Location: Contaminant Fate and Transport ResearchTitle: Assessing the diversity and composition of bacterial communities across a wetland, transition, upland gradient in Macon County Alabama Author
|Ibekwe, Abasiofiok - Mark|
Submitted to: Diversity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2013
Publication Date: 7/3/2013
Publication URL: http://www.ars.usda.gov/SP2UserFiles/Place/53102000/pdf_pubs/P2441.pdf
Citation: Shange, R., Haugabrooks, E.M., Ankumah, R.O., Ibekwe, A.M., Smith, R.C., Dowd, S. 2013. Assessing the diversity and composition of bacterial communities across a wetland, transition, upland gradient in Macon County Alabama. Diversity. 5(3):461-478. Interpretive Summary: Wetlands provide essential functions to our ecosystem that range from water filtration to flood control and areas for wildlife reservations. Wetlands are currently evaluated based on three distinctive characteristics that they are associated with, namely; soils type, vegetation, and hydrology. Based on such wetland characteristics, a variety of assessment methods have been developed to evaluate wetland functionality and effectiveness of wetland mitigation. Although these assessment methods have gained broad support from the regulatory agencies, many researchers have questioned their efficacy in measuring the functional ability of constructed and mitigated wetlands, and some have challenged the validity of these evaluations. Microbial processes drive many wetland functions, and thus any change in their communities in response to environmental and anthropogenic perturbation can affect the ability of the wetlands to perform their ecosystem services. In this study, we characterized soil bacterial communities using deep sequencing along a gradient in a forested wetland ecosystem to quantify changes in soil biochemical and microbial properties. Proteobacteria were the most abundant bacterial group throughout the soils followed by Acidobacteria and Verrucomicrobia. This information will be of interest to scientists, water quality managers, and wildlife conservationists who are interested in preserving wetlands through various mitigation measures.
Technical Abstract: Wetlands provide essential functions to the ecosphere that range from water filtration to flood control. Current methods of evaluating the quality of wetlands include assessing vegetation, soil type, and period of inundation. With recent advances in molecular and bioinformatic techniques, measurement of the structure and composition of soil bacterial communities have become an alternative to traditional methods of ecological assessment. The objective of the current study was to determine whether soil bacterial community composition and structure changed along a single transect in Macon County, AL. Proteobacteria were the most abundant phyla throughout the soils in the study (ranging from 42.1% to 49.9% of total sequences). Phyla Acidobacteria (37.4%) and Verrucomicrobia (7.0%) were highest in wetland soils, Actinobacteria (14.6%) was highest in the transition area, and Chloroflexi (1.6%) was highest in upland soils. Principle Components Analysis (relative abundance) and Principle Coordinates Analysis (PCoA) (Unifrac weighted metric) plots were generated, showing distinction amongst the ecosystem types through clustering by taxonomic abundance and Unifrac scores at 3% dissimilarity, respectively. Selected soil properties (soil organic carbon and phosphatase enzyme activity) also differed significantly in transition soil ecosystem types, while showing predominance in the wetland area. This study suggests that with further study the structure and composition of soil bacterial communities may eventually be an important indicator of ecological impact in wetland ecosystems.