Ecosystem composition and

export production variability

Corinne Le Quéré, Erik Buitenhuis, Christine

Klaas

Max-Planck-Institute for Biogeochemistry, Germany

and Olivier Aumont

Laboratoire de Dynamique du Climat et des Océans, France

1850 today 2100

CO

2 s

ink (

Pg

C/y

)

Prentice et al., 2001

OCEAN

LAND

climate feedback

4

NPZD

PISCES

Dynamic Green Ocean Model

(DGOM)

SeaWiFS

Chla (mgChl/m3

)

SeaWiFS

NPZD

PISCES

DGOMChla

(mgChl/m3)

SeaWiFS

50%

Interannual standard deviation of Chla (%)

Chla (mgChl/m3)

SeaWiFS

NPZD

PISCES

DGOM

50%

Interannual standard deviation of Chla (%)

Chla (mgChl/m3)

Nano Cocco. Diatoms

Description

maximum growth rate µ at 0°C (1/d)

0.6 0.4 0.6

half sat. P (nM) 19 4 75

half sat. Si (µM) 2

half sat. Fe (pM) 20 20 120

Light affinity dependence 6 6 4

Phytoplankton traits

cocco

diatoms

nano

Abundance of PFT (%)

DGOM

cocco

diatoms

nano

70N

0

70Srelative contribution

cocco

diatoms

nano

Interannual standard deviation of chla per PFT (%)

cocco

diatoms

nanno

Interannual standard deviation of chla per PFT (%)

5 PFTs 4 PFTs

1997 1998 1999 2000 2001 2002 2003

diatoms

coccolithophorids

nano phytoplankton

0.02

0.1

1.5

Plankton-specific chla in the North Atlantic

(40N-45N, mgChla/m3)

DGOM

Abundance of diatoms (%)

Uitz, Claustre et al., from an HPLC pigment and SeaWIFS Chla

cocco

diatoms

nano

70N

0

70Srelative contribution

Coccolithophorid bloom frequency

Analysis from C. Brown

cocco

diatoms

nano

DGOM

70N

0

70Srelative contribution

Global Bloom

Model 8.0 (0.22) 1.0 (0.03)

Seawifs 1 (BF + Laws)

17.3 (0.46) 6.2 (0.35)

MEAN (Standard deviation)

Export Production (PgC/y)

Total

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MLD Fe PO4 Si PP EXPorg EXPco3 Chl DCHL/ NCHL/ CCHL/ MES MIC

Sarm

Obs

EQUL

EME2

EMES

EMI2

EMIC

Total

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MLD Fe PO4 Si PP EXPorg EXPco3 Chl DCHL/C NCHL/C CCHL/C MES MIC

Sarm

Obs

SWAM

SWFE

SWPO

SWSI

sensitivity of plankton sensitivity of plankton biomass tobiomass to

growthgrowth grazinggrazing

diatoms

nano

Cocco.

Meso-zoo

Micro-zoo

diatoms

nano

Cocco.

Meso-zoo

Micro-zoo

Conclusions

• More complexity in marine ecosystems gives more variability in fluxes

• More in line with observations

• Mean spatial distribution in PFTs is critical to reproduce chl variability

Description PCUL DGSW SWAM SWFE SWPO SWSI

half sat. P diatoms (nM) 75 75 300 75 300 75

half sat. P nano/pico(nM) 19 19 100 19 100 19

half sat. PCoccolith. (nM)

4 4 4 4 4

half sat. SiDiatoms (µM)

4 4 0.4 4 4 0.4

half sat. Fe diatoms (aM) 120 120 700 700 120 120

half sat. Fe nano/pico (aM) 25 25 300 300 25 25

half sat. FeCoccolith. (aM9

25 300 300 25 25

Phytoplankton traits

Description Units PCUL DGSWSWAM

SWFE SWPOSWSI

half saturation PO4 diatoms

nM 75 75 300 75 300 75

half saturation PO4

nanophytoplankton

nM 19 19 100 19 100 19

half saturation PO4

coccolithophorids

nM 4 4 4 4 4

half saturation SiO3

diatoms

µM 4 4 0.4 4 4 0.4

half saturation Fe diatoms

aM 120 120 700 700 120 120

half saturation Fe nanophytoplankton

aM 25 25 300 300 25 25

half saturation Fecoccolithophorids

aM 25 300 300 25 25

Phytoplankton traits

Total

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MLD Fe PO4 Si PP EXPorg EXPco3 Chl DCHL/ NCHL/ CCHL/ MES MIC

SarmObsPCULDGSWSWAMSWFESWPOSWSI

Description PCUL EQUL EME2 EMES EMI2 EMIC

max. growth rate Meso-zoo (1/d)

0.9 0.24 0.24 0.9 0.24 0.24

half sat. Meso-zoo (µM) 18 0.29 0.29 0.29 0.29 0.29

mortality rate Meso-zoo (1/d)

0.1*mes 0.0580.058*mes

0.1*mes

0.058 0.058

max growth rate Micro-zoo (1/d)

4 2 2 2 4 2

half saturation Micro-zoo (µM)

18 18 18 18 18 3

Zooplankton traits

DescriptionUnits

PCUL EQULEME2EMESEMI2 EMIC

max. growth rate mesozooplankton

1/d 0.9 0.24 0.24 0.9 0.24 0.24

half saturation mes

µM 18 0.29 0.29 0.29 0.29 0.29

mortality rate mes

1/d0.1*mes

0.058

0.058*mes

0.1*mes

0.058

0.058

max growth rate microzooplankton

1/d 4 2 2 2 4 2

half saturation mic

µM 18 18 18 18 18 3

Zooplankton traits

Total

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MLD Fe PO4 Si PP EXPorg EXPco3 Chl DCHL/ NCHL/ CCHL/ MES MIC

SarmObs

PCULEQULEME2EMESEMI2EMIC

POC

CaCO3

Si

sediment trap data base of C. Klaas

Impact of El Nino in % on Chla (full line from SeaWiFS) and export (dots from traps)

cocco

diatoms

nanno

Abundance of PFT (%)

DGOM PISCES