[meteorite-list] How Did Life Arise? Fuel Cells May Have Answers

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 13 Mar 2014 14:58:57 -0700 (PDT)
Message-ID: <201403132158.s2DLwvEi024659_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?release=2014-079

How Did Life Arise? Fuel Cells May Have Answers
Jet Propulsion Laboratory
March 13, 2014

How life arose from the toxic and inhospitable environment of our planet
billions of years ago remains a deep mystery. Researchers have simulated
the conditions of an early Earth in test tubes, even fashioning some of
life's basic ingredients. But how those ingredients assembled into
living cells, and how life was first able to generate energy, remain
unknown.

A new study led by Laurie Barge of NASA's Jet Propulsion Laboratory in
Pasadena, Calif., demonstrates a unique way to study the origins of
life: fuel cells.

Fuel cells are found in specialized cars, planes and NASA's human
spacecraft, such as the now-retired space shuttle. The cells are similar
to batteries in generating electricity and power, but they require fuel,
such as hydrogen gas. In the new study, the fuel cells are not used for
power, but for testing chemical reactions thought to have led to the
development of life.

"Something about Earth led to life, and we think one important factor
was that the planet provides electrical energy at the seafloor," said
Barge. "This energy could have kick-started life -- and could have
sustained life after it arose. Now, we have a way of testing different
materials and environments that could have helped life arise not just on
Earth, but possibly on Mars, Europa and other places in the solar system."

Barge is a member of the JPL Icy Worlds team of the NASA Astrobiology
Institute, based at NASA's Ames Research Center in Moffett Field, Calif.
The team's paper appears online March 13 in the journal Astrobiology.

One of the basic functions of life as we know it is the ability to store
and use energy. In cells, this is a form of metabolism and involves the
transfer of electrons from one molecule to another. The process is at
work in our own bodies, giving us energy.

Fuel cells are similar to biological cells in that electrons are also
transferred to and from molecules. In both cases, this results in
electricity and power. In order for a fuel cell to work, it needs fuel,
such as hydrogen gas, along with electrodes and catalysts, which help
transfer the electrons. Electrons are transferred from an electron donor
(such as hydrogen) to an electron acceptor (such as oxygen), resulting
in current. In your cells, metal-containing enzymes -- your biological
catalysts -- transfer electrons and generate energy for life.

In the team's experiments, the fuel cell electrodes and catalysts are
made of primitive geological material thought to have existed on early
Earth. If this material can help transfer electrons, the researchers
will observe an electrical current. By testing different types of
materials, these fuel cell experiments allow the scientists to narrow in
on the chemistry that might have taken place when life first arose on
Earth.

"What we are proposing here is to simulate energetic processes, which
could bridge the gap between the geological processes of the early Earth
and the emergence of biological life on this planet," said Terry Kee
from the University of Leeds, England, one of the co-authors of the
research paper.

"We're going back in time to test specific minerals such as those
containing iron and nickel, which would have been common on the early
Earth and could have led to biological metabolism," said Barge.

The researchers also tested material from little lab-grown "chimneys,"
simulating the huge structures that grow from the hydrothermal vents
that line ocean floors. These "chemical gardens" are possible locations
for pre-life chemical reactions.

When the team used material from the lab-grown chimneys in the fuel
cells, electrical currents were detected. Barge said that this is a
preliminary test, showing that the hydrothermal chimneys formed on early
Earth can transfer electrons - and therefore, may drive some of the
first energetic reactions leading to metabolism.

The experiments also showed that the fuel cells can be used to test
other materials from our ancient Earth. And if life did arise on other
planets, those conditions can be tested, too.

"We can just swap in an ocean and minerals that might have existed on
early Mars," said Barge. "Since fuel cells are modular -- meaning, you
can easily replace pieces with other pieces -- we can use these
techniques to investigate any planet's potential to kick-start life."

At JPL, fuel cells are not only for the study of life, but are also
being developed for long-term human space travel. Hydrogen fuel cells
can produce water, which can be recycled and used as fuel again.
Researchers are experimenting with these advanced regenerative fuel
cells, which are highly efficient and offer long-lasting power.

Thomas I. Valdez, who is developing regenerative fuel cells at JPL,
said, "I think it is great that we can transition techniques used to
study reactions in fuel cells to areas such as astrobiology."

Other authors of the paper are: Ivria J. Doloboff, Chung-Kuang Lin,
Richard D. Kidd and Isik Kanik of the JPL Icy Worlds team; Joshua M. P.
Hampton of the University of Leeds School of Chemistry, Mohammed Ismail
and Mohamed Pourkashanian at the University of Leeds Centre for Fluid
Dynamics; John Zeytounian of the University of Southern California, Los
Angeles; and Marc M. Baum and John A. Moss of the Oak Crest Institute of
Science, Pasadena.

JPL is managed by the California Institute of Technology in Pasadena for
NASA.

For more information about the NASA Astrobiology Institute, visit:
http://astrobiology.nasa.gov/nai

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin at jpl.nasa.gov

2014-079
Received on Thu 13 Mar 2014 05:58:57 PM PDT