Lisa Fauteux
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514-987-3000, ext 1463
Université du Québec à Montréal
Pavillon des sciences biologiques, SB-2385
2080 St-Urbain
Montréal, Québec
H2X 3X8
Canada
Master in Biology, UQÀM
Undergrad in biology, UQÀM
Aquatic bacteria are key players of their ecosystems in terms of the biogeochemistry of carbon. Yet they remain relatively understudied. Hence even if mixotrophy as been recognized for a while it's contribution to community metabolism remains largely unknown. One type of mixotrophic metabolism is based on bacteriochlorophyll-a, and collectively the bacteria who posses it are identified as aerobic anoxygenic phototrophic (AAP). This metabolism is thought to supply up to 30% of their metabolic requirements. Even though their presence has been detected in freshwater lakes no study has yet addressed the specific question of their ecology. The project we carried out on over 40 lakes from three regions (Eastern-Townships, Laurentides, Eastmain) over the course of a year aimed at identifying any emerging patterns in their distribution. In terms of abundance we found that they represent on average 5% of the bacterial community, however we did find a maximum at 37%. In addition, these bacteria are on average twice as big, hence in terms of biomass their presence is much more important. Finally, we found that AAP bacteria are a dynamic component of the community since we found significant regional differences as well as important seasonal and diurnal variation in their abundance as well as size.