Stromatolites declined definitively; a modest recovery occurred only during the Cambrian-Ordovician transition. This decline is attributable to the appearance of the first grazing metazoans and fossa-forming organisms that biodisturbed the texture of the plates. In Italy, they are quite common in the Lower Cambrian formations of Sardinia and the Triassic formations of the Alps and Apennines; they have never been recorded in the Precambrian period. Currently, stromatolites form in marine environments of the intertidal zone at normal or high salinity, but also in subtidal environments in some areas of Australia, Florida, the Bahamas, and the Persian Gulf.
