Volcanoes ‘may have kick-started life on Earth’

March 22nd, 2011 - 1:35 pm ICT by ANI  

Washington, Mar 22 (ANI): Volcanoes might have played a crucial role in kick-starting life on Earth, according to new results from an old experiment that sat on the shelf for more than 50 years.

Chemists Harold Urey and Stanley Miller performed a landmark experiment in 1953 intended to mimic the primordial conditions that created the first amino acids, by exposing a mix of gases to a lightning-like electrical discharge.

Five years later, Miller performed another variation on this experiment - by adding hydrogen sulphide, a gas spewed out by volcanoes, to the mix.

He, however, never analysed the products of the hydrogen sulphide reaction.

Following Miller’s death in 2007, his former student Jeffrey Bada, a marine chemist at the Scripps Institution of Oceanography in California, inherited the contents of his lab and office and discovered the old samples, reports Fox News.

Using modern analytical techniques, Bada and his team reanalysed the products of the reaction, which were housed in small vials.

They found an abundance of promising molecules: 23 amino acids and four amines, another type of organic molecule.

The addition of hydrogen sulfide had also led to the creation of sulphur-containing amino acids, which are important to the chemistry of life. One of these, methionine, initiates the synthesis of proteins.

The results of the experiment - which exposed a mix of volcanic gases, including hydrogen sulphide, methane, ammonia and carbon dioxide gas to an electrical discharge - tell us that volcanic eruptions coinciding with lightning may have played a role in synthesizing large quantities and a variety of biologically crucial molecules on the primitive Earth, said co-author Eric Parker.

Bada said that the results of the 1958 experiment, however, show that adding hydrogen sulphide to the reaction enriches the mixture of organic molecules produced.

The 1958 reaction - which also incorporated carbon dioxide, a gas not included in the earlier experiment - created a mix more like that which geoscientists now believe made up the atmosphere of primordial Earth, said Parker.

Bada’s team compared the amino acids produced by the 1958 experiment with those contained in a type of carbon-rich meteorite, known as a carbonaceous chrondite.

These meteorites are believed to provide snapshots of the types of organic reactions that took place in the early solar system.

The researchers compared the amino acids produced by the hydrogen sulphide experiment with those contained by several carbonaceous chrondites.

Some matched well, while others did not, suggesting that hydrogen sulphide played a role in the synthesis of amino acids in some solar system environments but not in others, said Bada.

The study is published in the journal Proceedings of the National Academy of Sciences. (ANI)

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