|
Untitled 1
|
 |
ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2004 Conference Abstract
| Type of Submission |
 |
Submission Type: |
Poster |
|
Subject Category: |
Applied and Environmental Microbiology |
|
| Session Information |
|
Presentation Date: |
June 21, 2004 |
|
Abstract ID: |
A08 |
|
Session: |
Poster Session 1 |
|
Time: |
15:00-16:30 |
|
| Presenting Author |
|
M.R. CHÉNIER, Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec, Canada, H4P 2R2
martin.chenier@cnrc-nrc.gc.ca |
|
| Other Authors |
|
R. ROY, Department of Biology, University of Victoria, Victoria, British Columbia
D. BEAUMIER, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec
B.T. DRISCOLL, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec
J.R. LAWRENCE, National Water Research Institute, Environment Canada, Saskatoon, Saskatchewan
C.W. GREER, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec
|
|
| Title |
|
Impact of nutrients, hexadecane and temporal variations on the activity and composition of river biofilms. |
|
| Abstract Text |
|
In aquatic ecosystems, biofilm bacteria play key roles in biogeochemical cycling and biodegradative activities, although the impact of environmental variables on aquatic biofilms is poorly understood. This study focused on the impact of nutrients, hexadecane (a petroleum hydrocarbon pollutant) and temporal variations on replicated river biofilms. Biofilms were cultivated on polycarbonate strips in rotating annular reactors using South Saskatchewan River water supplemented with carbon, nitrogen, phosphorus, or combined nutrients (CNP), with or without hexadecane, during the fall of 1999 and during the fall of 2001. The impact of these treatments on nitrification and on the composition of river biofilms was determined. In the fall of 1999, the presence of CNP had a dramatic positive effect on ammonium oxidation, nitrate production and nitrous oxide production, whether hexadecane was present or not. Phosphorus also stimulated these activities in the absence of hexadecane, but did not affect them when hexadecane was present. Phosphorus stimulation was less than that observed for CNP. Hexadecane had a negative impact on the assessed activities. In fall 2001, the response of biofilms to nutrient additions was rather complex, and did not permit the identification of any global trend or pattern as to the impact of nutrients. This suggests that the microbial community and the chemical structure/composition of fall 2001 biofilms were more stable than the ones of fall 1999. Surpringly, hexadecane slightly enhanced ammonium oxidation by CNP and control (no nutrients) biofilms, nitrate production by CNP and N biofilms, and nitrous oxide production by CNP and P biofilms. The results show that nutrients (especially P) were limiting for bacterial activity and production in the South Saskatchewan River water in fall 1999, and that hexadecane had a negative impact on bacterial activity in fall 1999 but a slight positive impact in fall 2001. This study also demonstrated that the community response to environmental stress can have significant temporal variations, and that there are interactive effects between nutrients and hexadecane. |
|
|
|
|
