An international team of scientists discovered the oldest color in the geological record in rocks beneath the Sahara desert: the bright pink pigment aged 1.1 billion years old.
Nur Gueneli, from The Australian National University, said the ancient pigment was extracted from marine black shales of the Taoudeni Basin in Mauritania, West Africa. The bright pink color is believed to be more than half a billion years older than other prehistoric pigments.
The Ancient Bright Pink
The fossils from where the archaic bright pink was discovered appeared to have a variety of colors. The fossils were originally green and then became blood red to deep purple in their concentrated form. When the fossils were diluted, their final form revealed the bright pink pigment in an oil form.
Upon analysis, Gueneli said the ancient pigment resulted from molecular fossils of chlorophyll that were processed by ancient photosynthetic organisms that once ruled the oceans. To give context, the molecular fossils the team found were 10 times older than a Tyrannosaurus rex would have been.
The discovery of the ancient bright pink pigment could offer new insights into why it took 4 billion years before the first animal life evolved on Earth.
For the study, published in the Proceedings of the National Academy of Sciences on July 9, Gueneli and her team pulverized the billion-year-old rocks they found beneath the Sahara desert. The team then extracted and analyzed the rocks' powdered form.
Their analysis revealed that the rocks contained molecules of ancient organisms known as the cyanobacteria. Gueneli explained these microorganisms once dominated the base of the food chain in the oceans a billion years ago. This meant that all organisms at the time were feeding on the cyanobacteria.
The size of the cyanobacteria, however, was so minute that they were not sufficient for larger organisms such as animals.
Indeed, animal life appeared on Earth at a much later time.
The Earth, The Cyanobacteria, And The Algae
Earth is approximately 4 billion years old. More sophisticated life forms, however, began appearing 600 million years ago.
It was previously thought that the lack of oxygen may have prevented larger creatures to thrive shortly after life started on Earth. The discovery of the ancient bright pink, however, can change this narrative.
The emergence of bigger life forms may have been hampered by lack of larger food particles, according to Jochen Brocks, the senior lead researcher for the study. In comparison, the microscopic algae are a thousand times larger in volume than the cyanobacteria. In fact, the ancient oceans that were once dominated by the cyanobacterial started to disappear when algae became prevalent.
"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," explained Brocks.