1. GEOTRACES 40 o S Cruise Planning Meeting Oxford, 24th March 2009

2. Published in late 2006 Download PDF from http://www.geotraces.org/ Or hard copies available here (also substantially replicated in Chemie de Erde paper in your workshop folders) Science Plan

3. Mission GEOTRACES guiding mission To identify processes and quantify fluxes that control the distributions of key trace elements and isotopes (TEIs) in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions.

4. Mission What are “key” elements? They include: -Those acting as micronutrients to control ocean productivity and ecosystems -Those tracing modern processes in the ocean -Contaminants in the present and future ocean -Chemical species used as proxies to reconstruct past climate

5. Mission Include, but not limited to…

6. Mission Proposed Atlantic sections

7. Some GEOTRACES news “Enabling” -Second US-led intercalibration cruise will sail in May/June -Data management is set up at BODC jointly funded by NERC and NSF -The IPO is funded and will be set up in Toulouse -An ESF COST Action is enabling a networking and meetings across Europe The actual science: Successful IPY cruises have occurred in 2008, more in 2009 Germany will sail tropical Atlantic cruise in 2010 USA will sail A03 during 2010 Netherlands will sail some of A01 during 2010 UK will sail A10 during 2010 UK proposal for A06 is under review

8. The UK 40oS Atlantic Cruise Henderson, Mills, Pancost and Rickaby (Oxford, NOCS, Bristol) Submitted standard NERC proposal to Dec 2007 round Funded 32 day cruise plus calibration work on four paleoproxies: -Pa/Th -Cd -Si isotopes -Organic biomarkers

9. The two points to this meeting: 1.Fill this cruise with as much good science as possible (with GEOTRACES theme) 2.Plan funding for this research, including a NERC consortium proposal for July 1st 2010

10. An intro to 40oS in the Atlantic Crosses deep basins (Argentine and Cape) and Mid-Atlantic Ridge

11. Comparison with WOCE

12. An intro to 40oS in the Atlantic Productive region with appreciable sedimentation

13. An intro to 40oS in the Atlantic Samples major deep water masses in Atlantic

14. Iron as a limiting nutrient in HNLC regions

16. Input fluxes of bioactive metals

17. DataLimited for Fe Present ignorance: Existing deep ocean Fe data Stations with Fe concentrations at depths > 2000 m. As of 2003. From P. Parekh (MIT) Paucity of information about deep Fe distribution limits understanding of upwelling supply and internal cycling.

18. Other essential TEIs Iron is not the only trace metal crucial for ocean biology Figure from F. Morel

19. Deep-water supply to productive regions

20. Sources of micronutrients to oceans

21. Dust inputs are uncertain…

22. Substantial river input

23. MAR inputs are likely de Baar et al. Zero and Drake cruise

24. Mission Proposed Atlantic sections

25. MAR inputs are likely de Baar et al. Zero and Drake cruise

26. Margin sediments with somewhat varied conditions

27. Tracing sources of metals E.g. REEs and Al in Equatorial Pacific (Yang et al) Short-lived radioisotopes, Mn, radiogenic isotopes (Nd, Pb)

28. Sources of micronutrients to oceans

29. Provide nutrients for richly productive and varied region

30. DataLimitsModels Constraining fluxes with models (Parekh et al. 2005)

31. Some things to consider: Cruise co-ordination and logistics Equipment for clean sampling and shipboard analysis Wire time and water budget Funding Will need to make tough choices re. berths, water, budgets

32. Two possible cruise tracks (approximate!)