Carbon monoxide consumption and production by wetland peats

Wetland peats were analyzed for their potential to consume and produce carb on monoxide (CO) under aerobic and anaerobic conditions. Kinetic and functi onal characteristics of anaerobic CO consumption were compared with those o f methanogenesis. Inhibitors of methanogenesis and sulfate reduction decrea sed the rate of CO consumption by 30 and 20%, respectively, suggesting that methanogens and sulfate reducers played secondary roles in CO uptake. Low concentrations of nitrate (0.2 mM) stimulated CO uptake? while high concent rations (20 mM) were partially inhibitory. Sulfate (20 mM), ferric iron (60 mu mol cm(-3)), and acetate (10 mM) had no effect on CO consumption. Forma te and glucose (10 mM) temporarily stimulated net CO and H-2 production. Ae robic incubations of previously anaerobic peat stimulated transient CO prod uction. Kinetic analysis of anaerobic CO consumption by two sediment types (organic peal and mineral silt) showed that maximum potential uptake veloci ties (V-maxp) in each sediment were similar, 1-2 nmol CO cm(-3) sediment h( -1), with apparent half saturation constants (K-app) ranging from 5 to 37 n M CO. Anaerobic CO consumption may limit CO accumulation in wetland peats a nd sediments, thereby affecting CO emissions. Understanding the role and ch aracteristics of wetland CO consumption may help explain current and future patterns in wetland CO dynamics. (C) 1999 Federation of European Microbiol ogical Societies. Published by Elsevier Science B.V. All rights reserved.