1. Mean Ocean Concentrations

2. Vertical Variations Biolimiting

3. The “biological pump”

4. 2-Box model Physical transport balances biological export

5. Radioactive Carbon Surface ~ 6% below standard Mean deep ocean ~ 10% below surface (plotted relative to an arbitrary standard) Residence time of deep ocean ~1000 years!

6. Removal of carbon from surface ocean by photosynthesis is ~5 x 10 15 grams/year! How did we get this?

7. rivers sediments ff External inputs vs internal recycling PsPs PdPd f PO4 = 0.03 f Ca =0.20

8. Wind-driven circulation

9. Vertical Motions

10. Upwelling/downwelling

11. Sea Surface Height H L H

12. Ocean gyres in theory

13. Density of Seawater σ What is salinity? What is density (  or σ)? What are their units?

14. Temperature Identify the influence of the wind-driven circulation. Temperature must be responsible for stratification. But everywhere?

15. Stratification and the Thermocline Label depths with strong and weak stratification. Where is sinking water most likely (easy to achieve)? Where is it least likely (difficult to achieve)?

16. Ocean model mixed layer

17. Summary of vertical circulation What is happening above the thermocline boundary? Fill in appropriate arrows.

18. The Ocean Conveyor What is it conveying? (at the surface? and at depth?)

19. Observed surface nutrients What is the role of ocean circulation in this pattern? What else is needed?

20. Turning off biology

21. CO 2 C org Phytopl. Zoopl. Bacteria Respiration (Heterotrophic) Photosynthesis “Net Primary Production (NPP)” RhRh NPP Export Production EP Productivity

22. To what degree does Temperature appear to limit productivity? Are there warm (cold) waters with low (high) productivity? NPP vs SST

23. Seasonal light limitation Where should light never be limiting? Where is it limiting in winter? And why (what combination of two factors?). What about summer?

24. [NO 3 ] < K N γ(N)<<1 [NO 3 ] >> K N γ(N) ≈ 1 The importance of nutrients Where are high nutrients NOT associated with high productivity? Are there places with high productivity but low nutrients?

25. Nutrient Limitation: NO 3 or PO 4 ? Release Uptake Nutrient Uptake and Release N:P = 16:1 Indicate surface and deep waters. Which nutrient typically runs out first?

26. NO 3 N org Phytopl. Zoopl. Bacteria Regenerated (“Recycled”) Production New Production Export Production EP New and Regenerated Production NH 4 How could you use NO 3 and NH 4 to measure the f-ratio?

27. Export Production

28. Observed surface nitrate This is what we want to understand!