%0 Journal Article %9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES %A Gorgues, T. %A Menkès, Christophe %A Aumont, Olivier %A Vialard, Jérôme %A Dandonneau, Yves %A Bopp, L. %T Biogeochemical impact of tropical instability waves in the equatorial Pacific - art. no. L24615 %D 2005 %L PAR00000704 %G ENG %J Geophysical Research Letters %@ 0094-8276 %M CC:0002343643-0003 %N 24 %P NIL_45-NIL_49 %R 10.1029/2005GL024110 %U https://www.documentation.ird.fr/hor/PAR00000704 %V 32 %W Horizon (IRD) %X Tropical Instability Waves (TIW) have been suggested to fertilize the equatorial Pacific in iron leading to enhanced ecosystem productivity. Using a coupled dynamical-biogeochemical model, we show that contrary to this suggestion, TIWs induce a decrease of iron concentration by 10% at the equator and by about 3% over the Wyrtki box [90 degrees W-180, 5 degrees N-5 degrees S]. Chlorophyll decreases by 10% at the equator and 1% over the Wyrtki box. This leads to a decrease of new production up to 10% at the equator (4% over the Wyrtki box). TIW-induced horizontal advection exports iron-rich equatorial water to the north, but also brings iron-depleted water to the equator leading to a net decrease in iron. Additional iron decrease is caused by TIW-induced iron vertical diffusion. These two mechanisms are partly counter balanced by a decrease of iron biological uptake, driven by lower phytoplankton concentrations, and to a lesser extent by TIW-induced iron vertical advection. %$ 066 ; 021