Institut universitaire europeen de la mer (iuem)Laboratoire des sciences l’environnement marin (LEMAR)

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Up or down:Modeling the fates and rates of phytoplankton carbon in

the North Atlantic Ocean

Christoph Stegert

Laurent MemeryThomas GorguesJulie Deshayes

MOTIVATION: Where does the carbon go?

Background

MOTIVATION: Where does the carbon go?

Background

Background

PDIC

MOTIVATION: Where does the carbon go?

Background

PDIC

fisheries

MOTIVATION: Where does the carbon go?

Z

Fish

Food web dynamics

Background

PDIC

Z

Fish

D

Deep Sea

fisheries

Carbon export

MOTIVATION: Where does the carbon go?

Food web dynamics

CO2 storage

Background

PDIC

D

Deep Sea

fisheries

Carbon export

RemineralisationSedimentation

MOTIVATION: Where does the carbon go?

CO2 storage

Z

Fish

Food web dynamics

Background

PDIC

D

Deep Sea

fisheries

Carbon export

RemineralisationSedimentation

UP or

DOWN

What is/ What

determines this ratio

MOTIVATION: Where does the carbon go?

CO2 storage

Z

Fish

Food web dynamics

Background

PDIC

D

Deep Sea

CO2 storage

fisheries

Carbon export

RemineralisationSedimentation

UP or

DOWN

Possible consequences

of climate change on the

ratio

What is/ What

determines this ratio

MOTIVATION: Where does the carbon go?

Z

Fish

Food web dynamics

How much of Primary Production is transported to the deep ocean (carbon export)?

What are regional differences in the carbon transport and how do they change during the 1990-2010 period?

What is the structure of the links of primary production and carbon export in the North Atlantic Ocean?

MOTIVATION: Where does the carbon go?

Specific questions I want to answer in this talk:

Besides carbon the nutrient (N,P,Si,Fe) and Oxygen cycles are simulated

Model concept: Carbon cycle

DIC PdiatPnano

Zmicro Zmeso

DOC POC GOC

1

2 3

46 579

10

8

11 11

Model configuration:Physics:NEMO3.4Biogeochem ics:PISCESArea:North Atlantic

20S to 80NResolution: 1/4°Simulation:1978-2010

Major fluxes:1 Primary Production New Production [100m integrated annual avg.]

2+3 Zoo Grazing4+5 Mortality6-8 Plankton losses9 Nitrification10 Remineralisation11 Carbon Export[at 1000m, annual average]

11

Validation of model variables

Validation: Surface Nitrate annual cycle (log 10 )

WOA09 MODEL

Validation of model variables

Validation: Ratio of Diatoms and Nanoplankton

PHYSAT MODEL

Validation of model variables

Validation: Carbon export at 100m (gC/m2/yr)

Schlitzer MODEL

SPG and STG have contrasting environment

UP or DOWN: regional variability

STGsubtropical

gyre

SPGsubpolar gyre

NECSEurop. Shelf

GSTGulf Stream

CUWCanary Upwelling

Sea surface temperature

F-ratio shows higher pelagic production in the Northern NA and SPG

UP OR DOWN: NewP : TPP (f-ratio)

Highest f-ratio in SPG, very strong correlation in Canarian Upwelling and STG

UP or DOWN: regional variability

STG

SPGNECS

GST CUW

avg = 0.69 p = 0.61 avg = 0.41

p = 0.89

avg = 0.34 p = 0.99

avg = 0.38 p = 0.93

avg = 0.33 p = 0.58

New P (y)--------------

TPP (x)

[MolC/m2/y]

High ratio in Labrador Sea

UP OR DOWN ep-ratio: Export (1000m): TPP

Export highest in SPG, and strong correlation in CUW and STG

UP or DOWN: regional variability: Carbon export at 1000m

STG

SPGNECS

GST CUW

Export (y)--------------

TPP (x)

[MolC/m2/y]

avg = 0.15 p = 0.02 avg = 0.09

p = 0.55

avg = 0.04 p = 0.98

avg = 0.05 p = 0.95

avg = 0.06 p = 0.71

Increased TPP is followed by increased grazing and export except in SPG

UP or DOWN: interannual variabilityTPP PHY ZOO GRAZING EXPORT

GST

SPG

STG

NECS

CIW

1990-2010 1990-2010 1990-2010 1990-2010

Provinces: Clustering

Longhurst provinces based on physical/ biogeochmical variables

CLUSTER: Export (1000m) and TPP

Differences in the structure compared to upper layer dynamics

CLUSTER: Grazing and TPP

Regional differences in the structure of coupling to export

Background

PDIC

Z

Fish

D

Deep Sea

CO2 storage

fisheries

Carbon export

Food web

RemineralisationSedimentation

UP or

DOWN

OUTLOOK the role of zooplankton

Background

PDIC

Z

D

Deep Sea

CO2 storage

fisheries

Carbon export

RemineralisationSedimentation

UP and

DOWN

OUTLOOK the role of zooplankton

Verticalmigration

Fish

Food web

Conclusions

THANK YOU for your interest.

This work was done within the FP7 program

Basin-Scale Analysis , Synthesis and Integration

We would like to thank- TANGGO consortium:

travel support

Different biological processes, e.g. zooplankton behavior, can influence these ratios.

How much of Primary Production is transported to the deep ocean (carbon export)?Export at 1000m is ca. 5-15% of PP in upper 100m, while New Production is highest in the northern North Atlantic.

What are regional differences in the carbon transport and how do they change during the 1990-2010 period?Dynamics in SPG are significantly different to STG and other regions.Coupling of PP and EXP in the STG and for PP and Grazing in most regions. Strong decoupling in SPG.

What is the structure of the links of primary production and carbon export in the North Atlantic Ocean?

Grazing lowest in SPG, all other regions show strong correlation

UP or DOWN: regional variability

STG

SPGNECS

GST CUW

Grazing--------------

TPP

[gC/m2/y]

avg = 1.01 p = 0.59 avg = 1.17

p = 0.98

avg = 1.38 p = 0.99

avg = 1.25 p = 0.99

avg = 1.30 p = 0.98