Martin, Hanna, Biology, Bloomsburg University, 396 Penn Argyle Ave, Bloomsburg, PA, 17835, hem946622@huskies.bloomu.edu; Rier, Steven, Department of Biology, Watershed Ecology Center, Commonwealth University of Pennsylvania, 400 East Second Street, Bloomsburg, PA, 17815, srier@commonwealthu.edu.
Aquatic primary producers release labile carbon exudates into streams that can either increase or decrease the rate of decomposition of terrestrial detritus. The direction and magnitude of this interaction, creating a positive or negative priming effect, on both more recalcitrant or more labile organic matter is not fully understood.
The goal of this study was to better understand the priming effect while considering microbial biomass, enzyme activities, and decomposition rates under different nutrient and light conditions. This experiment investigated the role of priming using cotton and veneer substrates. Modified enclosed rain gutters either allowed or prevented algal growth on the standardized substrates and were submerged in five high nutrient and six low nutrient streams. After incubation, the cotton and veneer were tested on tensile strength, penetrability, fungal sporulation, algal biomass, and enzymatic activities.
We hypothesize there will be a negative priming effect and slower decomposition rates in low nutrient conditions when algal growth is present due to the absorption of labile carbon exudates by decomposers than in low light and high nutrient conditions. Preliminary data analysis indicates there may be priming responses between substrates and across nutrient treatments but additional analysis is required. Further testing of the substrates will include bacterial and fungal biomass, biofilm nitrogen and phosphorus, and percent biomass lost. Additional data analysis will give a clearer understanding of the direction and magnitude of priming occurring in the conditions investigated in this study.
decomposition, priming effect, labile carbon, algae