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Corals as paleoclimatic archives Jens Zinke

Corals as paleoclimatic archives Jens Zinke. PROPER June 2004, VU Amsterdam. Coral study sites. Massive coral Porites sp. Coral drilling. Coral core recovery. 60cm. Emerged fossil coral Porites. Fossil corals: storm deposits. Environmental tracers in corals. Oxygen isotopes:

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Corals as paleoclimatic archives Jens Zinke

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  1. Corals as paleoclimatic archives Jens Zinke PROPER June 2004, VU Amsterdam

  2. Coral study sites

  3. Massive coral Porites sp.

  4. Coral drilling

  5. Coral core recovery 60cm

  6. Emerged fossil coral Porites

  7. Fossil corals: storm deposits

  8. Environmental tracers in corals • Oxygen isotopes: • - Sea surface temperature • Seawater isotopic composition • Carbon isotopes: • cloud cover • Sr/Ca, U/Ca, Li/Ca (?): • Sea surface temperature • U/Ca, Mg/Ca: • Salinity • U/Th dating of fossil corals • Combined Sr/Ca and d18O: • - Hydrologic balance • 14C, Pb-isotopes: • Ocean circulation • Atmospheric circulation • - Upwelling • Ba/Ca, Cd/Ca: • Terrestrial river runoff • upwelling • Rare Earth Elements (REE): • - biological activity in seawater

  9. Techniques for isotope and trace element ratios: - Oxygen and carbon isotopes on Mass Spectrometer - Sr/Ca, Mg/Ca, Ba/Ca on ICP-OES - U/Ca, Li/Ca, Sr/Ca, Mn/Ca, Ba/Ca on ICP-MS and Laser Ablation ICP-MS - Sr/Ca, U/Ca, U/Th on TIMS - Rare Earth Elements with Laser Ablation ICP-MS - Element mapping and ultra-high-resolution with SIMS and PIXE

  10. Basal ectoderm of coral polyp with symbionts from seawater Extracellular calcifying fluid Exoskeleton (Aragonite crystals)

  11. Growth rate effects McConnaughey, 2003, Coral Reefs 22 slow growth rates (below 3mm/year) = heavy isotopes

  12. Isotopic fractionation Non-photosynthetic photosynthetic Kinetic fractionation McConnaughey, 2003, Coral Reefs 22

  13. Density banding: first age model Major growthaxis Low density = summer 10-15 mm High density = winter

  14. Age model and data interpolation X-ray with density banding

  15. Madagascar coral record Zinke et al. 2003, Springer

  16. Calibration vs .instrumental data: Linear Regression Inverse relationship to temperature in isotopes and Sr/Ca ratios !

  17. Reconstruction of SST: Core top calibration

  18. Calibration/Validation of proxy data: annual means

  19. Combined use of 18O and Sr/Ca: Hydrologic balance Method in Ren et al., 2002 Geochimica et Cosmochimica Acta 67 (9)

  20. Hendy et al., 2002, Science 295

  21. Time series analysis and advanced statistics

  22. Advanced Statistics: Cross spectral analysis Zinke et al. 2003

  23. ENSO Teleconnections

  24. ENSO phenomenon

  25. Webster et al., 1999

  26. Coral sites superimposed on SST and monsoonal winds SST / Wind Precip.Evap. Winter monsoon (January) January Summer monsoon (July) July

  27. Coral records from the Indo-Pacific

  28. Western Indian Ocean coral time series Pfeiffer, 2002; Pfeiffer et al., 2004, Quaternary Research; Zinke et al. (subm)

  29. Tarawa coral record, Cole et al., 1993, Science 260

  30. Changing El Nino frequency derived from a coral d18O record at Kiribati Island (1°N) located within the Nino3 region in the Pacific

  31. Spatial correlation maps coral vs. Global SST: Indian Ocean - ENSO teleconnection: 1970‘s shift? before 1970 after1970

  32. U/Th dating of fossil reef cores (corals) for exact timing of sea level changes

  33. Future needs: • proxies for environmental changes in coastal waters • process studies of incorporation of proxies into skeleton • multiple core replication of single core results • use of more statistical methods to unravel climate information • net work of coral records for each ocean basin for large scale • climate reconstruction • collaboration with climate modeling community to test future • scenarios

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