文本内容:
Sharksarevitaltomaintainingthehealthofthemarineecosystemandtheycanevenhelpfightclimatechange.InWesternAustraliasSharkBayasystemofpredator-preyrelationshipsplaysoutthatiscrucialtothelocalecosystem.Tigersharksrelyonseacowsforfoodwhichareinturnfeedingonseagrass.Bykeepingtheseacowpopulationincheckthetigersharksensurethattheseagrassmeadows（草地）thrive.ThesemeadowsareparticularlyimportantbecausetheystoretwiceasmuchCO2persquaremileasforestsdoonland.Unfortunatelytigersharknumbersaredeclining.Overfishingisestimatedtobethecauseofatleasta71percentreductioninpopulationsoffthenortheastcoastofAustralia.Thisdeclinemeansthatthereismoreseagrassbeingconsumedbyherbivores（食草动物）leadingtoadecreaseinthecarbonstoredinseavegetation.Thequestionthenarises:WouldtheSharkBaysseagrass-dominatedecosystemsurvivewithouttigersharksResearchersledbyRobNowickiofFloridaInternationalUniversitysetouttoanswerthisquestionbycomparingtheeffectsofuncheckedseacowsinEasternAustraliawheresharknumberswerelower.Theyfoundthatwhenseacowsconsumeseagrasswithoutpredatorpressuretheycanrapidlydestroylargeareasofseagrassandwhentheseagrassregrowstherearemoretropicalspeciesdominating.ThesefindingshighlighttheimportantrolethattigersharksareplayinginSharkBayandthedecliningpopulationssignalpotentialissuesfortheresilience（恢复力）ofcarbon-richoceanecosystems.Sustainablefishinghasbeenproposedasawaytoboostsharknumbersbuttheindustrylargelyremainsunchangedwhichisamajorreasonwhythepopulationofmanymarinetoppredatorscontinuestodecline.TotrulyprotectmarinelifeaccordingtoNowickiweneedtoreduceglobalgreenhousegasemissions.Withoutthiswewillbeunabletoconserveourecosystemsintheyearstocome.Solvingclimatechangeandmeanwhileundertakingspeciesconservationiscrucialtoensureahealthyandsustainablefuturefbrouroceans.TigersharksarevitaltotheecosysteminSharkBaybecause.theyfeedonvariousseaanimalsandinfluencetheirdistributiontheycanstorelargeamountsofCO2andhelpfightclimatechangetheycancontrolthenumberofseacowsandpreventthelossofseagrasstheyrelyonseacowsandseagrassforfoodandthereforecontroltheirnumbers
9.WhatmainlycausesthedeclineoftigersharkpopulationA.Rapidhabitatloss.B.Seriousoceanpollution.C.Dramaticclimatechange.D.Improperfishingpractices.HowdidNowickisteamfindouttheroletigersharksplayinWesternAustraliasSharkBayA.Byconductingvariouslabexperimentsabouttigersharks9lifecycle.BycomparingtheimpactsofuncontrolledseacowsinEasternAustralia.Byanalyzingtherelationshipsbetweendifferentmarinespeciesinthisarea.Byinterviewinglocalfishermenaboutwhattheyhadfoundabouttigersharks.WhatdoesNowickithinkisthekeytoprotectingmarinelifePracticingsustainablefishing.Rebuildingthemarineecosystem.Cuttinggreenhousegasemissions.Controllingthetoppredatornumber.8〜11CDBC。
个人认证
优秀文档
获得点赞 0
