1. Dissolved iron distributions and Fe-limitation C. Guieu & S. Bonnet Laboratoire d’océanographie de Villefranche S. Blain Laboratoire d’océanographie et de biogéochimie (Marseille)

2. Gyre pacific Nord no data in the BIOSOPE area. - To gather the first Fe data set in the South Pacific gyre including deep waters. EqPac 140°W 12°S. (< 0.05 nM 0-200m) 0.6 nM?? Objective 1 :

3. - Does natural Fe enrichment of surface waters exist in the wake of Marquesas islands? Does it explain chlorophyll plume? Objective 2 :

4. (Lacan & jeandel 2001) Profile 0-400m : with special attention paid to the sharing area between SEEC and SEC. What ’s about water circulation around Marquesas islands? Importance of the location of the stations

5. - To investigate role of iron on biological activity in the oligotrophic area. First priority : In situ observations : To compare the depth of the Fecline and the depths of other nutriclines, max of chloro… Objective 3 : Second priority : Incubation experiments (long station gyre 2) : ?? - Effect of dust addition on biological activity - Others???

6. Material and methods Ultra-clean sampling technique: -goflo + kevlar line: 0-400m (nutrient analysis required to validate sampling) -or clean pump (10-50m) -or zodiac for surface waters (0-10 m) -rosette for deep profiles (0-4000m) (?) -Clean container. On the deck!!! -On board measurement of Fe by chemiluminescence for different fractions: - ‘dissolvable’ unfiltered and acidified - dissolved - <0.2 µm - soluble (dissolved – colloidal) < 0.02 µm -other analysis - Fe-ligand type porhyrine (analysis at LOB) Concentrations of dissolved iron

7. - Only possible at long stations (priority gyre 2) To be decided soon because it requires a specific logistic. Incubators, incubation and sub sampling bottles... Material and methods Incubation experiments ?? - But clean seawater can be provided at short stations if requested for specific experiments.