Microbial Gene Analysis of Mid-Atlantic CEAP Wetlands.

The Mid-Atlantic Regional CEAP-Wetland Study is one of five regional studies underway as part of the national CEAP-Wetland effort. This study collected information at sites in the DelMarVa and North Carolina coastal plain regions, and were equally divided between three sets of wetland managements: hydrologically restored wetlands; prior converted wetlands; and natural wetlands. All sites were selected in sets of three, including one of each wetland management types.Microbial activity and communities were measured by denitrification enzyme activity (DEA) and second generation DNA sequencing respectively, while wetland nitrogen cycling potentials were analyzed by gene specific analysis using quantitative Real-Time PCR (qPCR). DEA revealed that natural wetlands produced the largest percentage of nitrous oxide from denitrification (> 50%), while prior converted wetlands produced the least (< 30%). Results from qPCR revealed that the type of wetland management had different effects on the genes involved in nitrogen cycling. Overall bacterial abundances, using the 16S rDNA gene as measured by qPCR, were greatest in restored and converted wetlands. Gene abundances to examine wetland nitrogen cycling potential were likewise also measured by qPCR:  nifH, the gene responsible for nitrogen fixation, was greatest in restored and natural wetlands, while nirS, a gene which encodes one of two forms of bacterial nitrite reductase, was greatest in restored and converted wetlands. Second generation DNA sequencing, produced over a half million reads and revealed three major phyla predominant across all three wetland management types: Bacteroidetes (12%), Proteobacteria (21%), and Firmicutes (52%).