FattyacidcompositionsoftwostrainsofmarinediatomsNitzschiaclosterium(MACCB222)andChaetocerosgracilis(MACCB13)havebeenexamined.ThemicroalgaehavebeengrownatdifferentinitialNaNO3concentrations(75,375,750,1125,1500,1875mg/L)andharvestedatthelateexponentialphase.TheresultsbyonefactoranalysisofvarianceshowthattheNaNO3concentrationshavenosignificantinfluenceontherelativegrowthrateoftwostrainsofmarinediatoms;theinfluenceofNaNO3concentrationsonthefattyacidsdiffersfromspeciestospecies.Themajorfattyacidsoftwodiatomstrainsare14:0,16:0,16:ln-7and20:5n-3(EPA),B13alsohashighpercentageof20:4n-6(6.0～9.1%).
