OXIDATION AND ACIDIFICATION OF ANAEROBIC SEDIMENT-WATER SYSTEMS BY AUTOCLAVING

The effect of autoclaving on the acid/base and redox properties of ana erobic sediment slurries was determined to facilitate the interpretati on of autoclaved controls in studies of environmental reduction reacti ons. Autoclaving decreased electrode measurements of pH by 0.26 to 0.6 8 units and increased electrode measurements of Eh by 34 to 94 mV. To corroborate this effect, we added redox indicators to the slurries and observed that autoclaving caused a shift in color consistent with the change in electrode measurements. Further investigation demonstrated that the observed effects are a common characteristic of autoclaving a naerobic sediment and are not limited to very restricted sediment type s and are not artifacts of the way the experiments were performed.