Uptake Rates as Fundamentals of Iron Availability to

Phytoplankton

Yeala Shaked

Interuniversity Inst. for Marine Sciences, Eilat

Hebrew University, Jerusalem, Israel

GEOTRACES Synthesis Workshop Aug 1-4th 2016

Interac(onsandecosystemprocesses

!  Bio-mediatedtransforma(onsofFespecia(on

!  Physicaleffects(e.g.light,temperature)onphytoplanktonphysiology&ecologyandFespecia(on&fate

!  Feinputs,recycling&residence(mes

!  Chemical&photochemicaltransforma(onsofFe

!  Foodwebinterac(ons

!  Phytoplanktonphysiology,biochemistryandspeciescomposi(on

Whatdeterminesthebioavailabilityofirontophytoplankton?

ShakedandLis,2012

PathwaysandratesofFeacquisi(onbyphytoplankton

Chemicalreac(vityofFespecies&compa(bilitywithuptakesystems

FundamentalsofFeavailability

FeL, Fe’

Fe(II)

FeL

Uptakepathways&ratesChemicalspecia(onandkine(cs

Organic Inorganic

Par(cles Colloids Dissolved

Fe(III) Fe(II)

Emphasisonkine(cs-Usinguptakerateconstants(Kin)forcomparisons&extrapolaBontotheenvironment

FundamentalsofFeavailability

Lis,Shaked,Kranzler,KerenandMorel.2015.ISMEIronbioavailabilitytophytoplankton:anempiricalapproach

Syenchococcus

Trichodesmium

T.weisfloggii

T.psuedonana

P.tricornutum

E.hux

Phaeocys:s

Psuedo-nitzschia Thalassiosira

P.minimum

P.micans N.oculata

ChaetocerousT.antarc:ca

Anabaena

Phaeocys:s Psuedo-nitzschia

Thalassiosira

P.calceolata

• DophytoplanktondifferintheirabilitytoacquireFe?

• Aretherelower/upperlimitstouptakerates?

• WhichFecomplexesaremore/lessavailable?

• CanlabstudieshelpdefineFeavailabilityinnaturalenvironments?

Compiling5decadesofuptakestudies:

Syenchococcus

Trichodesmium

T.weisfloggii

T.psuedonana

P.tricornutum

E.hux

Phaeocys:s

Psuedo-nitzschia Thalassiosira

P.minimum

P.micans N.oculata

ChaetocerousT.antarc:ca

Anabaena

Phaeocys:s Psuedo-nitzschia

Thalassiosira

P.calceolata

Compiling5decadesofuptakestudies:

18studiesfrom13researchgroupsShorttermandlongterm(growth)uptake

15phytoplanktonspeciesand28strains5majordivisions(Euks&Cyanos)

16Fe-substrates

~25%ourowndata

StringentdataselecBoncriteria(Felimitedcells,logphase,[Fe]belowthatofVmax,etc..)

U

UU

Time(hrs)

IntracellularFeU

U

Fe-replete

Felimited

Uptakeratebasics&selec(oncriteria

Steadystate

Time(hrs)

IntracellularFe

Fe

Fe Fe

X2

Fe

Fe

Fe

FeFe

Fe

Fe Fe

[Fe]>Kρ

Sub-saturaBon

Vmax

FeconcentraBon

Uptakerate

Uptakeratebasics&selec(oncriteria

Fe

Fe’

Fe’

FeFe’Fe’

Fe'Fe' InorganicFe–limitedbylowsolubility

FeInorganicFe–bufferedbyEDTA

Fe'

Fe'

FeStrongLigands–FeDFB

Uptakeratebasics&selec(oncriteria

UptakeofinorganicIron(Fe')

U

UU

U

UU

UU

U

U

Largecells

Smallcells

growth(days)

shortterm(hrs)

UptakeofinorganicIron(Fe')

Regressionline:DirectproporBonalitybetweenparametersandR2=0.94

Surfaceareanormalizeduptake(kin/S.A)issimilaramongallstudiedeukaryotes

UptakeofsiderophoreboundFe(FeDFB)

Regressionline:DirectproporBonalitybetweenparametersandR2=0.9

UptakeofFe‘andsiderophoreboundFe(FeDFB)

Fe‘(inorganic)

FeDFB(Fe-siderophore)

Surfaceareanormalizeduptake(Kin/S.A)issimilaramongallEuksforFe’andforFeDFB.ButFe’>>FeDFB(x1000)

Up

take

rat

e /

[Fe

Su

b]

ThebioavailabilityenvelopeEmpiricalresultsoflabstudieswitheuks

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-061 10 100 1000 10000

k in(Lcell-1hr-1)

surfacearea(μm2)

Fe'

Up

take

rat

e /

[Fe

Su

b]

Comparewithotherorganisms,fieldstudies,differentFesubstrates…

1.E-15

1.E-14

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-050.1 1 10 100 1000 10000

kin(Lcell-1hr-1)

surfacearea(μm2)

marinesynBrackishSynSynechosys)sProchTrichoAnbn

FeDFBeuk

aryotes

Fe' eukaryot

es

Thebioavailabilityenvelope:cyanobacterialuptakekin/S.AissimilaramongallstudiedorganismsforFe’

FeDFBuptakeofcyanosisslowerthanineuks

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-061 10 100 1000 10000

k in(Lcell-1hr-1)

surfacearea(μm2)

siderophore porphyrinfreshferrihydrate Fe-dPSsaccharide organicaminenatural humicacid

Thebioavailabilityenvelope:comparingFesubstrates

Fe'

FeDFB

More

bioavailab

le

Less

ligands

Thebioavailabilityenvelope:comparingFesubstrates

MorebioavailableFesubstrates

Fe’FeDFB

LessbioavailableFesubstrates

log(kin/S.A)

ConclusionsandImplica(ons

"  WepresentaconvenientframeworkforaddressingbioavailabilitybycomparingacrossFe-substratesandorganisms.

"  Feuptakeratesofdefinedsubstratescanbepredictedaccordingtocellsize.

ConclusionsandImplica(ons

#  Ifphytoplanktoncannotfurtherincreaseuptakerates,acompeBBveadvantageinFe-limitedwatersmustbegainedthroughalternaBvemeans.

Decreasecellsize,decreaseFedemands,usealternaBveFesources

# Allphytoplanktonarelimitedbythesamefundamentalphysical,chemicalorbiochemicalfactors.Uptakesystemshaveevolvedtooperateattheirmaximalefficiency.

# Phytoplanktonmayemployasimilarironuptakemechanism:reducBveFeuptake

Experimentaldatafor~10cyanosand~30euks!!

Whichphysico-chemicalformcanthecellaccess?

Dissolved(generatedfromtheparBcles)

Availabilityextractedfromsolubility&dissolu(onrates

Howsolubleisthemineral?(chemicalreacBvity,[ligand],lightetc…)

Colloidal/Par(culate(directlyingested)

ThewholepFepoolisavailable

" RemovingFe’(shikingequilibrium)" AcBvedissoluBonbyphytoplankton" Team-upwithbacteria(siderophores)

Cancellsenhancemineraldissolu(onrate? Addbio-mediateddissolu(on

Mineralresidence(meinupperwater Longer-availability

CanphytoplanktonkeepmineralFeattheoceansurface?

AvailabilityofSolidPhaseFetoPhytoplankton:Definingmajorfactorsatplay

Rubinetal.2011

Dust-Fecapturingandmodifica(onbynaturalTrichodesmium

Ydistan

ce(m

m)

00.20.40.60.81.01.21.4

00.20.40.60.81.01.21.4

Xdistance(mm)

SynchrotronstudywithSaBshMyneni

Dust-Fecapturingandmodifica(onsbynaturalTrichodesmium

Rapid&significantFereducBon

Fe(II)

InsituassociaBonwithFe-richparBcles

CenteringofFe-richdust

t0 1hour 1.5hour 24hour

1.01.21.41.61.82.02.22.42.62.83.0

InteracBonMovement RetenBon

Inde

x

NaturaldustAcidcleaneddustFecoateddust

Aveof9Exps30coloniesineach

SensingofFeinpar(clesbyTrichodesmium

t0 1hour 1.5hour 24hour

SensingofFeSensingofFeinpar(clesbyTrichodesmium

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

Shorttermin

teraction

Overnightretention

BiogenicSilica FecoatedbiogenicsilicaQuartz Fecoatedquartz

0.0E+00

1.0E-09

2.0E-09

3.0E-09

4.0E-09

5.0E-09

6.0E-09

18-Nov 9-Dec 16-Mar 17-Mar 19-Mar 28-Mar 4-Apr 10-Apr 14-Apr

Fewithincells

DissFewithcells

DissSid-Fe(abio(c)

Dust-Fecapturingandmodifica(onsbynaturalTrichodesmium

Feconc(M)

Lowlevelassayfor55Fe-oxdissoluBonwithSid

0.0E+00

1.0E-09

2.0E-09

3.0E-09

4.0E-09

5.0E-09

6.0E-09

18-Nov 9-Dec 16-Mar 17-Mar 19-Mar 28-Mar 4-Apr 10-Apr 14-Apr

Fewithincells

DissFewithcells

DissSid-Fe(abio(c)

Dust-Fecapturingandmodifica(onsbynaturalTrichodesmium

Feconc(M)

Bio-mediated55Fe-oxdissoluBon

Dust-FeuptakebynaturalTrichodesmiumAssistedbyBacteria

LFeL

BACTERIA

?

TRICHODESMIUM

MineralFe

55Fe-Ox,Naturalcolonies,RedSea,Mar2016

0.E+00

4.E-10

8.E-10

1.E-09

-Sid +Sid

Uptake&Dissolutio

nrates

(M/d)

TrichouptBactuptdissolution

Thankyou

PhytoplanktonmayacBvelymineFefrommineralsandeffecttheirfateintheocean