Fig. S1. Rarefaction curves for pyrosequencing data.

A. At an OTU definition of 97% similarity.

B. At an OTU definition of 95% similarity.

Fig. S2. Unique OTUs for known FeOB and FeRB genera, shown as proportions of the total unique OTUs for the genera shown.

Fig. S3. Tagged pyrosequencing data – comparison of proportions of phylum and class level classifications of raw read to unique OTU data.

Table S1. Comparison of alpha diversity indices of bacterial communities in iron mat samples from the Sheepscot River.

Table S2. FISH results. Note samples from 2010 are reported at ± only, due to preservation problems.

Table S3. This Table details modifications made to the trainset 6 RDP improvements. Modified RDP classifier trainset 6 (JMM version 1.5).

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