.Deep-sea phytoplankton communities,characterized by elevated diatom-to-dinoflagellate ratios and dominance of fast-sinking species,play a significant role in organic carbon export and biogeochemical cycling processes.展开更多
In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Pe...In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Peninsula in February 1985.Forty years later,in February 2024,China’s fifth research station,Qinling Station,commenced operations on Inexpress-ible Island near Terra Nova Bay.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.T2261149752,41976163,42476172)。
文摘Bathymetric measurement of shallow water is of fundamental importance to coastal environment research and resource management.However,there are still great challenges in estimating water depth using satellite observations in turbid coastal waters.In this paper,we developed a physicsenhanced deep neural network to estimate bathymetry of highly turbid waters of the Changjiang(Yangtze)River estuary from dual-polarized synthetic aperture radar(SAR)images.Sentinel-1A/B SAR images with a spatial resolution of 20 m×22 m were collected and matched with water depth data from nautical charts during 2017-2023.For the input parameters of the model,in addition to the normalized radar backscatter cross section(NRCS)at single polarization and incidence angle,the impacts of both polarimetric characteristics and physical environmental factors on model performance were discussed in detail.Results of feature importance analysis and sensitivity experiments indicate that the polarization ratio and NRCS after removing the influence of background sea surface wind field make significant contributions to the bathymetry retrieval model.The root mean square error(RMSE)of SAR derived water depth decreases from 1.44 to 0.78 m within 0-30-m depth,and the mean relative error(MRE)is reduced from 15.6%to 8.6%.Compared with other machine learning models such as ResNet,XGBoost,and Random Forest,the MRE is reduced by 3.9%,5.7%,and 7.4%,respectively.The spatial distribution of SAR derived water depth also exhibits a high degree of consistency with observations,demonstrating the great potential of the model in estimating the depth of turbid shallow waters.
基金supported by the National Key Research and Development Program of China(No.2024YFC2815400)the European Commission(Nos.HORIZON MSCA-2024-PF-01 and 101200637)+2 种基金the Opening Fund of the State Key Laboratory of Water Resources Engineering and Management at Wuhan University(No.2024SGG07)the Shandong Provincial Natural Science Foundation(No.ZR2025MS647)the Sand Hazards and Opportunities for Resilience,Energy,and Sustainability(SHORES)Center,funded by Tamkeen under the NYUAD Research Institute Award CG013.
文摘Retrogressive landslides in sensitive clays pose significant risks to nearby infrastructure,as natural toe erosion or localized disturbances can trigger progressive block failures.While prior studies have largely relied on two-dimensional(2D)large-deformation analyses,such models overlook key three-dimensional(3D)failure mechanisms and variability effects.This study develops a 3D probabilistic framework by integrating the Coupled Eulerian–Lagrangian(CEL)method with random field theory to simulate retrogressive landslides in spatially variable clay.Using Monte Carlo simulations,we compare 2D and 3D random large-deformation models to evaluate failure modes,runout distances,sliding velocities,and influence zones.The 3D analyses captured more complex failure modes—such as lateral retrogression and asynchronous block mobilization across slope width.Additionally,the 3D analyses predict longer mean runout distances(13.76 vs.11.92 m),wider mean influence distance(11.35 vs.8.73 m),and higher mean sliding velocities(4.66 vs.3.94 m/s)than their 2D counterparts.Moreover,3D models exhibit lower coefficients of variation(e.g.,0.10 for runout distance)due to spatial averaging across slope width.Probabilistic hazard assessment shows that 2D models significantly underpredict near-field failure probabilities(e.g.,48.8%vs.89.9%at 12 m from the slope toe).These findings highlight the limitations of 2D analyses and the importance of multi-directional spatial variability for robust geohazard assessments.The proposed 3D framework enables more realistic prediction of landslide mobility and supports the design of safer,risk-informed infrastructure.
基金Supported by the National Natural Science Foundation of China(NSFC)Shared Voyage Project(Nos.41776088,41976018,42049911,U20A20103,U2005207)the Natural Science Key Foundation of Fujian Province,China(No.2020J01412103)+5 种基金the Hainan Province Science and Technology Special Fund(No.ZDYF2022SHFZ317)the Guangxi Talent and Innovation Base Project(No.2018AD19280)the Guangxi Funding Project(No.04024XM20N0006)the Beihai Science&Technology Project(Nos.201995037,202082031,202082022)the Natural Science Foundation of Xiamen City of China(No.502Z20227322)the China Scholarship Council(CSC Marine Scholarship)。
文摘Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.
基金jointly supported by the National Key Research and Development Program of China(2022YFC3104304)the National Natural Science Foundation of China(Grant No.41876011)+1 种基金the 2022 Research Program of Sanya Yazhou Bay Science and Technology City(SKJC-2022-01-001)the Hainan Province Science and Technology Special Fund(ZDYF2021SHFZ265)。
文摘Three-dimensional ocean subsurface temperature and salinity structures(OST/OSS)in the South China Sea(SCS)play crucial roles in oceanic climate research and disaster mitigation.Traditionally,real-time OST and OSS are mainly obtained through in-situ ocean observations and simulation by ocean circulation models,which are usually challenging and costly.Recently,dynamical,statistical,or machine learning models have been proposed to invert the OST/OSS from sea surface information;however,these models mainly focused on the inversion of monthly OST and OSS.To address this issue,we apply clustering algorithms and employ a stacking strategy to ensemble three models(XGBoost,Random Forest,and LightGBM)to invert the real-time OST/OSS based on satellite-derived data and the Argo dataset.Subsequently,a fusion of temperature and salinity is employed to reconstruct OST and OSS.In the validation dataset,the depth-averaged Correlation(Corr)of the estimated OST(OSS)is 0.919(0.83),and the average Root-Mean-Square Error(RMSE)is0.639°C(0.087 psu),with a depth-averaged coefficient of determination(R~2)of 0.84(0.68).Notably,at the thermocline where the base models exhibit their maximum error,the stacking-based fusion model exhibited significant performance enhancement,with a maximum enhancement in OST and OSS inversion exceeding 10%.We further found that the estimated OST and OSS exhibit good agreement with the HYbrid Coordinate Ocean Model(HYCOM)data and BOA_Argo dataset during the passage of a mesoscale eddy.This study shows that the proposed model can effectively invert the real-time OST and OSS,potentially enhancing the understanding of multi-scale oceanic processes in the SCS.
基金supported by the National Natural Science Foundation of China(32200667)Shandong Provincial Special Funds for Taishan Scholars(tsqn202306104)+1 种基金Hainan Province“South China Sea New Star”Science and Technology Innovation Talent Platform Project(NHXXRCXM202365)Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City Grant(2021JJLH0090)。
文摘Bivalve mollusks represent a taxonomically and economically significant clade within Mollusca.However,the regulatory mechanisms governing their embryonic development remain poorly characterized.The dwarf surf clam(Mulinia lateralis),characterized by a short generation time and high fecundity,has recently gained recognition as an ideal model system for bivalve embryological research.This study explored the epigenetic mechanisms driving embryogenesis in M.lateralis,with a particular focus on the maternal-to-zygotic transition(MZT),by integrating chromatin-state profiling and transcriptomic analysis.For the first time in this species,CUT&Tag was employed to generate high-resolution landscapes of histone modifications H3K4me1,H3K4me3,H3K27me3,and H3K27ac across key developmental stages.The resulting data revealed extensive reprogramming of histone marks,indicating dynamic shifts in chromatin architecture during early embryonic development.Integration with transcriptomic data identified the timing of MZT in M.lateralis between the morula and gastrula stages and highlighted a suite of candidate genes essential for embryogenesis.These findings provide mechanistic insight into chromatin-mediated control of bivalve embryogenesis and establish M.lateralis as a robust platform for epigenomic research in marine invertebrates,with implications for functional gene studies and aquaculture advancement.
基金supported by the National Natural Science Foundation of China(Nos.52271295,52088102).
文摘To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave attenuation in random waves.First,the flow velocity distribution characteristic of the pitching flap at typical times was summarized.Then,the effects of random wave and flap parameters on the flap’s significant pitching angle amplitude θ_(s) and hydrodynamic coefficients were investigated.The results reveal that θ_(s) and wave reflection coefficient K_(r) values increase with increasing significant wave height Hs,random wave steepnessλs,and flap relative height.As Hs andλs increase,the wave transmission coefficient K_(t) increases while the wave dissipation coefficient K_(d) decreases.Additionally,K_(t) decreases with increasing flap relative height.With increasing equivalent damping coefficient ratio,θ_(s) and K_(t) decrease,while K_(r) and K_(d) increase.The relationships betweenλs and flap relative height on the one hand andθ_(s),K_(r),K_(t),and K_(d) in random waves on the other hand are compared to those in regular waves.Based on the equal incident wave energy and the equal incident wave energy flux,the pitching flap performs better in the wave attenuation capability under random waves than in regular waves.Finally,the dimensionless parameters with respect to random wave and flap were used to derive the K_(r) and K_(t) for-mulae,which were validated with the related data.
基金supported by the Hainan Province Science and Technology Talent Innovation Project(KJRC2023A02)Project of Sanya Yazhouwan Science and Technology City Management Foundation(SKJC-KJ-2019KY01)Sanya Science and Technology Special Fund(2022KJCX91)。
文摘The silver-lipped pearl oyster(Pinctada maxima)is the largest and most commercially valuable pearl-producing oyster,renowned for its ability to generate large,lustrous pearls.This species is a sequential hermaphrodite,with pearl production displaying notable sexual dimorphism.Consequently,understanding the molecular mechanisms governing sex determination and differentiation is crucial for advancing breeding strategies in the pearl oyster industry.To elucidate these mechanisms,this study conducted integrative transcriptomic analyses of P.maxima gonadal tissues using isoform sequencing(Isoseq)and RNA sequencing(RNA-seq).Comparative analysis of ovarian and testicular tissues identified 2768 differentially expressed genes(DEGs).Gene coexpression network analysis delineated four key modules,including three sex-specific modules and one shared module.Key genes implicated in sex determination and maintenance were identified,including FOXL2,NANOS1,andβ-catenin,important for ovarian maintenance,and DMRT,SOX30,FEM1,and FOXJ1,crucial for testicular maintenance.These genes,widely studied in other taxa,were confirmed as hub genes in the sex-related modules of P.maxima.Interestingly,genes within the shared module were significantly enriched in the spliceosome pathway.Alternative splicing analysis highlighted its extensive role in gonadal tissues,with more pronounced activity observed in the testis compared to the ovary.Nearly half(47.83%,375)of the identified genes undergoing differential alternative splicing(DASGs)also exhibited differential transcript usage(DTUGs),while only 17%of DTUGs overlapped with DEGs.Genes associated with sex differentiation,such as DMRT,β-catenin,and U2AF2,displayed sex-specific and/or sex-biased isoforms.These findings offer novel insights into the molecular basis of sex differentiation in P.maxima,which could inform the development of targeted breeding strategies aimed at sex control,thereby enhancing pearl quality and yield in aquaculture.This study offers a robust molecular foundation for advancing breeding programs and optimizing production in the pearl oyster industry.
基金supported by the National Key R&D Program of China(Grant no.2022YFC2807502)Qingdao Marine Science and Technology Center(Grant no.2022QNLM030003-1)Taishan Scholar Distinguished Expert Program in Shandong Province(Grant no.tstp20240504).
文摘A polyketide synthase-nonribosomal peptide synthetase gene cluster twn in Talaromyces sp.HDN1820200 was activated by overexpression of the pathway-specific transcriptional factor TwnD.Large-scale fermentation and chemical investigation of the mutant strain HDN1820200/TwnD led to the discovery of one new polyketide-amino acid conjugate,bipolamide C and one new polyketide compound,variotin A.The structures of the new compounds were determined by nuclear magnetic resonance(NMR)analysis,high-resolution electrospray ionization mass spectrometry,feeding experiments,NMR calculation and DP4^(+)analysis.This study revealed that the overexpression of the pathway-specific transcriptional factor represents a promising approach for the discovery of new natural products in fungi within specialized habitat.
基金supported by grants from the Key R&D Program of Shandong Province(No.2022LZGCQY010)the National Natural Science Foundation of China(No.32373115)the China Agriculture Research System Project(No.CARS-49).
文摘Triploid oysters are widely cultured due to their superior growth compared to diploids.However,differences in tempera-ture-salinity adaptation between di-and triploid oysters remain inconclusive.This study compared the survival rates,antioxidant en-zyme activities,and gene expressions in di-and triploid Pacific oyster Crassostrea gigas cultured in different temperatures(17,20,23,26,and 29℃)and salinities(18,22,26,30,and 34).Results showed that the optimum survival condition for both di-and triploids is 23℃/30.At 23℃,triploids exhibited significantly higher superoxide dismutase activity and lower heat shock protein 70(Hsp70)expression than diploids.At 29℃,triploids exhibited significantly higher survival rates than diploids.Across varying tem-peratures,triploids demonstrated significantly higher survival rates and antioxidant enzyme activities,along with lower malondialdehyde(MDA)levels and Hsp70 expression compared to diploids.The overall results demonstrate that triploids have a more robust antioxidant ca-pacity,reduced oxidative damage,and lower mortality than diploids under temperature treatments.Additionally,at a salinity of 18,triploids showed significantly higher catalase(CAT)level than diploids.Across varying salinities,triploids maintained lower MDA levels.These results suggest that triploids possess a stronger antioxidant defense under salinity treatments.In conclusion,triploid C.gigas demonstrates superior adaptation to diverse temperature and salinity conditions over diploids and are recommended for culture to improve oyster production.
基金supported by grants from the National Natural Science Foundation of China(No.32373115)the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(Nos.2022LZGCQY010,2021ZLGX03 and 2021TSGC1240)the China Agriculture Research System Project(No.CARS-49)。
文摘Crassostrea gigas is distinguished by its robust fertility,adaptability to various environmental conditions,and rich nutritional profile,which render it a cornerstone of the global shellfish market.Tetraploid oysters,in particular,is a pivotal role within the oyster industry,however,their growth and survival characteristics need to be improved.This study aimed to assess the viability of enhancing the growth and survival characteristics of tetraploid C.gigas through genetic selection.This was achieved by investigating the heritability and genetic correlation of growth and survival at various stages of C.gigas development.Genetic parameters were assessed based on in-group correlations in 28 full-sib families during the larval stage(days 3,8,13,18,and 23 after fertilization).The heritability of larval shell height and shell length ranged from 0.50 to 0.71 and 0.44 to 0.71,respectively,and varied with age.The heritability of larval survival was 0.40–0.64,indicating that it is viable to enhancelarval survival through selection.The genetic correlation between the growth traits of larvae at different ages was highly positive(0.959–0.999),indicating that the selection of a single growth trait could cause the positive response of other growth traits.However,the genetic correlation between larval survival and growth traits was low,showing a significant negative correlation(-0.198–-0.293)at day 23 of age,suggesting thatselecting for enhanced survival in tetraploid C.gigas may result in a detrimental impact on growth traits.The results are helpful for future researches to evaluate the genetic parameters related to growth and survival traits in juvenile and adult stages of the tetraploid family of C.gigas,which can provide further guidance for the selection of tetraploid C.gigas.
基金supported by grants from the National Key R&D Program of China(No.2022YFD2400305)the Key R&D Program of Shandong Province(Nos.2022LZ GCQY010,2021ZLGX03 and 2021TSGC1240)the China Agriculture Research System Project(No.CARS-49).
文摘Tetraploid oysters frequently exhibit growth and survival rates inferior to diploid and triploid oysters.Tetraploid Pacific oysters(Crassostrea gigas)are pivotal as broodstock in the triploid C.gigas industry.However,the high mortality of tetraploid C.gigas has occurred in production practice with the increasing temperature.The transcriptional patterns of high temperature-susceptible and-tolerant tetraploid C.gigas were compared in response to prolonged thermal treatment.The H was defined as oysters that have not been thermally treated.The susceptible and tolerant oysters after thermal treatment were designed as TS and TH,respectively.The survival rate of tetraploid C.gigas was low(6.33%±2.87%)after thermal treatment.A total of 5147,5250,and 433 differentially expressed genes(DEGs)were detected in TS vs.TH,TS vs.H,and TH vs.H groups,respectively.Functional enrichment analysis indicated that DEGs were notably enriched in various pathways,including the NF-kappa B signaling pathway,apoptosis,TNF signaling pathway,and arginine and proline metabolism,across both TS vs.TH and TS vs.H groups.Among the DEGs under thermal treatment in susceptible oysters,the translation regulation genes like eIF2a kinase 1,eIF2a kinase 3,MKNK1,and ATF-4 exhibited differential expressions.Susceptible oysters displayed a higher number of differentially expressed IAP genes compared to tolerant oysters,while the expression pattern of HSP genes differed between susceptible and tolerant oysters.This study underscores the contrasting response of susceptible and tolerant tetraploid C.gigas to thermal treatment,suggesting that high temperature-susceptible tetraploid C.gigas may be more responsive to rapid alterations in immune response and apoptosis compared to high temperature-tolerant tetraploid C.gigas.It is necessary to improve the high temperature tolerance of tetraploid C.gigas by selective breeding to promote the development of the triploid industry.
基金supported by the open funding of the Technology Innovation Center for South China Sea Re-mote Sensing,Surveying and Mapping Collaborative Ap-plication,Ministry of Natural Resources,P.R.China(No.RSSMCA-2024-B001)the National Natural Science Foundation of China(Nos.T2261149752 and 42476172).
文摘Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurnal and semidiurnal tidal constituents.We integrated the development technique of the Technical University of Denmark(DTU10)model and calculated the residual tides using the intermediary FES2012 model.We utilized all available Topex/Poseidon,Jason-1,Ocean Surface Topography Mission(OSTM)/Jason-2 primary and tandem missions to develop the new model.To reduce the discrepancies between the model and in situ measurements estimated S2 tide constituent,the ERA-Interim model was selected for dry tropospheric correction of altimetry data.The newly developed model with an improved spatial resolution from 1/8°×1/8°to 1/16°×1/16°was assessed and compared against contemporary global ocean tide models using in situ measurements in coastal regions,continental shelf waters,marginal seas,and deep waters.The results demonstrate improvements in shallow waters and coastal regions,particularly in representative coastal re-gions such as the Northwest European Shelf and East Asian Marginal Seas.Moreover,the model performs well in simulating S_(2) and K_(2) tides with root mean square differences of 0.355 and 0.234 cm,respectively,against in situ measurements in deep waters world-wide.Compared with that of DTU10,the root sum square of the new model for the eight main tidal constituents decrease by 8.4%to 0.997 cm.
基金supported by the National Natural Sci-ence Foundation of China(No.U22A20112)the Hainan Provincial Natural Science Foundation(No.522CXTD520)the Key Research and Development Project of Hainan Province(No.ZDYF2021GXJS029).
文摘Capsaicin-containing polymer materials with functional structure were successfully prepared by simple free radical poly-merization of capsaicin functional monomers(Poly(AMTHBA-co-NVP))with 1-vinyl-2-pyrrolidone.Compared with pure capsaicin polymer,the adsorption content of the obtained Poly(AMTHBA-co-NVP)increased by more than 3 times,which has huge potential research value.The composition and morphology of Poly(AMTHBA-co-NVP)before and after adsorption were analyzed using XRD,FT-IR,XPS,SEM and TEM.The mechanism of the adsorption process was summarized,through the study of the optimal molar ratio of reactants,acid-base environment,adsorption model fitting,characterization data results,and pollutant competition experiments.The following conclusions can be drawn:1)The pseudo-second-order kinetic model better matches the adsorption kinetics of partial Cr(VI).2)Part of the restored Cr(III)is trapped by specific groups on Poly(AMTHBA-co-NVP)and part of the Cr(III)is released back into solution.3)The adsorption mechanism includes ion exchange,coordination and chemical bonding.4)The highest adsorp-tion capacity of the polymeric material was up to 370.59 mg/g when the molar ratio of reactants was AMTHBA:NVP=2:8.This work not only provides ideas for the synthesis of capsaicin structural and functional polymers,but also provides inspiration for wastewater treatment measures.
基金supported by the Scientific Research Project funded by the Qingdao Postdoctoral Science Foundation(No.QDBSH20230102075)the China Postdoctoral Science Foundation(No.2023M733337)the National Natural Science Foundation of China(No.U2141251).
文摘All maritime industries are plagued by marine biofouling pollution,which causes large economic and environmental costs.Therefore,there is an urgent need for ecofriendly alternatives that can effectively reduce the negative consequences of biofouling pollution.This study aimed to produce novel capsaicin-inspired amide derivatives(CIADs)with multifunctional antifouling features by introducing amide compounds to aromatic compounds via a Friedel-Crafts alkylation reaction.The structure of the CIADs was characterized using FTIR,1H NMR,13C NMR,and HRMS,and the comprehensive antifouling capacity was determined by thermal stability,anti-ultraviolet,antibacterial,anti-algal,and marine field experiments.CIADs showed good thermal stability and did not show obvious weight loss before 226°C.2,4-dihydroxy-3,5-diphenylimidemet-hylbenzophenone(DDB)had an excellent ultraviolet absorption effect,which was even better than that of 2-hydroxy-4-(octyloxy)benzophenone.The antibacterial and anti-algal rates of N-(2,4-dimethyl-3-chloro-5-benzamide-methyl-6-hydroxybenzyl)benzamide(NDCBHB)were more than 99.5%and 64.0%,respectively,and the surface of antifouling coating with NDCBHB(NDCBHB-AC)was covered with only a small amount of sludge and biofilm,its antifouling effect was better than that of chlorothalonil.The above work provides a reference for preparing green and multifunctional antifouling agents.
基金financial support from the National Key R&D Program of China(No.2024YFC2815400)the Young Taishan Scholars Program(No.TSQN202507107)+1 种基金the Shandong Natural Science Foundation(No.ZR2025MS647)the European Commission(HORIZON MSCA-2024-PF-01,101200637).
文摘1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against this strategic backdrop,deep-sea mineral and energy resources are increasingly viewed as essential supplements to terrestrial supply bottlenecks and as strategic safeguards for the future low-carbon economy.The international seabed forms a vast strategic resource of global significance,offering great potential to support energy transition and security.Therefore,under sound scientific evaluation and strict regulation,prudent development of this resource should serve both economic needs and the broader goals of sustainable energy transformation[1].
基金The National Natural Science Foundation of China under contract Nos T2261149752 and 42476172the Open Funding of the Technology Innovation Center for South China Sea Remote Sensing,Surveying and Mapping Collaborative Application,Ministry of Natural Resources,P.R.China under contract No.RSSMCA-2024-B001。
文摘High-accuracy Sea level prediction is important for understanding marine environments and climate change.In this work,a deep convolutional neural network(CNN)combined with attention mechanism(ADNN)is established for sea level anomaly(SLA)prediction from historical satellite observations.Multi-year(1998-2020)radar altimetry observed SLA pattern samples in the South China Sea are used for model training and testing.Compared with existing deep learning models such as CNN and convolutional long short-term memory(ConvLSTM)network,ADNN demonstrates the highest accuracies of 94.0%,91.1%,88.4%and 86.2%for 1-d,3-d,5-d and 7-d SLA field predictions,with regional average root mean square errors(RMSE)of 0.27 cm,0.51 cm,0.80 cm and 1.09 cm,respectively.The integration of CNN and attention mechanism significantly improves the model performance,especially in estimating short-term sea level changes,with a 74.7%reduction in the RMSE for 1-d predictions compared to the baseline CNN model.Comparative experiments also show that the ADNN model performs well when the input data contains a certain degree of noise.Moreover,a multivariate ADNN(M-ADNN)model is designed to investigate the impacts of environmental variables such as sea surface temperature(SST)and wind on SLA prediction.The model yields a slightly higher accuracy but the results are quite similar to those of the ADNN model.The findings suggest that,although SST or wind can affect sea level changes,the ADNN model demonstrates the ability to identify and learn sufficient information about sea level changes solely from satellite altimetry measurements of SLA,especially for relatively long-term(≥5 d)predictions.This eliminates the need for additional input parameter data,thereby improving the SLA prediction efficiency.
基金The National Natural Science Foundation of China under contract No.32501444.
文摘This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physical processes including eddy dynamics and Kuroshio intrusions.Our observations revealed a significant reorganization in phytoplankton community structure,with the harmful algal bloom(HAB)—forming dinoflagellate Scrippsiella acuminata now dominating euphotic zone assemblages,followed by Nitzschia spp.The pronounced shift toward HAB species dominance elevates ecological risks associated with dinoflagellate blooms,while the concurrent decline in diatom abundance may indicate reduced marine primary productivity.Phytoplankton communities displayed clear spatial segregation,characterized by cyanobacterial dominance in Kuroshio intrusion zones,preferential distribution of dinoflagellates in warm eddy regions,and diatom prevalence in cold eddy systems and deep-current environments.Phytoplankton community composition showed distinct spatial patterns,driven primarily by temperature and nutrient gradients.Deep-sea phytoplankton communities,characterized by elevated diatom-to-dinoflagellate ratios and dominance of fast-sinking species,play a significant role in organic carbon export and biogeochemical cycling processes.
文摘In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Peninsula in February 1985.Forty years later,in February 2024,China’s fifth research station,Qinling Station,commenced operations on Inexpress-ible Island near Terra Nova Bay.
