1. Constraining Hydrological Cycle Characteristics of Early Eocene Hyperthermals Srinath Krishnan

2. Reasons for study  Rainfall has direct impact on human society  Impact of anthropogenic activity on rainfall patterns is not well understood  Modern studies suggest intensification of hydrological cycle with warming  Wet Wetter  Dry Dryer  Lack of data inhibits validation of these models in a complex natural system

3. Reasons for study  Rainfall has direct impact on human society  Impact of anthropogenic activity on rainfall patterns is not well understood  Modern studies suggest intensification of hydrological cycle with warming  Wet Wetter  Dry Dryer  Lack of data inhibits validation of these models in a complex natural system

4. Reasons for study  Rainfall has direct impact on human society  Impact of anthropogenic activity on rainfall patterns is not well understood  Modern studies suggest intensification of hydrological cycle with warming  Wet Wetter  Dry Dryer  Lack of data inhibits validation of these models in a complex natural system

5. Reasons for study  Rainfall has direct impact on human society  Impact of anthropogenic activity on rainfall patterns is not well understood  Modern studies suggest intensification of hydrological cycle with warming  Wet Wetter  Dry Dryer  Lack of data inhibits validation of these models in a complex natural system

6. Early Eocene Hyperthermals Paleocene-Eocene Thermal Maximum ~3-5 0 C rise in temperature Negative carbon isotope excursion of 2.5-6‰ Eocene Thermal Maximum-2 Smaller rise in temperature compared to the PETM set on a warming trend Carbon isotopic excursion about half of the PETM Adapted from Zachos et al. (2001)

7. Early Eocene Hyperthermals  Causes  Methane Hydrates (Dickens et al., 1995)  Burning of terrestrial organic matter (Kurtz et al., 2003)  Estimates of greenhouse gas concentrations  Pre-PETM: ~600 – 2,800 ppm of CO 2  PETM: ~750 – 26,000 ppm of CO 2  ~1,500 – 55,000 Gt C in the atmosphere  ~3,900 – 57,000 Gt C released in the oceans  Modern atmospheric CO 2 concentration: ~360 ppm  Modern Conventional fossil fuel reserves: ~5,000 Gt C

8. Early Eocene Hyperthermals  Causes  Methane Hydrates (Dickens et al., 1995)  Burning of terrestrial organic matter (Kurtz et al., 2003)  Estimates of greenhouse gas concentrations  Pre-PETM: ~600 – 2,800 ppm of CO 2  PETM: ~750 – 26,000 ppm of CO 2  ~1,500 – 55,000 Gt C in the atmosphere  ~3,900 – 57,000 Gt C released in the oceans  Modern atmospheric CO 2 concentration: ~360 ppm  Modern Conventional fossil fuel reserves: ~5,000 Gt C

9. GOAL  Use early Eocene hyperthermals as analogues to study changes in the hydrological cycle during extreme warming events

10. Schematic of a Water Cycle Adapted from NASA Goddard Flight Center

11. Expected changes with warming  Increased lower tropospheric water vapor  In the extra-tropics, the important components of the hydrological cycle that affect isotopic signals are  Horizontal poleward flow of moisture  Changes in precipitation and evaporation Dr. Raymond Schmitt: http://www.whoi.edu/sbl/liteSite.do?litesiteid=18912&articleId=28329

12. Variations in Precipitation with warming Held and Soden (2006) Increased Evaporation 2.8 0 c in 2100

13. Held and Soden (2006) Increased Precipitation Variations in Precipitation with warming 2.8 0 c in 2100

14. Isotopes and Precipitation

15. Modern annual precipitation http://www.waterisotopes.org

16. Rayleigh Distillation Clark and Fritz, 1997

17. Rayleigh Distillation Clark and Fritz, 1997 Increased depletion with progressive rainout events

18. Hypotheses  There is a systematic change in moisture transport to the higher latitudes during warming events  Are there similar changes in δ D between the two hyperthermals at the higher latitudes?  Can these changes be detected on a global scale?  Can this theoretical model be reproduced with an isotope coupled climate model?

19. Proxies  n-alkanes: Single chain hydrocarbon with long chain lengths (n-C 23-35 ) indicating terrestrial plant/leaf wax sources  Compound-specific hydrogen isotopic composition represents meteoric water modified by evapotranspiration  Compound-specific carbon isotopic compositions represents environmental and ecological conditions

20. Proxies  n-alkanes: Single chain hydrocarbon with long chain lengths (n-C 23-35 ) indicating terrestrial plant/leaf wax sources  Compound-specific hydrogen isotopic composition represents meteoric water modified by evapotranspiration  Compound-specific carbon isotopic composition represents environmental and ecological conditions

21. n-alkanes and precipitation Adapted from Sachse et al., 2006) Deuterium n- alkanes

22. Biomarker transport Adapted from Eglinton and Eglinton, 2008 ContinentOceans Wind Terrestrial Plants Rivers Aerosols (with waxes)

23. Methods Samples Total Lipid Extract n-alkane and biomarker fractions Compound Detection & Identification Compound-specific Deuterium & Carbon isotope compositions Crushing and Extraction Compound Separation Gas Chromatogram Analyses Compound-specific Isotope Ratio Mass Spectrometer Clean-up Procedures Analytical Uncertainty: ±5‰

24. IODP-302 Arctic Coring Expedition

25. Arctic Paleocene-Eocene Thermal Maximum Modified from Pagani et al., 2006 ~55.6 Ma Duration: ~150-200 kyrs

26. Arctic Eocene Thermal Maximum-2 This work ~54 Ma Duration: ~75-100 kyrs

27. Preliminary Conclusions  Enrichment at the onset for both events with different magnitudes  Decreased rainout for moisture reaching the poles  15-20‰ magnitude depletions during the events  Similar variations during both the events

28. Preliminary Conclusions  Enrichment at the onset for both events with different magnitudes  Decreased rainout for moisture reaching the poles  15-20‰ magnitude depletions during the events  Similar variations during both the events

29. Hypotheses  There is a systematic change in moisture transport to the higher latitudes during hyperthermal events  Are there similar changes in δ D during the two hyperthermals at the higher latitudes?  Preliminary Conclusion: Enrichments in δ D do correspond with the hyperthermals at the onset of the event with similar magnitude depletions during the event Number of samples Arctic ETM-2: 29 samples

30. Hypotheses  There is a systematic change in moisture transport to the higher latitudes during hyperthermal events  Are there similar changes in δ D during the two hyperthermals at the higher latitudes?  Can these changes be detected on a global scale?  Can this theoretical model be reproduced with an isotope coupled climate model?

31. Tropical PETM: Tanzania (Handley et al., 2008)

32. Tropical PETM: Colombia (This work)

33. Mid-latitudes PETM: Bighorn Basin Smith et al. (2006)

34. PETM: High Latitudes Pagani et al. (2006)

35. Summary of changes during PETM  Tropics  Tanzania – 15‰ enrichment  Colombia - ~30‰ depletion  Mid-latitudes  Lodo – No change during the event with hints of depletion at the onset and the end  Bighorn Basin – No significant change  Forada - ~10‰ enrichment at the onset followed by a10‰ depletion during the event  High Latitudes  Arctic – 60‰ enrichment at the onset followed by 20‰ depletion through the event

36. Summary of changes during PETM  Tropics  Tanzania – 15‰ enrichment  Columbia - ~30‰ depletion  Mid-latitudes  Lodo, California – No change during the event with hints of depletion at the onset and the end  Bighorn Basin – No significant change  Forada, Italy - ~10‰ enrichment at the onset followed by a10‰ depletion during the event  High Latitudes  Arctic – 60‰ enrichment at the onset followed by 20‰ depletion through the event

37. Summary of changes during PETM  Tropics  Tanzania – 15‰ enrichment  Columbia - ~30‰ depletion  Mid-latitudes  Lodo – No change during the event with hints of depletion at the onset and the end  Bighorn Basin – No significant change  Forada - ~10‰ enrichment at the onset followed by a10‰ depletion during the event  High Latitudes  Arctic – 60‰ enrichment at the onset followed by 20‰ depletion through the event

38. Hypotheses  There is a systematic change in moisture transport to the higher latitudes during hyperthermal events  Can these changes be detected on a global scale?  Preliminary Conclusion: Existing data not sufficient to draw conclusions about regional & hemispherical changes. Requires further studies on a global scale

39. Ongoing Work

40. Ongoing Work: Giraffe Core C29

41. Ongoing Work: 1051 C29

42. Ongoing Work: 1263 C29

43. Ongoing Work: 690 C29

44. Hypotheses  There is a systematic change in moisture transport to the higher latitudes during hyperthermal events  Are there similar changes in δ D during the two hyperthermals at the higher latitudes?  Can these changes be detected on a global scale?  Can these changes predicted be reproduced with an isotope coupled climate model?

45. Future Work: Eocene Modeling  Goal  To utilize the global dataset developed to compare the hydrological response in terms of isotopes, temperatures and precipititation signals  Simulations planned  Hyperthemal scenarios (PETM vs. ETM2)  Different CO 2 concentrations  Background Eocene

46. Thank You Acknowledgments Joint Oceanographic Institute, ODP/IODP Mark Pagani, Matt Huber, Appy Sluijs, Carlos Jaramillo Peter Douglas, Sitindra Dirganghi, Micheal Hren, Brett Tipple, Katie French, Keith Metzger, Courtney Warren, Matt Ramlow, Gerry Olack, Dominic Colosi Yale G&G Faculty, Staff & Students

47. Mid-latitudes PETM: Forada Tipple (unpublished)

48. Mid-latitudes PETM: Lodo Tipple (unpublished)

49. Paleogeography

51. C-3 Biosynthetic pathway

52. C-4 Biosynthetic pathway

53. Modern mean annual poleward flux

54. Changes in northward polar flux with doubling of CO2 – IPCC AR-4 scenario Held & Soden, 2006

55. Proxies  TEX-86  Derived from marine pico plankton Crenarchaeota  Vary membrane fluidity and composition depending on the temperature  Has recently been applied to analyze paleo-SST

57. Changes in GWML

58. Theoretical Model  Warming results in increased lower tropospheric water vapor  Scales according to the Clausius-Clayperon relationship  In the extra-tropics, the important components of the hydrological cycle that affect isotopic signals are horizontal poleward flow of moisture and changes in precipitation and evaporation  Simple models have been developed by scaling with the Clausius-Clayperon relation

59. Energy Use Phase

60. Energy generation Phase

61. FATTY ACID BIOSYNTHESIS PYRUVATE ACETYL CO-A MALONYL CO-A ACETOACETYL-ACP BUTYRYL-ACP 6 × MALONYL CO-A PALMITATE (16:0 FATTY ACID) C O2 NAD PH H2 O CO2 ACETYL CO-A

62. ISOPRENOID BIOSYNTHESIS 2×ACETYL CO-A ACETOACETYL CO-A 3-HYDROXY-3-METHYL GLUTARATE MEVALONATE DIPHOSPHATE ISOPENTENYL DIPHOSPHATE MVA- PATHWA Y 2NADPH - CO 2 PYRUVATE NON-MVA-PATHWAY GLYCERAL- DEHYDE-3P DEOXY- XYLULOSE-P METHYL ERYTHROSE-P METHYL ERYTHRITOL-P ISOPENTENYL DIPHOSPHATE ACETYL CO-A - CO 2 2NADPH NADPH H2 O