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In this study， a high-resolution atmosphere-ocean coupled numerical model was constructed based on the WRF model and FVCOM model to investigate a storm surge event induced by a severe cold wave in the Bohai Sea， Yellow Sea and East China Sea during winter 2022. The temporal-spatial evolution characteristics and dynamic mechanism of this event were systematically analyzed. The simulation results showed that in the early stage of the cold wave， under the forcing of strong northerly winds， seawater in the Bohai Sea was transported from the north to the south， leading to significant water level drawdown in Liaodong Bay and Bohai Bay， while Laizhou Bay experienced wind-driven set-up （water level increase） due to coastal blocking； as the cold air progressed southward， seawater masses transported toward the Yellow Sea and East China Sea， and the entire Bohai Sea sequentially entered a set-down（water level drawdown） state. This process induced two distinct water level setup events along the coasts of the Bohai Sea， Yellow Sea and East China Sea. By applying empirical mode decomposition （EMD） to the residual water levels at validation stations along both coasts of the Yellow Sea， it was found that the IMF3 mode clearly captured the physical characteristics of shelf waves propagating southward along the west coast of the Korean Peninsula， crossing the Yellow Sea， and reaching the southern Shandong Peninsula. The findings demonstrated that the first water level setup event was co-driven by local wind stress forcing and shelf wave propagation， while the second water level setup event was mainly controlled by the free propagation of shelf waves. This study revealed the important contribution of remotely propagating shelf waves to coastal water level fluctuations under the background of winter cold wave， which could provide scientific support for disaster prevention and mitigation.

In view of the frequent trend of northward-moving typhoons in Zhejiang coastal areas， taking typhoon Chan-hom （1509） as an example， a wind-wave-current coupled model of the China Seas-Zhejiang coastal area was constructed based on the Delft3D model. The temporal and spatial evolution of storm surge in Zhejiang coastal area during 24 hours before and after typhoon landing were analyzed， and the relative contribution of dynamic factors such as wind stress， air pressure， wave and astronomical tide were quantified. The results showed that in the 24 hours before and after the typhoon landed， the Sanmen Bay， Xiangshan Port and Hangzhou Bay appeared the extreme value of surge in turn， and the maximum surge was 3.4 m. The northern Zhejiang sea area experienced high surge intensity and slow recession， while the southern area showed a more uniform surge distribution and rapid recession. The spatial distribution of wind stress induced surge was consistent with the total surge， with the highest contribution to the total surge （60%-90% or higher）， and the surge was concentrated in the low tide stage. Air pressure induced surge was more uniformly distributed， with a secondary contribution （20%-50%）. Wave induced surge mainly occured in nearshore shallow waters during low tide， contributing the least （10%-20%）. Tide-surge interaction could amplify localized peak surges and delay the recession process， accounting for 30%-50% of the total surge in areas such as Hangzhou Bay and Sanmen Bay. Normalized analysis of factor contributions indicated that wind stress contribution was significantly higher in the north than in the south. The contributions of air pressure and tide-surge interaction were generally equivalent； specifically， tide-surge interaction was dominant in the north， while air pressure was more significant in the south. The contribution of wave induced surge was slightly higher in the south than in the north. Overall， northward-moving typhoons like "Chan-hom" led to storm surges characterized by high intensity， long duration， and slow recession in northern Zhejiang， thereby posed a higher risk of coastal flooding.

To address the scarcity of modern East Asian Summer Monsoon （EASM） observations， improve dynamical mechanisms and enhance future projection capability， multiple CMIP6-PMIP4 models were adopted to investigate EASM responses to the Holocene Thermal Maximum and current warming， with their differences， mechanisms and controlling factors were clarified. The EASM intensification during the Holocene Thermal Maximum was far stronger than that under current warming， which originates from distinct forcings between the Holocene Thermal Maximum and current warming， and aerosol emissions under current warming further dampen the response amplitude of the EASM. Remarkable EASM intensification occurred during the Holocene Thermal Maximum， featuring increased northern precipitation and reduced southern precipitation. By contrast， weak monsoon responses appeared under current warming with distinct precipitation spatial patterns. Summer land-sea thermal contrast differences dominated such divergent responses. This study elucidates the response law of the EASM to warming driven by distinct external forcings， deepens the understanding of monsoon dynamics， and provides theoretical support for future EASM projection.

Based on a satellite altimetry-derived eddy dataset， this study conducted a classification-based statistical and characteristic analysis of mesoscale eddies in the Northwestern Pacific. A composite analysis method was further employed to reconstruct the spatial structures of sea surface temperature anomalies （SSTAs） and sea level anomalies （SLAs） associated with different eddy categories and to investigate the distribution characteristics of mesoscale eddies in the study area. The study region was divided into three subregions： the North Equatorial Current （NEC）， the Subtropical Countercurrent （STCC）， and the Kuroshio Extension （KE）. November to December and January to April were defined as the cold season， while May to October were defined as the warm season. Eddies were classified， counted， and analyzed according to their polarity. The results show that mesoscale eddies in the study region are generally characterized by cold-core cyclonic eddies and warm-core anticyclonic eddies. However， two types of abnormal eddies， namely warm-core cyclonic eddies and cold-core anticyclonic eddies， are also identified， accounting for approximately 22.5%of the total eddy population. The occurrence probability of abnormal eddies is higher at low latitudes than at high latitudes， and higher in the warm season than in the cold season. For normal eddies， SSTA is positively correlated with eddy amplitude， increases with latitude， and is generally stronger in the cold season than in the warm season. In contrast， abnormal eddies exhibit overall weaker SSTAs than normal eddies and show no obvious regional or seasonal differences. Composite analysis further reveals that compared with normal eddies， abnormal eddies are less circular in shape and have smaller amplitudes and weaker SSTA variations.

The Indian Ocean subduction zone is one of the most active plate boundaries in the world and an important region for studying plate subduction. While many studies have examined the structure and evolution in the subduction zone， research on lithospheric flexure along the trench’s oceanward slope remains relatively limited. To clarify the characteristics of lithospheric flexure during subduction of the India-Australia Plate and its geodynamic implications， this study takes the South Sumatra-Java Trench as the research area for flexural modeling. Based on crustal thickness， geoid undulation， and bathymetric data， the lithospheric flexures of the eastern， central， and western segments of the South Sumatra-Java Trench were simulated. Using nonlinear least-squares fitting， we obtained the flexural characteristics and lithosphere effective elastic thickness （T_e） of each segment’s oceanward slope. The simulation results indicate that the flexure zone lies roughly between 16-76 km from the trench axis， with an amplitude of 68-192 m， and T_e of 20-34 km. T_e is the largest in the central segment and smaller in the eastern and western segments. T_e in the eastern segment is slightly larger than that in the western segment. The flexure of the trench exhibits significant spatial variability， primarily controlled by distinct geological and tectonic factors. The low T_e in the eastern segment is mainly attributed to lithospheric weakening caused by thermal upwelling from the lower mantle. The high T_e in the central segment indicates that its lithosphere is generally more rigid； however， influenced by local structures such as the Roo Rise and seamount emplacement， stress concentration at the plate forebulge leads to large flexural amplitudes in some profiles. The low T_e in the western segment may be related to reduced lithospheric strength associated with a young plate， stronger tectonic activity， and fluid effects. Nevertheless， because this segment is characterized by a lower subduction rate， shallower slab descent， and limited extensional deformation， its overall flexural response remains comparatively weak.

The Qiongdongnan Basin， a Cenozoic petroliferous basin in the northern South China Sea， is rich in deepwater hydrocarbon resources and represents a critical frontier for Chinese offshore exploration. This study integrated core samples， well logging data， and analytical techniques including fluid inclusion petrography， oil inclusion abundance （GOI） analysis， and homogenization temperature measurements from four wells （W1-W4） targeting the Lingshui Formation in the Yongle 10-6 Structure. Burial-thermal history modeling combined with hydrocarbon generation evolution and fault activity analysis were employed to reconstruct hydrocarbon charging episodes and accumulation processes. The results showed that three distinct inclusion types were identified in Member 3 of the Lingshui Formation： liquid oil inclusions， single CH₄ gas inclusions， and CO₂-bearing aqueous inclusions. Blue fluorescence of oil inclusions indicated a high-maturity oil charging. GOI values of 1.23% （W2） and 3.5% （W3） suggested the study intervals served as hydrocarbon migration pathways. Three hydrocarbon charging episodes were constrained： Early Miocene （20.9-17.2 Ma）， Late Miocene （10.2-7.6 Ma）， Pliocene to present （5.0-0.0 Ma）. Among them， oil-dominated charging occurred in the Early Miocene and Pliocene， whereas gas-dominated charging prevailed in the Late Miocene and Pleistocene. Since the Pleistocene （2.0 Ma）， mantle-derived CO₂ charging had been ongoing and continued to the present. Spatially， hydrocarbon charging occurred earlier in northern structural belt （W1， W2） than that in southern structure belt （W3， W4）. While CH₄ and CO₂ charging were recorded in all four wells， oil accumulation was observed only in W2 and W3 with relatively high-maturity. The Baodao Sag exhibited two-phase hydrocarbon generation from source rocks. Early fault activity （later ceasing） resulted in differential accumulation characterized by early oil and late gas charging， earlier accumulation in the north and later in the south， and multi-stage accumulation. This work delineates the hydrocarbon charging phases in the less-explored Baodao Sag of the Qiongdongnan Basin， reconstructs the hydrocarbon accumulation history， and provides guiding significance for predicting future exploration targets.

During the propagation of waves from deep sea to nearshore， reflection and transmission occur due to changes in water depth and complex topography. In particular， when the seabed topography exhibits periodic variations， the well-known wave Bragg resonance phenomenon emerges. Based on the modified mild-slope equation， this paper established a corresponding finite-difference numerical model to investigate the effects of cross-sectional topography of a coral reef profile on wave reflection and transmission. First， the model was validated by simulating wave reflection over a periodically undulating trapezoidal topography on a horizontal seabed. The numerical results showed good agreement with existing analytical solutions， confirming the reliability of the model. Subsequently， the systematic analysis was conducted to examine the effects of the relative lagoon depth （lagoon depth relative to the water depth in the study area， h₁/h₀） and the relative excavation pit depth （excavation pit depth relative to the water depth in the study area， h_p/h₀） on the coefficients of wave reflection and transmission. The results indicate that as h₁/h₀ increases， the reflection coefficient corresponding to wave resonance increases significantly， while the transmission coefficient gradually decreases. Moreover， the bandwidth of the resonance band widens， and the resonance frequencies of both reflected and transmitted waves shift downward. In contrast， with an increase in h_p/h₀， the reflection coefficient at resonance decreases slightly， while the transmission coefficient shows a certain increasing trend. Additionally， as h_p/h₀ increases from 3/7 to 5/7， the resonance frequencies of both reflected and transmitted waves shift upward.

Manganese， as an important metal mineral resource， has a wide range of application value， at the same time， the potential environmental hazards associated with it cannot be ignored. The discharge of pollutants from nearshore land-based sources and the release of Mn²⁺ during deep-sea seabed mining processes may cause excessive manganese content in marine water. However， the molecular mechanism of the reaction of marine megabenthos to metals is still unclear. In this paper， a transcriptomic study of response to manganese exposure was carried out for the widely distributed marine brittle star Ophiothrix exigua. Differentially expressed genes were identified through transcriptome sequencing. Our study identified 3 756 DEGs between the manganese exposure group and the control group， among which 1 347 unigenes were upregulated， while 2 409 unigenes were downregulated. GO and KEGG pathway enrichments showed that excessive manganese ions had significantly impacted the nervous system and metabolism of the O. exigua.

Under global climate change， the combined effects of ocean acidification and warming on mercury （Hg） ecotoxicity and their underlying mechanisms have become a research focus in environmental science. This paper has comprehensively reviewed existing studies and analyzed the interactive effects of acidification and warming on Hg bioaccumulation， toxicity effects， and biological responses. The key findings reveal that ocean acidification primarily mitigates Hg toxicity by inhibiting Hg bioaccumulation and inducing energy compensation and stress responses in organisms， demonstrating their antagonistic interaction. In contrast， warming exerts a synergistic effect with Hg pollution， i.e.， exacerbating Hg toxicity by increasing metabolic rates， promoting Hg accumulation， and inducing oxidative damage. Under the more realistic scenario of combined acidification and warming， the inhibitory effect of acidification on Hg accumulation is partially offset， while immune defense downregulation and reproductive damage are intensified， ultimately leading to an overall enhancement of Hg toxicity. These findings suggest that assessments based solely on single climate stressors （acidification or warming） may substantially underestimate the long-term ecological risks of Hg pollution in marine ecosystems. Such underestimation stems from the neglect of warming’s counteraction on acidification and the dual energy demand arising from combined acidification and warming exceeding an organism’s compensatory capacity. Future research should prioritize integrated assessments across multi-stressors， multigenerational exposure， and ecosystem levels to reveal the complex mechanisms of Hg toxicity under global climate change， provide a scientific basis for developing accurate risk management strategies.

The vertical structure of phytoplankton is key to understand the biological carbon pump in the Southern Ocean-Indian sector. This study systematically analyzed the seasonal and interannual variability in the vertical distribution of chlorophyll a （Chl a） and phytoplankton carbon biomass （C_phyto） and their environmental drivers in this region， using satellite observations， BGC-Argo floats， and reanalysis data （2015-2018）， with a focus on the 2015/2016 El Niño event. Results showed that Chl a was mainly distributed in the upper 0-100 m， with a pronounced subsurface chlorophyll maximum layer （SCML） at 10-100 m. Seasonal variability was significant： during austral summer （Dec-Feb）， sufficient light （PAR>100 μmol·m^-2·s^-1） supported peak Chl a and C_phyto in the upper 0-100 m [ρ（Chl a）>0.75 mg·m^-3， C_phyto>20 mg·m^-3）. In austral winter （Jun-Aug）， reduced light availability and a deeper mixed layer collectively led to the dissipation of the SCML and the lowest annual values of Chl a and C_phyto [ρ（Chl a）<0.5 mg·m^-3， C_phyto<10 mg·m^-3]. The deepening of the mixed layer extended the vertical distribution of Chl a to approximately 200 m， whereas the vertical structure of C_phyto showed no corresponding significant change， leading to a pronounced decoupling between Chl a and C_phyto in the 0-200 m. During the 2015/2016 El Niño， enhanced Ekman pumping shoaled the thermocline， increasing nutrient supply to the euphotic zone and intensifying and prolonging the summer phytoplankton bloom [ρ（Chl a）>1 mg·m^-3， lasting about 7 months]. This study provides scientific support for accurately assessing the Southern Ocean’s carbon sink potential and predicting the impact of extreme climate events on the phytoplankton-driven carbon pump.

Organic carbon is one of the key variables in the carbon cycle of the river-estuary-coastal continuum （hereinafter referred to as the “continuum”）. Clarifying its spatiotemporal distribution characteristics and influencing factors is an important foundation for conducting carbon cycle research. Based on observational data in February 2023 （dry season） and July 2023 （wet season）， this study analyzed the mass concentrations， spatial distribution， and seasonal variation characteristics of particulate organic carbon （POC） and dissolved organic carbon （DOC） in the continuum of the Oujiang River. The results showed that both POC and DOC generally exhibited higher mass concentrations in the wet season than those in the dry season. Specifically， the range of POC mass concentration in the dry season was 0.43-20.56 mg/L， with an average of 3.91 mg/L； in the wet season， the range was 0.15-32.78 mg/L， with an average of 7.89 mg/L. For DOC， the range in the dry season was 0.82-2.17 mg/L， averaging 1.37 mg/L， while in the wet season， it ranged from 1.35 to 3.80 mg/L， with an average of 2.16 mg/L. Spatially， POC mass concentration was higher in the estuarine section but lower in the riverine and coastal sections， whereas DOC mass concentration was relatively higher in the riverine and estuarine sections and lower in the coastal section. Notably， both POC and DOC mass concentrations in the estuarine section displayed non-conservative behavior with respect to salinity. Through comprehensive analysis of factors such as salinity， total suspended matter （TSM） mass concentration， the maximum turbidity zone， and other environmental variables， it is concluded that the increased precipitation and runoff during the wet season enhanced fluvial erosion and lateral leaching， which were the main reasons for the higher organic carbon content in the wet season compared to the dry season. Meanwhile， the development of the maximum turbidity zone and the input of organic matter from human activities were key factors contributing to the enrichment of organic carbon in the estuarine section.