- LIU Yaqian;SHI Jiuxin;SUN Yongming;HOU Saisai;XIE Chunhu;WILLIAMS Guy D.;
The characteristics of modified Circumpolar Deep Water(m CDW) on the continental shelf in Prydz Bay, East Antarctica, are studied based on hydrographic data obtained by the Chinese National Antarctic Research Expeditions across 14 summers from1999 to 2022. In austral summer, the m CDW upwells along the upper continental slope then intrudes on the continental shelf across the shelf break in a warm tongue that gradually upwells poleward. The m CDW intrusion at the 73°E section is relatively weaker in December and stronger in February while showing significant interannual variability. During strong intrusions(January 2000 and February 2003), the m CDW extends southward to 68°S and upwells to 50 m, whereas the m CDW only reaches the shelf break during weak intrusions(December 2004, January 2006, January 2011, and February 2015). The intensity of the m CDW intrusions correlates strongly with the accumulated wind stress curl(30 days prior) north of the shelf break(73.5°–78.0°E, 64.5°–66.0°S). The summertime westerly winds play a key role in regulating the interannual variability of m CDW intrusion onto the continental shelf. A southward shift of the westerly winds promotes the upwelling and southward intrusion of m CDW across the shelf break. In addition,m CDW at 73°E can reach as far as 68°S due to the southward flow of m CDW being hindered by a northward outflowing branch of the coastal current at the Amery Ice Shelf(AIS) front. In austral summer, the m CDW had never been observed at the section along the AIS front; thus, it cannot directly contribute to the basal melting of the ice shelf.
2025年03期 v.24 533-544页 [查看摘要][在线阅读][下载 5391K] - XU Fan;LI Haiyan;WANG Ru;WEN Zhiqiang;YANG Kun;ZHANG Menghao;
In recent years,research investigations have focused on the substantial freshwater storage in the Beaufort Gyre (BG) region due to climate change.Despite active mesoscale eddies in the area,a notable gap in understanding the three-dimensional structure and induced transport has been observed.This study concentrates on the Canada Basin in the western Arctic Ocean,specifically examining a subsurface anticyclonic eddy (SAE) sampled by a Mooring A in the BG region.Hybrid Coordinate Ocean Model (HY-COM) analysis data reveal its lifecycle from February 15 to March 15,2017,marked by initiation,development,maturity,decay,and termination stages.This work extends the finding of SAE passing through Mooring A by examining its overall effects,spatiotemporal variations,and swirl transport.SAE generation through baroclinic instability,which contributes to the westward tilt of the vertical axis,is also confirmed in this study.Swirl transport induced by SAE is predominantly eastward and downward due to its trajectory and background flow.SAE temporarily weakens stratification and extends the subsurface depth but demonstrates transient effects.Moreover,SAE transports upper-layer freshwater,Pacific Winter Water,and Atlantic Water downward,emphasizing its potential influence on freshwater redistribution in the Canadian Basin.This research provides valuable insights into mesoscale eddy dynamics,revealing their role in modulating the upper water mass in the BG region.
2025年03期 v.24 545-556页 [查看摘要][在线阅读][下载 1123K] - CHEN Wanqian;GAO Jinpeng;XU Minjie;LIU Zezheng;LI Bingtian;LV Jing;LI Shujiang;SUN Junchuan;
Ocean remote sensing satellites provide observations with high spatiotemporal resolution.However,the influence of clouds,fog,and haze frequently leads to significant data gaps.Accurate and effective estimation of these missing data is highly valuable for engineering and scientific research.In this study,the radial basis function (RBF) method is used to estimate the spatial distribution of total suspended matter (TSM) concentration in Hangzhou Bay using remote sensing data with severe data gaps.The estimation precision is validated by comparing the results with those of other commonly used interpolation methods,such as the Kriging method and the basic spline (B-spline) method.In addition,the applicability of the RBF method is explored.Results show that the estimation of the RBF method is significantly close to the observation in Hangzhou Bay.The average of the mean absolute error,mean relative error,and root mean square error in all the experiments is evidently smaller than those of the Kriging and B-spline interpolations,indicating that the proposed method is more appropriate for estimating the spatial distribution of the TSM in Hangzhou Bay.Finally,the TSM distribution in the blank observational area is predicted.This study can provide some reference values for handling watercolor remote sensing data.
2025年03期 v.24 557-568页 [查看摘要][在线阅读][下载 1770K] - XIE Xiaoru;GUO Peifang;LI Jing;ZHANG Kuncheng;
Storm surge events (SSEs) involve multiple hazard-causing factors,such as surges,extreme rainfall,strong winds,waves,and ocean currents,which have destructive impacts on coastal regions.For a quantitative multi-hazard assessment of SSEs,this study introduced the concept of the storm surge event seawater-atmosphere system (SSE-SAS) and proposed the system energy equivalence (SEE) model from a systemic energy perspective.SEE was obtained by employing a parameterization approach,and the hazard index (HI) and the concept of most significant hazard (MSH) were adopted to evaluate the severity of SSE-SAS.SEE at five stations in the Shandong Peninsula was calculated from 2005 to 2019,and probability analysis and hazard assessment were further conducted.Results show that the SEE of SSE-SAS ranges from 0.029×10~3 to 30.418×10~3 J/m~2,and it exhibits an insignificant decreasing trend from 2005 to 2019.The SEE of SSE-SAS in the west of the Shandong Peninsula is greater than that in the east.Moreover,storm waves,storm surges,and storm rainfall are the major contributors to SEE,which exhibit different spatial patterns and characters in different SSE-SAS types.The HI of SSE-SAS at five stations is no more than medium hazard level,with MSH at return periods of 2-to 4-year level.This study provides a new approach for quantifying multi-hazard SSEs,which offers scientific insights for regional multi-hazard risk reduction and mitigation efforts.
2025年03期 v.24 569-583页 [查看摘要][在线阅读][下载 943K] - LIU Guilin;JI Tao;SUN Yinghao;YU Pubing;SONG Shichun;
The local time-stepping (LTS) algorithm is an adaptive method that adjusts the time step by selecting suitable intervals for different regions based on the spatial scale of each cell and water depth and flow velocity between cells.The method can be optimized by calculating the maximum power of two of the global time step increments in the domain,allowing the optimal time step to be approached throughout the grid.To verify the acceleration and accuracy of LTS in storm surge simulations,we developed a model to simulate astronomical storm surges along the southern coast of China.This model employs the shallow water equations as governing equations,numerical discretization using the finite volume method,and fluxes calculated by the Roe solver.By comparing the simulation results of the traditional global time-stepping algorithm with those of the LTS algorithm,we find that the latter fit the measured data better.Taking the calculation results of Typhoon Sally in 1996 as an example,we show that compared with the traditional global time-stepping algorithm,the LTS algorithm reduces computation time by 2.05 h and increases computation efficiency by 2.64 times while maintaining good accuracy.
2025年03期 v.24 583-591页 [查看摘要][在线阅读][下载 947K] - BAO Jian;YU Dingyong;QU Ming;XU Zhigang;WANG Xiaofan;
This study applies a double snap-through mechanism on a box-type oscillating buoy (OB) wave energy converter (WEC)-floating breakwater integrated system (OB WEC-FB) to simultaneously achieve efficient wave energy conversion and nearshore protection within a low-frequency bandwidth.This mechanism consists of four oblique springs and can operate in mono-stable,bi-stable,and tri-stable modes.A viscous-flow-based numerical model is established to investigate the hydrodynamic performance and dynamic behavior of the proposed multi-stable breakwater.The operational performance of the breakwater at different dynamic modes is first compared.The effects of the springs’original length and stiffness coefficient are then analyzed.The results show that the tri-stable breakwater has a wider resonance frequency tuning range than the bi-stable one,both of which outperform the mono-stable and linear ones in shifting the effective bandwidth to a lower frequency range.For a tri-stable breakwater,a large distance between outermost potential wells is conducive to tuning resonance frequency,whereas shallow potential wells limit this effect.The increase in spring stiffness distinctly causes a higher potential barrier and thus constrains the motion response of the breakwater.A well-designed double snap-through mechanism can excite large-amplitude inter-well motion,tune the resonance frequency of breakwater from 3.98 to 1.96 rad/s,and decrease the lower limit of the effective transmission bandwidth from 3.75 to 3.00 rad/s.It is crucial for improving the power absorption and wave attenuation capabilities of multi-stable OB WEC-FB.This study contributes to the limited research on the implementation of a double snap-through mechanism on multifunctional marine structures.It establishes the underlying connection between nonlinear dynamic behaviors and hydrodynamic coefficients.
2025年03期 v.24 592-604页 [查看摘要][在线阅读][下载 1831K] - LE Conghuan;ZHANG Yuyang;BAI Yu;ZHANG Puyang;DING Hongyan;
This study investigates the wet towing characteristics of an integrated wellhead platform supported by a bucket foundation. These characteristics are crucial for optimizing offshore construction efficiency and enabling the development of small marginal oil fields. The wet towing behavior of the integrated wellhead platform was explored through a combination of physical experiments and numerical simulations. Physical experiments were conducted to validate the accuracy of the numerical simulations. Subsequently,numerical simulations were employed to determine the impacts of towing speed and wave direction on the towing process of the integrated wellhead platform. Finally, the impact of compartment failure due to bulkhead damage on towage stability was analyzed. Findings indicate that the wave and towing directions influence the motion of the platform at various degrees of freedom. The platform demonstrates optimal stability when towing against waves, particularly when the towing direction aligns at a specific angle relative to the wave direction. In addition, a controlled increase in towing speed within a specific range effectively mitigates roll and pitch motions, which enhances the overall tow stability of the platform. Notably, compartment failure has an adverse effect on the towing stability, particularly in aft compartments. Therefore, it requires careful consideration and attention in practical engineering scenarios.
2025年03期 v.24 605-617页 [查看摘要][在线阅读][下载 1797K] - LI Gaocong;YUAN Mingming;TANG Jieping;LIAO Jian;
The investigation of whether sediment samples contain representative grain size distribution information is important for the accurate extraction of sediment characteristics and conduct of related sedimentary record studies.This study comparatively analyzed the numerical and qualitative differences and the degree of correlation of 36 sets of the characteristic parameters of surface sediment parallel sample grain size distribution from three sampling profiles at Jinsha Bay Beach in Zhanjiang,western Guangdong.At each sampling point,five parallel subsamples were established at intervals of 0,10,20,50,and 100 cm along the coastline.The research findings indicate the following:1) relatively large differences in the mean values of the different parallel samples (0.19–0.34Φ),with smaller differences observed in other characteristic grain sizes (D_(10),D_(50),and D_(90));2) small differences in characteristic values among various parallel sample grain size parameters,with at least 33% of the combinations of qualitative results showing inconsistency;3) 50% of the regression equations between the skewness of different parallel samples displaying no significant correlation;4) relative deviations of -47.91% to 27.63% and -49.20% to 2.08% existing between the particle size parameters of a single sample and parallel samples (with the average obtained) at intervals of 10 and 50 cm,respectively.As such,small spatial differences,even within 100 cm,can considerably affect grain size parameters.Given the uncertain reasons underlying the representativeness of the samples,which may only cover the area immediately surrounding the sampling station,researchers are advised to design parallel sample collection strategies based on the spatiotemporal distribution characteristics of the parameters of interest during sediment sample collection.This study provides a typical case of the comparative analysis of parallel sample grain size parameters,with a focus on small spatial beach sediment,which contributes to the enhanced understanding of the accuracy and reliability of sediment sample collection strategies and extraction of grain size information.
2025年03期 v.24 618-636页 [查看摘要][在线阅读][下载 1329K] - XIANG Dan;LIANG Naiyao;LING Jing;LI Jianxin;QU Qiang;ZHONG Junliu;
Situated in the southwestern Pacific,the Tonga-Kermadec subduction zone is separated into two parts by the Louisvlle Ridge Seamount Chain (LRSC),i.e.,the Tanga subduction zone and the Kermadec subduction zone.Known for its vigorous volcanic activity,frequent large earthquakes,rapid plate subduction,and distinctive subducting plate morphology,this subduction zone provides valuable insights into its structures,dynamics,and associated geohazards.This study compiles geological and geophysical datasets in this region,including seismicity,focal mechanisms,seismic reflection and refraction profiles,and seismic tomography,to understand the relationship between lithospheric structures of the subduction system and associated seismicity-volcanic activities.Our analysis suggests that variations in overlying sediment thickness,subduction rate,and subduction angle significantly influence the lithospheric deformation processes within the Tonga-Kermadec subduction system.Furthermore,these factors contribute to the notable differences in seismicity and volcanism observed between the Tonga subduction zone and the Kermadec subduction zone.This study enhances our understanding of plate tectonics by providing insights into the interplay between subduction dynamics and lithospheric deformation,which are crucial for analyzing geological and geophysical behaviors in similar subduction environments.
2025年03期 v.24 631-646页 [查看摘要][在线阅读][下载 1538K] - ZHENG Yu;PENG Bo;SONG Rujuan;LIU Yingjie;LI Hongzhi;
This study investigates inductively coupled transmission technology using seawater and underwater anchor chains as the transmission medium for real-time data transfer from underwater measurement instruments.Because of the physical properties of seawater,challenges,such as frequency selective fading and multipath effect,limit long-distance current signal transmission.Conventional modulation techniques,such as amplitude shift keying (ASK) and differential phase shift keying (DPSK),are constrained by low bandwidth utilization and high bit error rates (BER).To address these issues,we optimize the seawater channel model using data from the National Oceanographic Data Center and previous measurements,analyzing the relationship between seawater conductivity,depth,and signal frequency.We constructed an experimental platform using a six-winding manganese-zinc ferrite ring based on an inductive coupling model for data transmission.A steel cable is anchored at both ends of a seawater bucket through two rings,exposing the cable core to establish a closed loop in seawater.An orthogonal frequency division multiplexing (OFDM) algorithm is used to improve transmission performance by distributing data across multiple subcarriers,effectively mitigating multipath fading and frequency selective fading.Compared with ASK and DPSK,this method significantly reduces the BER and improves the channel capacity,exhibiting robustness in underwater communication.Finally,in our study,a mathematical model of the underwater multipath channel for distances of 300,1000,and 2000 m is established,showing an improvement in channel capacity of approximately 2.5 bps/Hz based on the OFDM algorithm.This advancement is essential for enhancing the performance of underwater signal transmission and supporting its practical application.
2025年03期 v.24 647-656页 [查看摘要][在线阅读][下载 906K] - CHEN Wei;ZHANG Guoliang;
Subduction zones,linking the surface and deep carbon reservoirs,significantly affect the Earth’s long-term climate change and habitability.The subducting slabs undergo decarbonation with increasing pressure and temperature,during which partial carbon mobilizes out of the slab and returns to the surface by arc volcanism or degassing,while the residual carbon continues to descend to greater depths in the mantle.The estimated carbon influx at subduction zones depends strongly on the calculation model,with contributions from sediments ranging from 15 to 60 Mt C/yr,altered ocean basalts from 18 to 61 Mt C/yr,and serpentinized perdotites from 1.3 to 36 Mt C/yr.The carbon influx varies in space and time.Carbon removal from subducting slab occurs through metamorphic reactions,carbonate dissolution,diapirism,hydrocarbon formation and melting.Among these decarbonation mechanisms,diapirism and slab meting play a decisive role in dictating the depth at which surface carbonates can subduct.Specifically,diapirism may restrict sedimentary carbonates at shallow depths (<200 km),while slab melting exhausts all carbonates from the altered ocean crust near transition zones (410–660 km).Consequently,a mechanism enabling surface carbonates to reach the lower mantle,i.e.,ultra-deep carbon cycle,is required to be in accordance with observations by natural samples.
2025年03期 v.24 657-671页 [查看摘要][在线阅读][下载 1049K] - ZHANG Shuang;ZHANG Yinquan;QIN Jinxing;LI Zhenglin;GUO Yonggang;WU Shuanglin;
Normal mode extraction has attracted extensive attention over the past few decades due to its practical value in enhancing the performance of underwater acoustic signal processing.Singular value decomposition (SVD) is an effective method to extract modal depth functions using vertical line arrays (VLA),particularly in scenarios when no prior environment information is available.However,the SVD method requires rigorous orthogonality conditions,and its performance severely degenerates in the presence of mode degeneracy.Consequently,the SVD approach is often not feasible in practical scenarios.This paper proposes a full rank decomposition (FRD) method to address these issues.Compared to the SVD method,the FRD method has three distinct advantages:1) the conditions that the FRD method requires are much easier to be fulfilled in practical scenarios;2) both modal depth functions and wavenumbers can be simultaneously extracted via the FRD method;3) the FRD method is not affected by the phenomenon of mode degeneracy.Numerical simulations are conducted in two types of waveguides to verify the FRD method.The impacts of environment configurations and noise levels on the precision of the extracted modal depth functions and wavenumbers are also investigated through simulation.
2025年03期 v.24 672-684页 [查看摘要][在线阅读][下载 1025K] - CHE Yachen;WEI Lianxue;DIAO Yaqi;JIA Wenjuan;LI Hongzhi;
The use of antifouling agents is suggested to be a promising method for protecting oceanic instruments from biological contamination. We developed a novel antifouling material doped with capsaicin(CAP) as a filler and montmorillonite(MMT) as a carrier for the practical application of CTD(conductivity, temperature, depth) protection. The optimal parameters for preparing the material were established, and the obtained material achieved the maximum CAP loading capacity of 32.74%. The proposed material exhibited great release properties in acidic environments, which is beneficial for reducing bacterial attachment. Furthermore, the optimal conditions(temperature, flow rate, and pressure in the aquatic environment) for a better release rate of the material were determined through a series of simulation tests in lab. It provided good guidance and basis for practical application of the material. The CAP@MMT composite showed excellent efficiency and effectiveness in preventing the attachment of microorganisms during the four-month marine field tests. In the subsequent experiments, the great properties of the antifouling material were further confirmed by retesting the conductivity of four instruments participating in marine field tests. The measuring errors of CTD protected by the antifouling material are both within 0.01 mS/cm, which is far lower than that of the other two instruments.
2025年03期 v.24 685-694页 [查看摘要][在线阅读][下载 833K] - WANG Xuan;MO Weijun;ZHANG Guanglong;JIANG Xiaohui;CHEN Guobo;YU Liangmin;
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, ~(13)C 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.
2025年03期 v.24 695-711页 [查看摘要][在线阅读][下载 2816K]
- LI Haoyang;LI Hao;LI Chengtian;JIN Xi;LI Weiwei;WEN Haishen;LI Yun;LAI Qianyan;NIU Chunxiang;QI Xin;
Deep-sea aquaculture is an emerging trend due to the contamination and overexploitation of nearshore mariculture areas.However,the complex water conditions in the deep sea impose higher demands on the swimming performance of farmed animals.Spotted sea bass (Lateolabrax maculatus) is one of the most economically important fish species in China.To investigate the mechanisms underlying the individual variations in swimming performance among spotted sea bass,we measured their critical swimming speed (U_(crit)) and morphological phenotypes.Total length,body length,body weight,caudal region length,and condition factor showed significant positive correlations with absolute U_(crit).In contrast,caudal fin length and pectoral fin length tended to hinder the swimming performance of individual spotted sea bass.Additionally,white muscle tissues from fish exhibiting good swimming performance (relative U_(crit)>8.20 BL/s) and poor swimming performance (relative U_(crit)<7.31 BL/s) were sampled for RNA-seq.A total of694 differential expression genes (DEGs) were identified through gene expression analysis,with significant enrichment in GO terms such as mitochondrial protein complex,ribosomal subunit,structural constituent of ribosome,and oxidative phosphorylation,as well as genes in KEGG pathways including ribosome and metabolic pathways.In conclusion,our study for the first time comprehensively elucidated the impact of morphology of spotted sea bass on its individual differences in swimming ability,and analyzed the genetic basis underlying swimming ability using transcriptomic methods.This study provides a theoretical basis for the potential breeding varieties of spotted sea bass suitable for deep-sea aquaculture.
2025年03期 v.24 707-720页 [查看摘要][在线阅读][下载 581K] - BAI Xianchao;ZHOU Yaru;BI Wenlong;HU Hong;XU Chengxun;LI Qi;
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 e IF2a kinase 1, e IF2a 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.
2025年03期 v.24 721-734页 [查看摘要][在线阅读][下载 721K] - BAI Huaiyu;HUANG Lingfeng;SUN Yao;
Fish scale δ~(15)N(δ~(15)N_(sca)) records trophic information of the whole life history for marine fishes. Data from gut content and values calculated from white muscle tissue(WMT) are insufficient for assessing trophic level(TL) of marine fishes as they only provide the information of several months or even several days. Stable isotope analysis(SIA) of nitrogen was carried out in fish scales and WMT of 16 species from a total of 28 individuals captured from the Yellow Sea and northern East China Sea in October and November of 2019, aiming at discovering the correlation between δ~(15)Ns ca and fish WMT δ~(15)N(δ~(15)N_(WMT)), so as to use δ~(15)N_(sca) for the characterization of TLs of marine fish. Scales were analyzed without prior carbonate dissolution as a pre-processing step. TL calculated from δ~(15)Ns ca was compared to traditional TL formula calculated with δ~(15)N_(WMT) to estimate the accuracy. We found that there was a highly significant and positive correlation(r=0.830, P<0.001) between δ~(15)Ns ca and δ~(15)N_(WMT). TL calculation results using fish scale(TLs ca) and WMT(TL WMT) showed congruence(r=0.773, P<0.001), and the regression coefficient between δ~(15)N_(sca) and δ~(15)N_(WMT) was used for calculating TLs ca. The conversion was conducted for the purpose of comparison with previous δ~(15)N_(WMT)-based calculation results of TL. TLs ca calculation results were 81.25% within the TL range of ±10% calculated with δ~(15)N_(WMT). The findings in the present study showed that δ~(15)N_(sca) is a viable technique for the characterization of the TL of marine fish and can help to predict food web and support the study of marine ecosystem.
2025年03期 v.24 735-744页 [查看摘要][在线阅读][下载 758K] - HU Shiwei;GAO Shuang;REN Zhaocai;ZHANG Peijie;WANG Jinhui;
Swimming crab(Portunus trituberculatus) eggs contain abundant phospholipids and polyunsaturated fatty acids with specific bioactivities. However, more studies on the functions of other nutrients are needed. Here, a novel sialoglycopeptide from P.trituberculatus eggs, which was termed as Pt-SGP, was isolated with enzymolysis. Pt-SGP was a 6480-Da pure sialoglycopeptide.O-glycan units existed between peptides and sugars. Pt-SGP was composed of 10.69% protein, 71.43% hexose, and 11.27% Neu5Gc acid. Analyzed with HPLC, GC-MS, and NMR spectrometry, the carbohydrate chain of Pt-SGP was {(4GlcNAc1-2Man1-3)/(4GlcNAc1-2Man1-6)Man1-6}/{4Glc1-4}Glc1-4Glc1-3GlcNAc1. The MS spectrometry analysis result showed that the peptide chain was Val-Ala-Thr*-Val-Ser*-Leu-Pro-Arg. The results on mice showed Pt-SGP could reduce body weight gain by 18.13%, white adipose weight by 28.57%, serum TC by 22.32, serum TG by 9.46%, serum LDL-C by 27.69%, hepatic TC by 73.21%, and hepatic TG by25.20%. Furthernore, it could increase serum HDL-C by 75.96%, mitigate adipocyte size and hepatic lipid accumulation in high fat diet-fed mice. Pt-SGP significantly down-regulated C/EBPα signaling and up-regulated AMPKα signaling in the epididymal fat tissues. The findings indicate that Pt-SGP exhibits notable anti-obesity properties, and can potentially become a promising dietary supplement for anti-obesity.
2025年03期 v.24 745-754页 [查看摘要][在线阅读][下载 700K] - LI Hongda;LI Shikang;GUO Hong;LV Shuhang;WANG Bin;BI Jinhong;NIE Hongtao;
In order to cultivate Manila clam varieties in northern China, we crossed the Dalian wild population(referred to as D)and the Weihai wild population(referred to as W) to create a 2×2 complete diallel hybrid. Ultimately, we obtained two hybrid groups(D♀×W♂(DW) and W♀×D♂(WD)) and two inbred groups(D♀×D♂(DD) and W♀×W♂(WW)). We measured their growth and survival during the larval and juvenile stages and compared the data between hybrid and inbred groups to study the potential heterosis of the hybrid. With the exception of slightly lower values in the WD group, fertilization and hatching rates did not differ significantly among the other groups. However, during the larval stage(days 1–15), we observed significant differences in the growth rate of Manila clam in the hybrid groups at days 1, 3, and 6 of age(P<0.05). Among the groups, the clams in the DW group had the highest survival rate, which was indicative of significant heterosis. After entering the juvenile stage(days 30–120), both hybrid groups showed high heterosis in terms of growth and survival. The DW group had the greatest amount of heterosis for survival performance,and the WD group had the greatest amount of heterosis for shell length and height growth. These results indicated that this hybrid combination had great breeding potential, and provided a useful hybrid strategy for producing genetic improvements in R. philippinarum.
2025年03期 v.24 755-762页 [查看摘要][在线阅读][下载 404K] - LU Xinyue;ZHANG Lin;HAN Jichang;TIAN Jiaojiao;WANG Yumeng;LUO Jiansen;YE Lingzhi;HUA Suping;HUANG Zhen;XU Jilin;
Isochrysis zhanjiangensis is a dietary microalga renowned for its high content of polyunsaturated fatty acids(PUFAs).However, research on the genes essential for PUFA synthesis in Isochrysis zhanjiangensis is limited. This study successfully isolated two Δ9 fatty acid desaturase genes, IZ-delta9-1 and IZ-delta9-2, from Isochrysis zhanjiangensis, which are classified as acyl-lipid desaturases based on phylogenetic analysis. When heterologously expressed in yeast, both genes were confirmed to catalyze the conversion of C16:0 and C18:0 into C16:1 and C18:1, respectively. Furthermore, the impacts of environmental factors on algal growth, fatty acid composition, and transcription levels were explored. Using gas chromatography-mass spectrometry(GC-MS), the fatty acid profiles of I. zhanjiangensis were evaluated. The findings showed that under low temperature(LT) and low nitrogen(LN) conditions,the saturated fatty acids(SFAs) content decreased, and the monounsaturated(MUFAs) and unsaturated fatty acids(UFAs) contents increased. Changes in salinity had a minimal impact on the fatty acid composition. The qPCR analysis revealed that high temperature(HT) and high salt(HS) increased the transcription of IZ-delta9-1, while low nitrogen(LN) and high nitrogen(HN) decreased it. Unlike IZ-delta9-1, the transcription of IZ-delta9-2 significantly increased under both low and high temperature treatments, especially in LT groups. Moreover, compared to the control, the transcription levels of IZ-delta9-1 decreased under improper salinity and nitrogen concentrations. This study is helpful for understanding the fatty acid synthesis pathway in I. zhanjiangensis.
2025年03期 v.24 763-773页 [查看摘要][在线阅读][下载 586K] - LIU Rongxin;CHEN Xiaoqun;ZHOU Yangen;TAN Jinxiao;HUANG Ming;XU Tao;LI Li;DONG Yunwei;GAO Qinfeng;DONG Shuanglin;
Gene expression and the content of hormones regulating feed intake and digestion are crucial for understanding gastric evacuation(GE) and feeding frequency in fish. This study assessed the effects of temperature and size on these parameters by examining the domestication of steelhead trout(Oncorhynchus mykiss) at four temperatures(8 °C, 12 °C, 16 °C, and 20 °C) and with two sizes(75.99 g±10.48 g and 140.21 g±22.08 g) over two weeks. The trout were fasted for 72 h before the GE trial to ensure complete gastric emptying. In each GE trial, the expressions of peptide tyrosine(PYY), cholecystokinin(CCK), and ghrelin genes, along with corresponding serum hormone levels, were measured before feeding and at 0 h and 24 h after feeding, in conjunction with feed intake and 24-h gastric content mass. Results revealed significant effects of temperature on the expression of the three gastric genes. CCK expression increased at 8 °C, correlating with reduced feed intake, while PYY and CCK increased at 20 °C, correlating with accelerated gastric evacuation. Size significantly influenced serum levels of all three hormones, but the interaction between temperature and size did not affect PYY and ghrelin expression or their serum contents. This study provides molecular insights into how temperature and size regulate the digestion of steelhead trout, offering a theoretical framework for optimizing feeding frequency in aquaculture practices.
2025年03期 v.24 774-783页 [查看摘要][在线阅读][下载 497K] - AHMED Nedaa;EL-TABAKH Mohamed A.M.;MOHAMED Hala F.;XU Changan;HUANG Lingfeng;
Tissue culture is one of the most promising and practical methods for conserving endangered plant species. Therefore,the present study evaluates the conservation of the endangered seaweed Sargassum fusiforme through tissue culturing techniques from different explants for the first time. Besides, the genetic variation of the mother plant and cultivated explants using inter-simple sequence repeat(ISSR) techniques; this methodology was the first to be illustrated in such work for algae tissue culturing. The regeneration results have shown that different explants could induce shoot and rhizoid morphogenesis with a total number of blades of 2436,1011, 1466, 678, and 6 from apical parts, stipe with blades, two-segmented seedlings, rhizoids, and stipe without blades, respectively.The total length was 234, 181.8, 83.5, and 81.8 cm from the two-segmented seedlings, apical parts, stipe without blades, and stipe with blades, respectively. At the same time, the total wet weight was 73.148, 48.369, 35.731, 18.588, and 2.035 g from the apical parts, the two-segmented seedlings, stipe with blades, rhizoids, and stipe without blades, respectively. Micropropagation of S.fusiforme was successfully achieved with apical, stipe, and stolon segments using free PES media. It is suggested that the applied genetic fingerprint is valid for S. fusiforme and will respond well to molecular marker assistance in cultivation. The significance of S.fusiforme and its exposure to being endangered due to over-exploitation have made its regeneration in vitro a subject of interest in this study. Thus, this report represents the successful regeneration of S. fusiforme and explores the genetic uniformity or somaclonal variation of the obtained seedlings using the ISSR-PCR marker for the first time.
2025年03期 v.24 783-796页 [查看摘要][在线阅读][下载 974K] - WAN Jiyue;MA Hui;XU Yuxuan;ZHANG Shumiao;LI Jian;LI Guiling;HUANG Shiying;YE Xiaotong;ZHANG Zhengxiao;LIU Jingwen;
Melanosomes are specialized membrane-bound organelles within which melanin is synthesized and stored. The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy. Ceramide, a central molecule in sphingolipid metabolism, has been widely implicated in the regulation of autophagy. Few researchers have addressed the potential effects of ceramide analogs on suppressing melanin synthesis. However, whether ceramide can induce melanosome autophagy and the potential autophagy-dependent mechanism underlying this phenomenon remain unknown. Here, an active compound from the marine microalgae Emiliania huxleyi extract was firstly isolated and identified as a long-chain C22-ceramide(C22-Cer). In vitro results of mouse B16 melanoma cell experiments showed that treatment with 2–5 μmol/L C22-Cer significantly suppressed the increase of α-MSH-induced melanin levels and tyrosinase activity without cytotoxicity. C22-Cer induced typical hallmarks of autophagy such as accumulation of autophagosomes, enhanced autophagic flux and microtubule-associated protein light chain 3, LC3-II expression, and p62 degradation through activating c-Jun N-terminal kinase(JNK) directly. Furthermore, C22-Cer activated JNK-Bcl-2 signaling, dissociated the Beclin1/Bcl-2 complex, and induced melanosome autophagy without affecting the expression of MITF. Besides, the Ca~(2+) influx induced by treatment with C22-Cer further increased the substantial accumulation of autophagosomes. Together, we found a novel marine-derived compound, C22-Cer, targeting JNK pathway and Ca~(2+) signaling to induce melanosome autophagy and suppress melanin accumulation in B16 cells. This study implicates that C22-Cer might be a potential therapeutic mediator against skin pigmentation in mammals.
2025年03期 v.24 792-810页 [查看摘要][在线阅读][下载 1906K] - NOUF Al-Enazi;
This study aims to optimize biosurfactant production by Streptomyces gobitricini strain BS-2. After the initial screening,the effective factors on the production of biosurfactant were investigated with the two-level factorial statistical. The physical and chemical features and structure of the biosurfactant crafted were analyzed using FTIR, CHNS, EDX, and SEM. The extracted biosurfactant resulted in a decrease in interfacial tension from 72 mN/m to 29 mN/m, with a critical micelle concentration(CMC) of300 mg/mL. The optimum medium for biosurfactant production that led to utmost diminution in culture broth surface tension(29 mN/m) was: crude oil(1.5%, v/v), hydrolyzed protein(1 g/L), yeast extract(0.5 g/L), molasses(1.5 g/L) and olive oil(1% v/v).The glycolipid organization of the microbial surfactant was confirmed via FTIR, CHNS, EDX, and SEM analysis. Analysis using GC indicated that the presence of biosurfactant increased crude oil degradation by S. gobitricini strain BS-2 dramatically(87%) and this bacterium effectively degraded most of its alkane components. Furthermore, the glycolipid biosurfactant displayed significant development repression against therapeutic bacterial microbes. In summary, the glycolipid biosurfactant produced by S. gobitricini strain BS-2 exhibited diverse functional properties and showed promise for potential biomedical and biotechnological applications.
2025年03期 v.24 809-820页 [查看摘要][在线阅读][下载 868K]