Nutrientsupplydoesplayaroleonthestructureofmarinepicophytoplanktoncommuni5es

BeatrizMouriño-Carballido1,JoséLuisOtero-Ferrer1,SusanaAgusG2,AntonioBode3,PedroCermeño4,PalomaChouciño1,JosédaSilva5,BieitoFernández-Castro1,JosepGasol4,MiguelGilcoto6,RocíoGraña6,MikelLatasa7,LuisLubián8,EmilioMarañón1,XoséAnxeluG.Morán2,EnriqueMoreno-Ostos8,Víctor

Moreira1,ManuelRuiz3,RenateScharek8,SergioVallina4,MartaVarela3,MarinaVillamaña1

1.UniversidadedeVigo,Spain2.KingAbdullahUniversityofScienceandTechnology,SaudiArabia

3.IEO-Coruña,Spain4.CSIC-Barcelona,Spain

5.PortoUniversity,Portugal6.CSIC-Vigo,Spain7.IEO-Xixón,Spain

8.UniversidaddeMálaga,Spain

OSMMee5ngNewOrleans21-26Feb2016

SketchofturbulentflowbyLeonardodaVinci

AndreyNikolaevichKolmogorov(1903-1987)

MicrostructureturbulenceprofileronboardRVLura(NWSpain)

Revisi5ngthemandalaofMargalef(1978)

Nutrie

nts

Mixing

Revisi5ngthemandalaofMargalef(1978)

Methodologicaldifficul5estoquan5fymixing(Kz)inthefield

Nutrie

nts

Mixing

Mixingandstra5fica5on:relatedbutnotthesame

InternalwavemixingandnutrientsupplyontheshelfoffRíadeVigo(NWSpain)

Villamaña-Rodríguezetal(inprep.)

Revisi5ngthemandalaofMargalef(1978)

Thesmaller-sizepicophytoplanktongroupswerenotincludedintheoriginaldiagram

Nutrie

nts

Mixing

Picoplankton(∼<2µm)olendominateprimaryproduc5on,andrecentstudiessuggestasignificantcontribu5ontocarbon

export(RichardsonandJackson,2007;Guidietal,2016)

Flombaumetal.(2013,PNAS)

ControlfactorsonProchlorococcusandSynechococcusregionaldistribu5ons

Norela5onshipbetweennutrientsconcentra5onandcellabundance

Thevariabilityinnutrientconcentra5onscanbedisconnectedfromchangesinnutrientsupply

Nitratefluxversussurfacenitrateinoligotrophicregions

0 0.1 0.2 0.3 0.4 0.5−2

−1.5

−1

−0.5

0

Surface Nitrate (mmol m−3)

Log1

0 (F

luxN

O3)

(mm

ol m

−2 d−1

)

Mouriño-Carballidoetal.(2011,L&O)

OurhypothesisTheMargalef’smandalaalsoapplieswithinthe

picoplanktonsize-class

Datasetofmicrostructureturbulenceandpicoplanktonproper5es(2006-2013)

117Sta5ons:• Microturbulence(MSTprofiler,0-200m)• Nitrateconcentra5on(0-200m)• Picoplanktonabundanceandcellproper5es(Flowcytometry,pho5clayer)

ProchlorococcusSynechococcusSmallpicoEuk

MSS(Micro-Structure-Turbulence)profiler

Kz = 0.2 εN 2

Ver5caldiffusivity(Kz):

Howdidwequan5fyver5calmixing(Kz)?

Osborn(1980)

εN

Dissipa5onrateofturbulentkine5cenergyBrüntVäissäläfrequency

ISWWassermesstechnik(hup://www.ISW-Wasser.com)

Howdidwecalculatethediffusivetransportofnitrateacrossthenutricline?

F3–Sta5on14

Howdidwecalculatelightavailability(LA)?

1%PAR

Depth

PARI0

k<LO>pl

εN

Dissipa5onrateofturbulentkine5cenergyBrüntVäissäläfrequency

I0k

SurfacePAR(Photosynthe5cAc5veradia5on)LightEx5n5onCoefficient

<LO>pl Averagedpho5clayerOsmidozScale

Whatdidwefind…?

Variabilityinnitratediffusivefluxes

Pho5clayerdepth-integratedpicoplanktonbiomassvsNO3diffusiveflux

ProchlorococcuswashighwhenNO3supplywaslow,whereasSynechococcusandpicoeukaryotesincreasedathighsupply

R2=0.227p<0.001***

R2=0.115p<0.001***

R2=0.270p<0.001***

Prochlorococcus Synechococcus SmallpicoEuk

Thefateofthecarbonfixedintheupperlayerdependsonthecomposi5onofthepicoplanktongroups(ra5oprokaryotespicoeukaryotes)(Cornoetal.,2007)

Ra5oProkaryotetopicoEukaryotebiomassvsNO3fluxes

Thera5oProktopicoEukbiomassdecreaseswithnutrientsupply

R2=0.120p<0.001***

Log 1

0(Prok:picoE

uk)

GeneralizedAddi5veModels(GAM):NO3Flux,Lightavailability(LA),Temperature(T)

Log10(Prok:picoEuk)=-0.220*Log10(NO3Flux)-s(LA)+0.028T

R2=0.120p<0.001***

R2(adj)=0.389p<0.05*

Log 1

0(Prok:picoE

uk)

é×3,2

Lightavailabilityandtemperaturedoalsoplayarole

Chemostatscompe5onexperiments

Picoplanktongroups:•  Synechococcussp.(RCC-2366)•  Micromonaspusilla(RCC-450)

Fully-aclimatedpopula5ons:•  Media:modificatedPCR-S11(N:P=5:1)•  Light:100µE•  Temperature:21ºC•  Steady-state(Dilu5onrate:0.225d-1)

Nutrientperturba5ons(5µMNO3):•  0.5pulsesd-1

•  2pulsesd-1

•  3pulsesd-1

SartoriusBiostatPlus

Popula5ondynamicsundernitrate-limi5ngandnitrate-pulsingcondi5ons

Abun

dance(celm

l-1)x107

Time(days)

Ra5oProk:picoEuk

SynechococcuspicoEukRa5oProk:picoEuk

Steady-state

0.5pulsesd-1

2pulsesd-1

3pulsesd-1

Popula5ondynamicsundernitrate-limi5ngandnitrate-pulsingcondi5ons

Abun

dance(celm

l-1)x107

Time(days)

Ra5oProk:picoEuk

SynechococcuspicoEukRa5oProk:picoEuk

Steady-state

0.5pulsesd-1

2pulsesd-1

3pulsesd-1

Tropicalandsubtropical

Mediterranean

GalicianUpwellingSystem

OurhypothesisTheMargalef’sMandalaalsoapplieswithinthe

picoplanktonsize-class

Dominanceofpicophytoplanktongroupstobiomass

Duetodifferencesinnutrientuptakeabili5es,picophytoplanktongroupsexhibitdifferentbehaviourtonutrientsupply

Mouriño-Carballidoetal.(2016,MEPS)

Thanksto…

•  GrantCTM2012-30680toB.Mouriño-Carballido(Spanishgoverment)

•  GrantCTM2009-06712-E/MARtoB.Mouriño-Carballido(Spanishgoverment)

•  GrantCSD2008-00077toC.Duarte(Spanishgoverment)

•  GrantCTM2008-06261-C03toM.Latasa(Spanishgoverment)

•  GrantCTM2004-05174-C02toE.Marañón(Spanishgoverment)

Dominanceofpicophytoplanktongroupstobiomassvsnitrate,mixingandNO3fluxes

Picophytoplanktongroupsexhibitdifferentbehaviourtonutrientsupply,probablyreflec5ngdifferencesinnutrientuptakeabili5es

−6 −5 −4 −3 −2 −10

1

2

3

4

5

6

7

Log10 Kz (m2 s−1)

Surfa

ce N

itrat

e (m

mol

m−3

)

ProSynpicoEuk

Log1

0 (F

luxN

O3)

(mm

ol m

−2 d−1

)

−1.5

−1

−0.5

0

0.5

1

1.5