World's oldest colour may help shed light on mystery of life on earth

Canberra - By Subel Bhandari, - Scientists believe they have discovered the oldest colours in the world - and they are bright pink - and hope the discovery of the biological pigment could shed light on the mystery of life on earth.

Researchers discovered the pigments, produced by ancient microscopic cyanobacteria, after extracting 1.1 billion-year-old rocks found in marine black shale deep beneath the Sahara desert in Mauritania, according to the study published in science journal PNAS.
The scientists said the pigments were the "oldest biological colour" and was more than half a billion years older than previous pigment discoveries. 
"The bright pink pigments are the molecular fossils of chlorophyll that were produced by ancient photosynthetic organisms inhabiting an ancient ocean that has long since vanished," said Nur Gueneli, a scientist from Australian National University who found the molecules as part of her PhD studies.
The researchers crushed the billion-year-old rocks to powder, before extracting and analysing molecules of ancient organisms from them. 
The fossils range from blood red to deep purple in their concentrated form and bright pink when diluted, the scientists said.
"The precise analysis of the ancient pigments confirmed that tiny cyanobacteria dominated the base of the food chain in the oceans a billion years ago, which helps to explain why animals did not exist at the time," Gueneli said.
The rocks had been sent to the university from an oil company looking for oil in the Sahara desert about 10 years ago. 
"Everything has a colour and colours go back to the beginning of time. The more correct term to describe the finding would be the oldest organic biological colour," said Jochen Brocks, a German scientist at ANU and senior lead researcher of the study.
It means what the researchers found is a molecule with a biological pigment more than a billion years old that is still preserved today.
He said it is akin to finding fossilised dinosaur skin after 100 million years with the colour of the animal still intact.
"[I have] Just pure curiosity and amazement that such pigment could survive for such a long time," Brocks told dpa. 
He also said the isotopic structure of the molecule could help to solve the puzzle about large, complex life appearing so late in the earth’s 4.6 billion-years-old history. 
The emergence of large, active organisms was likely to have been restrained by a limited supply of larger food particles such as algae, Brocks added.
In size, cyanobacteria measure one-millionth of a metre, he said, while the smallest microscopic algae are "a thousand times larger in volume than cyanobacteria and a much richer food source."
"The cyanobacterial oceans started to vanish about 650 million years ago when algae began to rapidly spread to provide the burst of energy needed for the evolution of complex ecosystems, where large animals, including humans, could thrive on Earth," Brocks said.
It means the lack of oxygen may not be the reason why the larger animals did not exist earlier; instead, it could be because there was no food for complex life to evolve. 

Tuesday, July 10th 2018
By Subel Bhandari,

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