PMC

(a) Relative abundance of mRNA reads matching selected genomes from bacteria with relevant characteristic metabolisms: iron oxidation (red), methanotrophy (blue) and anaerobic iron respiration (green). (b) Relative abundance of pmoCAB matching transcripts coding for the three subunits of the methane monooxygenase. Error bars correspond to standard deviation from the replicates.

The rRNA reads from each triplicate are combined and average values shown. (a) Comparison of the five samples at the phylum level. (b) Comparison of the combined two surfaces (S1 and S2) and the subjacent depth (D1 and D2) samples at the phylum, class and order level. Error bars indicate the standard deviations among the replicates.

Ribosomal RNA reads covering the variable 16S rRNA gene regions V3, V4 and V5 (393–925 E. coli positions) were analyzed on 462 positions (56.600 sequences). (a) Rarefaction curves for all five samples with combined replicates. For illustration purposes the curves were shorted to 7.000 sequences sampled. (b) Rank abundance distribution of OTUs from Methylococcales, Burkholderiales and Nitrosomonadales. All five samples and replicates were combined. (c) OTU abundance ratio of Methylococcales, Burkholderiales and Nitrosomonadales. Parentheses: Number of sequences included. Error bars: standard deviation. P-value from Wilcoxon signed rank test for each OTU group comparing surface versus depth: Nitrosomonadales: p<10⁻⁵, Burkholderiales p<10⁻⁸, Methylococcales p<10⁻⁷.