design: Peat cores were collected from below the water level at 20-30 cm from peat surface. Peat was used in a stable isotope probing experiment with 13C-cellobiose under anoxic conditions. RNA was extracted using a phenol-chloroform method and separated into heavy (13C) and light (12C) fractions with isopycnic centrifugation in a cesium trifluoroacetate. After reverse transcription, 16S rRNA genes were amplified with bacterial primers 341F and 804R (Herrleman et al. 2011).