Plankton浮游生物

Plankton浮游生物Scatteredthroughtheseasoftheworldarebillionsoftonsofsmallplantsandanimalscalledplankton.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,itisnotsurprisingthateachonedevoursmorethanonetonofkrilldaily.