Power behind primordial soup discovered

Researchers at the University of Leeds may have solved a key puzzle about how objects from space could have kindled life on Earth.

While it is generally accepted that some important ingredients for life came from meteorites bombarding the early Earth, scientists have not been able to explain how that inanimate rock transformed into the building blocks of life.

This new study shows how a chemical, similar to one now found in all living cells and vital for generating the energy that makes something alive, could have been created when meteorites containing phosphorus minerals landed in hot, acidic pools of liquids around volcanoes, which were likely to have been common across the early Earth.

The mystery of how living organisms sprung out of lifeless rock has long puzzled scientists, but we think that the unusual phosphorus chemicals we found could be a precursor to the batteries that now power all life on Earth. But the fact that it developed simply, in conditions similar to the early Earth, suggests this could be the missing link between geology and biology, said Dr Terry Kee, from the University's School of Chemistry, who led the research.

All life on Earth is powered by a process called chemiosmosis, where the chemical adenosine triphosphate (ATP), the rechargeable chemical 'battery' for life, is both broken down and re-formed during respiration to release energy used to drive the reactions of life, or metabolism. The complex enzymes required for both the creation and break down of ATP are unlikely to have existed on the Earth during the period when life first developed. This led scientists to look for a more basic chemical with similar properties to ATP, but that does not require enzymes to transfer energy.

Phosphorus is the key element in ATP, and other fundamental building blocks of life like DNA, but the form it commonly takes on Earth, phosphorus (V), is largely insoluble in water and has a low chemical reactivity. The early Earth, however, was regularly bombarded by meteorites and interstellar dust rich in exotic minerals, including the far more reactive form of phosphorus, the iron-nickel-phosphorus mineral schreibersite.

The scientists simulated the impact of such a meteorite with the hot, volcanically-active, early Earth by placing samples of the Sikhote-Alin meteorite, an iron meteorite which fell in Siberia in 1947, in acid taken from the Hveradalur geothermal area in Iceland. The rock was left to react with the acidic fluid in test tubes incubated by the surrounding hot spring for four days, followed by a further 30 days at room temperature.