- HAO Mengyu;HU Yuyi;SHAO Weizeng;MIGLIACCIO Maurizio;JIANG Xingwei;WANG Zhenyuan;
Synthetic aperture radar(SAR) aboard SEASAT was first launched in 1978. At the beginning of the 21st century, the Chinese remote sensing community recognized the urgent need to develop domestic SAR capabilities. Unlike scatterometers and altimeters, space-borne SAR offers high-resolution images of the ocean, regardless of weather conditions or time of day. SAR imagery provides rich information about the sea surface, capturing complicated dynamic processes in the upper layers of the ocean, particularly in relation to tropical cyclones. Over the past four decades, the advantages of SAR have been increasingly recognized, leading to notable marine applications, especially in the development of algorithms for retrieving wind and wave data from SAR images. This study reviews the history, progress, and future outlook of SAR-based monitoring of sea surface wind and waves. In particular, the applicability of various SAR wind and wave algorithms is systematically investigated, with a particular focus on their performance under extreme sea conditions.
2025年04期 v.24 821-839页 [查看摘要][在线阅读][下载 1658K] - LU Kecheng;LI Yiran;HU Haibo;WANG Ziyi;
The Madden-Julian Oscillation(MJO) is a key atmospheric component connecting global weather and climate. It functions as a primary source for subseasonal forecasts. Previous studies have highlighted the vital impact of oceanic processes on MJO propagation. However, few existing MJO prediction approaches adequately consider these factors. This study determines the critical region for the oceanic processes affecting MJO propagation by utilizing 22-year Climate Forecast System Reanalysis data. By introducing surface and subsurface oceanic temperature within this critical region into a lagged multiple linear regression model, the MJO forecasting skill is considerably optimized. This optimization leads to a 12 h enhancement in the forecasting skill of the first principal component and efficiently decreases prediction errors for the total predictions. Further analysis suggests that, during the years in which MJO events propagate across the Maritime Continent over a more southerly path, the optimized statistical forecasting model obtains better improvements in MJO prediction.
2025年04期 v.24 840-850页 [查看摘要][在线阅读][下载 6307K] - CUI Yanxing;JIANG Wensheng;
Progressive modifications in submarine topography and shorelines drastically affect tidal dynamics in bays. This study examines the influence of topographic slope, bay length, and driving forces on tidal currents following land reclamation. Tidal equations are analytically solved using infinite series, deriving expressions for tidal levels and currents in narrow bays with varying topography. Tidal levels, influenced by topographic variations, are characterized by amplitude and phase lag of their complex amplitude.These levels demonstrate high sensitivity to longitudinal slope variations but remain relatively stable under lateral slope changes. Under constant topographic slopes, even minor changes in bay length can drastically modify amplitude and phase lag, highlighting the sensitivity of tidal dynamics to geometric alterations. Tidal velocity notably increases with steeper longitudinal slopes and modestly rises with elevated lateral slopes. However, changes in longitudinal and lateral slopes do not considerably alter flow patterns. While external forces predominantly regulate tidal velocity with negligible effects on flow patterns, endogenous resistance influences velocity but minimally impacts flow structure. These findings enhance the understanding of tidal responses to geometric and topographic changes, providing valuable guidance for land reclamation projects and coastal management strategies.
2025年04期 v.24 851-864页 [查看摘要][在线阅读][下载 1534K] - ZHAO Shengnian;MA Ruiqian;SUN Jiwei;LI Longsheng;YUAN Xiaofan;LIANG Hui;SHI Hongyuan;
The coastal regions of Laizhou Bay are highly susceptible to cold surges. This study used ERA5 reanalysis data from2007 to 2022 and employed a hybrid model that integrates single-particle Lagrangian trajectories to statistically analyze the paths and intensity characteristics of cold surges in the Laizhou Bay area. Based on this analysis, a comparative analysis of outbreak processes,formation mechanisms, and causes of three different types of cold surge pathways was conducted. Results indicate variations in the characteristics of different cold surge pathways. Cold surges along the northern pathway originate from the Kara Sea. From a circulation perspective, the presence of a warm ridge over the Ural Mountains leads to the formation of a blocking system and an inverted‘Ω' flow pattern over Siberia. In contrast, cold surges along the northwest pathway originate from the Barents Sea, the Kara Sea, and the plains of Eastern Europe, with a pre-outbreak circulation displaying a characteristic ‘ridge–trough–ridge' pattern. Finally, cold surges along the western pathway originate from the Norwegian Sea and the nearby plains of Eastern Europe, transitioning from a blocking pattern to a ‘ridge–trough–ridge' pattern before the outbreak, distinguishing them from the northern and northwest pathways. This research provides a basis for forecasting cold surge events in Laizhou Bay and for disaster prevention and mitigation in the coastal regions.
2025年04期 v.24 865-874页 [查看摘要][在线阅读][下载 1708K] - SHEN Xinyu;YAO Zhigang;BAO Xianwen;LI Xibin;DING Yang;
This study examines in-situ temperature profiles in three representative sections, namely, the Dalian–Chengshantou(DC), the Chengshantou–Changsangot(CC), and the 36°N, to delineate the interannual variations of the Yellow Sea Cold Water Mass(YSCWM) and investigate their potential connections, along with forcing factors, across different regions. The findings reveal the following insights: 1) The YSCWM experiences warming trends at DC, CC, and the western segment of the 36°N, revealing corresponding minimum temperature rates of 0.021 °C/yr, 0.043 °C/yr, and 0.063 °C/yr, respectively. Conversely, the eastern portion of the36°N displays a slight cooling trend, resulting in a pronounced zonal disparity in long-term temperature trends. 2) The changes in the YSCWM are closely linked to the atmospheric wind patterns. Notably, the weakening of northerly winds during winter corresponds to the rise in YSCWM temperature, which is accompanied by a westward shift in the cold core of the 36°N section. 3) Correlation analysis with factors such as the Arctic Oscillation(AO), Pacific Decadal Oscillation(PDO), and El Ni?o-Southern Oscillation(ENSO), etc., indicates that changes in large-scale climate systems influence the spatiotemporal variations of the YSCWM, resulting in seasonal differences.
2025年04期 v.24 875-885页 [查看摘要][在线阅读][下载 2116K] - GAI Yunyun;YU Mingqi;ZHANG Jian;QIAO Shouwen;
As China's second longest river, the Yellow River (YR) carries a large volume of fresh water into the Bohai Sea with abundant nutrients and, thus, plays a crucial role in regulating the temperature and salinity near the YR Delta. In this study, using the runoff data and the Finite Volume Community Ocean Model, we simulated the salinity distribution near the YR Estuary for 2013–2022. We investigated the effect of the YR runoff on salinity dispersion and established the relationship between salinity distribution and the river's runoff volume. Additionally, we analyzed the relationship between fish eggs and salinity distribution using fish egg data. Findings indicated that the freshwater discharged from the YR converged into Laizhou Bay under the influence of tide. The several years of simulation results (2013–2022) showed that the salinity field near the YR Estuary changed with the variations of river runoff entering the sea. Simultaneously, we found a positive correlation between the area of low-salinity zones (below 27) and the monthly average river runoff, and this relation could be expressed as Y_s=0.7457X_r+78.904. The characteristics of fish egg distribution revealed that fish eggs were primarily distributed in the areas characterized by salinity in the range of 25–29.
2025年04期 v.24 886-899页 [查看摘要][在线阅读][下载 2127K] - SANTHOSH Nagulan;VINU KUMAR Shettahalli Mantaiah;SAKTHIVEL MURUGAN Erusagounder;
Scientists have introduced new methods for capturing energy from ocean waves. Specifically, scientists have focused on a type of wave energy converter(WEC) that is nonbuoyant(i.e., a body that cannot float). Typically, the WEC is most effective when it is in resonance, which occurs when the natural frequency of the WEC aligns with that of the ocean waves. Therefore, accurately predicting the movement of the WEC is crucial for adjusting its system to resonate with the incoming waves for optimal performance.In this study, artificial intelligence techniques, such as random forest, extra trees(ET), and support vector machines, are created to forecast the vertical movement of a nonbuoyant WEC. The developed models require two variables as input, namely, the water wave height and its time period. A total of approximately 4500 data points, which include nonlinear water wave height and duration obtained from a laboratory experiment, are used as the input for these models, with the resulting vertical movement as the output. When comparing the three models based on their processing speed and accuracy, the ET model stands out as the most efficient. Ultimately,the ET model is tested using data from a real ocean setting.
2025年04期 v.24 897-908页 [查看摘要][在线阅读][下载 1042K] - LE Conghuan;QI Xiling;XIONG Lichao;ZHANG Puyang;DING Hongyan;
Offshore floating photovoltaic systems have tremendous potential to address the energy crisis.As a novel type of floating photovoltaic system,membrane structures are increasingly applied due to their advantages of being lightweight and cost-effective.A 1:40 scaled model for laboratory experiments was designed and developed,considering Ocean Sun’s membrane structure.The study aims to investigate the hydrodynamic characteristics of the membrane structure under wave loading by testing its various motion responses and mooring forces at different wave heights and periods.The conclusions indicate that as the wave period decreases within the range of 1.75 to 1.25 s,the heave motion response of the structure decreases,whereas pitch,surge motion response,heave acceleration,and mooring force increase.The amplitudes of various motions and mooring forces of the structure decrease with decreasing wave height.The hydrodynamic responses under irregular and regular waves follow similar patterns,but the responses and mooring forces induced by irregular waves are more significant.The structure should be designed based on the actual wave height.In addition,the same frequency resonance phenomenon is avoided because the movement period of each degree of freedom is close to the wave period.
2025年04期 v.24 909-923页 [查看摘要][在线阅读][下载 6144K] - YANG Jun;ZHANG Guanglu;ZHAO Yanyan;WEI Haotian;LIU Sheng;LI Sanzhong;XU Jishang;ZHANG Yang;WANG Nan;
Palaeoceanographic and palaeoclimatic reconstructions, particularly on the spatial and temporal evolution across different regions, can offer valuable insights into global changes. At present, abundant data recorded in sediments indicate a phase asynchrony from land to sea during the Holocene. This has raised great debate about the forcing mechanisms of paleoclimatic evolution. In this study, we reconstructed sea surface temperature and salinity during the Holocene from the northern South China Sea(SCS) by the Mg/Ca ratios and δ~(18)O values of Globigerinoides ruber sensu stricto(s.s.) in the core SH-CL38. By comparing the results with records from other cores in the SCS, it indicates that during the Holocene, the climatic changes in the SCS are mainly influenced by the East Asian summer monsoon driven by Northern Hemisphere summer insolation. The lower salinity in the early Holocene compared to the mid-late Holocene is mainly controlled by palaeogeographic changes in the SCS Basin related to sea level. The fitted sea surface temperature anomaly results from the northern and southern SCS show that the climate evolution in the entire SCS during the early Holocene was asynchronous. The multi-year mean air mass backward trajectory results indicate that the northern SCS is significantly influenced by moisture originating from the tropical western Pacific, while the southern SCS exhibits notable local or regional contributions. Therefore, the differences in the composition of moisture contributions caused by changes in the strength and path of the summer monsoon may be a factor driving the different spatial climate patterns in the SCS.
2025年04期 v.24 924-940页 [查看摘要][在线阅读][下载 1835K] - WANG Yangyang;LIANG Weixing;LOU Min;WANG Yu;
Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate production. The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model considering hydrate phase transition kinetics with heat and mass transfer behaviors. The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics. The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore, the hydrate volumetric fractions under different pressure and temperature conditions are predicted. The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity, and the gas and liquid fractions, void fraction in liquid slug, and unit length tend to decrease. The increase in outlet pressure leads to an increased hydrate formation rate, which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.
2025年04期 v.24 941-953页 [查看摘要][在线阅读][下载 1199K] - XU Bowen;SONG Peng;CAO Yanling;WANG Ruxi;FENG Qiwei;LIU Qianran;JING Lu;ZHAO Bo;XU Yongchen;TIAN Mingyang;
Kirchhoff integral migration imaging is widely used in industrial production due to its advantages of not being limited by observation systems, good target imaging effects, and high computational efficiency. Vertical transversely isotropic(VTI) media, as a typical anisotropic media, has always been a primary focus of anisotropic migration imaging research. We focus on the problems of low accuracy and efficiency in travel-time calculations associated with conventional Kirchhoff integral migration for VTI media. A travel-time calculation method based on physical-informed neural network(PINN) for VTI media is introduced into the process of Kirchhoff integral migration imaging. Model experiments and field data processing have shown that the travel-time calculation based on PINN can significantly improve both the accuracy and efficiency when compared to traditional finite difference algorithms, thereby enabling high-precision Kirchhoff integral migration imaging for VTI media.
2025年04期 v.24 954-966页 [查看摘要][在线阅读][下载 2004K] - HU Guang;LI Yan;YANG Shengxiong;ZHANG Heng;LIU Xin;LI Yuanheng;TIAN Dongmei;
Multiple suppression is an important element of marine seismic data processing. Intelligent suppression of multiples using artificial intelligence reduces labor costs, minimizes dependence on unknown prior information, and improves data processing efficiency. In this study, we propose an intelligent method for suppressing marine seismic multiples using deep learning approaches.The proposed method enables the intelligent suppression of free-surface-related multiples from seismic records. Initially, we construct a multi-category marine seismic multiple dataset through finite difference forward modeling under different boundary conditions.We use various models and data augmentation methods, including sample rotation, noise addition, and random channel omission. Then,we apply depthwise separable convolution to develop our deep learning Mobilenet-Unet model. The Mobilenet-Unet framework significantly reduces the number of operations required for multiple elimination without sacrificing model performance, ultimately realizing the optimal multiple suppression model. The trained Mobilenet-Unet is applied to the test set for verification. Moreover, to determine its generalization ability, it is implemented to seismic records containing multiples generated by two marine geophysical models that were not included in the training process. The performance of Mobilenet-Unet is also compared with that of different network structures. The results indicate that, despite its small size, our proposed Mobilenet-Unet deep learning model can rapidly and effectively separate multiples in marine seismic data, possessing reasonable generalization ability.
2025年04期 v.24 967-978页 [查看摘要][在线阅读][下载 908K] - WANG Xinhua;SONG Xiangyang;LI Zhuang;WANG Heqi;
Underwater imaging is frequently influenced by factors such as illumination, scattering, and refraction, which can result in low image contrast and blurriness. Moreover, the presence of numerous small, overlapping targets reduces detection accuracy. To address these challenges, first, green channel images are preprocessed to rectify color bias while improving contrast and clarity. Second, the YOLO-DBS network that employs deformable convolution is proposed to enhance feature learning from underwater blurry images. The ECA attention mechanism is also introduced to strengthen feature focus. Moreover, a bidirectional feature pyramid network is utilized for efficient multilayer feature fusion while removing nodes that contribute minimally to detection performance. In addition, the SIoU loss function that considers factors such as angular error and distance deviation is incorporated into the network.Validation on the RUOD dataset demonstrates that YOLO-DBS achieves approximately 3.1% improvement in m AP@0.5 compared with YOLOv8n and surpasses YOLOv9-tiny by 1.3%. YOLO-DBS reduces parameter count by 32% relative to YOLOv8n, thereby demonstrating superior performance in real-time detection on underwater observation platforms.
2025年04期 v.24 979-992页 [查看摘要][在线阅读][下载 1639K] - DJAROUN Roufida Rana;FAN Linlin;HUANG Yanming;ZHANG Jinchang;
The Equatorial Atlantic Ocean, a region crucial to understanding Earth's tectonic processes and advancing the theory of plate tectonics, remains the focus of extensive research aimed at unraveling its evolution. However, its complex structural setting and contentious formation timeline have posed significant challenges. Through a comprehensive review of contemporary scientific literature, we have identified three distinct phases for its evolution: pre-breakup, syn-breakup, and post-breakup, providing more detailed insights into the tectonic evolution of the Equatorial Atlantic. Prior to 110 Myr, the African and South American Plates underwent stretching predominantly from North to South, with the emergence of the Parana plume. This condition has led to the formation of numerous fracture zones and a triple junction. During the syn-breakup phase, spanning from 110 Myr to 90 Myr, the central region of the Equatorial Atlantic fully opened up, establishing a connection between the northern and southern waterways. However, the development of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable complexity. The underlying causes for these complex structural formations remain elusive. Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot, a pair of oceanic plateau ‘twins' and a series of seamount chains were formed as a result of mantle plume tails. Consequently, the timeline of the Equatorial Atlantic's tectonic evolution has gradually become clearer. However, due to the extensive timescale and the multitude of events involved in its formation, disputes about the precisetiming of various events still remain. The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations, hotspot formations, and meteorite impacts, highlighting the need for further investigation into their interactions. The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geophysical data.
2025年04期 v.24 993-1001页 [查看摘要][在线阅读][下载 1009K] - JIANG Xiaohui;SONG Xinyu;CHEN Chen;ZHAO Xinbo;YU Liangmin;
Capsaicin-containing polymer materials with functional structure were successfully prepared by simple free radical polymerization 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 adsorption 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.
2025年04期 v.24 1002-1016页 [查看摘要][在线阅读][下载 1424K] - LIAO Yingdi;ZHANG Huan;WANG Xin;CHEN Li;HUANG Chenggeng;ZHAO Yazhou;DA Bo;
Reinforcing bars in concrete structures in marine environment are prone to pitting corrosion, which threatens the safety of engineering structures. In order to effectively mitigate the pitting corrosion of reinforcing bars, the electrochemical testing and atomic force microscopy are adopted, the effect of triethanolamine dodecylbenzene sulfonate(TDS) on metastable pitting behavior of304 stainless steel(304 SS) in simulated concrete pore solutions(SCPS) with chlorine contamination was studied. The results show that the corrosion potential(Ecorr) and breakdown potential(Eb) increased with the growth of the TDS concentrations. Statistical characteristics of metastable pits suggested that as the TDS concentrations increased in the SCPS, the parameters were all decreased. The Mott-Schottky tests exhibited that, although the donor density(ND) diminished, the thickness of the space charge layer(W) increased with increasing TDS concentrations. Investigation results showed that TDS inhibited the sprouting and growth of metastable pits, and with greater TDS concentration, it becomes more difficult for metastable pits to transfer into stable pits in the SCPS, the generated stable passive film prevented the sprouting of pitting corrosion, It is recommended to use TDS with a concentration of not less than3.364×10~(-4) mol/L in engineering, so that the sensitivity of passivation film of 304SS to chloride erosion is reduced.
2025年04期 v.24 1017-1026页 [查看摘要][在线阅读][下载 1610K] - SONG Jingjing;CHOONG Khai Hang;TAN Kianann;KWAN Kit Yue;TAN Karsoon;
Climate change is a natural phenomenon. Over the past billions of years, Earth's climate has experienced many ice and warm periods. These changes have created various environments, directly benefiting and disadvantaging certain species, eventually leding to extinction and evolutionary diversification through natural selection. However, rapid and drastic changes in Earth's climate could be destructive and may lead to mass extinction. It is generally believed that four of the five mass extinction events were caused by drastic changes in the level of atmospheric greenhouse gases. In the recent period(the Anthropocene epoch), when human activities began to significantly impact the Earth's climate, numerous pieces of scientific evidence indicate that anthropogenic activities are associated with the extinction of plants and animals and may lead to the sixth mass extinction. However, some scientists deny the possibility of the 6th mass extinction. Therefore, there is an urgent need to comprehensively review the impact of anthropogenic global warming on our natural environment. This article reviews the scientific evidence of the synergistic impact and chain effects of anthropogenic global warming on ecosystems and living organisms on Earth. It earnestly attempts to summarize relevant data published for specific research questions to improve the understanding of diverse evidence. This helps clarify the current state of research and raises public awareness of the impact of anthropogenic global warming on all stakeholders on Earth.
2025年04期 v.24 1027-1038页 [查看摘要][在线阅读][下载 372K]
- XU Meng;LIU Wenguang;LU Jianguo;
The giant triton snail Charonia tritonis is a marine large carnivorous gastropoda inhabiting in the Indo-Pacific Ocean.Their splendid and highly organized Charonia tritonis shells are attractive;however few studies have been conducted on shell ultrastructure and pigmentation.The arrangements of crossed-lamellar structures were distinctive for the giant triton snail shell,showing three layers of mineral structures in the cross-section.The 1st-order and 2nd-order lamellae of the shell were around 10-20 μm and the crystals in outer layers intersected at right angles in this species.They were identified as aragonite crystals by Raman scattering,and granular organic matrix were attached to the aragonite mineral phase closely.Furthermore,the dominant Raman spectra from polyene pigments in the shell were characterized at wavenumbers of 1123 cm~(-1) and 1504 cm~(-1),assigned to stretching vibrations of carbon-carbon single(C-C) and double(C=C) bonds,and the polyene chain was confirmed with 11-12 C-C bonds and 12-13 conjugated C=C bonds.The research will lay a foundation for exploring the relationship between the calcareous shell and the formation of shell color in the giant triton snail.
2025年04期 v.24 1039-1044页 [查看摘要][在线阅读][下载 703K] - ANSARI Kapuli Gani Mohamed Thameemul;MANOKARAN Seerangan;RAJA Sanjeeve;BOUFAHJA Fehmi;
Two new free-living marine nematode species belonging to the genus Tricoma Cobb, 1894(Desmoscolecidae) are identified from the continental shelf region of the Bay of Bengal. Tricoma ajmalia sp. nov. is characterized by the number of main rings(84male and 85 female), the arrangement of somatic setae, the head shape with broadly truncated end, the relatively long cephalic setae(69%–73% of corresponding head diameter), the amphids extending up to second main ring, slender spicules slightly curved and guberbaculum with dorsocaudally directed apophyses. The second new species, Tricoma sampadansis sp. nov. is characterized by the number of rings(64), the arrangement of somatic setae(14–13 subdorsal, 16 subvenral), the head shape with broadly truncated end,the relatively long cephalic setae(75% corresponding head diameter), the amphidial fovea extending over first main ring, anterioirly bent spicules and gubernaculum with hooked proximal end. An updated valid species list of Tricoma is also presented.
2025年04期 v.24 1045-1057页 [查看摘要][在线阅读][下载 512K] - XU Gang;CHEN Yulei;MEI Haize;YANG Ruqing;XIAO Xuchen;WENG Ling;CAO Minjie;
Matrix metalloproteinases(MMPs) play essential roles in the metabolism of collagens; however, information regarding MMPs in aquatic animals is limited. To elucidate the specific role of MMPs in shrimp muscle degradation, proteinases with gelatinolytic activity were identified in the hepatopancreas of Litopenaeus vannamei(Lv). The gelatinolytic activity was suppressed by metalloproteinase inhibitors EDTA and EGTA to some degree, suggesting the existence of metalloproteinases. Then the catalytic domain of LvMMP-2(LvMMP-2c) was cloned and expressed heterologously in the Pichia pastoris expression system. rLvMMP-2c(recombinant LvMMP-2c) demonstrated optimal gelatinolytic activity at pH 8.0 and 50 °C, and its activity could be enhanced by Ca~(2+)and Ba~(2+). Type I collagen and myofibrillar proteins from shrimp were effectively hydrolyzed by rLvMMP-2c not only at 37 °C, but also at 4 °C, indicating its involvement in the postmortem tenderization of shrimp muscle. Our present study provided new information to elucidate the role of metalloproteinase underlying shrimp meat softening during cold storage, and suggested new strategies to prevent shrimp quality decrement during cold storage.
2025年04期 v.24 1058-1071页 [查看摘要][在线阅读][下载 1186K] - WEI Lian;YU Yong;XU Bo;GAO Zhiwei;DING Haitao;
The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factors shaping these variations.This study aimed to investigate the variation in the types and concentrations of elements within the otolith nuclei of three Antarctic fish species,including Pagothenia borchgrevinki,Trematomus hansoni,and Trematomus bernacchii,collected from Prydz Bay,East Antarctica.Nine elements,~(23)Na,~(24)Mg,~(29)Si,~(31)P,~(39)K,~(57)Fe,~(66)Zn,~(88)Sr,and ~(137)Ba,were selected for analyses because of their concentrations and ecological significance.Ratios of each element to Ca (Me/Ca) were used for analysis,and Me/Ca in the otolith nuclei of these species were analyzed to explore species-specific variations in element types.Significant differences in element composition,except for Fe/Ca and Ba/Ca,were found in different species.Temperature,salinity,reproduction,pelagic larval lifestyle,and diet composition were considered as key endogenous and exogenous factors influencing these differences.Decision tree discriminant analysis,based on the variation of the types and concentrations of elements,was used to identify P.borchgrevinki,T.hansoni,and T.bernacchii with accuracy rates of 86.54%,82.61%,and 73.33%,respectively.Principal component analysis showed overlapping 95%confidence ellipses for the three species at 79.96%,67.31%,and 56.71%,respectively.As these species belong to the Nototheniidae family and share a similar hatching period,the accuracy of species discrimination is reduced.Considering the high probability of error in distinguishing species using otolith nucleus elements,we recommend otolith shape should also be considered to improve identification accuracy.
2025年04期 v.24 1071-1082页 [查看摘要][在线阅读][下载 935K] - ZHANG Yanhao;LIU Jinji;XU Jieying;ZHANG Zhen;LU Jia;LI Wentao;ZHANG Peidong;
We subjected seeds and shoots of eelgrass Zostera marina to different combinations of sediment loosening(0(control),5, 10 cm in depth) and sediment fertilization(0(control), 40, 80, 120, 160 g/m~2) through a field experiment involving seed sowing and shoot transplantation from September 2020 to September 2021. Growth analysis revealed optimum ranges for sediment fertilization and sediment loosening were 88.8–93.8 g/m~2 and 5.3–5.8 cm for Z. marina seed sowing, as well as 79.7–86.7 g/m~2 and 5.9–6.5cm for Z. marina shoot transplanting, respectively. The shoot densities of Z. marina exposed to these optimum range of sediment fertilization and sediment loosening were 1.1–1.3 times of those in the control group. Porewater nutrients are key environmental factors affecting seed germination and shoot growth of Z. marina. The results provide valuable insights for enhancing restoration effects of Z.marina.
2025年04期 v.24 1083-1098页 [查看摘要][在线阅读][下载 1266K] - LI Shaopeng;GENG Ying;LU Na;ZHU Tianjiao;FENG Zhengfu;ZHU Wei;
In order to verify the synthesis pathway of linoleic acid(LA) to generate arachidonic acid(ARA), the functions of Δ6FAD and Elovl 5 in Apostichopus japonicus were tested by heterologous expression in Pichia pastoris. A 60-day feeding experiment was conducted to evaluate the effects of dietary LA and ARA on growth, polyunsaturated fatty acids(PUFA) biosynthesis and immune function of A. japonicus. Seven diets containing graded levels of LA or ARA were formulated, and one diet without PUFA was applied as a control. The results confirmed that Δ6 FAD from A. japonicus has a double desaturation ability of Δ6 and Δ5 for PUFA,and it works together with Elovl 5 enzyme play important roles in biosynthesis of ARA from LA. With increasing dietary LA from4.9 to 12.1 g/kg, the expressions of Δ6 FAD and Elovl 5, levels of LA, ARA and EPA in tissues increased, and the activities of ACP,AKP and CAT enzymes in intestine initially increased and then decreased. Additionally, by increasing dietary ARA from 0.7 to 3.8g/kg, the contents of ALA, EPA and DHA decreased, while the Δ6 FAD expression and the activities of ACP, AKP and CAT in intestine increased significantly. Therefore, appropriate dietary levels of LA(12.1 g/kg) or ARA(3.8 g/kg) build a reasonable composition of n-3/n-6 PUFA in A. japonicus, and improved its growth, antioxidant capacity and immunological defenses.
2025年04期 v.24 1099-1110页 [查看摘要][在线阅读][下载 1496K] - JI Cheng;XIA Zefeng;NIU Chunyu;CHEN Yan;PEI Jinfeng;CHEN Yin;
The polysaccharides from Sepia esculenta ink are potential candidates for biomedical applications due to their functional properties. In our study, a heteropolysaccharide, SE-1, isolated from Sepia esculenta ink, had a molecular weight of 13.1 kDa and a monosaccharide composition of Man:GlcN:GlcUA:GalN:Xyl:Fuc=1.00:1.38:0.65:2.89:0.76:1.99. Through partial acid hydrolysis, methylation and one-and two-dimensional nuclear magnetic resonance(1D and 2D NMR) spectroscopic analyses, it is indicated that the structure of SE-1 consists of →4)-α-D-Glcp NAc-(1→, →4)-α-L-Fucp-(1→, →3)-α-D-Galp NAc-(1→, →2,6)-α-D-Manp-(1→ and →3)-β-D-Glcp UA-(1→ as the main chain and single terminal β-D-Xylp-(1→, which links to O-2 of(1→2,6)-α-Manp, as the side chain. A new aminosugar-abundant heteropolysaccharide was isolated from S. esculenta ink for the first time.
2025年04期 v.24 1111-1120页 [查看摘要][在线阅读][下载 741K] - SUN Lingling;JIANG Gaowei;XU Chengxun;LI Qi;
Triploid oysters are widely cultured due to their superior growth compared to diploids. However, differences in temperature-salinity adaptation between di-and triploid oysters remain inconclusive. This study compared the survival rates, antioxidant enzyme 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 temperatures, 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 capacity, 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.
2025年04期 v.24 1121-1129页 [查看摘要][在线阅读][下载 378K] - ALTALBAWY Farag M.A.;HASSANSHAHIAN Mehdi;MAKARINASAB Fatemeh;JASIM Saade Abdalkareem;BANSAL Pooja;KAUR Harpreet;JAWAD Israa Abed;DEORARI Mahamedha;KUMAR Abhinav;SHNISHIL Ali Turki;ABOSAODA Munther Kadhim;
The Makran Sea is a complex marine environment. The purpose of this research is screening of emulsifier-producing bacteria in this marine environment and optimization of emulsifier production by the best-producing strain. Marine samples(seawater and sediments) were collected from four different zones in the Makran Sea. The emulsification activity index(E_(24)) and Bacterial Adhesion To Hydrocarbons(BATH) were used to select the best emulsifier-producing strains. The prevalent strains were identified by PCR. The optimization of the emulsifier production medium by the best strain was done by two-level factorial design. Seventeen emulsifier-producing strains were isolated from sediments and seawater in the Makran Sea. The strains M6, BS-2, and J6 were selected between all isolates because they have 83%, 91%, and 85% emulsification activity(E_(24)) respectively. The results of sequencing confirmed that these three strains(M6, BS-2, and J6) belong to Cobetia marina, Shewanella alga, and Thalassospira permensis respectively. Maximum emulsifier production occurred at crude oil concentration(4%, v/v), peptone(2.5 g/L), yeast extract(1.5 g/L),molasses(2%), and at a temperature of 25 °C. The results of this research confirmed that the Makran Sea has the potential to reach robust marine bacteria with different biotechnological applications.
2025年04期 v.24 1130-1138页 [查看摘要][在线阅读][下载 1141K] - GUAN Yongjing;WU Weihao;XIE Yian;ZHAO Runfan;CHEN Yaobin;ZHANG Huiying;WANG Jing;ZHAO Chao;
Marine algae and shellfish are contributing positively to carbon sinks. As the world's largest algae and shellfish producer,the carbon sinks potential in China is crucial. Here, the situation of algae and shellfish cultivation in China's offshore from 2011 to 2020 was elaborated. The intensity of carbon sequestration by algae and shellfish annually was estimated. In 2020, the production of algae and shellfish in China has already reached to 2.62 million tons and 14.8 million tons, with an annual growth rate of 7.03% and3.14%, respectively. Their annual productivity also maintained an increasing trend, while the rate of productivity increase decreased over ten years except for Porphyra haitanensis, Sinonovacula constricta, and Haliotis discus hannai. Crassostrea gigas and Ruditapes philippinarum were the highest fixed carbon shellfish, and Saccharina japonica was the dominant algae. Meanwhile, the relatively high carbon sink intensity was found in Shandong, Fujian, and Liaoning. In the last decade, the total carbon sink of algae and shellfish was 1.62 million tons and 7.16 million tons, with an increase of 90.55% and 31.73%, respectively. This created an economic value of 3.293 billion dollars. Results indicated that China's offshore mariculture algae and shellfish assumed the considerable carbon sink capacity. Through rational utilization of the carbon sink resources in algae and shellfish, it provides potential ideas for China to pursue personalized carbon neutrality.
2025年04期 v.24 1139-1157页 [查看摘要][在线阅读][下载 1429K] 下载本期数据