what is a stromatolite
A stromatolite (literally, âlayered rockâ) is a solid structure created by single-celled microbes called cyanobacteria (blue-green algae). The cyanobacteria form colonies and trap sediment with their sticky surface coatings.The trapped sediment reacts to calcium carbonate in the water to form limestone. These limestone deposits build up very slowly â it can take a stromatolite 100 years to grow 5 cm.A 1 m-high stromatolite might be 2,000 years old!he cyanobacteria form colonies and trap sediment with their sticky surface coatings. The trapped sediment reacts to calcium carbonate in the water to form limestone. These limestone deposits build up very slowly â it can take a stromatolite 100 years to grow 5 cm. A 1 m-high stromatolite might be 2,000 years old!