The Recent: Living Stromatolites

Living stomatolites at Monkey Mia, Shark Bay, Aus (
With the discovery of modern stromatolites in Shark Bay, Australia, and the Bahamas much was learned about the mystery of stromatolites.  By using the theory "the present is the key to the past" researchers derived that ancient stromatolites were very similar to the living ones.  These few places  with living marine stromatolites, or "living fossils" have generally been found to be hypersaline
and many other organisms such as grazers and seagrasses cannot live there. Generally these areas are broad and shallow, with water depth at a maximum of 20m.  The climates are temperate to semiarid.  Stromatolites have been found in the subtidal, intertidal and supratidal zones.

Very small stromatolites growing at the present day on an old steel drum that has sunk into a soft sediment with hypersaline brines at Umm Said, Qatar. (
Hypersaline lagoon effectively "pickled" the remains of trees. The stumps and fallen logs were coated in cyanobacterial limestone in conditions similar to those of  Shark Bay, Western Australia. The mounds shown here cover two stumps and a fallen trunk. (