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Constraining Hydrological Cycle Characteristics of Early Eocene Hyperthermals   . Srinath Krishnan. Reasons for study. Rainfall has direct impact on human society Impact of anthropogenic activity on rainfall patterns is not well understood

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constraining hydrological cycle characteristics of early eocene hyperthermals

Constraining Hydrological Cycle Characteristics of Early Eocene Hyperthermals   

Srinath Krishnan

reasons for study
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
reasons for study1
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
reasons for study2
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
reasons for study3
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
early eocene hyperthermals
Early Eocene Hyperthermals

Paleocene-Eocene Thermal Maximum

  • ~3-50C 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)

early eocene hyperthermals1
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 CO2
    • PETM: ~750 – 26,000 ppm of CO2
      • ~1,500 – 55,000 Gt C in the atmosphere
      • ~3,900 – 57,000 Gt C released in the oceans
  • Modern atmospheric CO2 concentration: ~360 ppm
  • Modern Conventional fossil fuel reserves: ~5,000 Gt C
early eocene hyperthermals2
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 CO2
    • PETM: ~750 – 26,000 ppm of CO2
      • ~1,500 – 55,000 Gt C in the atmosphere
      • ~3,900 – 57,000 Gt C released in the oceans
  • Modern atmospheric CO2 concentration: ~360 ppm
  • Modern Conventional fossil fuel reserves: ~5,000 Gt C
slide9
GOAL
  • Use early Eocene hyperthermals as analogues to study changes in the hydrological cycle during extreme warming events
schematic of a water cycle
Schematic of a Water Cycle

Adapted from NASA Goddard Flight Center

expected changes with warming
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

variations in precipitation with warming
Variations in Precipitation with warming

2.80c in 2100

Increased

Evaporation

Held and Soden (2006)

variations in precipitation with warming1
Variations in Precipitation with warming

2.80c in 2100

Increased Precipitation

Held and Soden (2006)

modern annual precipitation
Modern annual precipitation

http://www.waterisotopes.org

rayleigh distillation
Rayleigh Distillation

Clark and Fritz, 1997

rayleigh distillation1
Rayleigh Distillation

Increased depletion with progressive rainout events

Clark and Fritz, 1997

hypotheses
Hypotheses
  • There is a systematic change in moisture transport to the higher latitudes during warming events
    • Are there similar changes in δD 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?
proxies
Proxies
  • n-alkanes: Single chain hydrocarbon with long chain lengths (n-C23-35) 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
proxies1
Proxies
  • n-alkanes: Single chain hydrocarbon with long chain lengths (n-C23-35) 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
n alkanes and precipitation
n-alkanes and precipitation

Deuterium

n-alkanes

Adapted from Sachse et al., 2006)

biomarker transport
Biomarker transport

Continent

Oceans

Aerosols

(with waxes)

Wind

Terrestrial Plants

Rivers

Adapted from Eglinton and Eglinton, 2008

methods
Methods

Samples

Crushing and Extraction

Total Lipid Extract

Compound Separation

n-alkane and biomarker fractions

Clean-up Procedures

Gas Chromatogram

Analyses

Compound Detection & Identification

Compound-specific Isotope

Ratio Mass Spectrometer

Compound-specific Deuterium & Carbon isotope compositions

Analytical Uncertainty: ±5‰

arctic paleocene eocene thermal maximum
Arctic Paleocene-Eocene Thermal Maximum

~55.6 Ma

Duration: ~150-200 kyrs

Modified from Pagani et al., 2006

arctic eocene thermal maximum 2
Arctic Eocene Thermal Maximum-2

~54 Ma

Duration: ~75-100 kyrs

This work

preliminary conclusions
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
preliminary conclusions1
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
hypotheses1
Hypotheses
  • There is a systematic change in moisture transport to the higher latitudes during hyperthermal events
    • Are there similar changes in δD during the two hyperthermals at the higher latitudes?
    • Preliminary Conclusion: Enrichments in δD 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

hypotheses2
Hypotheses
  • There is a systematic change in moisture transport to the higher latitudes during hyperthermal events
    • Are there similar changes in δD 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?
summary of changes during petm
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
summary of changes during petm1
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
summary of changes during petm2
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
hypotheses3
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
hypotheses4
Hypotheses
  • There is a systematic change in moisture transport to the higher latitudes during hyperthermal events
    • Are there similar changes in δD 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?
future work eocene modeling
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 CO2 concentrations
    • Background Eocene
thank you
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

proxies2
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
theoretical model
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
slide61
FATTY ACID BIOSYNTHESIS

PYRUVATE

ACETOACETYL-ACP

NADPH

CO2

H2O

ACETYL CO-A

BUTYRYL-ACP

ACETYL CO-A

6 × MALONYL CO-A

CO2

MALONYL CO-A

CO2

PALMITATE

(16:0 FATTY ACID)

slide62
ISOPRENOIDBIOSYNTHESIS

NON-MVA-PATHWAY

MVA-PATHWAY

2×ACETYL CO-A

PYRUVATE

GLYCERAL-DEHYDE-3P

ACETOACETYL CO-A

ACETYL CO-A

-CO2

DEOXY-XYLULOSE-P

3-HYDROXY-3-METHYL GLUTARATE

METHYL ERYTHROSE-P

2NADPH

NADPH

METHYL ERYTHRITOL-P

MEVALONATE DIPHOSPHATE

H2O

-CO2

ISOPENTENYL DIPHOSPHATE

ISOPENTENYL DIPHOSPHATE

2NADPH

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