The Kitchener (Waterloo Region)

The Record (Waterloo Region)
Grand river life, Saturday, April 23, 2005, p. G1

How life began; Hydrogen is the missing link, UW professor's research finds

BARBARA AGGERHOLM
FOR GRAND RIVER LIFE

In the murky water world that was Earth billions of years ago, life could have sprung up almost anywhere. Not just in the warm fissures in the ocean floor or fresh-water hot springs, but virtually anywhere.

According to surprising new research from a professor at the University of Waterloo and three colleagues in the United States, Earth's early atmosphere was rich in hydrogen.

With up to 40 per cent hydrogen in the atmosphere, it was a friendly environment for the birth of very basic molecules, those "prebiotic" organic compounds that led to "the little creatures that we can actually see in geological records," said Hans De Sterck, of the department of applied mathematics at the University of Waterloo.

"We were surprised, but then we got very excited because of the significance of that," De Sterck said in an interview.

"There are experiments that show if you have enough hydrogen, then you can form these prebiotic molecules. And that could be like a link, like the chain of events that led to the formation of life, and this was like a missing link."

The finding is causing scientists to re-think what they have believed for the last 25 years about the origin of life. It's bound to spark discussion, even controversy, once the results are published in Science magazine May 13. The study appeared in Science Express, the magazine's online edition, earlier this month.

The research is the collaborative work of four scientists: De Sterck, whose area is mathematical equations, another who specializes in atmospheres, one who knows early Earth, and a graduate student who put it all together.

The study disproves the view that Earth's atmosphere was rich in carbon dioxide and poor in hydrogen, said Owen Toon, an atmospheric physicist at the University of Colorado at Boulder who teamed up with De Sterck and University of Colorado colleagues Feng Tian and Alexander Pavlov.

It was thought that in early times, hydrogen was escaping at a high rate from the top of the atmosphere, said De Sterck, 36. "That turned out to be wrong."

But that earlier conclusion had scientists looking for clues to the origin of life in exotic places, like hydrothermal vents in the sea, hot springs and organic materials that came from meteorites or space dust.

Using mathematics and a single computer work station, De Sterck found that the hydrogen escape from the top of Earth's atmosphere was 100 times slower than previously believed. Hydrogen was also being vented by Earth's volcanoes several billion years ago.

Add a photochemical reaction or an electrical discharge like lightning, and you've got a recipe for life.

The existence of so much hydrogen opens up the possibility of life beginning "anywhere in the world ocean," De Sterck said. And it allows for the production of more complicated molecules, like amino acids, which are considered to be the building blocks of life.

"An early Earth's atmosphere with high hydrogen concentration has important consequences for the origin and evolution of life," the scientists' paper says

De Sterck, who came to Waterloo from the University of Colorado at Boulder in August, credits computational mathematics for the "breakthrough result."

Computational mathematics, the subject of a new UW program, exploits "the increasing power of computers for solving industrial-size mathematical problems," the university says.

De Sterck built a mathematical model that gave "the density and the pressure and the velocity of the (hydrogen) gas as a function of the radial distance from the centre of Earth."

Equations that describe how gas flows are basically the same as those used to describe the flow of air around an airplane, or aerodynamics.

At Boulder, fellow professors asked De Sterck to look at hydrogen on early Earth.

"I was pretty confident that I knew how to solve this type of equation, but we didn't know what kind of numbers would come out of it," De Sterck said.

"We didn't know that the concentration of hydrogen would be as high as we found. That was really a surprise for us as well."

This summer, De Sterck and two undergraduate students will look at two- and three-dimensional models for even better hydrogen estimates.

But they'll need more than a single work station. The complicated work will require parallel computers, or one computer with many processors.

De Sterck might also take advantage of the high-performance computer project known as SHARCNET, or Shared Hierarchical Academic Research Computing Network, which joins computers from more than 10 Ontario universities and colleges.

Meanwhile, he is excited about the possibilities that computational mathematics offer in answering complex questions. Using mathematics and computers, he has looked at the atmosphere of an extrasolar planet -- a planet which orbits a star other than the sun. He can simulate solar flare eruptions from the sun, and he can examine how sediment settles on the bottom of a river.

"If you know the techniques, you can apply them in many fields," De Sterck said.

baggerholm@therecord.com