Biological N2 fixation in the upwelling region off NW Iberia: magnitude, relevance and main players

Ni ogen ixa ion,and,di usi e luxes in, he upwelling egion o ,NW,Ibe ia Víc o ,Mo ei a<Coello*,,Bea iz,Mou iño<Ca ballido,,Emilio,Ma añón,,Ana, Fe nández,,Paloma,Chouciño,,E a,Sin es,,Ma a,M.,Va ela,&,An onio,Bode Session,10.,A mosphe e<Ocean in e ac ion:, ood chains,, biogeochemis y and,nu ien s 22,July,2016 16:30 2 Modi ied, om Sohm e ,al.,,2011 Wha ,is,Biological,Ni ogen,Fixa ion? Biological con e sion N2®NH4+ NH4 + 3 Backg ound:, e idences,o ,N2 ixa ion,in,N,en iched,en i onmen s NE,USA,coas (Mulholland e ,al.,,2012) NW,Ibe ia (Bena ides, e ,al.,,2011) W,English, Channel (Rees e , al.,,2009) 1) To desc ibe he seasonal a iabili y in he magni ude o N2 ixa ion in he upwelling ecosys em o NW Ibe ia. 2) To quan i y he biogeochemical ele ance o N2 ixa ion as a mechanism o new ni ogen supply in his sys em. 3) To iden i y he main diazo ophs in he egion du ing aseasonal cycle. 4 Ou ,goals 5 S udy a ea Modi ied, om, Pi che ,e ,al.,, 2010 Downwelling Upwelling Me hods 10 samplings (Feb ua y, May, Decembe 2014;Ap il –Decembe 2015): § Size< ac iona ed N2 ixa ion a es a 0, 20,40 and 70 mdep h (15N2up ake echnique, Mon oya e al.1996). § Size< ac iona ed P ima y P oduc ion (14C<up ake incuba ions). § Size< ac iona ed Chlo ophyll a (spec o luo ome ic me hod) . § Nu ien s concen a ion (ni a e, e c.). § Diazo ophic communi y composi ion (ni H PCR amplicons cloned and sequenced by Illumina® Technology<NGS) . § Mic o u bulence. 6 How,did,we,quan i y,mic o u bulence? MSS,(Mic o<S uc u e<Tu bulence),p o ile ISW,Wasse mess echnik,(h p://www.ISW<Wasse .com) Ve ical,di usi i y,(Kz) Osbo n,(1980) ε:(dissipa ion, a e,o , u bulen ,kine ic,ene gy. N:(B ün Väissälä equency. 7 8 Calcula ion,o ,di usi e, anspo ,o , ni a e,ac oss,10<40,m,laye 9 Hyd og aphic,condi ions 16 Ou ,goals 1) To desc ibe he seasonal a iabili y in he magni ude o N2 ixa ion in he upwelling ecosys em o NW Ibe ia. 2) To quan i y he biogeochemical ele ance o N2 ixa ion as a mechanism o new ni ogen supply in his sys em. 3) To iden i y he main diazo ophs in he egion du ing aseasonal cycle. 17 Diazo ophic communi y,(clus e s), B ay-Cu is simila i y 50% P incipal Coo dina e Analysis PERMANOVA by Hyd og aphic condi ions p- alue < 0.05 18 Diazo ophic communi y,and,en i onmen , B ay-Cu is simila i y 50% P incipal Coo dina e Analysis 19 B ay-Cu is simila i y 50% N2, ixe s,phylo ypes P incipal Coo dina e Analysis 20 21 Conclusions 1) Dep h<in eg a ed N2 ixa ion a es anged be ween 0.1 < 15 µmol N m<2d<1 (10 μm size< ac ion dominan )and we e compa able o hose ob ained in he NE Sub opical A lan ic (NASE). 2) The con ibu ion o N2 ixa ion as a mechanism o new Nsupply, compa ed o ni a e di usi e luxes, was < 2%. 3) The diazo ophic communi y composi ion exhibi ed a clea seasonal a iabili y and was domina ed by UCYN<A (mainly unde he mal s a i ica ion condi ions), ollowed by he e o ophic Bac e ia om Cl. Gammap o eobac e ia and Ph. Fi micu es (unde mixing condi ions). 22 1< To quan i y mos equen diazo ophs (UCYN<A and Gammap o eobac e ia). < nes ed,PCR ni H(amplicons Illumina®, sequencing Bioin o ma ics Composi ion,o , he,diazo ophic communi y qPCR,(mos equen diazo ophs) Fu u e,wo k 2< To quan i y P ymnesiophy a & UCYN<A symbiosis and o de e mine i s ime<space dis ibu ion. Acknowledgmen s: § FPU ellowship o V.M. om Spanish Minis y o Educa ion, Cul u e and Spo s (FPU13/01674). § S udy suppo ed by NICANOR p ojec om Xun a de Galicia, Galician Go e nmen (EM2013/021). 23 Thank you o you a en ion! Con ac he au ho Víc o Mo ei a: mo ei a@u igo.es