Pumice, the rock used remove dry skin from feet, could have been responsible for the birth of life on Earth, scientists have claimed.By Richard Gray,
Science Correspondent
It is commonly known for its ability to remove dry skin from feet, but pumice stone may have had a far more important role in our lives than we realise.
Scientists claim the rock, which is produced as volcanic gases bubble through lava as it solidifies, may have been responsible for the birth of life on Earth more than 3.5 billion years ago.
In a surprising new theory for how life evolved our planet, palaeobiologists believe the tiny pores in the volcanic rock provided the perfect environment for the first living cells to develop.
Read moreThey say they have found evidence that the essential cocktail of chemicals that make up all organisms on Earth can accumulated inside the pumice pores while other chemicals commonly found there could have kick started biological reactions in the presence of ultraviolet light.
Pumice is also well known for its ability to float and massive rafts of the rock have washed up on shorelines around the world decades after major volcanic eruptions.
Professor Martin Brasier, a palaeobiologist at Oxford University who led the team behind the research, said: "This rock sat at the interface between the air and the sea, which is exactly where life would have thrived.
"It is a very light and very porous rock. It has the maximum surface area of any known rock and so it provides the reactive surface for the first complex organic molecules to form.
"It is also geologically durable and can sit on a shoreline where it has washed up for thousands of years being continually refloated and washed up again.
"This long period of time that would have been needed for chemicals to accumulate in one place has always been missing from other theories for how life first evolved.
"Lighting and foams simply did not last long enough to allow these chemicals to form into living cells."
Professor Brasier, who presented his findings at the European Geosciences Union last week and will publish a more detailed paper on his findings in the journal of Astrobiology later this year, has examined pumice that is around 3.5 billion years old from Western Australia and found that is contains key mineral deposits such as phosphate, which is a key ingredient in living cells.
The pores were also lined with catalysts such as titanium oxide, which is used by industrial chemists today to fix nitrogen from the atmosphere to create ammonium used in fertilisers.
Professor Brasier believes that oil films on the surface of the oceans would have got inside the rock and created oily vesicles that were the beginning of the first cells.
He said: "Titanium oxide was very common in these pumice pores in the presence of ultraviolet light, it can combine nitrogen from the atmosphere with hydrogen. This would have created the building blocks for the first amino acids that now make up the proteins found in all living things.
"As the pumice floated in the water, oily material at the surface would have coated part of the pumice and this would have been essential for forming the walls or membranes of what would have become living cells.
"Osmotic gradients would also have seen other important organic chemicals accumulate inside these vesicles. What we end up with is a substrate that provides all the conditions for the first living cells to form."
Professor Brasier and his colleagues now hope to carry out some laboratory experiments using pumice to test whether these conditions would have allowed life for form.
He added: "There is a lot of work to do, so I hope other groups also start to look at this seriously and use pumice."
© The Telegraph Group
London 2011
