Presenter Information

Jennifer Bell, University of Wyoming

Department

Department of Botany

First Advisor

Dr. Elise Pendal l

Second Advisor

Colin Tucker PhD candidate

Description

Soil organic matter represents one the largest pools of stored carbon on the planet and is a major contributor to terrestrial CO 2 fluxes. Decomposition of soil organic matter adds c arbon dioxi de to the atmosphere, which could lead to even higher temperatures, creating a positive feedback, lessening the carbon storage rate and accelerating climate change. However, this positive feedback may be decreased if soil microorganisms can accl imate , or down - regulate their metabolism, in response to elevated temperatures. To investigate this phenomenon, we set up a short - term laboratory incubation in which soils from a forest ecosystem were incubated at three different temperatures. I n half the samples, dextrose was added to alleviate substrate limitation . Respiration and microbial biomass measurements were taken throughout the month. After a month, the soils were split up and moved to the other temperatures and respiration measurements were take n after six hours. We found that the soil had increased rates of decomposition with increasing temperature and that the microorganism did experience acclimation acclimate suggesting that the positive feedback of increased decomposition rates will not be le ssened.

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The temperature dependence of decomposition of soil organic matter and thermal a ccli

Soil organic matter represents one the largest pools of stored carbon on the planet and is a major contributor to terrestrial CO 2 fluxes. Decomposition of soil organic matter adds c arbon dioxi de to the atmosphere, which could lead to even higher temperatures, creating a positive feedback, lessening the carbon storage rate and accelerating climate change. However, this positive feedback may be decreased if soil microorganisms can accl imate , or down - regulate their metabolism, in response to elevated temperatures. To investigate this phenomenon, we set up a short - term laboratory incubation in which soils from a forest ecosystem were incubated at three different temperatures. I n half the samples, dextrose was added to alleviate substrate limitation . Respiration and microbial biomass measurements were taken throughout the month. After a month, the soils were split up and moved to the other temperatures and respiration measurements were take n after six hours. We found that the soil had increased rates of decomposition with increasing temperature and that the microorganism did experience acclimation acclimate suggesting that the positive feedback of increased decomposition rates will not be le ssened.