Aumento de fijación de nitrógeno en diazótrofos unicelulares versus Trichodesmium tras un evento de deposición de polvo atmosférico en las Islas Canarias

Enhancemen o ni ogen ixa ion a es by unicellula diazo ophs e sus T ichodesmium a e a dus deposi ion e en in he Cana y Islands Ma Bena ides •Reduc ion o a mosphe ic ni ogen o ammonium N2NH4+ •Diazo ophic o ganisms (diazo = ni ogen, ophykos = nu i ion) Cyanobac e ia, Bac e ia, A chaea •N2 ixa ion uels up o 50% o open ocean p ima y p oduc ion (Capone e al., 2005) •Ni ogenaseni H gene •Diazo ophs limi ed by Fe and P In oduc ion Unicellula cyanobac e ia Eg. Cyano hece sp. Symbio ic cyanobac e ia Eg. Richelia in acellula is Colonial cyanobac e ia Eg. T ichodesmium hiebau ii Riemann e al., 2010 In oduc ion UCYN-A UCYN-B Moisande e al., 2010 •T ichodesmium only appea s in opical and sub opical a eas •Wide dis ibu ion o he ni H gene bu … •Lack o N2 ixa ion da a The impo ance o unicellula diazo ophs In oduc ion Cana y Cu en •S ong su ace hea ing h oughou he yea •Quasi-pe manen he moclineoligo ophic wa e s •Mixing Janua y-Ma ch‘la e win e bloom’ •Dus deposi ionP and Fe A ís egui e al., 2009 •S a ion 2 Sampling each 15 days / 3 mon hs LuCIFe P ojec Objec i es • Sho - e m a iabili y o N2 ixa ion ac i i y in Cana y Cu en wa e s • In luence o Saha an dus deposi ion on diazo ophic ac i i y and di e si y N2 ixa ion •Ace ylene Reduc ion Assay (ARA) (S al, 1988) H−CΞC−HNΞN Con e sion ac o C2H2:N2= 4:1 •Su ace wa e (Niskin 30 L) •On-deck incuba ions (ligh /da k) Me hods 20x 10x Abundance o T ichodesmium sp. •Plank on ne 50 μm •Ve ical cas s o 100 m •ARA >50 µm >50 µm N2 ixa ion a es = T ichodesmium N2 ixa ion a es •Co ela ions be ween >50 µm N2 ixa ion a es and T ichodesmium abundance 2=0.86 (ligh ) 2=0.69 (da k) p<0.05 Su ace seawa e N2 ixa ion a es = Unicellula diazo oph N2 ixa ion a es •Low p obabili y o ca ching T ichodesmium wi h Niskin bo les when i s abundance is low (Chang, 2000) Unicellula diazo oph abundance Ty amide Signal Ampli ica ion – Fluo escen In Si u Hyb idiza ion (TSA-FISH) Me hods •Fil a e seawa e on PC il e s •P obe Ni o821 ni H gene •Classi ica ion Leica DM 2500 Size Type <1 µm Small F ee-li ing >1 - <3 µm Medium A ached o o ganic ma e >3 µm La ge Symbion Me hods Dus deposi ion and composi ion •Ae osol Op ical Dep hGio anni NASA •PM10, PM2.5Gobie no de Cana ias Calidad del Ai e •Me al analysis Hyd og aphy and Chl a •CTD SBE 25 •Tu ne AU-10 Fluo ome e Resul s & Discussion Tempe a u e, MLD, Chl a, nu ien s •Highe empe a u es han p e ious yea s •S a i ica ion •Lowe Chl a •Low nu ien concen a ions No clea ‘la e win e bloom’ G acias!