Laurie Barge
Caltech 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
Liesegang bands form
in the presence of
organic impurities (Barge
et al. 2010, Chem. Phys. Lett.)
Barge et al. 2011, Geofluids
Prebiotic Earth and Early Mars
Credit: Minik Rosing
Higher geothermal gradients
CO2-rich atmosphere
No atmospheric O2
No land
Oceans contained dissolved metals (Fe, Ni)
Credit: Daniel Smith
Emergence of life at alkaline hydrothermal vents
Kelley, D. S. et al;
Nature 412, 145-149
(12 July 2001)
Russell and Hall 2006; GSA Memoir 198, 1-32.
Emergence of life at alkaline hydrothermal vents
Emergence of life at alkaline hydrothermal vents
Emergence of life at alkaline hydrothermal vents
Hadean ocean:
CO2, Fe+2, PO43pH ~ 5
Hydrothermal fluid:
HS-, H2, pH ~ 11
pH gradient
Photo credit: Kirt Robinson, Shawn McGlynn
Hydrothermal vents offer natural energy sources for emerging life
0.7
0.6
• pH gradient
0.5
• Ion gradients
0.3
• Thermal gradients
V
0.4
0.2
Potential of membrane formed with
Fe(II) and sulfide
0.1
0
-0.1 0
1
• Electrical potential
• Catalytic minerals to drive organic chemistry
2
Time (min)
3
4
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
Pyrophosphate
forms in membrane
experiments
Iron sulfide
stabilizes
pyrophosphate in
hydrothermal
systems
Astrobiology Graduate Conference, Seattle
Winter School, U of Arizona:
“Habitable Planets: Common or Rare?”
International Summer School, Santander, Spain
“Origins: From the Big Bang to Life”
NASA Academy
U of Hawaii Astrobiology Winter School:
“Water on Earth and in Space”
Petrophysics Internship, Marathon Oil Company
Astrobiology Graduate Conference, Tällberg, Sweden
NASA/Nordic Astrobiology Summer school, Iceland
São Paulo Advanced School of Astrobiology
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
unknown.txt
Model : R(CR) Wgt : Modulus
Z , Msd.
Z , Calc.
5,500
5,000
35.6
4,500
- Z '' (ohm)
4,000
37.7
42.2
53
3,500
33.5
39.8
44.7
50.1
Iter #: 4
Chsq: 3.27E-01
63.2
59.6
79.5
75.1
100
94.4
133
126
212
189
376
298
711
562
2k
1.34k
5.63k
3,000
2,500
2,000
1,500
1,000
500
# of pars with
rel. std. errors
>10%: 1 / 3
>100%: 0 / 3
0
0
2,000
4,000
6,000
Z ' (ohm)
8,000
10,000
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)