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WHAT IT MEANS TO BE AN ASTROBIOLOGIST
Laurie BargeCaltech Postdoctoral Scholar
Jet Propulsion Laboratory / NASA Astrobiology Institute (Icy Worlds)
Astrobiology: fundamental questions
How does life begin and evolve?
Does life exist elsewhere in the universe?
What is the future of life on Earth and beyond?
• Navajo Sandstone, UT, USA• Analog for “blueberries” at Meridiani Planum, Mars – self-organizing precipitates
formed in an aqueous environment
Utah
Mars
Chan et al. 2007, Geofluids
Barge et al. 2011, Geofluids
Liesegang bands form in the presence of organic impurities (Barge et al. 2010, Chem. Phys. Lett.)
Prebiotic Earth and Early Mars
Credit: Daniel Smith
Higher geothermal gradientsCO2-rich atmosphereNo atmospheric O2
No landOceans contained dissolved metals (Fe, Ni)
Credit: Minik Rosing
Emergence of life at alkaline hydrothermal vents
Russell and Hall 2006; GSA Memoir 198, 1-32.
Kelley, D. S. et al; Nature 412, 145-149 (12 July 2001)
Emergence of life at alkaline hydrothermal vents
Emergence of life at alkaline hydrothermal vents
Photo credit: Kirt Robinson, Shawn McGlynn
Hadean ocean:CO2, Fe+2, PO4
3-
pH ~ 5
Hydrothermal fluid:HS-, H2, pH ~ 11
pH gradient
Emergence of life at alkaline hydrothermal vents
Hydrothermal vents offer natural energy sources for emerging life
• pH gradient
• Ion gradients
• Thermal gradients • Electrical potential
• Catalytic minerals to drive organic chemistry
0 0.5 1 1.5 2 2.5 3 3.5-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Time (min)
V
Potential of membrane formed with Fe(II) and sulfide
Laboratory studies of emerging metabolism at hydrothermal vents
• Electrochemical measurements of iron sulfide membranes • (Generation of membrane potential as the hydrothermal mound forms – an energy source
for proto-metabolism)
Credit: Ivria Doloboff
Laboratory studies of emerging metabolism at hydrothermal vents
• Simulating formation of pyrophosphate (PPi), a necessary prebiotic energy storage molecule (similar to ATP)
Milner-White and Russell 2010, J. Cosmol.,10, 3217-3229.
31P NMR spectroscopy
Pyrophosphateforms in membrane
experiments
Iron sulfide stabilizes pyrophosphate in hydrothermal systems
NASA/Nordic Astrobiology Summer school, IcelandAstrobiology Graduate Conference, Tällberg, Sweden
São Paulo Advanced School of Astrobiology
Astrobiology Graduate Conference, SeattleInternational Summer School, Santander, Spain“Origins: From the Big Bang to Life”
U of Hawaii Astrobiology Winter School:“Water on Earth and in Space”
Winter School, U of Arizona:
“Habitable Planets: Common or Rare?”
Petrophysics Internship, Marathon Oil Company
NASA Academy
What does it mean to be an astrobiologist?
Work between disciplines to answer fundamental questions How does life begin and evolve? Does life exist elsewhere? What is the future of life?
What does it mean to be an astrobiologist?
Work between disciplines to answer fundamental questions How does life begin and evolve? Does life exist elsewhere? What is the future of life?
Collaboration - combine skills with other scientists to approach astrobiology questions in new ways
Creativity – try new things, learn new skills and generate new research ideas
Z , Msd.Z , Calc.
unknown.txtModel : R(CR) Wgt : Modulus
Z ' (ohm)10,0008,0006,0004,0002,0000
- Z ''
(oh
m)
5,500
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
05.63k
2k1.34k
711562
376298
212189
133126
100 94.4
79.5 75.1
63.2 59.6
53 50.1
44.7 42.2
39.8 37.7
35.6 33.5
Iter #: 4Chsq: 3.27E-01
# of pars with rel. std. errors>10%: 1 / 3>100%: 0 / 3
Acknowledgements
Isik Kanik Michael Russell Ivria Doloboff Laura Zwicker Lauren White Richard Kidd David VanderVelde / Caltech Liquid
NMR Facility JPL Education Office (SIRI, JVSRP,
USRP Intern programs)
