A study completed in 2006 focused on the exotic plant invasion of Cheboygan Marsh, a freshwater wetland in Michigan. Previous studies have shown that the introduction of an invasive plant species can alter the microbial community and carbon or nitrogen cycling systems of that area. In this study, researchers focus on an exotic cattail plant species, which they call Typha. Chemical and physical sediment analyses were done by multiple methods to examine nitrate, ammonium, and phosphate concentrations. They also measured sediment water content and organic matter content. Microbial analysis was performed using DNA sequencing and PCR to amplify 16S rRNA. To analyze the composition of genes for denitrification (nirS and nirK), they used specific primers and 16S rRNA amplicon sequencing. Results from sediment chemical and physical analysis suggested that there was a significant increase in nitrate, ammonium, and phosphate concentrations in the Typha infested area. The microbial analysis suggested that there was a significant difference in microbial community composition between the Typha zone and the native plant zone, with the Typha zone showing more bacterial species richness. This was surprising considering the native zone had higher plant species diversity. The nirK gene could not be amplified possibly due to inhibitory compounds blocking the PCR from working. The nirS gene was significantly more rich in the Typha zone than the native plant zone. Overall, this study found that the invasive Typha plant species could be affecting the marsh’s ability to remove certain nutrients from the water by increasing the amount of soluble nutrients put into the environment and allowing for a shift microbial community composition and denitrifying microbes.
Citation: Angeloni, N. L., Jankowski, K. J., Tuchman, N. C., & Kelly, J. J. (2006). Effects of an invasive cattail species (TyphaÃ— glauca) on sediment nitrogen and microbial community composition in a freshwater wetland. FEMS microbiology letters, 263(1), 86-92.