Metazoans, Arch Enemy of Cyanobacteria
  •  Metazoans foil the development of stromatolites during the Phanerozoic. 
  • unless stromatolite formed a hard, lithified structure while it was growing, or lived in an environment where Metazoans could not, burrowing and grazing animals would destroy the microbial mats forming stromatolites 
  • this would prevent the mat from becoming established or destroy it soon after it had been accumulated