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高中英语现代文背诵篇章33Plankton素材.doc

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33PlanktonScatteredthroughtheseasoftheworldarebillionsoftonsofsmallplantsandanimalscalledplankton.Mostoftheseplantsandanimalsaretoosmallforthehumaneyetosee.Theydriftaboutlazilywiththecurrentsprovidingabasicfoodformanylargeranimals.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinentsandthecomparisonisanappropriateone.Inpotentialfoodvaluehoweverplanktonfaroutweighsthatofthelandgrasses.Onescientisthasestimatedthatwhilegrassesoftheworldproduceabout49billiontonsofvaluablecarbohydrateseachyearthesea’splanktongeneratesmorethantwiceasmuch.Despiteitsenormousfoodpotentiallittleeffectwasmadeuntilrecentlytofarmplanktonaswefarmgrassesonland.Nowmarinescientistshaveatlastbeguntostudythispossibilityespeciallyasthesea’sresourcesloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.Nooneyethasseriouslysuggestedthat“plankton-burgers”maysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsourcehoweverplanktonisgainingconsiderableinterestamongmarinescientists.Onetypeofplanktonthatseemstohavegreatharvestpossibilitiesisatinyshrimp-likecreaturecalledkrill.GrowingtotwoorthreeincheslongkrillprovidesthemajorfoodforthegreatbluewhalethelargestanimaltoeverinhabittheEarth.Realizingthatthiswhalemaygrowto100feetandweigh150tonsatmaturityitisnotsurprisingthateachone