Stromatolite-building communities include the oldest known fossils, dating back some 3.5 billion years when the environments of Earth were too hostile to support life as we know it today.We can presume that the microbial communities consisted of complex consortia of species with diverse metabolic needs, and that competition for resources and differing motility among them created the intricate structures we observe in these ancient fossils.
Microbial communities diversified through time, with eukaryotic organisms eventually joining the mix.
Excluding some exceedingly rare Precambrian fossils such as the Russian White Sea Ediacaran fauna, stromatolites and thare the only fossils encoding the first 7/8th of the history of life on earth.
Stromatolites are not only Earth's oldest of fossils, but are intriguing in that they are our singular visual portal (except for phylogenetic determination of conserved nucleic acid sequences and some subtle molecular fossils) into deep time on earth, the emergence of life, and the evolving of the beautiful forms of life of modern time.
A small piece of stromatolites encodes biological activity perhaps spanning thousands of years.
New stromatolite localities have continued to be discovered in various places such as the Bahamas, the Indian Ocean and Yellowstone National Park, to name but a few localities.