Poster Details
EFFECTS OF LIGHT AND NUTRIENT AVAILABILITY ON ALGAL STIMULATION OF MICROBIAL HETEROTROPHS ASSOCIATED WITH DECOMPOSING WOOD
Recent evidence suggests periphytic algae stimulate leaf litter heterotrophs and decomposition in the presence of light, but these algal priming effects have yet to be tested on highly recalcitrant wood. To better understand algal stimulation of heterotrophic activity and organic matter decomposition, we incubated wood veneers of Quercus alba in aquatic mesocosms under separate light/dark conditions and low or high concentrations of dissolved nitrogen and phosphorus. After 7 and 18 weeks of biofilm establishment, we measured mass loss and sectioned veneers to measure biomass and growth rates of wood-associated algae, bacteria, and fungi. We found that increased dissolved nutrient availability coupled with light increased algal production rates on wood in an additive manner (P<0.05). In turn, increased light and nutrients interactively stimulated fungal growth rates (P=0.004) but decreased fungal biomass accrual (P<0.05), with light effects consistently stronger under high nutrient levels. Rates of wood decomposition were consistently greater in the dark treatment, and light more strongly suppressed decomposition under high nutrient levels (P<0.05). Our data advance understanding of autotroph-heterotroph interactions on decomposing wood, improving prediction of directions and strength of algal priming effects on decomposition in response to environmental factors.
Halvor Halvorson (Co-Presenter/Co-Author), University of Southern Mississippi, Halvor.Halvorson@usm.edu;
Tori A. Hebert (Co-Presenter/Co-Author), The University of Alabama, tahebert@crimson.ua.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;
Kevin A. Kuehn (Co-Presenter/Co-Author), University of Southern Mississippi, kevin.kuehn@usm.edu;
Cody Pope (Primary Presenter/Author), University of Southern Mississippi, Cody.pope@usm.edu;