Fig. 2

Schematic flow chart to characterize source-specific fecal contamination within an unknown environmental sample. (a) Determination of the bacterial profile of an environmental sample. (b) Selection of sequences in common with the classifier. (c) Comparison of the relative abundance of the selected sequences with the classifier. An unknown sample is considered contaminated by a source if the relative abundance for the majority of the selected sequences is similar to the one of the classifier