Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs rem...Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs remains unclear.In this study,the toxicokinetics and responses of multiple biomarkers in Bellamya aeruginosa,exposed to the three commonly used FQs(norfloxacin,NOR;ciprofloxacin,CIP;levofloxacin,LEVO)at envi-ronmentally relevant concentrations were investigated under sediment exposure scenario.The results revealed that FQs were effectively ingested by B.aeruginosa from sediments,CIP showing the highest bioaccumulation(180.59μg/kg),followed by NOR(74.49μg/kg)and LEVO(36.02μg/kg).CIP exhibiting a highest uptake rate constant(Ks)(4.64 g/(g·day))and the lowest elimination rate constant(K_(e))(0.05 g/(g·day)).The descending order of biological half-life is as follows:CIP(13.62 days),LEVO(8.14 days),and NOR(6.83 days).NOR induced the activity of superoxide dismutase,catalase,and glutathione-S-transferase while CIP and LEVO depressed their activities and increased malondialdehyde content,indicating a more pronounced oxidative damage to B.aerug-inosa caused by CIP and LEVO than NOR.Furthermore,all three FQs were found to induce DNA damage and elevate acetylcholinesterase activity,suggesting distinct genotoxic and neurotoxic effects.Interestingly,despite its low bioaccumulation potential,LEVO exhibited high toxicity towards B.aeruginosa.These findings enhance our understanding of the ecotoxicity of FQs in sediments,providing further evidence of their potential ecological risks.展开更多
Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections...Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.展开更多
With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving...With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.展开更多
Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluat...Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.展开更多
Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth eleme...Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth elements(REEs). With the growing emphasis on clean energy technologies, the Cenozoic organic deposits of India have gained renewed significance;however, those from the southern state of Kerala remain understudied. This study investigates lignite and associated carbonaceous sediments from the Cheruvathur and Warkalli Formations using a multi-proxy approach integrating organic petrography,infrared spectroscopy, stable carbon isotopes, and REE geochemistry. The lignite exhibits huminite dominance with Type Ⅲ kerogen, deposited in a wet, mesotropic bog forest swamp under anoxic conditions. The mineral assemblage, dominated by kaolinite, quartz, illite, montmorillonite, feldspar,and pyrite/marcasite, reflects strong chemical alteration in a reducing environment. The δ^(13)C values(-25.1 to-27.3) indicate a C_(3) angiosperm source and deposition in tropical to subtropical swamp settings. REE patterns reveal LREE enrichment in carbonaceous shales and HREE enrichment in lignite,with distinct Ce, Eu, and Gd anomalies associated with provenance and redox conditions. The findings provide new insights into the paleoenvironmental evolution of Kerala's Cenozoic basins and highlight their potential as unconventional REE-bearing resources in the context of the global energy transition.展开更多
This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the L...This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.展开更多
In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbu...In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbulence at various scales,from inertial large-scale motions to small viscous motions.This study analyzes the particle-resolved direct numerical simulation data of particle-laden two-phase flow with multilayers of particles in turbulent flows over static and mobile beds.The double-average method is adopted for energy transfer analysis.The result shows that the alternative streaky bedform in the spanwise directions correlates with the streak structures in the near-wall turbulence in the mobile bed case.The energy redistribution and exchange,as well as the dissipation,are analyzed in detail,and an energy transfer diagram is given in the last to summarize the energy transfer processes.In both the static and mobile bed cases,flow energy is introduced into the system via the work performed by volume forces acting on the mean flow.The viscous dissipations in the double mean and form-induced fields are more pronounced in the static bed case,and the work done by the fluid-particle interfacial stress in the double mean and turbulent fields is more pronounced in the mobile bed case.The prominent energy contribution in the form-induced field is the production by the form-induced stress on the mean strain in the mobile bed case.In addition,sediment transport involving a limited number of mobile particles is insufficient to capture the energy transfer processes that occur over the troughs and may intertwine the energy transfer processes over the mobile particles and the fixed particle bed.展开更多
Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications...Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.展开更多
Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river de...Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river delta coasts,the responses of the widely distributed small bays dominated by ocean dynamics, has received comparatively less attention. To address this gap, this study examines the Weihai Bay, located in the northeast of Shandong Peninsula,China. By integrating total organic carbon isotope tracers(δ^(13)C and C/N) with sediment transport modeling, we systematically analyze the spatiotemporal patterns of surface sediment grain size inside and outside the bay, along with their responses to natural and human-induced drivers. Our findings reveal that the sedimentary environment of Weihai Bay is governed by the combined effects of tidal currents, ocean currents, wave activity, and sediment supply. Tidal dynamics dominate the hydrodynamic conditions within the bay, while ocean currents predominate offshore. Surface sediments in the bay are primarily composed of silt, originating from sediments carried by the Yellow Sea Warm Current. These sediments enter the bay through the southern bay mouth under tidal forcing, are redistributed counterclockwise by residual tidal currents, and eventually exit via the northern bay mouth. Coarser sediments in specific areas are primarily controlled by strong wave action and terrestrial inputs. Between 1988 and 2023, Weihai Bay sediments have undergone a noticeable coarsening trend, primarily driven by anthropogenic modifications to sediment supply and hydrodynamic regimes. Coastal reclamation, shoreline modification, and infrastructure development have intensified coarse-grained terrestrial sediment input. Concurrently, shoreline advancement has reduced wave dissipation, enhancing nearshore hydrodynamics and accelerating sediment coarsening. This study highlights the sensitivity of small bay sedimentary environments to anthropogenic forcing, advancing our understanding of the coupled human-marine sediment system and providing a scientific basis for coastal sediment evolution under the dual influences of climate change and human activity.展开更多
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 ...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.ProvinceⅠ,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.ProvinceⅡ,situated to the north of ProvinceⅠ,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 ProvinceⅡ.ProvinceⅢextends 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.展开更多
Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various...Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.展开更多
The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for es...The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.展开更多
Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of...Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of SSDS preserved in a~166 m-long drill core(DX-2)extracted from the Late Pleistocene Diexi Palaeolake,eastern Tibetan Plateau.Two factors make this an outstanding site for studying SSDS:(1)it is among the most seismically active regions on Earth,and(2)it has experienced extremely fast sedimentation rates(~15 mm/yr)thanks to the prodigious sediment supply from seismically perturbed hillslopes and rivers upstream.We describe and interpret 13 SSDS types within the DX-2 based on detailed sedimentological,morphological,and lithological analysis.We consider the genesis of the abundant SSDS observed in the DX-2 core with several possibilities:mass movement,rock avalanche-driven tsunamis,rapid sedimentation,and seismic shaking as the most probable triggering mechanisms.We suggest high-intensity earthquakes of VI(Modified Mercalli Intensity)or greater as drivers of SSDS in the DX-2.Based on our observations,we propose a conceptual model that attempts to explain the transition from ductile to brittle SSDS behaviour with progressive accumulation and consolidation of the sediment pile.This paper highlights the value of SSDS analysis in palaeo-earthquake identification,aiming to improve the applicability of SSDS as a palaeo-earthquake marker in alpine and canyon areas.展开更多
The Central Yunnan Basin(CYB)that tectonically located on the southwest margin of the Yangtze Block and to the eastern segment of the Paleo-Tethys tectonic domain,is a typical‘red bed'sedimentary basin formed sin...The Central Yunnan Basin(CYB)that tectonically located on the southwest margin of the Yangtze Block and to the eastern segment of the Paleo-Tethys tectonic domain,is a typical‘red bed'sedimentary basin formed since Late Triassic.The CYB is composed of mega-thick fluvial and lacustrine facies successions.However,the tectonic evolution and sedimentary provenance studies on this basin are scarce.In this study,we report new detrital zircon ages of four sandstones from the Lower Jurassic Fengjiahe Formation(FJF),including four major clusters of 2060-1810,870-760,485-430,and 280-254 Ma,with sporadic Archean,Cambrian,and Triassic ages.We interpret that the Archaean and Proterozoic zircons were mainly derived from the western Yangtze Block,which may recycle from the Jiangnan Orogen,the Cathaysia Block and the Proterozoic igneous rocks.Ordovician and Silurian zircons were probably from the Ailaoshan orogenic belt,and the Lancang Group in western Yunnan,as well as the Yangtze,Cathaysia and Indosinian blocks.Permian zircons probably came from the Ailaoshan orogenic belt and the Emeishan basalt.The youngest zircon age of~212.9 Ma indicates that the depositional age of the FJF is younger than the Norian stage.We also proposed a geodynamic model of the CYB and the Ailaoshan orogenic belt during the Mesozoic.The Simao Block to the west of the CYB constituted the Ailaoshan orogenic belt and collaged with the Yangtze Block during the Early Triassic,provided sedimentary provenance to the CYB.The Changning-Menglian zone that composed of the Baoshan and the Simao Blocks,uplifted in the Late Triassic and provided provenance to the CYB.Collapse of the Ailaoshan orogenic belt in Late Triassic probably provided channel for source materials that transported from the Lincang granites to the CYB.We propose a transtensional tectonic setting of the central Yunnan during the Early Jurassic,after a short collision during the Indosinian Movement in the Late Triassic.展开更多
Sedimentation sludge water(SSW),a prominent constituent of wastewater from drinking water treatment plants,has received limited attention in terms of its treatment and utilization likely due to the perceived difficult...Sedimentation sludge water(SSW),a prominent constituent of wastewater from drinking water treatment plants,has received limited attention in terms of its treatment and utilization likely due to the perceived difficulties associated with managing SSW sludge.This study comprehensively evaluated the water quality of SSW by comparing it to a well-documented wastewater(filter backwash water(FBW)).Furthermore,it investigated the pollutant variations in the SSW during pre-sedimentation process,probed the underlying reaction mechanism,and explored the feasibility of employing a pilot-scale coagulation-sedimentation process for SSW treatment.The levels of most water quality parameters were generally comparable between SSW and FBW.During the pre-sedimentation of SSW,significant removal of turbidity,bacterial counts,and dissolved organic matter(DOM)was observed.The characterization of DOM components,molecular weight distributions,and optical properties revealed that the macromolecular proteinaceous biopolymers and humic acids were preferentially removed.The characterization of particulates indicated that high surface energy,zeta potential,and bridging/adsorption/sedimentation/coagulation capacities in aluminum residuals of SSW,underscoring its potential as a coagulant and promoting the generation and sedimentation of inorganic-organic complexes.The coagulation-sedimentation process could effectively remove pollutants from low-turbidity SSW([turbidity]0<15 NTU).These findings provide valuable insights into the water quality dynamics of SSW during the pre-sedimentation process,facilitating the development of SSW quality management and enhancing its reuse rate.展开更多
Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the m...Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.展开更多
The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate ch...The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.展开更多
Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initi...Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initiatives have been undertaken to mitigate the rising atmospheric CO_(2) concentrations along tropical ocean coasts worldwide.The expansion of mangrove forests has garnered significant attention for elucidating their contributions to the permanent storage of carbon in both surface and subsoil layers.In this study,we investigated a recently expanding mangrove forest in the Beilun River Estuary of Guangxi Province,focusing on the abundance and sources of organic carbon(OC)in surface sediments.We also analyzed sediment grain size distribution,SOC,total nitrogen(TN)content,and stable carbon isotope composition(δ^(13)C).Additionally,we determined the molar ratio of SOC to nitrogen(C/N).The SOC content ranged from 0.25%to 6.58%,the C/N ratio varied from 9.85 to 17.73,δ^(13)C values spanned from-29.58‰to-24.93‰,andδ^(15)N values ranged from 3.10‰to 7.36‰.A strong correlation was observed between SOC and TN content.However,particle size did not significantly influence these relationships.In terms of SOC sources in the sediments,contributions from mangrove,terrestrial,and marine sources accounted for 37.1%to 99.5%,0.5%to 47.4%,and 0%to 17.6%,respectively.The findings of this study provide essential insights for evaluating and managing carbon sinks within the mangrove ecosystems of the Beibu Gulf region,contributing to more effective carbon management strategies in coastal areas.展开更多
The grain-size distribution of surface sediments in the Bohai Sea(BS) and the northern Yellow Sea(NYS), and its relationship with sediment supply and hydrodynamic environment were investigated based on grain-size comp...The grain-size distribution of surface sediments in the Bohai Sea(BS) and the northern Yellow Sea(NYS), and its relationship with sediment supply and hydrodynamic environment were investigated based on grain-size compositions of surface sediments and modern sedimentation rates. The results showed that the surface sediments in the BS and the NYS were primarily composed of silty sand and clayey silt with a dominant size of silt. In addition, the Yellow River delivered high amount of water and sediments to the BS, and they are dominated in surface sediments(mainly silt) in the Bohai Bay, the Yellow River mouth, the center of the BS, and the north coast of Shandong Peninsula. The coarse-grained sediments were mainly deposited at the river mouth due to the estuarine filtration and physical sorting. Meanwhile, there was a significant relationship among the modern sedimentation rate, the surface sediment grain size distribution and sediment transport pattern. The areas with coarser surface sediments generally corresponded low sedimentation rates because of strong erosion;whereas the sedimentation rate was relatively high at the place that the surface sediments were fine-grained. Furthermore, the grain-size trend analysis showed that the areas with fine-grained surface sediments such as the mud area in the central BS and the upper Liaodong Bay were the convergent centers of surface sediments, except for the Bohai Bay and the subaqueous Yellow River Delta where offshore sediment transport was evident.展开更多
The rotary ring flume is used to study the silty sand movement in a periodic alternating current.Characteristics of sediment movement of different coasts in the tidal current are summarized.More detailed analysis of e...The rotary ring flume is used to study the silty sand movement in a periodic alternating current.Characteristics of sediment movement of different coasts in the tidal current are summarized.More detailed analysis of erosion-sedimentation function in a numerical simulation is made.The equilibrium sediment concentration is advanced.Based on the equilibrium sediment concentration,the seabed erosion-sedimentation index is derived and the seabed erosion-sedimentation calculation is analyzed.The seabed erosion-sedimentation index is used to calculate the seabed evolution of Yangshan sea area and a good agreement with field measurements is obtained.展开更多
基金supported by the Hunan Provincial Natural Science Foundation of China(Nos.2023JJ40518 and 2023JJ30490)the Scientific Research Foundation of Hunan Provincial Education Department(Nos.21B0511 and 22A0384)the Research Funding Project of Jishou University for talent introduction.
文摘Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs remains unclear.In this study,the toxicokinetics and responses of multiple biomarkers in Bellamya aeruginosa,exposed to the three commonly used FQs(norfloxacin,NOR;ciprofloxacin,CIP;levofloxacin,LEVO)at envi-ronmentally relevant concentrations were investigated under sediment exposure scenario.The results revealed that FQs were effectively ingested by B.aeruginosa from sediments,CIP showing the highest bioaccumulation(180.59μg/kg),followed by NOR(74.49μg/kg)and LEVO(36.02μg/kg).CIP exhibiting a highest uptake rate constant(Ks)(4.64 g/(g·day))and the lowest elimination rate constant(K_(e))(0.05 g/(g·day)).The descending order of biological half-life is as follows:CIP(13.62 days),LEVO(8.14 days),and NOR(6.83 days).NOR induced the activity of superoxide dismutase,catalase,and glutathione-S-transferase while CIP and LEVO depressed their activities and increased malondialdehyde content,indicating a more pronounced oxidative damage to B.aerug-inosa caused by CIP and LEVO than NOR.Furthermore,all three FQs were found to induce DNA damage and elevate acetylcholinesterase activity,suggesting distinct genotoxic and neurotoxic effects.Interestingly,despite its low bioaccumulation potential,LEVO exhibited high toxicity towards B.aeruginosa.These findings enhance our understanding of the ecotoxicity of FQs in sediments,providing further evidence of their potential ecological risks.
文摘Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.
基金supported by Shaanxi Key Research and Development Program(No.2024SF-YBXM-546)the National Natural Science Foundation of China(No.52470161)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21007).
文摘With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.
文摘Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.
文摘Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth elements(REEs). With the growing emphasis on clean energy technologies, the Cenozoic organic deposits of India have gained renewed significance;however, those from the southern state of Kerala remain understudied. This study investigates lignite and associated carbonaceous sediments from the Cheruvathur and Warkalli Formations using a multi-proxy approach integrating organic petrography,infrared spectroscopy, stable carbon isotopes, and REE geochemistry. The lignite exhibits huminite dominance with Type Ⅲ kerogen, deposited in a wet, mesotropic bog forest swamp under anoxic conditions. The mineral assemblage, dominated by kaolinite, quartz, illite, montmorillonite, feldspar,and pyrite/marcasite, reflects strong chemical alteration in a reducing environment. The δ^(13)C values(-25.1 to-27.3) indicate a C_(3) angiosperm source and deposition in tropical to subtropical swamp settings. REE patterns reveal LREE enrichment in carbonaceous shales and HREE enrichment in lignite,with distinct Ce, Eu, and Gd anomalies associated with provenance and redox conditions. The findings provide new insights into the paleoenvironmental evolution of Kerala's Cenozoic basins and highlight their potential as unconventional REE-bearing resources in the context of the global energy transition.
基金support in the literature analysis.This study has been carried out in the framework of the project funded by EU entitled“Bioremediation of contaminated sediments in coastal areas of exindustrial sites-LIFE SEDREMED”(No.LIFE20 ENV/IT/000572).
文摘This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.
基金supported by the National Natural Science Foundation of China(Grant Nos.12388101 and 12472221)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-oy10).
文摘In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbulence at various scales,from inertial large-scale motions to small viscous motions.This study analyzes the particle-resolved direct numerical simulation data of particle-laden two-phase flow with multilayers of particles in turbulent flows over static and mobile beds.The double-average method is adopted for energy transfer analysis.The result shows that the alternative streaky bedform in the spanwise directions correlates with the streak structures in the near-wall turbulence in the mobile bed case.The energy redistribution and exchange,as well as the dissipation,are analyzed in detail,and an energy transfer diagram is given in the last to summarize the energy transfer processes.In both the static and mobile bed cases,flow energy is introduced into the system via the work performed by volume forces acting on the mean flow.The viscous dissipations in the double mean and form-induced fields are more pronounced in the static bed case,and the work done by the fluid-particle interfacial stress in the double mean and turbulent fields is more pronounced in the mobile bed case.The prominent energy contribution in the form-induced field is the production by the form-induced stress on the mean strain in the mobile bed case.In addition,sediment transport involving a limited number of mobile particles is insufficient to capture the energy transfer processes that occur over the troughs and may intertwine the energy transfer processes over the mobile particles and the fixed particle bed.
基金Supported by the National Natural Science Foundation of China(Nos.42376185,41876111)the Shandong Provincial Natural Science Foundation(No.ZR2023MD073)。
文摘Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.
基金The Fund of National Archaeological Talent Promotion Program of China under contract No.2024-269“2024 Shandong Weihai Underwater Archaeological Survey” program by National Center for Archaeology under contract No. 20243160A0965+2 种基金Fujian Provincial Science and Technology Planning Projects under contract No. 2022L3001Provincial Natural Science Foundation of Fujian under contract No. 2023J01020MEL Internal Program of Xiamen University under contract No. MELRI2303。
文摘Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river delta coasts,the responses of the widely distributed small bays dominated by ocean dynamics, has received comparatively less attention. To address this gap, this study examines the Weihai Bay, located in the northeast of Shandong Peninsula,China. By integrating total organic carbon isotope tracers(δ^(13)C and C/N) with sediment transport modeling, we systematically analyze the spatiotemporal patterns of surface sediment grain size inside and outside the bay, along with their responses to natural and human-induced drivers. Our findings reveal that the sedimentary environment of Weihai Bay is governed by the combined effects of tidal currents, ocean currents, wave activity, and sediment supply. Tidal dynamics dominate the hydrodynamic conditions within the bay, while ocean currents predominate offshore. Surface sediments in the bay are primarily composed of silt, originating from sediments carried by the Yellow Sea Warm Current. These sediments enter the bay through the southern bay mouth under tidal forcing, are redistributed counterclockwise by residual tidal currents, and eventually exit via the northern bay mouth. Coarser sediments in specific areas are primarily controlled by strong wave action and terrestrial inputs. Between 1988 and 2023, Weihai Bay sediments have undergone a noticeable coarsening trend, primarily driven by anthropogenic modifications to sediment supply and hydrodynamic regimes. Coastal reclamation, shoreline modification, and infrastructure development have intensified coarse-grained terrestrial sediment input. Concurrently, shoreline advancement has reduced wave dissipation, enhancing nearshore hydrodynamics and accelerating sediment coarsening. This study highlights the sensitivity of small bay sedimentary environments to anthropogenic forcing, advancing our understanding of the coupled human-marine sediment system and providing a scientific basis for coastal sediment evolution under the dual influences of climate change and human activity.
基金the National Natural Science Foundation of China(Nos.42206076,42476078)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-SCSCJB01)the China-Malaysia Cooperation Project‘Effect on variability of seasonal monsoon on sedimentary process in Peninsular Malaysia waters’。
文摘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.ProvinceⅠ,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.ProvinceⅡ,situated to the north of ProvinceⅠ,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 ProvinceⅡ.ProvinceⅢextends 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.
基金supported by the Project of Ecological and Environmental Protection Integration Research Institute in Yangtze River Delta(No.ZX2023SZY118)the Special Basic Research Service for the Central Level Public Welfare Research Institute(No.GYZX230409)+1 种基金the National Natural Science Foundation of China(No.42407557)the Belt and Road Special Foundation of the National Key Laboratory of Water Disaster Prevention,China(No.2023491611)。
文摘Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.
基金supported by Geological Disaster Patterns and Mitigation Strategies Under River-Reservoir Hydrodynamics in the Three Gorges Reservoir Fluctuation Zone(5000002024CC20004)the National Key Research and Development Program of China(2023YFC3007205)+1 种基金the National Natural Science Foundation of China(No.42271013)the West Light Foundation of the Chinese Academy of Sciences.
文摘The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.
基金financially supported by the National Natural Science Foundation for Distinguished Young Scholars of China(42125702)the National Natural Science Foundation for International Cooperation and Exchange(W2412050)+4 种基金the National Science and Technology Major Project of Sichuan Province(2024ZDZX0020)the New Cornerstone Science Foundation through the XPLORER PRIZE(XPLORER-2022-1012)the Activity Prediction and Risk Identification of LargeScale Plateau Debris Flows(XZ202401ZY0029)the Formation Mechanisms and Monitoring-Warning Methods for Moraine Soil Debris Flows in the Eastern Himalayan Syntaxis Region(XZ202401ZR0073)funding from the Czech Science Foundation(22-13190S)。
文摘Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of SSDS preserved in a~166 m-long drill core(DX-2)extracted from the Late Pleistocene Diexi Palaeolake,eastern Tibetan Plateau.Two factors make this an outstanding site for studying SSDS:(1)it is among the most seismically active regions on Earth,and(2)it has experienced extremely fast sedimentation rates(~15 mm/yr)thanks to the prodigious sediment supply from seismically perturbed hillslopes and rivers upstream.We describe and interpret 13 SSDS types within the DX-2 based on detailed sedimentological,morphological,and lithological analysis.We consider the genesis of the abundant SSDS observed in the DX-2 core with several possibilities:mass movement,rock avalanche-driven tsunamis,rapid sedimentation,and seismic shaking as the most probable triggering mechanisms.We suggest high-intensity earthquakes of VI(Modified Mercalli Intensity)or greater as drivers of SSDS in the DX-2.Based on our observations,we propose a conceptual model that attempts to explain the transition from ductile to brittle SSDS behaviour with progressive accumulation and consolidation of the sediment pile.This paper highlights the value of SSDS analysis in palaeo-earthquake identification,aiming to improve the applicability of SSDS as a palaeo-earthquake marker in alpine and canyon areas.
基金supported by the Open Foundation of the State Key Laboratory of Continental Dynamics,Northwest University,China(No.16LCD06)the Basic Research Program from Department of Science and Technology Yunnan Province(No.202101AU070132)+1 种基金Jun Wang was also supported by the‘Double Top’Construction Projects(No.C176220100135)at Yunnan Universitysupported by the open fund from the Key Laboratory of Deep-Earth Dynamics of the Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing,10037,China(No.J1901)。
文摘The Central Yunnan Basin(CYB)that tectonically located on the southwest margin of the Yangtze Block and to the eastern segment of the Paleo-Tethys tectonic domain,is a typical‘red bed'sedimentary basin formed since Late Triassic.The CYB is composed of mega-thick fluvial and lacustrine facies successions.However,the tectonic evolution and sedimentary provenance studies on this basin are scarce.In this study,we report new detrital zircon ages of four sandstones from the Lower Jurassic Fengjiahe Formation(FJF),including four major clusters of 2060-1810,870-760,485-430,and 280-254 Ma,with sporadic Archean,Cambrian,and Triassic ages.We interpret that the Archaean and Proterozoic zircons were mainly derived from the western Yangtze Block,which may recycle from the Jiangnan Orogen,the Cathaysia Block and the Proterozoic igneous rocks.Ordovician and Silurian zircons were probably from the Ailaoshan orogenic belt,and the Lancang Group in western Yunnan,as well as the Yangtze,Cathaysia and Indosinian blocks.Permian zircons probably came from the Ailaoshan orogenic belt and the Emeishan basalt.The youngest zircon age of~212.9 Ma indicates that the depositional age of the FJF is younger than the Norian stage.We also proposed a geodynamic model of the CYB and the Ailaoshan orogenic belt during the Mesozoic.The Simao Block to the west of the CYB constituted the Ailaoshan orogenic belt and collaged with the Yangtze Block during the Early Triassic,provided sedimentary provenance to the CYB.The Changning-Menglian zone that composed of the Baoshan and the Simao Blocks,uplifted in the Late Triassic and provided provenance to the CYB.Collapse of the Ailaoshan orogenic belt in Late Triassic probably provided channel for source materials that transported from the Lincang granites to the CYB.We propose a transtensional tectonic setting of the central Yunnan during the Early Jurassic,after a short collision during the Indosinian Movement in the Late Triassic.
基金supported by the Ministry of Science and Technology of China (Nos.2021YFC3200904,and 2022YFC3203705)the National Natural Science Foundation of China (Nos.52070184,and 52270012)the Nanning Scientific Research and Technology Development Project (No.ZC20223238).
文摘Sedimentation sludge water(SSW),a prominent constituent of wastewater from drinking water treatment plants,has received limited attention in terms of its treatment and utilization likely due to the perceived difficulties associated with managing SSW sludge.This study comprehensively evaluated the water quality of SSW by comparing it to a well-documented wastewater(filter backwash water(FBW)).Furthermore,it investigated the pollutant variations in the SSW during pre-sedimentation process,probed the underlying reaction mechanism,and explored the feasibility of employing a pilot-scale coagulation-sedimentation process for SSW treatment.The levels of most water quality parameters were generally comparable between SSW and FBW.During the pre-sedimentation of SSW,significant removal of turbidity,bacterial counts,and dissolved organic matter(DOM)was observed.The characterization of DOM components,molecular weight distributions,and optical properties revealed that the macromolecular proteinaceous biopolymers and humic acids were preferentially removed.The characterization of particulates indicated that high surface energy,zeta potential,and bridging/adsorption/sedimentation/coagulation capacities in aluminum residuals of SSW,underscoring its potential as a coagulant and promoting the generation and sedimentation of inorganic-organic complexes.The coagulation-sedimentation process could effectively remove pollutants from low-turbidity SSW([turbidity]0<15 NTU).These findings provide valuable insights into the water quality dynamics of SSW during the pre-sedimentation process,facilitating the development of SSW quality management and enhancing its reuse rate.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272328 and 52108356).
文摘Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.
基金Supported by the Science and Technology Development Foundation of South China Sea Bureau,Ministry of Natural Resources,China(No.230204)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-IND-CJ04)+1 种基金the Natural Science Foundation of Guangdong Province,China(No.2021A1515012589)the Key Technologies Research and Development Program of Guangzhou,Guangdong Province,China(No.2023B03J1379)。
文摘The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.
基金The National Natural Science Foundation of China under contract No.42476043the Guangxi Key Research and Development Project under contract No.AB21076016+2 种基金the Scientific Research and Technology Development Project of Qinzhou under contract No.202116623the Natural Science Foundation of Guangxi under contract No.2021GXNSFAA075013the China College Students’Innovation and Entrepreneurship Training Program Project under contract No.S202411607002。
文摘Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initiatives have been undertaken to mitigate the rising atmospheric CO_(2) concentrations along tropical ocean coasts worldwide.The expansion of mangrove forests has garnered significant attention for elucidating their contributions to the permanent storage of carbon in both surface and subsoil layers.In this study,we investigated a recently expanding mangrove forest in the Beilun River Estuary of Guangxi Province,focusing on the abundance and sources of organic carbon(OC)in surface sediments.We also analyzed sediment grain size distribution,SOC,total nitrogen(TN)content,and stable carbon isotope composition(δ^(13)C).Additionally,we determined the molar ratio of SOC to nitrogen(C/N).The SOC content ranged from 0.25%to 6.58%,the C/N ratio varied from 9.85 to 17.73,δ^(13)C values spanned from-29.58‰to-24.93‰,andδ^(15)N values ranged from 3.10‰to 7.36‰.A strong correlation was observed between SOC and TN content.However,particle size did not significantly influence these relationships.In terms of SOC sources in the sediments,contributions from mangrove,terrestrial,and marine sources accounted for 37.1%to 99.5%,0.5%to 47.4%,and 0%to 17.6%,respectively.The findings of this study provide essential insights for evaluating and managing carbon sinks within the mangrove ecosystems of the Beibu Gulf region,contributing to more effective carbon management strategies in coastal areas.
基金supported by the National Natural Science Foundation of China (No.41525021)the Ministry of Science and Technology of People's Republic of China (Nos.2016YFA0600903 and 2017YFC0405502)。
文摘The grain-size distribution of surface sediments in the Bohai Sea(BS) and the northern Yellow Sea(NYS), and its relationship with sediment supply and hydrodynamic environment were investigated based on grain-size compositions of surface sediments and modern sedimentation rates. The results showed that the surface sediments in the BS and the NYS were primarily composed of silty sand and clayey silt with a dominant size of silt. In addition, the Yellow River delivered high amount of water and sediments to the BS, and they are dominated in surface sediments(mainly silt) in the Bohai Bay, the Yellow River mouth, the center of the BS, and the north coast of Shandong Peninsula. The coarse-grained sediments were mainly deposited at the river mouth due to the estuarine filtration and physical sorting. Meanwhile, there was a significant relationship among the modern sedimentation rate, the surface sediment grain size distribution and sediment transport pattern. The areas with coarser surface sediments generally corresponded low sedimentation rates because of strong erosion;whereas the sedimentation rate was relatively high at the place that the surface sediments were fine-grained. Furthermore, the grain-size trend analysis showed that the areas with fine-grained surface sediments such as the mud area in the central BS and the upper Liaodong Bay were the convergent centers of surface sediments, except for the Bohai Bay and the subaqueous Yellow River Delta where offshore sediment transport was evident.
基金The Public Science and Technology Research Funds Projects of Ocean under contract Nos 200905001 and 201005019UNESCO-IHE Partnership Research Fund (UPaRF) under contract No.60038881the National Natural Science Foundation of China under contract No.50939003
文摘The rotary ring flume is used to study the silty sand movement in a periodic alternating current.Characteristics of sediment movement of different coasts in the tidal current are summarized.More detailed analysis of erosion-sedimentation function in a numerical simulation is made.The equilibrium sediment concentration is advanced.Based on the equilibrium sediment concentration,the seabed erosion-sedimentation index is derived and the seabed erosion-sedimentation calculation is analyzed.The seabed erosion-sedimentation index is used to calculate the seabed evolution of Yangshan sea area and a good agreement with field measurements is obtained.
