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SFS Annual Meeting

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THE EFFECTS OF LIGHT AND TEMPERATURE ON FRESHWATER MICROBIAL BIOMASS, PRODUCTION, COMPOSITION AND INTERACTIONS

Decaying plant litter in aquatic ecosystems harbors autotrophic and heterotrophic microorganisms, as algae, bacteria, and fungi often form complex litter-associated biofilms. We hypothesized that microbial groups would differ in their overall responses to temperature manipulation, which could have implications upon microbial communities via seasonal temperature shifts and as global warming continues. We used wetland mesocosms at the University of Alabama to assess the effects of light and temperature on freshwater microbial communities colonizing submerged Typha domingensis litter. Biomass and production of algae, bacteria, and fungi, as well as algal community composition, were measured after 78 and 127 days of growth. Initial results indicate that all groups grew best when exposed to light, suggesting positive stimulation of heterotrophs by algal photosynthesis. Algal, bacterial, and fungal communities displayed different temperature optima, suggesting that temperature may influence autotrophic/heterotrophic balance in litter-associated microbial communities. Analysis of a potential interaction between temperature and algal photosynthetic stimulation of heterotrophs is ongoing.

Kevin Kuehn (Co-Presenter/Co-Author), The University of Southern Mississippi, kevin.kuehn@usm.edu;


Halvor Halvorson (Co-Presenter/Co-Author), University of Southern Mississippi, Halvor.Halvorson@usm.edu;


Robert Findlay (Co-Presenter/Co-Author), University of Alabama, rfindlay@ua.edu;


Steven Francoeur (Co-Presenter/Co-Author), Eastern Michigan University, sfrancoeu@emich.edu;


Joel Bonney (Primary Presenter/Author), Eastern Michigan University, jbonney@emich.edu;