1. Trace Metals & Phytoplankton Gert Vlaming 24-01-2003

2. Contents Introduction Trace metals Importance of phytoplankton Conclusion

3. Gaia theory EnvironmentLife

4. Trace metals

5. Trace metals of importance Fe 3+ Mn 2+ Co 2+ Cu 2+ Ni 2+ Cd 2+ Zn 2+

6. Complexation field diagram Whitfield, 1997

7. Recycled elements Low concentrations in the surface layer Enhanced concentrations in the deeper water Residence time: intermediate (10 3 – 10 5 yrs) Concentrations: 10 -12 – 10 -5 M

8. ElementAtlantic - Surface Atlantic - Deep Pacific - Surface Pacific - Deep Fe 3+ 2.0 *10 -9 7.0*10 -9 0.2*10 -9 2.0*10 -9 Cu 2+ 1.3*10 -9 2.0*10 -9 1.3*10 -9 4.5*10 -9 Ni 2+ 2.0*10 -9 7.0*10 -9 2.0*10 -9 10*10 -9 Cd 2+ 0.1*10 -10 3.5*10 -10 0.1*10 -10 10*10 -10 Zn 2+ 1.5*10 -10 1.6*10 -9 1.5*10 -10 8.2*10 -9 Mn 2+ 1.9*10 -9 1.8*10 -9 1.9*10 -9 8.0*10 -10 Co 2+ 2.7*10 -11 1.5*10 -11 2.3*10 -11 1.5*10 -11 Concentrations mol/l

9. Concentrations II Atlantic ocean receives a greater flux of windborne dust and atmospheric contaminants than the Pacific Accumulated elements released from the decaying particulate matter Mn and Co: adsorption onto particles

10. Biochemical functions Fe nitrogen fixation transport of oxygen protection Zn Food digestion Ni hydrolysis of urea reactions with H 2 And many enzymatic reactions

11. Availability > 97% of the total metal in solution is held in strong organic complexes These complexes are not available for phytoplanktonic uptake The essential trace metals have very low concentrations

12. Importance of life for trace metal concentrations

13. Fractionation Broecker & Peng, 1982

14. Recycling ratio flux circulating within the ecosystem flux circulating through the environment R = Cd494 P214 C54 N33 Cu2.2 Zn1.9 Fe1.8 Mn1.4 RR

15. Recycling ratio Whitfield, 1997

16. Recycling ratio II The inability of phytoplankton to exercise absolute discrimination Phytoplankton are capable of actively regulating their internal economy For most essential trace metals the cells are at, or close to, their nutrient limitation levels

17. Adaptations Internal External Interspecific Collective There’s a “chemical war” going on...

18. Uptake Diffusion Transfer of complexes Capture Uptake by Michaelis-Menten kinetics

19. Organic complexation Cells release organic complexing agents Beneficial for Fe, Cu en Mn Enabling large pool of Fe to be maintained Maintaining concentrations below toxic levels

20. Conclusions Availability of trace metals is a significant factor regulating primary production Phytoplankton is strongly effecting the concentrations of trace metals

21. Questions

22. Additional

23. Evolution of life Prokaryotic life: 3.5 Ga Eukaryotic life: 1.5 Ga Multicellular life: 600 Ma

24. Possibly because: Start of multicellular life Lowering of the alkalinity of the oceans The attainment of an appropriately low global mean temperature The maintenance of a critical level of dissolved oxygen in the sea The establishment of the required cocktail of available trace metals