OPA – PlankTOM5.0 - DMS

Meike Vogt * Corinne Le Quéré Erik T. Buitenhuis

Sergio Vallina * Laurent Bopp

PlankTOM Series

N2 fixersDMS

producers

coccolith.Nano

phytoplankton

Fe NO3Si

CaCO3

PO

4

NH4

DOM

diatoms

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

Food Web PlankTOM5.0

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

DMSPp

DMS

DMSPd

mortality

grazing/exudation

grazing/exudation

bacteriafree lyase

sea-air flux

photolysis

PO4

T

Fe

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

ii

i

PC

SDMSPp )(

DMS Dynamics

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)

mortalityexudation/leakage cleavage of DMSPd by free DMSP-lyasebacterial consumption of DMSP (microbial yield 10%)

DMS degradation: bacterial consumption of DMSphotolysis at the sea surfacesea-air flux

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]

Seasonality

Low seasonality! High latitudes a mess But I am working on it!

DJF

JJA

MAM

SON

DMS & Chlorophyll

Get decoupling for cell quota

= f(stress) Very little decouping without