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Title:Bacterial community composition in stream biofilms is influenced by algal response to varying light and phosphorus ratios
Author(s):Chang, Yu-Rui
Advisor(s):Kent, Angela D.
Department / Program:Natural Res & Env Sci
Discipline:Natural Res & Env Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
light and nutrient hypothesis
light and phosphorus ratio
algal exudate
glycolate oxidase
glcD gene
microbial community
automated ribosomal intergenic spacer analysis (ARISA)
Terminal Restriction Fragment Length Polymorphism (T-RFLP)
16S ribosomal RNA gene
Abstract:Strong correlations between bacterial communities and algal seasonal succession have been previously observed. In aquatic systems, dissolved organic carbon derived by algae is an important resource for bacteria. Light and phosphorus availability are two factors that influence biomass and abundance of algae, and the changes will be reflected in the bacterial portion of the microbial community. Glycolate is an algal-specific exudate produced under excess light conditions. Glycolate uptake by bacteria has been shown to correlate with algal primary productivity. Bacterial populations that utilize glycolate possess the gene, glycolate oxidase subunit D (glcD). This gene was used as a marker to identify changes in specific bacterial populations that respond to algal exudates. In this study, development of periphyton biofilms in an experimental stream system was monitored across different light and phosphorus levels. Samples were collected every two days for community and chemistry analyses. Bacterial communities were monitored using DNA fingerprinting techniques based on ribosomal RNA genes and the glcD gene. We demonstrated that bacterial community composition changed significantly over the course of biofilm development, and light and phosphorus availability contributed to those differences in community composition. Our results suggest that a strong coupling between carbon flow and bacterial community composition. These results increase our understanding of the ecological drivers that impact benthic biofilm communities that carry out transformation of nutrients in streams.
Issue Date:2010-05-18
Rights Information:Copyright 2010 Yu-rui Chang
Date Available in IDEALS:2010-05-18
Date Deposited:May 2010

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