According to the original experimental design, sodium-benzoate served as a positive control. However, it was later decided that oxygen consumption curves obtained with this substrate are also to be evaluated. We found it interesting to compare temperature response of these two carbon sources as one of them (crude oil) is characterized by low solubility and decreasing bioavailability at lower temperatures, while the other (sodium-benzoate) is characterized by high water solubility and equal bioavailability at all the tested temperatures.