- LIANG Jie;ZHANG Penghui;GOLSANAMI Naser;ASIF Inam;DHANASUVARNACHOTE Dhiti;
<正>1 Introduction The Maritime Silk Road, once a historic network of trade routes that connected continents and facilitated centuries of cultural and economic exchange, has become a region of profound scientific importance. Stretching from East Asia to Europe and Africa, its marine environments are among the most complex and dynamic on Earth. This region encompasses diverse geological settings, including tectonically active zones, varied sedimentary basins, and extensive continental shelves. These features make it a unique natural laboratory for studying various geological and geophysical processes. A comprehensive understanding of these processes is not only of academic value but also essential for addressing contemporary challenges,such as tectonic hazard assessment, sustainable exploration and management of marine resources, and reconstruction of past environmental changes to better anticipate future trends.
2025年06期 v.24 1447-1449页 [查看摘要][在线阅读][下载 146K] - GUO Dingrui;GOLSANAMI Naser;ZHANG Zhi;GYIMAH Emmanuel;BAKHSHI Elham;AHMAD Qazi Adnan;BEHNIA Mahmoud;SABERALI Behzad;YAN Weichao;DONG Huaimin;SHENDY Saeid Ahmadizadeh;JAYASURIYA Madusanka N.;FERNANDO Shanilka G.;
The accurate identification of microporosity is crucial for the characterization of hydrocarbon reservoir permeability and production. Scanning electron microscopy(SEM) is among the limited number of methods available to directly observe the microscopic structure of the hydrocarbon reservoir rocks. Nevertheless, precise segmentation of microscopic pores at different depths in SEM images remains an unsolved challenge, known as the ‘depth-related resolution loss' problem. Therefore, in this study, a 3D reconstruction technique for regions of interest(ROI) was developed for in-depth pixel analysis and differentiation among various depths of SEM images. The processed SEM images, together with the processing outcomes of this technique, were used as the input database to train a stochastic depth with multi-channel residual pathways(SdstMcrp) deep learning model programmed in Python to develop a tool for segmenting the microscopic pore spaces in SEM images obtained from the Beibuwan Basin. The more accurate segmentation helped to detect an average of 1.2 times more microporosity in SEM images, accounting for about 1.6 times more pixels and 1.2 times more pore surface area. Finally, the impact of the accurate segmentation on the calculation of permeability, a significant reservoir production property, was investigated using fractal geometry models and sensitivity analysis. The results showed that the obtained permeability values would vary by a factor of 6, which represents a considerable difference. These findings demonstrate that the proposed models can effectively identify features across a wide range of grayscale values in SEM images.
2025年06期 v.24 1450-1479页 [查看摘要][在线阅读][下载 3964K] - SONG Junlan;PANG Yumao;YANG Chuansheng;YANG Yanqiu;SHANG Luning;YANG Changqing;SUN Jing;
The study of back-arc sedimentary basins is key to understanding oceanic and continental geodynamic processes and mechanisms. The East China Sea Shelf Basin(ECSSB), a back-arc sedimentary basin in a continent-ocean transition zone of the western Pacific Ocean, exhibits remarkable differences in terms of the tectonic deformation characteristics of the basin and the evolutionary features of its sags. These features have led to varied understandings of deep dynamic mechanisms driving the evolution of the basin. In this study, which is based on a detailed interpretation of two-dimensional multichannel seismic data from the ECSSB, the tectonic deformation of the basin is analyzed and the tectonic evolutionary process of the basin is reconstructed. The above research work combines plate convergence processes and deep crust-mantle interactions to explore the controlling factors and deep dynamic mechanisms of the tectonic deformation in the ECSSB. The results of this study indicate that there are significant differences in tectonic deformation between the southern and northern parts of the basin and that the deformation is characterized by eastward migration. Deep crust-mantle interactions are coupled with the development of these differences. The tectonic deformation of the ECSSB is driven by the interactions of the paleo-Pacific, Pacific, Indian, and Philippine Sea Plates with the Eurasian Plate, which have shaped the tectonic pattern of the ECSSB, resulting in east-west zoning, north-south blocking, and pronounced spatiotemporal variability in tectonic deformation. This research provides new insights into the differential development of sags within the ECSSB and provides an important reference for studying back-arc sedimentary basins.
2025年06期 v.24 1469-1484页 [查看摘要][在线阅读][下载 2532K] - LIANG Jie;LI Sen;WANG Jianqiang;LIAO Jing;CHEN Jianwen;GONG Jianming;INAM Asif;SYED Waseem Haider;ZHANG Penghui;
Recent advances in earth science and exploration have made deepwater channel-levee systems a research focus. We collected and analyzed over 10000 km of two-dimensional multichannel seismic data from the offshore Indus Basin to identify channellevee systems at various hierarchical levels depending on their seismic reflection characteristics. Seismic facies analysis was integrated with well data to map the spatial distribution of channel-levee systems in the offshore Indus Basin across various geological periods, and the factors influencing their development were discussed. These systems within the basin were identified using a developed,refined three-tier classification method. The first-order system consists of multiple spatially stacked complexes, the second-order system continuously developed multistage channel-levee bodies, and the third-order system represents the smallest identifiable sedimentary units on seismic profiles. Our findings demonstrate the evolution of the offshore Indus Basin from a single-stage channel with lateral migration to multistage vertical channel stacking from the Miocene to the Pleistocene. Tectonic activities exert their effect on channel-levee systems through their influence on the relative sea level. They also trigger volcanic or seismic events and affect siliciclastic supply. Warm and humid climate conditions form large river systems, which aid in the transport of terrestrial debris to the basin margin. Most channel-levee systems are assumed to have formed during low sea-level periods. This study offers new insights into the formation and evolution of turbidite sedimentary systems in the offshore Indus Basin and presents a practical classification method for comprehending gravity-flow sedimentary configurations and deepwater hydrocarbon exploration.
2025年06期 v.24 1485-1499页 [查看摘要][在线阅读][下载 2503K] - HASSAN Hafiz Ahmed Raza;LIU Keyu;LIU Jianliang;MUNAWAR Muhammad Jawad;REHMAN Saif Ur;HUSSAIN Abid;
Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution of the modern Indus River Delta offers a rare opportunity to study the interplay between sea level fluctuations, tectonism, sediment supply, and the corresponding fluvial responses. This study employs the ‘SedSim' stratigraphic forward model to simulate the delta's evolution from 200 kyr to the next5 kyr, drawing on data from field observations, Landsat imagery, digital elevation models, and previous studies. The model consists of 205 layers, each representing a 1-kyr time step, covering the last two glacial-interglacial cycles. Between 200 kyr and 130 kyr, during a lowstand period, sedimentation on the delta plain continued due to partial flow from the Indus River. During the last interglacial(130–60 kyr), rising sea levels led to peak sediment deposition, characteristic of a highstand phase. From 60 kyr to 18 kyr, sea levels dropped to their lowest during the Last Glacial Maximum(LGM), resulting in extensive erosion and minimal deposition on the delta plain. From 18 kyr to the present, rapidly rising sea levels, coupled with intensified monsoon activity, increased sedimentation rates and triggered avulsion and aggradation processes. The model accurately predicted depositional thickness across the delta plain, indicating a maximum of ca. 200 m at the shoreline platform, ca. 175 m in the northeastern delta, and ca. 100 m in the central delta. The study underscores the delta's vulnerability to future sea level rise, which–at a projected rate of 1 m/kyr–could significantly influence the densely populated, low-lying delta plain. These findings offer valuable insights into the geomorphic evolution of the Indus Delta and emphasize the socioeconomic implications of sea level change, underscoring the importance of proactive management and adaptation strategies.
2025年06期 v.24 1500-1518页 [查看摘要][在线阅读][下载 1978K] - LIAO Jing;LIANG Jie;ZHAO Chen;WANG Xiaojie;GONG Jianming;SYED Waseem Haider;
The Makran Accretionary Prism is one of the largest accretionary prisms in the world and hosts substantial natural gas hydrate resources. However, research on the distribution characteristics and accumulation mechanisms of free gas remains limited.This study identifies structural elements associated with free gas, such as thrust faults, piggyback basins, unconformities, and décollements, through detailed interpretation of newly acquired seismic data. Free gas reservoirs within piggyback basins are located in the folded zone of the accretionary prism, whereas unconformity-type and horizontal sandstone-type free gas reservoirs are identified in undeformed areas. In the folded zone, décollement, thrust faults, and permeable sand layers act as primary migration pathways for free gas, which accumulates in turbidite sands beneath bottom simulating reflectors(BSRs) in piggyback basins. In the undeformed zone, free gas migrates along décollements and thrust faults into horizontal sandstones, where substantial accumulations are found near unconformities below BSRs. The distribution of free gas reservoirs across the study area is extensive and diverse. This study is the first to document unconformity-type and horizontal sandstone-type free gas reservoirs in the undeformed zone, highlighting their considerable resource potential. The findings are of substantial value for oil and gas exploration at the front of the accretionary prism and provide important theoretical and practical insights into natural gas accumulation systems along active continental margins.
2025年06期 v.24 1519-1533页 [查看摘要][在线阅读][下载 3536K] - GAO Shunli;SONG Peng;WEI Yun;WANG Wenjun;TAN Jun;ZHAO Caixia;MAO Shibo;DONG Jianghe;LI Qingquan;
The East China Sea Shelf Basin, especially the Xihu depression in its northeastern region, has long been regarded as an important target area for oil and gas exploration in China. Since the development of the late Cretaceous, this region has experienced complex and multistage tectonic movements, such as extensional faulting and compressional inversion, forming its current unique geological structure pattern. As one of the largest Mesozoic–Cenozoic sedimentary basins offshore China, the East China Sea Shelf Basin not only contains abundant oil and gas resources but also occupies a key strategic position. In addition, it is gradually becoming an important base and strategic core area for China's oil and gas resource development. Although remarkable progress has been achieved in oil and gas exploration, seismic exploration in the Xihu depression still faces many challenges. Especially in deep target layers, weak seismic reflection energy, low signal-to-noise ratio, and poor wave group continuity seriously affect the efficiency and accuracy of oil and gas exploration. In addition, given the considerable influence of folds and faults in the East China Sea Xihu Basin,transverse anisotropy is widespread, which causes difficulty for conventional imaging technologies based on isotropic assumptions to achieve accurate imaging. Therefore, to address these challenges and meet the need for accurate imaging of complex structures in the Xihu depression of the East China Sea Basin, it is essential to advance research on anisotropic imaging technologies. This study responds to that need by integrating the reverse time migration method under a tilted transversely isotropic(TTI) medium model and applying it to the imaging of the Xihu depression. The imaging profiles based on the TTI medium can substantially improve the imaging accuracy and signal-to-noise ratio, effectively improve the imaging quality of the fault systems and mid-deep strata in the area,and provide new technical support and progress momentum for oil and gas exploration in the Xihu depression of the East China Sea.
2025年06期 v.24 1534-1544页 [查看摘要][在线阅读][下载 1042K] - YUAN Yong;LI Qing;CHEN Jianwen;CAO Ke;WANG Jianqiang;ZHAO Hualin;LAN Tianyu;ZHANG Penghui;LUO Di;
Offshore carbon dioxide(CO_2) geological storage is a promising strategy for reducing carbon emissions and supporting sustainable development in coastal regions within a carbon neutrality framework. However, only a few works have focused on offshore basins in China. To address this gap, this study established a dual indicator system that comprises necessary and critical indices and is integrated with the analytic hierarchy process. A coupled analysis was then performed to evaluate the suitability of 10 offshore sedimentary basins in China for CO_2 geological storage. The necessary indicator system focuses on storage potential, geological conditions, and engineering feasibility. Meanwhile, the critical indicator system emphasizes the safety of storage projects and the viability of drilling operations. Evaluation results revealed that China's offshore basins have undergone two geological evolution stages,namely, the rifting and post-rifting phases, leading to the formation of a dual-layer structure characterized by faulted lower layers and sagged upper layers. These basins have thick and widespread Cenozoic strata, generally low seismic activity, and medium-to-low geothermal gradients. They form five reservoir-caprock systems with favorable geological conditions for CO_2 storage. The Pearl River Mouth, East China Sea Shelf, and Bohai Basins emerged as primary candidates that offer substantial storage potential to support carbon neutrality goals in the Bohai Rim Economic Zone, Yangtze River Delta Economic Zone, and Guangdong-Hong Kong-Macao Greater Bay Area. The Beibu Gulf and South Yellow Sea Basins were identified as secondary candidates, and the Qiongdongnan and Yinggehai Basins were considered potential alternatives.
2025年06期 v.24 1545-1560页 [查看摘要][在线阅读][下载 4071K] - ZHANG Hui;LIU Shengfa;WU Kaikai;AI Lina;CAO Peng;BAI Yazhi;WANG Xiaojing;WANG Hongmin;MOHAMED Che Abd Rahim;KHOKIATTIWONG Somkiat;KORNKANITNAN Narumol;SHI Xuefa;
The transport of suspended particulate matter is a crucial aspect of studies on sediment source-to-sink processes. However,research on its transport patterns in high-erosion areas of low-latitude seas remains limited. To elucidate modern land-sea interaction processes controlled by the monsoon climate, this study investigates the seasonal transport patterns and control mechanisms of suspended particulate matter in the western Sunda Shelf. Results reveal significant seasonal variations in the spatial distribution of suspended particulate matter concentrations, with elevated levels observed during autumn compared with spring. These differences are directly attributed to the East Asian monsoon, including seasonal monsoon precipitation and the associated transport dynamics. During the northeast monsoon, the Malay Peninsula serves as a primary source for the western sea area, with terrestrial materials from its rivers transported to the northern Gulf of Thailand. This transport pattern shifts to an S-shaped, clockwise circulation during upwelling events. Conversely, in the southwest monsoon, rivers in the northern Gulf of Thailand become the predominant sources for the Sunda Shelf, with terrestrial materials carried by clockwise currents toward the eastern Malay Peninsula. When upwelling occurs off the southern Indochina Peninsula, one branch heads toward the South China Sea and the other toward the southern tip of the Malay Peninsula. The seasonal variation in material sources is further supported by the distribution of clay minerals and the discrimination results of rare earth element proxies, including(La/Sm)_(UCC)-(Gd/Yb)_(UCC) and(La/Yb)_(UCC)-(Gd/Yb)_(UCC), in surface sediments from the Sunda Shelf and surrounding marine areas.
2025年06期 v.24 1561-1574页 [查看摘要][在线阅读][下载 6911K] - MENG Di;LI Yiqiang;ZHANG Chong;TANG Xiaoyu;ZHAO Ning;ZHOU Wei;CHEN Jian;SUN Yu;
With the discovery of ultra-deepwater and ultra-shallow large natural gas reservoirs in the South China Sea, unconsolidated sandstone reservoirs have once again become a focal point of research. In response to the unclear controlling factors and the need for connectivity evaluation of unconsolidated sandstone reservoirs in the Ledong formation of the Lingshui A area in the Qiongdongnan Basin, this study employs a range of experimental techniques, namely, cast thin sections, scanning electron microscopy, Xray diffraction mineral analysis, laser granulometry, and nuclear magnetic resonance(NMR), to investigate the microstructural characteristics of these reservoirs. The primary objective is to elucidate the controlling mechanisms behind pore-throat variability and to identify how sedimentary factors, mineral composition, and gas hydrate occurrence modes collectively influence pore-throat structural characteristics. Guided by fractal theory, a multidimensional analysis of pore-throat modal characteristics is conducted using a combination of image analysis, mercury intrusion capillary pressure, and NMR techniques. Furthermore, connectivity evaluation factors(CEFs) are constructed based on reservoir parameters to quantitatively assess reservoir connectivity and to establish connectivity evaluation standards. Results indicate that sedimentary factors are the principal determinants of pore-throat differences in the study area. Coarse grains, low clay content, and enhanced reservoir porosity contribute to improved permeability. At the microscopic level,variations in mineral composition also play a critical role. Higher quartz content and reduced clay mineral content, particularly illite and chlorite, are associated with excellent reservoir properties. By contrast, diagenesis exhibits a limited effect on reservoir quality.The gas hydrate occurrence state is characterized as a pore suspension type, exhibiting a relatively uniform pore-throat distribution.This load-bearing hydrate type may enhance pore-throat heterogeneity. Pore-throat modes are classified into three types: bimodal,multimodal Ⅰ, and multimodal Ⅱ. The bimodal hydrate occurrence state is dominated by the pore suspension type and characterized by low sorting coefficients, reduced fractal dimensions, increased uniform pore-throat structures, and improved reservoir connectivity.Five key reservoir parameters are selected, forming the basis of the CEFs, which comprehensively characterize reservoir connectivity.Ultimately, a connectivity evaluation standard and a microscopic connectivity model for typical unconsolidated sandstones in the South China Sea are established, providing critical guidance for future reservoir development strategies.
2025年06期 v.24 1575-1595页 [查看摘要][在线阅读][下载 5010K] - SUN Bo;YU Fusheng;LIAO Jing;GONG Jianming;YAN Jiajie;LEI Wenhao;QU Jiajun;SUN Haoyue;CUI Zixuan;REN Jia;
The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel. However, the mechanisms underlying their formation and the factors controlling their development remain subjects of debate. This paper, based on seismic profile analysis, employs physical simulation experiments to establish a 'wedge' type subduction model. The study explores the influence of the initial wedge angle, horizontal sand layer thickness, and the presence or absence of a decollement layer on the structural styles of the thrust wedge. Experimental results indicate that as the initial wedge angle decreases from 11° to 8°, the lateral growth of the thrust wedge increases, whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm, the spacing between the frontal thrusts decreases and the number of thrust faults increases. Both lateral and vertical growth are relatively reduced, resulting in a smaller thrust wedge. When a decollement layer is present, the structural style exhibits layered deformation. The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts. In conclusion, the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.
2025年06期 v.24 1596-1612页 [查看摘要][在线阅读][下载 2335K] - AI Lina;LIU Shengfa;ZHANG Hui;CAO Peng;LI Xue;QI Wenjing;WU Kaikai;MOHAMED Che Abd Rahim;SHI Xuefa;
The Malacca Strait(MS) is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean, serving as a critical ‘gateway' for sediment transport. Here, we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait. The results reveal that the MS can be divided into three distinct geochemical provinces. Province Ⅰ, located in the central region of the strait, is characterized by residual deposits. The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions. Province Ⅱ, situated to the north of Province Ⅰ, exhibits provenance differences between its southern and northern regions. The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea, whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of Province Ⅱ. Province Ⅲ extends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf, while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible. River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents, which also facilitate the transportation of Sunda Shelf sediments within the strait, while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period. The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait. This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region.
2025年06期 v.24 1613-1623页 [查看摘要][在线阅读][下载 5771K]
- HOU Yingjie;ZHENG Xiaotong;
The Pacific Meridional Mode(PMM) and the Atlantic Meridional Mode(AMM) are key modes of interannual sea surface temperature(SST) variability in the Pacific and Atlantic Oceans, respectively. Analysis of CMIP6 model outputs reveals a robust intensification of the PMM under global warming, whereas the AMM exhibits no consensus among models. These different responses are attributed to mid-to-high latitude atmospheric forcing and subtropical feedback mechanisms. Changes in the upper-level westerly jet drive distinct atmospheric variability over the North Pacific and Atlantic, amplifying sea-level pressure variations associated with the PMM but weakening those linked to the AMM. The SST response to atmospheric forcing shows an increase in the Pacific and a decrease in the Atlantic, both of which are significantly positively correlated with the respective changes in each mode.The enhanced wind-evaporation-SST(WES) feedback, primarily driven by rising background SSTs, positively impacts the intensification of both modes. In the subtropical Pacific, the PMM is further strengthened by an increasing latent heat flux response. The enhancement of the PMM is principally connected to intensified atmospheric forcing and strengthened subtropical feedback. Although the WES feedback is enhanced to some extent, wind anomalies that oppose the climatological state reduce latent heat flux. Combined with the weakening of atmospheric forcing over the Atlantic, this phenomenon contributes to the uncertainty in the AMM's response to global warming.
2025年06期 v.24 1624-1640页 [查看摘要][在线阅读][下载 10582K] - LIAO Zhenkun;ZHAO Yuliang;DONG Sheng;
The Barents Sea is a marginal sea of the Arctic Ocean and contains substantial hydrocarbon resources. In recent years,the Barents Sea has emerged as one of the Arctic regions with the most pronounced sea ice variability. To analyze sea ice changes in the Barents Sea, sea ice data from the National Snow and Ice Data Center were utilized. A remarkable decline in sea ice has been witnessed in the northern and eastern regions. This phenomenon has expanded the ice-free operational area for marine structures, highlighting the significance of wave factors. A site within this area was chosen to estimate the wave parameters. The wave data from ERA5 were categorized according to wave energy in each season. Four mixture joint distribution models for the wave height and period were constructed based on the mixture distribution method and copula theory, and environmental contours were developed and compared with the conditional probability method. Despite differences in the design parameter results, the mixture models demonstrate good performance in sample fitting, particularly in the distribution tails. Among these models, the Gaussian copula offers the best fit.
2025年06期 v.24 1641-1656页 [查看摘要][在线阅读][下载 6247K] - JIANG Yufeng;ZHENG Zepeng;LIU Yu;WANG Shuqing;LIU Yuchi;YANG Zeyun;YANG Yuan;
A deep-sea riser is a crucial component of the mining system used to lift seafloor mineral resources to the vessel. Even minor damage to the riser can lead to substantial financial losses, environmental impacts, and safety hazards. However, identifying modal parameters for structural health monitoring remains a major challenge due to its large deformations and flexibility. Vibration signal-based methods are essential for detecting damage and enabling timely maintenance to minimize losses. However, accurately extracting features from one-dimensional(1D) signals is often hindered by various environmental factors and measurement noises. To address this challenge, a novel approach based on a residual convolutional auto-encoder(RCAE) is proposed for detecting damage in deep-sea mining risers, incorporating a data fusion strategy. First, principal component analysis(PCA) is applied to reduce environmental fluctuations and fuse multisensor strain readings. Subsequently, a 1D-RCAE is used to extract damage-sensitive features(DSFs) from the fused dataset. A Mahalanobis distance indicator is established to compare the DSFs of the testing and healthy risers. The specific threshold for these distances is determined using the 3σ criterion, which is employed to assess whether damage has occurred in the testing riser. The effectiveness and robustness of the proposed approach are verified through numerical simulations of a 500-m riser and experimental tests on a 6-m riser. Moreover, the impact of contaminated noise and environmental fluctuations is examined.Results show that the proposed PCA-1D-RCAE approach can effectively detect damage and is resilient to measurement noise and environmental fluctuations. The accuracy exceeds 98% under noise-free conditions and remains above 90% even with 10 dB noise. This novel approach has the potential to establish a new standard for evaluating the health and integrity of risers during mining operations,thereby reducing the high costs and risks associated with failures. Maintenance activities can be scheduled more efficiently by enabling early and accurate detection of riser damage, minimizing downtime and avoiding catastrophic failures.
2025年06期 v.24 1657-1669页 [查看摘要][在线阅读][下载 933K] - TU Chaofan;GAO Xiaoyu;ZHANG Shuqin;
This study aims to analyze the synoptic patterns conducive to extreme rainfall(ER) over the South China Coast(SCC)and the low-level thermodynamic structure over the sea. Using observational and reanalysis data, a clustering analysis of the 700 hPa synoptic conditions is conducted during the pre-summer rainy seasons of South China from 1988 to 2017. The conditions are classified into three patterns: Type-L(Low-pressure type), Type-I(Intermediate type), and Type-H(High-pressure type). The circulation characteristics and diurnal variations associated with ER in each pattern are examined. Type-L is characterized by a low-level southwest airflow from the South China Sea(SCS), which strengthens coastal convergence, providing abundant moisture and favorable thermodynamic conditions. Therefore, Type-L is associated with more ER events than the other patterns. In Type-I, the SCC lies between a shallow trough and a ridge, influenced by southerly airflow. Type-H is dominated by a high-pressure system over the eastern SCS, where moisture conditions are weaker than in the first two patterns, leading to fewer ER events. During ER events, a significant warm belt below 850 hPa forms on the lee side of the Indochina Peninsula due to descending motion. In all synoptic patterns, a profound low-level warm advection occurs from the southwest. However, moisture transfer paths notably differ. In Type-L, low-level moisture primarily originates from the western SCS, driven by strong southwesterly winds in the boundary layer. In contrast, moisture in Type-I and Type-H is sourced from the central and eastern SCS, respectively. The diurnal variation of low-level winds is a key factor in controlling the diurnal cycles of moisture transport and rainfall. The enhancement of ER at night is related to the land-sea thermal contrast over the SCC, coupled with an increase in moisture and meridional winds. Among the three patterns, Type-I is primarily driven by local thermal convection, which plays an important role in ER.
2025年06期 v.24 1670-1682页 [查看摘要][在线阅读][下载 1688K] - YAN Zhenyu;ZHOU Tian;ZHU Jianjun;LI Tie;DU Weidong;ZHANG Baihan;
In the task of inspecting underwater suspended pipelines, multi-beam sonar(MBS) can provide two-dimensional water column images(WCIs). However, systematic interferences(e.g., sidelobe effects) may induce misdetection in WCIs. To address this issue and improve the accuracy of detection, we developed a density-based clustering method for three-dimensional water column point clouds. During the processing of WCIs, sidelobe effects are mitigated using a bilateral filter and brightness transformation. The cross-sectional point cloud of the pipeline is then extracted by using the Canny operator. In the detection phase, the target is identified by using density-based spatial clustering of applications with noise(DBSCAN). However, the selection of appropriate DBSCAN parameters is obscured by the uneven distribution of the water column point cloud. To overcome this, we propose an improved DBSCAN based on a parameter interval estimation method(PIE-DBSCAN). First, kernel density estimation(KDE) is used to determine the candidate interval of parameters, after which the exact cluster number is determined via density peak clustering(DPC). Finally,the optimal parameters are selected by comparing the mean silhouette coefficients. To validate the performance of PIE-DBSCAN, we collected water column point clouds from an anechoic tank and the South China Sea. PIE-DBSCAN successfully detected both the target points of the suspended pipeline and non-target points on the seafloor surface. Compared to the K-Means and Mean-Shift algorithms, PIE-DBSCAN demonstrates superior clustering performance and shows feasibility in practical applications.
2025年06期 v.24 1683-1691页 [查看摘要][在线阅读][下载 1114K] - XIAO Shaoke;HAO Wen;JIN Zihan;NIU Jiaohong;WU Cheng;ZHOU Chenhaojin;DING Haibing;
Amino acids are widely present as intermediates in marine nitrogen cycle. However, amino acid distributions in deep-sea seawater, especially in abyssal and hadal zones, are very limited. This study investigated the occurrence, vertical variations, and degradation behavior of dissolved free amino acids(DFAA), dissolved combined amino acids(DCAA), and total hydrolyzable amino acids(THAA) in seawater from the sea surface to the hadal zone of the northern Yap Trench. The results showed that concentrations of ΣDFAA, ΣDCAA and ΣTHAA ranged from 0.09 to 1.78, 0.99 to 17.69 and 1.18 to 18.01 μmol/L in the study area, respectively. In the seawater from the trench, glycine was the predominant DFAA, while the DCAA and THAA was dominated by threonine. Mean concentrations of DFAA, DCAA and THAA in different water layers were in the order of: mesopelagic>euphotic>abyssal>bathyal.The concentrations of DCAA and THAA in the sediment-seawater interface were higher than those from the euphotic to abyssal layer. The organic matter(OM) in the seawater of the stations near the Yap Islands were older, while the OM in the stations near the Yap Trench axis was relatively fresh above 1000-m depth. The OM in the sediment-seawater interface is older, especially on the west side of the trench. This is the first systematic survey of DCAA and THAA in the Yap Trench, providing insights into the vertical variations and degradation behaviors of amino acids from the sea surface to the hadal environment.
2025年06期 v.24 1692-1718页 [查看摘要][在线阅读][下载 814K] - LI Mei;MIAO Xiaoxiang;WANG Yanqun;MA Xiaojun;ZANG Yu;LIU Xiaoxue;FAN Shiliang;ZHANG Xuelei;WANG Zongling;XIAO Jie;
The large-scale green tide(YSGT) has been persisting in the Yellow Sea over a decade, while its impacts on various trophic organisms remained inconclusive. Field surveys were conducted to investigate the dynamic of planktonic crustacean community in response to the massive blooming of Ulva biomass in the Subei Shoal and the adjacent water. A rapid change of the planktonic crustacean populations during the development process of YSGT was revealed by this study. Copepods, mysids and euphausiids,and amphipods were three major groups of the planktonic crustacean community in the survey region. Copepods were the dominant group, accounting for 82.16%±3.41% of the total biomass. The total biomass of planktonic crustaceans decreased from 70.98 mg/m~3 to 7.36 mg/m~3 with the bloom of Ulva algae. Copepods, mysids and euphausiids were the two groups contributing for the rapid decline. At the same time, amphipods showed evident species succession. The planktonic Themisto gaudichaudii absolutely dominated before the green tide, while the epizootic Sunamphitoe tea and Apohyale sp. succeeded during the bloom. Based on this study, the massive YSGTs seriously destructed the planktonic crustacean community and reduced the secondary productivity, which likely impaired the fishery resources and benthos through trophic chains.
2025年06期 v.24 1705-1718页 [查看摘要][在线阅读][下载 1146K]
- SHARON Joshi;ABRAHAM Thangapalam Jawahar;SEN Arya;SINHA Priyanka;DAS Ratnapriya;UMA Arumugam;PATIL Prasanna Kumar;
Streptococcus agalactiae(Sa) infection can result in severe economic losses in tilapia aquaculture. This study offered insights into the therapeutic potential of florfenicol(FFC) and the histopathological changes in the forebrain and midbrain of Sa-infected Oreochromis niloticus. Healthy tilapia(n=225) were divided into three groups: control, Sa-challenged and untreated, and Sa-challenged and FFC-treated. The Sa-infection was induced by intramuscular injection of 1.32×107 cells/fish, and the infected fish received FFC orally at 15 mg/kg biomass/day for 10 consecutive days. Sa exerted serious pathological effects on the forebrain and midbrain of O. niloticus. These effects include focal hemorrhage, mononuclear cell infiltration, lifting of the superficial layer, spongiform encephalopathy, intracellular edema, edematous optic tectum, connective tissue damage, and meningitis. Compared with the untreated group, the treated group demonstrated that FFC is a potential therapeutic agent for mitigating Sa-induced infections by reducing mortality and improving the overall brain histoarchitecture of O. niloticus.
2025年06期 v.24 1719-1727页 [查看摘要][在线阅读][下载 1239K] - XIE Dansheng;LI Fengping;LIU Mingjie;HENG Xin;FAN Likai;GUO Xingchen;DONG Qingqiu;AN Qianying;WANG Aimin;LIU Chunsheng;YANG Yi;
Hainan Island is one of the largest islands in China and is located in the Indo-Burma biodiversity hotspot region. Despite its ecological significance, comprehensive population genetic studies of key marine organisms along the entire coastline of Hainan Island have not been reported. This study examined the genetic diversity and population structure of the widely distributed oyster Saccostrea malabonensis around Hainan Island with analyzing mitochondrial COI gene sequences. The impacts of geographical, environmental and anthropogenic factors on genetic differentiation were also investigated. The results revealed a significant AT bias in the COI gene sequences, with transitions as the main mutation type. A total of 103 variable sites and 107 haplotypes were identified from480 COI sequences, with haplotype diversities from 0.067 to 0.782, and nucleotide diversities between 0.00011 and 0.00278. AMOVA analysis indicated that 86.65% of the variation occurred within one population while 13.35% among different populations. The average genetic distance across 16 populations was 0.00169, and the average genetic differentiation index was 0.13353. Distinct population patterns can be observed. The populations of Tonghai Village(THV) and Gangmen Mountain(GMM) in Lingshui showed similar genetic structures while those of Wanquan River Estuary(WQRE, Qionghai) and Wuzhizhou Island(WZZI, Sanya) displayed divergent evolutionary trends. Cluster analysis grouped the 480 individuals of S. malabonensis into six subpopulations. These findings are helpful for developing conservation strategies and genetic breeding programs, and are also helpful for understanding the evolutionary history of this oyster species in Hainan Island.
2025年06期 v.24 1728-1749页 [查看摘要][在线阅读][下载 798K] - CHEN Huiquan;XIAO Bingyan;CHEN Leshi;YI Meisheng;JIA Kuntong;
Leopard coral grouper(Plectropomus leopardus) is a commercially important marine fish species. It is important to study how to prevent it from infecting with various viruses. In this study, we established and characterized a new cell line derived from the fin tissue of leopard coral grouper(PLF). The PLF cells were cultured for more than 55 passages. Cytochrome B gene sequencing confirmed the origin of the PLF cells is P. leopardus. Immunostaining against cytokeratin indicated that the PLF cells predominantly consist of epithelial cells. The chromosome number of PLF was 48. The cells grew well in Dulbecco's modified Eagle's medium(DMEM) supplemented with 10%–20% fetal bovine serum(FBS) at temperature between 20–28 ℃, with the highest growth rate at28 ℃. Transfection with pEGFP-N3 plasmid showed the transfection efficiency was about 35%. Virus susceptibility tests revealed that PLF cells are susceptible to red-spotted grouper nervous necrosis virus(NNV) and viral hemorrhagic septicemia virus(VHSV),and viral proliferation was confirmed by qRT-PCR and western blot. The altered expressions of immune-related genes TBK1, IRF3,and Mx after NNV and VHSV infections suggested that PLF cells can mount an immune response to fish viruses. Thus the PLF cells can be employed for studying virus-host interactions and developing antiviral strategies.
2025年06期 v.24 1737-1747页 [查看摘要][在线阅读][下载 1215K] - FENG Jianxuan;JIANG Gaowei;SUN Lingling;XU Chengxun;LI Qi;
Recently, allotriploids from Pacific oysters(Crassostrea gigas) and Fujian oysters(C. angulata) have been grown for aquaculture. However, the viability of these allotriploids remains uncertain. In this study, two autotriploids, TGG(diploid C. gigas ♀×tetraploid C. gigas ♂) and TAA(diploid C. angulata ♀×tetraploid C. angulata ♂), and two allotriploids, TGA(diploid C. gigas♀×tetraploid C. angulata ♂) and TAG(diploid C. angulata ♀×tetraploid C. gigas ♂), were studied to assess the heterosis in growth and survival at different temperatures and salinities. The results showed that during the larval stage, TAG exhibited increased heterosis in growth and survival when temperature rose. During the adult stage, the growth of TGA significantly outperformed other triploids at higher temperatures(23 and 28 ℃) and salinities(25 and 30). In contrast, TAG demonstrated the highest survival probability across all conditions except at salinity 25, where it equaled TAA after day 19. The highest oxygen consumption rates(OCR) of TGA and TAG were observed at 23 and 28 ??℃, while the ammonia excretion rate(AER) of TAG was significantly higher than that of TGA at 23 ℃. These physiological parameters reflect the advantage of TAG in terms of survival. Notably, the temperature coefficient of allotriploids was higher than that of autotriploids in the range of 18–23 ℃. At 28 ℃, TAG showed the highest superoxide dismutase(SOD) and catalase(CAT) activities and the lowest malondialdehyde(MDA) content, showing its advantage when encountering high-temperature.
2025年06期 v.24 1747-1760页 [查看摘要][在线阅读][下载 857K] - YU Wenzhuo;ZHUANG Yunyun;WANG Ning;WANG Jing;CHEN Hongju;LIU Guangxing;
Blooms of the toxic dinoflagellate Alexandrium spp., which produce paralytic shellfish toxins(PSTs), have threatened marine ecosystems for decades. However, their impacts on benthic copepods remain underexplored. Here, we investigated the physiological and biochemical responses of marine benthic copepod Tigriopus japonicus to Alexandrium pacificum. Adult female showed no mortality within 24 h and maintained high survival(>80%) across all A. pacificum concentrations over 96 h, with no significant difference from non-toxic controls. Ingestion rates on A. pacificum and non-toxic controls were similar, when algal prey concentrations were lower than about 2500 ??gC/L. However, above this threshold, feeding of T. japonicus was significantly depressed by A.pacificum. Six-day exposure induced oxidative stress, marked by elevated level of reactive oxygen species, malondialdehyde, total antioxidant capacity and superoxide dismutase activity, while catalase activity showed a non-significant increase. Moreover, concentration-dependent increase was observed in acetylcholinesterase activity, and its positive correlation with oxidative biomarkers suggests additional roles in coping with stress. Chronic exposure over three generations did not consistently affect development, except for complete development failure in F2 and F3 at the highest concentration. However, moderate-to-high concentrations of A. pacificum significantly impaired reproduction, reducing egg production by 9.66%–96.07% and clutch numbers by 33.33%–55.56%. Our findings indicate that Alexandrium blooms can adversely impact benthic copepod feeding and population recruitment through neurotoxicity and oxidative stress, highlighting the ecological risks of prolonged algal blooms in benthic habitats.
2025年06期 v.24 1761-1786页 [查看摘要][在线阅读][下载 918K] - LI Chang;QIN Chunlai;CHEN Xinglong;FU Yangfei;HUANG Xiang;LI Yuanbo;XU Shangliang;YAN Xiaojun;HU Jiabao;WANG Yajun;
Myogenic regulatory factors(MRFs) serve as crucial transcription factors that regulate muscle development and differentiation. Although MRFs have been extensively studied across various species, their specific role in the muscle development of silver pomfret(Pampus argenteus) has not been fully understood. To elucidate the role of MRFs in the muscle development of silver pomfret, we characterized the muscle growth pattern during the rapid growth phase of this organism(60–120 days post-hatching, Dph).The analysis revealed a distinct transition in growth mechanisms: Hyperplasia dominated muscle development before 90 Dph, whereas hypertrophy became predominant thereafter. The period between 80–90 Dph was a critical transition stage in the muscle growth pattern. Subsequently, five MRF family members, namely, myogenic determination 1(MyoD1), MyoD2, myogenic factor 5(Myf5),Myf6, and myogenin(MyoG), were initially identified in silver pomfret. MRFs exhibited evolutionary conservation and were specifically expressed in the muscle of the silver pomfret. Differential expressions of MRFs were observed across various stages of rapid growth and among individuals with differing growth rates. Upon the addition of exogenous regulatory factors, insulin-like growth factor 1(IGF)-1 and transforming growth factor beta 1(TGF-β1) in vitro, MRFs exhibited the most significant upregulation in response to 100 ng/mL of IGF-1. Conversely, Myf5 demonstrated the most pronounced down-regulation at 100 ng/mL of TGF-β1. For the remaining genes, the most effective suppression was achieved with 1 ng/mL of TGF-β1. These findings indicate the crucial role played by MRFs in the regulation of muscle growth and development. This study not only provides new insights into the functional roles of MRFs in fish muscle development but also establishes a foundation for the optimization of silver pomfret aquaculture strategies through the modulation of these factors.
2025年06期 v.24 1775-1794页 [查看摘要][在线阅读][下载 1173K] - CONG Lin;YAN Yuehan;WANG Yuxiao;LI Liqiong;
Brachionus plicatilis, a type of rotifer, is a vital live feed in marine aquaculture, particularly during the early developmental stages of fish and crustacean larvae. However, under high-density culture conditions, rotifers tend to accumulate and transport substantial quantities of bacteria, fungi, and other microorganisms present in aquatic environments. Sustainable and efficient methods for suppressing pathogenic microorganisms in B. plicatilis cultures while simultaneously improving its safety and quality as a live feed in aquaculture remain underdeveloped. To address this gap, we investigated the effects of aquatic effective microorganisms(EMs) on the population density and microbial community structure of B. plicatilis under extensive culture conditions. We monitored changes in B. plicatilis population density in response to varying concentrations of the EM inoculants. The diversity, composition,and temporal dynamics of the intestinal and surface microbiota at an optimal EM inoculant concentration and analyzed microbial community dynamics through high-throughput sequencing, which allowed for a precise evaluation of the effects on microbial diversity. Results demonstrated that treatment with a 1.0% EM inoculant for 24 h considerably increased B. plicatilis density while effectively reducing the load of harmful pathogenic microorganisms. Additionally, these results suggest that EM inoculation regulates microbial community structure by inhibiting pathogenic microorganisms and promoting the growth of beneficial bacteria without introducing residual environmental contaminants. Overall, this study offers a viable approach for sustaining aquaculture practices, contributing to global food security initiatives by promoting environmentally friendly and safe fish feed production.
2025年06期 v.24 1794-1806页 [查看摘要][在线阅读][下载 964K] - CHENG Runqiang;GEN Changsheng;LI Ye;
In crustaceans, 20-hydroxyecdysone(20E), the primary bioactive form of ecdysteroid hormones, regulates molting and ovarian development. In vivo and in vitro approaches were used to examine the potential nongenomic mechanisms through which 20E modulates ovarian maturation in Chinese mitten crabs(Eriocheir sinensis) and its effects on signaling components and associated genes within the phospholipase C(PLC)-protein kinase C(PKC) pathway. The results demonstrate that the administration of 20E considerably upregulated the hepatopancreatic mRNA expression of G proteins(Gs and Gq), calmodulin-dependent protein kinase II,and inositol 1,4,5-trisphosphate receptors. Concurrent increases in phosphatidylinositol-specific PLC activity were observed, along with elevated levels of its catalytic products(i.e., inositol 1,4,5-trisphosphate and diacylglycerol). Moreover, 20E stimulation activated the phosphorylation and enhanced the transcriptional expression of PKC. Notably, in vitro pharmacological inhibition with U73122(a PLC inhibitor) and Go6983(a PKC inhibitor) resulted in the effective suppression of 20E-induced expression of downstream target genes, including the ecdysone receptor(Ec R), retinoid X receptor(RXR), vitellogenin(Vg), and Vg receptor(VgR).These findings suggest that 20E modulates hepatopancreatic Vg synthesis in the Chinese mitten crab through PLC-PKC signaling transduction, thereby exerting indirect regulatory effects on ovarian development.
2025年06期 v.24 1807-1817页 [查看摘要][在线阅读][下载 624K] - LIU Bao;WANG Luyao;WANG Renliang;ZHOU Zhengbang;PENG Chengxiang;LIU Zhengyi;QIN Song;FU Wantao;ZHONG Zhihai;
Dissolved organic carbon(DOC) and particulate organic carbon(POC) play essential roles in the carbon sequestration,with macroalgae being major producers of DOC and POC. The intertidal zone is the transition area between the ocean and the land,the main habitat of macroalgae. However, few studies have focused on the regulation of tidally induced desiccation-rewetting cycles on carbon sequestration by intertidal macroalgae. Therefore, we simulated the intertidal environments to investigate the effects of desiccation-rewetting cycles on the growth, DOC and POC release mechanisms of Ulva pertusa. After 14 days of experiments, the DOC release capacities of U. pertusa(per gram fresh weight) were 1.08, 5.31, 9.74 and 7.47 mg/g in the subtidal, low, middle and high tide zones, respectively. The corresponding POC release capacities were 0.04, 1.00, 3.90 and 1.38 mg/g. Combined biological carbon sequestration, the total carbon sequestration capacities of U. pertusa in the subtidal, low, middle and high tide zones were 24.73, 32.84,27.83 and 16.97 mg/g, respectively. The results indicated that the highest carbon sequestration capacity of U. pertusa occurred in low tide zones. In conclusion, the results will provide support for the application of seaweed negative emissions.
2025年06期 v.24 1818-1826页 [查看摘要][在线阅读][下载 472K] - XIN Wenyuan;ZHOU Yunbing;LIU Daixi;WANG Cong;SHERWIN K.B.Sy;
Astaxanthin(AX) and vitamin E(VE) are widely consumed nutritional supplements in China, with its beneficial effects predominantly attributed to all-trans AX and VE. The aim of this study is to develop and validate a rapid and accurate method for quantifying the content of AX and VE in nutritional supplement products using highly sensitive ~1H NMR method. Coumarin was chosen as the internal standard. Specific signals from AX was optimal at H-7,7' in the chemical shift range of δ 6.17–6.24 ppm, whereas the signals of VE at δ 2.59 ppm. To demonstrate the reliability of this analytical approach the proposed method underwent rigorous validation, specificity, limit of detection(LOD), limit of quantitation(LOQ), linearity, accuracy, precision, and recovery. The accuracy of the validation method was 3.10% for AX and 1.99% for VE. The results indicated that the method was precise and reliable. The method has been successfully applied to simultaneous quantification of AX and VE in nutritional supplements products.
2025年06期 v.24 1827-1833页 [查看摘要][在线阅读][下载 372K] - ZHANG Liang;WANG Lan;LIU Yumeng;JI Yinglu;GU Xueji;PU Sichao;ZHAO Chuanting;
This study analyzed data from zooplankton surveys conducted in the coastal waters of Rizhao during the summers of2020–2023 to deterine trends in the number of taxa, dominant taxa, biomass, abundance, and biodiversity over the 4 years. The results indicated the presence of 41 zooplankton species belonging to Hydromedusa, Ctenophora, Copepoda, Cladocera, Amphipoda,Decapoda, Tunicata, Chaetognatha, Chordata, along with 19 types of planktonic larvae. The total number of taxa showed little change over the 4 years. A total of 10 dominant species and 8 dominant larval types were identified in the surveyed waters, and the dominant species vary from year to year. In terms of community structure, planktonic larvae, hydromedusae, and copepods were the dominant taxa. The proportion of planktonic larvae showed an upward trend, while that of hydromedusae exhibited a downward trend. The zooplankton collected by the shallow water type I(SWI) net and shallow water type II(SWII) net in the survey area could each be divided into 2 communities. Correlation analysis revealed that the abundance of zooplankton collected by the(SWI) net was significantly negatively correlated with water temperature(P<0.05), while the Shannon-Wiener index(H') was significantly positively correlated with water temperature(P<0.05). However, the total number of taxa, abundance, and biomass were significantly higher in the(SWII)net compared to(SWI) net. The average abundance of zooplankton collected in the SWI net gradually decreased over the years(P<0.05). There was no obvious difference in the community diversity indices of zooplankton collected by the two types of nets,and the community structure of zooplankton communities was consistent.
2025年06期 v.24 1834-1849页 [查看摘要][在线阅读][下载 615K] 下载本期数据