Part 1: Identification of Microscopic Plankton · 2017-08-31 · microscope. They appear as...

Part1:IdentificationofMicroscopicPlankton

Organism Size Morphology MicroscopeIdentification

Virus 0.01to0.3µm

Viruseshaveacapsid,orproteincoatthatholdstheirDNA.Thiscapsidisoftenicosahedral(20equilateraltrianglesidesarrangedroughlyspherically).VirusesvarymorphologicallyaroundabasicbodyplaninvolvingthecapsidandsomestructuresforinjectingDNAorRNAintotheirhost.Somehavearelativelylongcontractiletailwithmanyfibersanddockingstructures(e.g.T-4phage).Othershaveshort,thick,fixedtails(e.g.podophages).Viruseshavelittleinternalmorphology.Theydonothaveanucleusororganelles.Theydonothavechlorophyll.Insideavirusthereisonlynucleicacid(DNAorRNA).

Cannotbeseenunderalightmicroscope,butdoappearassmallspecksunderUVepi-fluorescence.CanbeseenwithElectronMicroscopy.

Prokaryote 0.3to10.0µm

Fourmajorcelltypes:spherical,rod-shaped,spiralorcomma-shaped.Prokaryoteshaveanoutermembrane.Somehaveflagella,whicharetail-likeprojections,usedformotility.Forexample,Vibriobacteriaarecomma-shapedwithsingleflagellaatoneendwhileSynechococcusbacterialackanyflagella.Prokaryotesdonothaveanucleusormembrane-boundorganelles.Theyhaveacellularmembraneandsomeorganizedinternalstructure.Maycontainchlorophyll(e.g.cyanobacterialikeProchlorococcus)

Canbeseenunderalightmicroscope.Theyappearasspheres,commas,rods,orspirals.UnderUVlight,therewillnotbeaconcentrationofcolorinonearebecausethereisnonucleusinthesecells.

Eukaryote 2to200µm

Single-celledEukaryoteshaveawidediversityofexternalmorphology.Theycanhavecomplexshapes,modifiedformotility.Theymayalsohavebodiesmadeoutofcalciumcarbonate(ex.coccolithophores)orsilicaplates(ex.diatoms)orcellulosearmor(ex.dinoflagellates).Dinoflagellateshave2flagellaandsomehavearmorthatformselaborateshapeslike“horns”(e.g.Ceratium).Internally,eukaryoteshaveanorganizednucleusandmembrane-boundorganelles.Theycancontainchloroplasts(e.g.Coccolithophore)allowingthemtophotosynthesize.

Comparedwithvirusesandprokaryotes,eukaryotescanbeseenmuchmoreclearlyinmicroscopesbecausetheyaremuchlarger.UnderUVlight,thenucleuscanbeseenasaconcentrationofblueorgreenlightatthecenterofthecell.

EpifluorescenceMicroscope:BlueLight

Whenexcitedbybluelight,chlorophyllpigmentsinphytoplanktonnaturallyemitredlight.Organismsthathavechlorophyll,andthereforecanphotosynthesize,willbevisibleinthislight.

LightMicroscope

Lightmicroscopesusevisiblelightandaseriesoflensestoseemicroorganisms.Thistypeofmicroscopecanmagnifyupto1000timesthesizeoftheorganismwitharesolutionof0.2um.Stainscanbeusedtohelpvisualizeorganisms

EpifluorescenceMicroscope:UVlight

Fluorescenceoccurswhenmatterabsorbslightandthenemitslightatalongerwavelength.Microscopesthatopticallyseparatethesecolorsareusefulforidentifyingphytoplankton.CellsdyedwithDNAstainwillbeblueorgreenwhenexposedtoUVlight.

ElectronMicroscopeMicroscopethatusesaparticlebeamofelectronstoilluminatethespecimenandproduceamagnifiedimage.

Electronmicroscopeshaveagreaterresolvingpowerthanalight-poweredopticalmicroscopeandcanachievebetterthan0.0002umresolutionandmagnificationsofupto2,000,000x.

Organism1

LightMicroscope

Bar=5um

EpifluorescenceMicroscope:BlueLight

EpifluorescenceMicroscope:UVlight ElectronMicroscope

Organism2

LightMicroscope EpifluorescenceMicroscope:BlueLight

EpifluorescenceMicroscope:UVlight ElectronMicroscope

LightMicroscopeOrganism3

EpifluorescenceMicroscope:UV ElectronMicroscope

EpifluorescenceMicroscope:BlueLight

Organism4

LightMicroscope EpifluorescenceMicroscope:BlueLight

EpifluorescenceMicroscope:UVlight ElectronMicroscope

Organism5

LightMicroscope EpifluorescenceMicroscope:BlueLight

EpifluorescenceMicroscope:UVlight ElectronMicroscope

Bar=.05um

Organism6

LightMicroscope EpifluorescenceMicroscope:BlueLight

EpifluorescenceMicroscope:UVlight ElectronMicroscope