FIG 4.

Isotopic incorporation of ¹³C into DNA from [¹³C]methane by aerosolized methanotrophic enrichment cultures. Each graph shows the average amounts of pmoA copies determined from technical replicates of a fraction with a specific buoyant density. The pmoA copy number was normalized to the highest copy number of the collected fractions for a sample (left y axis). Amplicons from qPCR of experiments 2 and 4 were sequenced (right y axis), and methanotrophs were identified. (A) Experiment 5; (B) experiment 2; (C) experiment 7; (D) experiment 4.