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Hamburg - We all started out as diamonds in the rough - literally - according to German scientists who say crystalline interfacial water layers played a fundamental role in biology and evolution on planet Earth. These primordial pools of microscopic hydrogenated diamonds in the rough were the original soup from which all life sprang billions of years ago, say the scientists from the Institute of Micro and Nanomaterials at Ulm University in Germany.
When primitive molecules landed on the surface of these hydrogenated diamonds in the atmosphere of early Earth, the resulting reaction was sufficient to spawn the first complex organic molecules that eventually gave rise to life, the German scientists say. The diamonds, densely compressed carbon molecules, provided the structure needed to support organic molecules.
"The capacity of interfacial water layers to impose order was exposed in the process of formation of supercubane carbon nanocrystals," the Ulm scientists write in the current issue of the American Chemical Society's journal Crystal Growth & Design.
"It is important that the order imposed to molecules landing on hydrogenated diamond is more durable and superior to that realizable on any other origin of life platform, for instance, graphite. Hydrogenated diamond advances to the best of all possible origin of life.".
In lab experiments aimed to confirm work done more than three decades ago by other European researchers, German scientists Andrei Sommer, Dan Zhu, and Hans-Joerg Fecht at the University of Ulm, found that when treated with hydrogen, natural diamonds formed crystalline layers of water on the surface.
The German scientists noted that diamonds are crystallized forms of carbon that predate the oldest known life on the planet. Water is essential for life as we know it. All that was needed was an electrical spark, say, from a bolt of lightning.
"Origin-of-life models starting with a primordial soup work from two assumptions, which do not exclude each other: chemistry, which could trigger the self-assembly of abiotic organic compounds, and transfer of order from preexistent orderings," they wrote.
"Clearly, both organization processes must occur in a bio-relevant environment, that is, a wet milieu, and both are energy-consuming. Interestingly, a hostile planetary environment such as the primitive Earth, subject to rapid changes, including but not limited to volcanic and hydrothermal activity, acidic atmosphere, and virtually planet-sterilizing meteorite impacts, favours precisely the conditions necessary for the formation of first ordered structures, regarded as possible starting points of biological evolution.
"They concluded that natural diamonds are even more conducive to this life-spawning process than are synthetic diamonds.
"In our study the conductivity on natural diamond was better by a factor of 10 than that on synthetic diamond," they wrote. "We conclude that current ideas of surface-conducting diamond should be expanded to include the crystalline water layer.
"But the German scientists said their findings do not rule out the possibility that the first organic molecules arrived on Earth from outer space. This is the "panspermia" theory which claims that meteors plummeted to Earth from other places in the galaxy where life had already taken root.
"The emergence of bio-organic molecules under primitive Earth conditions is one of the major unsolved origin of life questions," the Ulm researchers said. "The principal problem is to identify physical and chemical conditions that are favourable for the formation of life precursor structures. Panspermia tries to circumvent the problem by assuming that primitive life forms, such as bacteria, have arrived on Earth from space, as star dust or via comets.
"Either way, of course, the evolution of life on Earth is something special. According to one theory, we are all stardust. According to the other theory, we are all diamonds.
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