简介：Ascientifichypothesisisproposedandpreliminarilyverifiedinthispaper:underthedrivingofseepageflows,theremightbeaverticalmigrationoffine-grainedsoilparticlesfrominteriortosurfaceofseabed,whichisdefinedas‘sub-bottomsedimentpumpaction’inthispaper.FieldexperimentswereperformedtwiceontheintertidalflatoftheYellowRiverdeltatostudythisprocessviabothtrappingthepumpedmaterialsandrecordingtheporepressuresinthesubstrate.Experimentalresultsarequiteinterestingaswedidobserveyellowslurrywhichismainlycomposedoffine-grainedsoilparticlesappearingontheseabedsurface;seepagegradientswerealsodetectedintheintertidalflat,undertheactionoftidesandsmallwindwaves.Preliminaryconclusionsarethat‘sedimentpump’occurswhenseepageforceexceedsacertainthreshold:firstly,itisbigenoughtodisconnectthesoilparticlesfromthesoilskeleton;secondly,thedegreeofseabedfluidizationorbioturbationisbigenoughtoprovidepreferredpathsforthedetachedmaterialstomigrateupwards.Thentheywouldbefirstlypumpedfrominteriortothesurfaceofseabedandtheneasilyre-suspendedintooverlyingwatercolumn.Influentialfactorsof‘sedimentpump’aredeterminedashydrodynamics(waveenergy),degreeofconsolidation,indexofbioturbation(permeability)andcontentoffine-grainedmaterials(sedimentaryage).Thisnewperspectiveof‘sedimentpump’mayprovidesomeimplicationsforthemechanisminterpretationofseveraluncleargeologicalphenomenaintheYellowRiverdeltaarea.

简介：LigninservesasoneofthemostimportantmolecularfossilsfortracingTerrestrialOrganicMatters(TOMs)inmarineenvironment.Extractionandderivatizationofligninoxidationproducts(LOPs)arecrucialforaccuratequantificationoflignininmarinesediment.Herewereportamodificationoftheconventionalalkalinecupricoxide(CuO)oxidationmethod,themodificationconsistinginasolidphaseextraction(SPE)andanovelon-columnderivatizationbeingemployedforbetterefficiencyandreproducibility.Inspikingblanks,recoverieswithSPEfortheLOPsarebetween77.84%and99.57%withrelativestandarddeviations(RSDs)rangingfrom0.57%to8.04%(n=3),whilethosewithtraditionalliquid-liquidextraction(LLE)arefrom44.52%to86.16%withRSDsbeingfrom0.53%to13.14%(n=3).Moreover,thereproducibilityisgreatlyimprovedwithSPE,withlesssolventconsumptionandshorterprocessingtime.Theaverageefficiencyofon-columnderivatizationforLOPsis100.8%±0.68%,whichissignificantlyhigherthanthoseofin-vialorin-syringederivatization,thusresultinginstilllessconsumptionofderivatizingreagents.LignininthesurfacesedimentssampledfromthesouthofYangtzeRiverestuary,China,wasdeterminedwiththeestablishedmethod.Recoveriesof72.66%to85.99%withstandarddeviationlessthan0.01mg/10gdryweightareobtainedexceptforp-hydroxyben-zaldehyde.ThelignincontentΣ8(producedfrom10gdrysediment)intheresearchareaisbetween0.231and0.587mg.S/VandC/Vratios(1.028±0.433and0.192±0.066,respectively)indicatethattheTOMsinthisregionareoriginatedfromamixtureofwoodyandnonwoodyangiospermplants;thehighvaluesof(Ad/Al)vsuggestthattheTOMshasbeenhighlydegraded.