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OPA – PlankTOM5.0 - DMS. Meike Vogt * Corinne Le Qu éré Erik T. Buitenhuis Sergio Vallina * Laurent Bopp. Si. PO 4. NO 3. NH 4. Fe. coccolith. Nano phytoplankton. DMS producers. N 2 fixers. diatoms. CaCO 3. DOM. PlankTOM Series . Physics: OPA-ORCA (NEMO2)
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OPA – PlankTOM5.0 - DMS Meike Vogt * Corinne Le Quéré Erik T. Buitenhuis Sergio Vallina * Laurent Bopp
Si PO4 NO3 NH4 Fe coccolith. Nano phytoplankton DMS producers N2 fixers diatoms CaCO3 DOM PlankTOM Series
Physics: OPA-ORCA (NEMO2) Resolution: ~2 deg, 31 depths 29 Tracers 3 Phytoplankton PFT: ‘Nanophytoplankton’, Diatoms, Coccolithophorids 2 Zooplankton PFT: Microzooplankton, Mesozooplankton PlankTOM 5.0
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
Chlorophyll - Seasonality • No extreme concentrations • Seasonality rather weak • Concentrations in uM • Low chlorophyll in the Southern Ocean • Influence on DMS?
DMS Module sea-air flux photolysis DMS T Fe DMSPp free lyase bacteria grazing/exudation PO4 DMSPd grazing/exudation mortality
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
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
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
Preliminary Results • 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… DMS Kettle [nM] DMS PlankTOM [nM]
Seasonality • Low seasonality! • High latitudes a mess • But I am working on it! MAM DJF SON JJA
DMS & Chlorophyll • Get decoupling for cell quota = f(stress) • Very little decouping without