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

1. 60 Up or down: Modeling the fates and rates ofphytoplankton carbon in the North Atlantic OceanChristoph Stegert Laurent MemeryThomas GorguesJulie Deshayes 40 20 0

2. MOTIVATION: Where does the carbon go? Background

3. MOTIVATION: Where does the carbon go? Background

4. MOTIVATION: Where does the carbon go? DIC P Background

5. MOTIVATION: Where does the carbon go? Fish fisheries Food web dynamics Z DIC P Background

6. MOTIVATION: Where does the carbon go? Fish fisheries Food web dynamics Z DIC P D Carbon export CO2 storage Deep Sea Background

7. MOTIVATION: Where does the carbon go? Fish fisheries Food web dynamics Z DIC P D Carbon export CO2 storage Deep Sea Remineralisation Sedimentation Background

8. MOTIVATION: Where does the carbon go? Fish fisheries Food web dynamics Z UP or DOWN What is/ What determines this ratio DIC P D Carbon export CO2 storage Deep Sea Remineralisation Sedimentation Background

9. MOTIVATION: Where does the carbon go? Fish fisheries Food web dynamics Z Possible consequences of climate change on the ratio UP or DOWN What is/ What determines this ratio DIC P D Carbon export CO2 storage Deep Sea Remineralisation Sedimentation Background

10. MOTIVATION: Where does the carbon go? Specific questions I want to answer in this talk: 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?

11. Model concept: Carbon cycle Model configuration: Physics: NEMO3.4 Biogeochemics: PISCES Area: North Atlantic 20S to 80N Resolution: 1/4° Simulation: 1978-2010 Major fluxes: 1 Primary Production New Production [100m integrated annual avg.] 2+3 Zoo Grazing 4+5 Mortality 6-8 Plankton losses 9 Nitrification 10 Remineralisation Carbon Export [at 1000m, annual average] Zmicro Zmeso 3 2 8 Pnano Pdiat DIC 1 7 5 4 6 9 DOC POC GOC 10 11 11 11 Besides carbon the nutrient (N,P,Si,Fe) and Oxygen cycles are simulated

12. Validation: Surface Nitrate annual cycle (log 10 ) WOA09 MODEL Validation of model variables

13. Validation: Ratio of Diatoms and Nanoplankton PHYSAT MODEL Validation of model variables

14. Validation: Carbon export at 100m (gC/m2/yr) Schlitzer MODEL Validation of model variables

15. UP or DOWN: regional variability NECS Europ. Shelf SPG subpolar gyre STG subtropical gyre GST Gulf Stream CUW Canary Upwelling Sea surface temperature SPG and STG have contrasting environment

16. UP OR DOWN: NewP : TPP (f-ratio) F-ratio shows higher pelagic production in the Northern NA and SPG

17. UP or DOWN: regional variability SPG NECS avg= 0.69 p = 0.61 New P (y) -------------- TPP (x) [MolC/m2/y] avg= 0.41 p = 0.89 STG GST CUW avg= 0.38 p = 0.93 avg= 0.34 p = 0.99 avg= 0.33 p = 0.58 Highest f-ratio in SPG, very strong correlation in Canarian Upwelling and STG

18. UP OR DOWN ep-ratio: Export (1000m): TPP High ratio in Labrador Sea

19. UP or DOWN: regional variability: Carbon export at 1000m SPG NECS avg= 0.15 p = 0.02 Export (y) -------------- TPP (x) [MolC/m2/y] avg= 0.09 p = 0.55 STG GST CUW avg= 0.05 p = 0.95 avg= 0.04 p = 0.98 avg= 0.06 p = 0.71 Export highest in SPG, and strong correlation in CUW and STG

20. UP or DOWN: interannual variability TPPPHYZOOGRAZINGEXPORT GST SPG STG NECS CIW 1990-2010 1990-2010 1990-2010 1990-2010 Increased TPP is followed by increased grazing and export except in SPG

21. Provinces: Clustering Longhurst provinces based on physical/ biogeochmical variables

22. CLUSTER: Export (1000m) and TPP Differences in the structure compared to upper layer dynamics

23. CLUSTER: Grazing and TPP Regional differences in the structure of coupling to export

24. OUTLOOK the role of zooplankton Fish fisheries Food web Z UP or DOWN DIC P D Carbon export CO2 storage Deep Sea Remineralisation Sedimentation Background

25. OUTLOOK the role of zooplankton Fish fisheries Food web Z UP and DOWN DIC P Vertical migration D Carbon export CO2 storage Deep Sea Remineralisation Sedimentation Background

26. Conclusions • This work was done within the FP7 program • Basin-Scale Analysis , Synthesis and Integration • We would like to thank • TANGGO consortium:travel support 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? Different biological processes, e.g. zooplankton behavior, can influence these ratios. . THANK YOU for your interest

27. UP or DOWN: regional variability SPG NECS avg= 1.01 p = 0.59 Grazing -------------- TPP [gC/m2/y] avg= 1.17 p = 0.98 STG GST CUW avg= 1.25 p = 0.99 avg= 1.38 p = 0.99 avg= 1.30 p = 0.98 Grazing lowest in SPG, all other regions show strong correlation