1. Ocean Circulation Changes 13-C Fractionation Palaeoclimate Gerrit Lohmann Carbon Course 16. January 2006 @PEP, University of Bremen, Germany

3. Ocean Circulation Methaphor surface deep conversion

4. Heat, freshwater surface fluxes Tropical Box T 2 S 2 High Latitude Box T 1 S 1 q > 0 Z: Depth Y: meridional direction Stommel (1961) Box Model

5. Salinity loop S 1 low q low q S 2 low S 1 low T 2 S 2 T 1 S 1 q > 0 Positive feedback

6. Flow in the direction of density

7. Tropical Box T 2 S 2 Northern High Latitude Box T 1 S 1 Southern High Latitude Box T 3 S 3 Rooth (1982) box model: Interhemispheric flow q > 0 SS NN  S+  N

12. Red arrows: motion of objects fixed to the globe Yellow and green arrows: not fixed, northern velocity Yellow arrows arrives ahead of a fixed object, green arrives behind

17. Rotation in The direction of rotation in draining sinks and toilets is NOT determined by the rotation of the Earth, but by rotation that was introduced earlier when it was being filled or subsequently being disturbed (say by washing). The rotation of the Earth does influence the direction of rotation of large weather systems and large vortices in the oceans

18. Ocean Circulation Methaphor surface deep conversion

19. Conveyor belt Warm water route

20. Conveyor belt Cold water route

21. Present Glacial S 1 > S 2 S 1 < S 2 South- Equator North- Atlantic Conceptual Model of the THC (~ Rooth) Cold & Warm water route Cold water route

24. Signature at the end of a meltwater pertubation SST deg°C YDH1H2 Bard et al. 2000 SU81-18 N S interhemispheric seesaw Knorr and Lohmann 2005

25. Physical System is important for the marine carbon cycle

30. 13-C Fractionation The photosynthetic activity in the oceans (limited to the photic zone) results in a very strong depletion of the surface waters in 12C (captured in organic matter), strong enrichment in 13C. Planktonic organisms living in the photic zone, and forming calcareous tests from dissolved inorganic carbon (largely HCO 3 - ) in these surface layers, thus use carbon that is enriched in 13C (isotopically heavy) for the formation.

31. Organic Carbon cycle

32. Photosynthesis -> low PO4, organic matter with 12-C, residual water high 13-C

33. Organic Carbon cycle oxidation

34. 13-C oxidation 13-C provides a measure of oxidation of organic carbon: CH2O + O2 --> CO2 + H2O The 13-C values of dissolved inorganic carbon at greater depths (and thus of benthic foraminifera) are quite different from those in surface waters, because carbon dioxide derived from oxidized organic material (thus isotopically light) is added to the deep waters. http://ethomas.web.wesleyan.edu/wescourses/2004s/ees227/01/229lab6.htm

35. ``13-C conveyor belt´´

38. 13-C To complicate factors, there is a difference in d13C of total dissolved inorganic carbon (TDIC) in deep waters with a different "age": waters that have been out of contact with the surface ocean for a long time, have accumulated much carbon derived from oxidation of organic material, thus their total dissolved inorganic carbon is isotopically light.

39. 13-C: climate changes

42. Paleoclimate

50. Eccentricity

51. Precession of the axis of the earth Year:

57. A holy grail

58. Theory of ice ages External: Increased eccentricity of the earth's orbit Changes in the intensity of solar radiation The earth passing through cold regions of space Internal: ice sheet, CO2, stochastic Amplifiers: thresholds, rectification