This is an electron micrograph taken using the UCMP Environmental Scanning Electron Microscope. It shows an extreme close-up of a bryozoan from Bahia de Animas, Baja California, Mexico. The calcareous shell of the bryozoan is perforated with a network of channels and tunnels, made by bacteria that bore into such shells. Such trace fossils have been found all through the last 600 million years of the fossil record, and add a new dimension to the study of the history of bacterial life.
Return to the fossil record of bacteria