Figure 1.

Degradation of bitumen in microcosms with sulfate as electron acceptor in microcosm 1 (black ■), 2 (red ●), 3 (green ▲), and 4 (blue ⧫) over 945 days of incubation. (1A) Degradation was measured by formation of carbon dioxide (solid lines) and depletion of sulfate (dashed lines). Error bars depict the standard deviation of triplicate analytical measurements but are barely visible because they are smaller than the symbol size. (1B) Microbial growth was assessed with light microscopy and a Thoma counting-chamber. Error bars depict the standard deviation of a minimum of six countings per sample.