Colour of the ancient chlorophyll, which wasn't green like the modern one, rendered the planet with a pink glow, making it the Earth's oldest colour. Evident through a 1.1 billion-year-old pigment, it informs us about the evolution of life and also why the larger life forms were comparatively slow to evolve.
"Planet Earth is Blue will unequivocally be the ascribed colour to the hurting rock that we inhabit. And if one Mr David Bowie, English musician, was to be evoked, then perhaps, "There's nothing I can do".
Now, say the musician be wheeled back to a Prehistoric age, at least 1.1 billion years ago, and a microscopic Bowie maintained his idiosyncratic proclivity to rock music, he would have to rhyme with pink and not blue.
Prehistoric oceans where actually bathed in a rosy cast than the illuminating blue that we see today.
Again, Why So?
Our oceans are blue because they absorb those lights of the spectrum that are longer in wavelength. Because the colour blue has a shorter wavelength, it gets scattered out. Aeons ago, it was the bacteria that were the dominant life form, the base of all food chains. They populated the then Earth's oceans and the top crust. These bacteria were coloured by a chlorophyll pigment which ranged from bloody red to deep purple in its concentrated form. When this pigment would be diluted with water or the moisture content of the soil, they would turn to a pinkish hue.
Isn't Chlorophyll Green In Colour?
Indeed it is. The green colour of the chlorophyll pigment lends itself to the majority of the leaves. But, obviously, it wasn't always so. Ancient chlorophyll and corresponding photosynthesis eventually lost out to their modern versions which evolved to be more efficient in harnessing the sun's energy.
How Was It Found?
Paleobiogeochemist, Nur Gueneli, while inspecting a crushed shale rock – picked up from several hundred meters deep, a decade ago by a mining company, from the Taoudeni Basin, beneath the Sahara desert, in Mauritania, West Africa – during her doctorate program at Australian National University, under Jochen Brock, found those hallelujah pink pigment in the cyanobacterial fossils. Thought to be dependent on sunlight cyanobacterial lorded over the ecosystem more than 650 million years ago, predating even the algae, which has been established to be one of the earliest building blocks of the evolutionary life of larger animals.
Published in the journal, Proceedings of the National Academy of Sciences, the feat is quite remarkable, rare as it is. On its own, biological pigment undergoes decay over time and determination of ancient colour is virtually impossible. Regarding the specimen, it's being surmised that a bloom of cyanobacteria might have sunk quickly to the seafloor where lack of oxygen prevented their decay. Also once fossilized into a rock, the rock itself remained motionless and intact before being extracted.