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简介：Thepursuitofhighoilrecoveryratehasbeenapersistentobjectiveforoilindustry.Pseudomonassp.LP-7andBacillussp.PAH-2wereisolatedfromoil-contaminatedsurfacesoilsamplesofanoilfield.Theantimicrobialdegradationrates(ADRs)ofpolymersachievedbyLP-7andPAH-2wereevaluatedatatemperatureof35°Cinthemineralsaltmediaduringtheshakenflasktrial.TheADRsofcopolymersynthesizedbyusingasurfactantwithaconcentrationof5%couldreach8.4%forPAH-2and15.3%forLP-7.TheADRsofcopolymercouldreach10.4%forPAH-2and21.3%forLP-7,whenthepolymerconcentrationwas2g/L.AllresultsconfirmedthattheADRsofcopolymersincreasedwithanincreasingcontentofHDDE(capsaicinderivativemonomer)inthepolymer.ThecopolymersalsomanifestedexcellentantimicrobialdegradationperformanceinthepresenceofCu2+,Zn2+,andPb2+ions,respectively,whichhadgreatpotentialforapplicationsinenhancedoilrecovery.

简介：Microbe-inducedcalciteprecipitationisasustainableimprovementtechniqueforsandysoil,whichcanalterthepropertiesofsandviamicrobialactivity.Inthisstudy,weinvestigatedtheloose-sand-consolidationeffectbycontrollingtheinjectionvelocity,bacterialandcementingsolutionconcentrations,andholdtimes.Theresultsdemonstratethat,asthecyclicbatchincreases,theutilizationrateofthebacterialfluidincreasesandboththeopticaldensity(OD600)ofthebacteriaandureaseactivitydecrease.Moreover,itwasdeterminedthata3-hholdtimefora0.5mol/Lcementingsolutionwithacementingfluidvelocityof2mL/minhasthegreatestbondingeffect.Thefinalstrengthoftheloosesandwithanincreaseincalciumcarbonatecontentwasfurtherdiscussed.

简介：TheTaixinanBasinisoneofthemostpotentialgashydratebearingareasintheSouthChinaSeaandabundantgashydrateshavebeendiscoveredduringexpeditionin2013.Inthisstudy,geochemicalandmicrobialmethodsarecombinedlyusedtocharacterizethesedimentsfromashallowpistonCoreDH_CL_11(gashydratefree)andagashydrate-bearingdrillingCoreGMGS2-16inthisbasin.Geochemicalanalysesindicatethatanaerobicoxidationofmethane(AOM)whichisspeculatedtobelinkedtotheongoinggashydratedissociationistakingplaceinCoreDH_CL_11atdeep.ForCoreGMGS2-16,AOMrelatedtopastepisodesofmethaneseepagearesuggestedtodominateduringitsdiageneticprocess;whiletherelativelyenrichedδ18Obulk-sedimentvaluesindicatethatmethaneinvolvedinAOMmightbereleasedfromthe'episodicdissociation'ofgashydrate.MicrobialanalysesindicatethatthepredominantphylainthebacterialcommunitiesareFirmicutesandProteobacteria(GammaproteobacteriaandEpsilonproteobacteria),whilethedominanttaxainthearchaealcommunitiesareMarine_Benthic_Group_B(MBGB),Halobacteria,Thermoplasmata,Methanobacteria,Methanomicrobia,GroupC3andMCG.Underparallelexperimentaloperations,comparabledominantmembers(FirmicutesandMBGB)arefoundinthepistonCoreDH_CL_11andthenearsurfacelayerofthelongdrillingCoreGMGS2-16.Moreover,thesemembershavebeenfoundpredominantinotherknowngashydratebearingcores,andthedominantofMBGBhasevenbeenfoundsignificantlyrelatedtogashydrateoccurrence.Therefore,ahighpossibilityfortheexistingofgashydrateunderlyingCoreDH_CL_11isinferred,whichisconsistentwiththegeochemicalanalyses.Inall,combinedgeochemicalandmicrobiologicalanalysesaremoreinformativeincharacterizingsedimentsfromgashydrate-associatedareasintheSouthChinaSea.

简介：Itisgloballyacceptedthatsoilcarbon(C)dynamicsareatthecoreofinterlinkedenvironmentalproblems,deterioratingsoilqualityandchangingclimate.Itsmanagementremainsacomplexenigmaforthescientificcommunityduetoitsintricaterelationshipwithsoilnitrogen(N)availabilityandmoisture-temperatureinteractions.ThisarticlereviewsthemanagementaspectsofsoilCdynamicsinlightofrecentadvances,particularlyinrelationtotheavailabilityofinorganicNpoolsandassociatedmicrobialprocessesunderchangingclimate.Globally,drasticalterationsinsoilCdynamicsunderchanginglanduseandmanagementpracticeshavebeenprimarilyattributedtothevariationinsoilNavailability,resultinginahigherdecompositionrateandaconsiderabledeclineinsoilorganicC(SOC)levelsduetoincreasedsoilCO_2emissions,degradedsoilquality,andincreasedatmosphericCO_2concentrations,leadingtoclimatewarming.PredictedclimatewarmingisproposedtoenhanceSOCdecomposition,whichmayfurtherincreasesoilNavailability,leadingtohighersoilCO_2efflux.However,aliteraturesurveyrevealedthatsoilmayalsoactasapotentialCsink,ifwecouldmanagesoilinorganicNpoolsandlinkmicrobialprocessesproperly.Studiesalsoindicatedthattherelative,ratherthantheabsolute,availabilityofinorganicNpoolsmightbeofkeyimportanceunderchangingclimate,astheseNpoolsarevariablyaffectedbymoisture-temperatureinteractions,andtheyhavevariableimpactsonSOCturnover.Therefore,multi-factorialstudiesarerequiredtounderstandhowtherelativeavailabilityofinorganicNpoolsandassociatedmicrobialprocessesmaydetermineSOCdynamicsforimprovedsoilCmanagement.