1. OPA – PlankTOM5.0 - DMS Meike Vogt * Corinne Le Quéré Erik T. Buitenhuis Sergio Vallina * Laurent Bopp

2. PlankTOM Series N 2 fixers DMS producers coccolith. Nano phytoplankton Fe NO 3 Si CaCO 3 PO 4 NH 4 DOM diatoms

3. PlankTOM 5.0 Physics: OPA-ORCA (NEMO2) Resolution: ~2 deg, 31 depths 29 Tracers 3 Phytoplankton PFT: ‘Nanophytoplankton’, Diatoms, Coccolithophorids 2 Zooplankton PFT: Microzooplankton, Mesozooplankton

4. Food Web PlankTOM5.0

5. Ecosystem High latitudes: Diatom dominated Coccolithophorids: Don’t grow south of 40 deg yet Nanophytoplankton: Describe ‘Rest’, include Phaeocystis Microzooplankton: Important around Equator and high latitudes Mesozooplankton: High latitudes Generally: No extreme chlorophyll values

6. Chlorophyll - Seasonality No extreme concentrations Seasonality rather weak Concentrations in uM Low chlorophyll in the Southern Ocean Influence on DMS?

7. DMS Module DMSPp DMS DMSPd mortality grazing/exudation bacteria free lyase sea-air flux photolysis PO 4 T Fe

8. DMS Model 3 additional tracers: DMSPp, DMSPd DMS DMSPp derived from biomass and cell quota (S/C ratio) S/C content varies with UV and nutrient stress (Sunda, 2000) S/C shows slight T dependence (cryohypothesis) (Stefels, 2007) Literature S/C values (Archer 2002) Diatoms: S/C = 0.002 Nanophytoplankton S/C = 0.01 Coccolithophorids: S/C = 0.012 Literature values = minimal DMSPp/cell content, can vary up to 3-fold for all PFTs

9. DMS Dynamics

10. DMS Model – SMS DMSPd production: grazing by micro-/mesozooplankton (~74% available) mortality exudation/leakage DMSPd consumption:bacterial consumption of DMSPd cleavage of DMSPd by free DMSP-lyase

11. DMS Module – SMS II DMS production: grazing by micro-/mesozooplankton (~74% DMSPd available) mortality exudation/leakage cleavage of DMSPd by free DMSP-lyase bacterial consumption of DMSP (microbial yield 10%) DMS degradation:bacterial consumption of DMS photolysis at the sea surface sea-air flux

12. Results very low compared to Kettle Equatorial regions ok. But what is happening in the high latitudes?????????  Lack of Phaeocystis may explain in parts  High latitudes diatom dominated  Poor DMS producers and grazed by large zooplankton… Preliminary Results DMS Kettle [nM] DMS PlankTOM [nM]

13. Seasonality Low seasonality! High latitudes a mess But I am working on it! DJF JJA MAM SON

14. DMS & Chlorophyll Get decoupling for cell quota = f(stress) Very little decouping without