When researchers from the Australian National University began studying ancient rocks from a marine shale deposit beneath the Sahara Desert in Mauritania, they discovered evidence of something incredible: the world's oldest known “biological color,” a bright pink pigment produced by cyanobacteria, photosynthetic microorganisms that lived more than a billion years ago. Cyanobacteria occupied a place at the bottom of the food chain in the Earth's ancient, long-vanished oceans and were 1,000 times smaller than today's microscopic algae.
Back when the Earth was pink:
- The fossilized chlorophyll inside the bacteria was dark red and purple in its concentrated form. When diluted by water or soil, the scientists said, it would have given land and sea a pink hue.
- The ancient rocks were unearthed by an oil company drilling in the Sahara about a decade ago. They hit black, oily shale, which turned out to be 1.1 billion years old.
- The colors were discovered by Dr. Nur Gueneli, who was working on her PhD at the time. She said that the bright pink colors are more than 500 million years older than the next oldest known pigments.