In our recently published article Klueglein and Kappler (2013), we identified an error in the calculation of the nitrate concentrations. Therefore, Fig. 1B has to be replaced by the following figure:
In contrast to our previously published data where nitrate stayed constant between days 2 and 4 and nitrite accumulated, we now show that nitrate is consumed completely in parallel to nitrite formation, and therefore, there is no discrepancy between nitrate reduction and nitrite accumulation as we had stated on pages 187 and 188. All conclusions of the paper are still valid. We apologize for any confusion caused.