Millions of years ago, when life emerged from the waves it was stromatalites and thrombolites that made it possible. They breathed oxygen into the atmosphere and life eventually moved onto the land once water had begun to fall from the heavens, nourishing the earth. 600 million years ago the ancestors of thrombolites and stromatolites produced the oxygen needed for life on land to exist and their ancient colonies can be found today in only a few rare places around the world.
They look like rocks but are really ancient forms of microbial communities that produce energy from sunlight. These ancient forms of life are found in specialized environments around the world. They require water to survive. Stromatalites need saline water and thrombolites require a greater measure of fresh water.