Synechococcus (sinm-eck-owe-cock-us), this pair of matched micrographs shows bacteria, mostly Synechococcus and Chloroflexus) from a mat sample. The phase contrast shot to the left shows the bacteria, the image to the right shows autofluorescence. Only the sausage-shaped Synechococcus exhibits autofluorescence. Phase contrast and fluorescence. Material provided by Mike Ferris from Mushroom Spring, a thermal site in Yellowstone National Park, photograph by Mike Ferris and David Patterson.