|Leddy, Menu -|
|Bold, Richard -|
|Graves, Alexandria -|
Submitted to: FEMS Microbiology Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2011
Publication Date: October 13, 2011
Repository URL: http://www.ars.usda.gov/SP2UserFiles/Place/53102000/pdf_pubs/P2381.pdf
Citation: Ibekwe, A.M., Leddy, M.B., Bold, R.M., Graves, A.K. 2011. Bacterial composition in sediment and surface water as indicators for pollution in a mixed watershed. FEMS Microbiology Ecology. 79:155-166. Interpretive Summary: The Santa Ana River (SAR) in southern Californian is impacted by one of the highest concentration of cattle in the United States. The watershed is undergoing drastic changes. In general, the varying land uses in the middle SAR (Chino Basin) watershed include agriculture, open space, and rapidly growing urban areas with many waste water treatment plants. In order to address changes in water quality within the middle Santa Ana River watershed, a comparative study of bacterial population in the surface waters and sediment was performed. These communities were also examined to understand how different environmental factors (pH, salinity, turbidity, dissolved oxygen, and temperature may influence the microbial population and their densities throughout the watershed. Our data showed that the use of deep sequencing technology provided the best opportunity to differentiate between bacterial populations from the different sources than the standard cloning method. This research will directly benefit water quality managers, water utility agencies, and the public.
Technical Abstract: Microbes in rivers are diverse and dynamic in composition due to different environmental factors and therefore, the composition of microbial community in a river may be indicators for pollution. However, the use of total bacterial composition as indicator for river pollution has not been studied in details; but rather, focus has been on the use of specific indicator bacteria such as E. coli, enterococci or other fecal indicator bacteria. In this study, bacterial community composition was monitored using Sanger and 454 pyrosequencing. The results were analyzed using nonmetric multidimentional scaling (NMDS) and UniFrac, coupled with principal coordinate analysis (PCoA) to compare diversity, abundance, community structure, and specific functional groups of bacterial in the sediment and surface water to determine bacterial composition in streams and creeks affected by different pollutants that contributes to the total quality of the Santa Ana River water in southern California USA. From all the sampling points, Bacteria were numerically dominated by three phyla—the Proteobacteria, Bacteroidetes, Cyanobacteria, Acidobacteria, and Actinobacteria—accounting for the majority of taxa detected. Overall results, using the ß diversity measures UniFrac, coupled with principal coordinate analysis (PCoA), showed that bacterial composition in sediment and surface water was significantly different (P =0.0001) between agricultural runoff and urban runoff based on parsimony test using 454 pyrosequencing data. Our results showed that large data set may be needed to truly understand contamination levels in surface water and river sediment.