Microsensor measurements of sulfate reduction and sulfide oxidation in compact microbial communities of aerobic biofilms

TY - JOUR

T1 - Microsensor measurements of sulfate reduction and sulfide oxidation in compact microbial communities of aerobic biofilms

AU - Kuhl, M.

AU - Jorgensen, B. B.

PY - 1992/1/1

Y1 - 1992/1/1

N2 - The microzonation of O2 respiration, H2S oxidation, and SO4 2- reduction in aerobic trickling-filter biofilms was studied by measuring concentration profiles at high spatial resolution (25 to 100 μm) with microsensors for O2, S2-, and pH. Specific reaction rates were calculated from measured concentration profiles by using a simple one-dimensional diffusion reaction model. The importance of electron acceptor and electron donor availability for the microzonation of respiratory processes and their reaction rates was investigated. Oxygen respiration was found in the upper 0.2 to 0.4 mm of the biofilm, whereas sulfate reduction occurred in deeper, anoxic parts of the biofilm. Sulfate reduction accounted for up to 50% of the total mineralization of organic carbon in the biofilms. All H2S produced from sulfate reduction was reoxidized by O2 in a narrow reaction zone, and no H2S escaped to the overlying water. Turnover times of H2S and O2 in the reaction zone were only a few seconds owing to rapid bacterial H2S oxidation. Anaerobic H2S oxidation with NO3 - could be induced by addition of nitrate to the medium. Total sulfate reduction rates increased when the availability of SO4 2- or organic substrate increased as a result of deepening of the sulfate reduction zone or an increase in the sulfate reduction intensity, respectively.

AB - The microzonation of O2 respiration, H2S oxidation, and SO4 2- reduction in aerobic trickling-filter biofilms was studied by measuring concentration profiles at high spatial resolution (25 to 100 μm) with microsensors for O2, S2-, and pH. Specific reaction rates were calculated from measured concentration profiles by using a simple one-dimensional diffusion reaction model. The importance of electron acceptor and electron donor availability for the microzonation of respiratory processes and their reaction rates was investigated. Oxygen respiration was found in the upper 0.2 to 0.4 mm of the biofilm, whereas sulfate reduction occurred in deeper, anoxic parts of the biofilm. Sulfate reduction accounted for up to 50% of the total mineralization of organic carbon in the biofilms. All H2S produced from sulfate reduction was reoxidized by O2 in a narrow reaction zone, and no H2S escaped to the overlying water. Turnover times of H2S and O2 in the reaction zone were only a few seconds owing to rapid bacterial H2S oxidation. Anaerobic H2S oxidation with NO3 - could be induced by addition of nitrate to the medium. Total sulfate reduction rates increased when the availability of SO4 2- or organic substrate increased as a result of deepening of the sulfate reduction zone or an increase in the sulfate reduction intensity, respectively.

UR - http://www.scopus.com/inward/record.url?scp=0026581545&partnerID=8YFLogxK

M3 - Journal article

AN - SCOPUS:0026581545

SN - 0099-2240

VL - 58

SP - 1164

EP - 1174

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

IS - 4

ER -