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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.Theydriftaboutlazilywiththecurrents,providingabasicfoodformanylargeranimals.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinents,andthecomparisonisanappropriateone.Inpotentialfoodvalue,however,planktonfaroutweighsthatofthelandgrasses.Onescientisthasestimatedthatwhilegrassesoftheworldproduceabout49billiontonsofvaluablecarbohydrateseachyear,thesea’splanktongeneratesmorethantwiceasmuch.Despiteitsenormousfoodpotential,littleeffectwasmadeuntilrecentlytofarmplanktonaswefarmgrassesonland.Nowmarinescientistshaveatlastbeguntostudythispossibility,especiallyasthesea’sresourcesloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.Nooneyethasseriouslysuggestedthat“plankton-burgers”maysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsource,however,planktonisgainingconsiderableinterestamongmarinescientists.Onetypeofplanktonthatseemstohavegreatharvestpossibilitiesisatinyshrimp-likecreaturecalledkrill.Growingtotwoorthreeincheslong,krillprovidesthemajorfoodforthegreatbluewhale,thelargestanimaltoeverinhabittheEarth.Realizingthatthiswhalemaygrowto100feetandweigh150tonsatmaturity,itisnotsurprisingthateachone