Bacterial community composition in stream biofilms is influenced by algal response to varying light and phosphorus ratios

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Chang, Yu-Rui

Contributors dc:contributor

• Kent, Angela D.

• biofilm
• periphyton
• light and nutrient hypothesis
• light and phosphorus ratio
• algal exudate
• glycolate
• glycolate oxidase
• glcD gene
• microbial community
• automated ribosomal intergenic spacer analysis (ARISA)
• Terminal Restriction Fragment Length Polymorphism (T-RFLP)
• 16S ribosomal RNA gene

Statement dc:rights

• Copyright 2010 Yu-rui Chang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/15997

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/15997