The oldest color seen in the geological record was produced by ancient organisms that once lived in the ocean. An international team of scientists found it under the Sahar desert. The color is a bright pink, and it is considered to be nearly 1.1 billion years old.
The leader of the study is Dr. Gueneli, from the Australian National University Research School of Earth Sciences. She discovered the pigment as she was working on her Ph.D. studies.
“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. The fossils range from blood red to deep purple in their concentrated form, and bright pink when diluted,” she explained.
To analyze the molecules and organisms inside the rocks, researchers had to crush the billion-year-old rocks and turn them into powder. The analysis confirmed that at the base of the food chain in the oceans, cyanobacteria were leading, said Dr. Gueneli:
“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.”
Filling a Gap in the Fossil Record
These pigments, being the remains of early microscopic organisms help scientists fill the gap in the fossil record, as not much is known about the Earth’s microorganisms between the period of 1.8 billion and 800 million years. There is no clear evidence of how larger animals began to evolve 600 million years ago.
The associate professor from the Australian National University and senior lead researcher Jochen Brocks explains that as soon as algae started to spread, cyanobacterial oceans vanished because they weren’t a rich food source for larger organisms. As algae spread, it led to the evolution of ecosystems that would later sustain animals and humans:
“Algae, although still microscopic, are a thousand times larger in volume than cyanobacteria, and are 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.”
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