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Shark Bay
RECORDS OF ANCIENT LIFE: For about 85% of the history of life on Earth, only microbes existed. The only large-scale evidence of their activities is preserved by stromatolites, ancient structural records of life on Earth which hold evidence both of the biology of the microbial mat communities that created them, and the nature of the environments in which they grew. They are rocky, dome-shaped structures formed in shallow water through the trapping of sedimentary grains by communities of microorganisms. When too much material becomes trapped in the mats and limits the amount of sunlight that can filter through, the organisms migrate up and form a new community on top of the old. Stromatolites are mostly found in lakes and marine lagoons where extreme conditions such as high saline levels prevent animals from grazing. One such location is the Hamelin Pool Marine Nature Reserve in Shark Bay, Western Australia, a UNESCO World Heritage Site where living specimens are preserved today. Image Credit: Mark Boyle
tags: shark-bay
