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The Everglades is a naturally oligotrophic system that has been subject to phosphorus (P) enrichment from agricultural areas to the north. Resultant shifts in vegetation communities, enzymatic activities, and nutrient cycling have been documented between impacted and unimpacted sites, and indicate a shift from the natural P-limitation at unimpacted sites to a potential nitrogen (N) limitation at impacted sites. This nutrient enrichment has resulted in changes in the composition of functional genes within microbial communities. Through Geochip 3.0 microarray analysis, a suite of functional genes responsible for C cycling, P cycling, and N cycling were found in varying abundances between sites. The ratios of select gene abundances along the gradient were found to be consistent with the shifts in nutrient limitation. Further work is being conducted to better elucidate the dynamics of P-cycling genes at these sites, in order to better understand how P enrichment may influence the functioning of native microbial communities. Microarray analysis found genes for exopolyphosphatase, polyphosphate kinase, and phytase along the gradient. Additionally, genes for high substrate affinity phosphatase (phoX) and genes associated with C-P lyase (phnD) were found through PCR and transcriptomic techniques. By coupling microarray analyses with transcriptomics, we hope to provide a more comprehensive picture of the response of microbial communities to nutrient enrichment in sensitive, oligotrophic systems such as the Everglades. An understanding of the response of peats to nutrient pollution at the molecular level is critical to our understanding of the mechanisms through which wetlands serve to improve water quality. Information such as this will improve our ability to predict interactions between water quality, wetland function, and changing environmental conditions. |