Date of Award

Spring 2007

Project Type

Thesis

Program or Major

Natural Resources

Degree Name

Master of Science

Abstract

Natural depressional wetlands carry out important functions related to C and N cycling, yet the ability of created wetlands to functionally replace natural wetlands in this capacity is not well understood. My objective was to apply the catabolic response profile (CRP) method to evaluate the functional capacity of the soil microbial community in a series of 15 freshwater depressional wetlands: five naturally-occurring wetlands and 10 created wetlands from 1 to 39 years old. I amended sediment samples with 20 labile carbon sources, and samples were analyzed for CO2 and CH4 efflux following a 4-hr incubation under either aerobic or anaerobic conditions. The richness and evenness of carbon-source utilization by the soil microbial community were both significantly higher in natural wetlands compared to created wetlands when measuring CO2 efflux under aerobic conditions (11.7 vs. 9.18 for evenness and 18.5 vs. 15.1 for richness). Significant differences in overall microbial functional capacity among wetland age-classes, as determined by principal components analysis, were apparent for each treatment. Under aerobic conditions, old wetlands differed from young and mid-aged created wetlands and natural wetlands. Under anaerobic conditions natural wetlands differed from all created wetlands. Functional differences under certain conditions between the soil microbial communities resident in natural and created wetlands support the conclusion that created wetlands are not serving as functional equivalents to their naturally-existing counterparts.

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