In April 2007, it was suggested that early archaea may have used retinal, a purple pigment, instead of chlorophyll, to extract energy from the sun. If so, large areas of the ocean and shoreline would have been colored purple; this is called the Purple Earth hypothesis.
In April 2007 it was suggested that early archaea may have used retinal a purple pigment instead of chlorophyll to extract energy from the sun If so large areas of the ocean and shoreline would have been colored purple; this is called the Purple Earth hypothesis