Influence of algal / bacterial interactions on denitrification in stream biofilms

Kelly, John J.; Rojas, Miguel; Peterson, Christopher G.; Kalscheur, Kathryn N.

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https://hdl.handle.net/2142/89964 Copy

Description

Title

Influence of algal / bacterial interactions on denitrification in stream biofilms

Author(s)

• Kelly, John J.
• Rojas, Miguel
• Peterson, Christopher G.
• Kalscheur, Kathryn N.

Contributor(s)

• Loyola University Chicago
• Northwestern University

Issue Date

2012

Keyword(s)

• Water resources development
• Water resources development--Illinois
• Aquatic ecology
• Stream biofilms
• Denitrification of water

Geographic Coverage

Illinois (state)

Abstract

Within aquatic ecosystems, periphytic biofilms can be hot spots of denitrification, and previous work has suggested that algal taxa within periphyton can influence the species composition and activity of resident denitrifying bacteria. This study tested the hypothesis that algal species composition within biofilms influences the structure and function of associated denitrifying bacterial communities through the composition of organic exudates. A mixed population of bacteria was incubated with organic carbon isolated from one of seven algal species or from one of two streams that differed in anthropogenic inputs. Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) revealed differences in the organic composition of algal exudates and stream waters, which, in turn, selected for distinct bacterial communities. Organic carbon source had a significant effect on potential denitrification rates (DNP) of the communities, with organics isolated from a stream with high anthropogenic inputs resulting in a bacterial community with the highest DNP. There was no correlation between DNP and numbers of denitrifiers (based on nirS copy numbers), but there was a strong relationship between the species composition of denitrifier communities (as indicated by tag pyrosequencing of nosZ genes) and DNP. Specifically, the relative abundance of Pseudomonas stutzeri-like nosZ sequences across treatments correlated significantly with DNP, and bacterial communities incubated with organic carbon from the stream with high anthropogenic inputs had the highest relative abundance of P. stutzeri-like nosZ sequences. These results demonstrate a significant relationship between bacterial community composition and function and provide evidence of the potential impacts of anthropogenic inputs on the structure and function of stream microbial communities.

Publisher

University of Illinois at Urbana-Champaign. Water Resources Center

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/89964

Sponsor(s)/Grant Number(s)

• U.S. Department of the Interior
• U.S. Geological Survey

Owning Collections