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Register Number: ER65204
Title: Exploratory Research - Using Volatile Organic Compounds to Separate Heterotrophic and Autotrophic Fo
Principal Investigator: Hatten, Jeff
Institution: MISSISSIPPI STATE UNIVERSITY
Institution Address: Mississippi State, MS 39762-5167
Awarded Amount to Date and B&R Code :
FY 2013$0 k
FY 2012$0 k
FY 2011$149 kKP170201
DOE Program Manager: Daniel Stover
BER Division: Climate and Environmental Sciences
Research Area: Terrestrial Ecosystem Science
Abstract Submit Date: 02/20/2012
Project Term: 09/01/2011 - 08/13/2013
Abstract: Soils contain about twice as much carbon as does the atmosphere and soil respiration is about 9 times that of global fossil fuel emissions. As a result, small increases in soil respiration driven by the mineralization of soil organic matter (heterotrophic respiration) caused by climate change could lead to elevated levels of atmospheric carbon dioxide and positive feedback on global warming. Research on soil respiration is complicated by the fact that carbon dioxide carries little information about its source. Therefore, determining whether carbon dioxide is being derived from autotrophic (e.g. roots) and heterotrophic (e.g. decomposition) sources requires methods that are destructive, invasive, and/or expensive. Our project proposes to investigate a new method using volatile organic compounds (VOCs) as indicators of carbon dioxide source. Our overall objective is to determine whether the composition and quantity of soil VOCs can be used to separate the respiration associated with roots (autotrophic respiration) and respiration associated with heterotrophic processes (i.e. decomposition of soil organic matter, dead roots, and root exudates). We propose to conduct a greenhouse study of soil respiration and VOC efflux where each respiration component is isolated utilizing pots with and without plants, litter bags, and destructive sampling. The results of this study will allow us to measure or calculate soil respiration and VOC efflux of each component. The impact of tree species, diurnal cycles, and soil moisture regime will be assessed within the boundaries of this greenhouse study. The specific objectives of the project are to: 1) Determine the VOCs that uniquely indicate each component of soil respiration; 2) Test the effectiveness of this method over a range of soil moisture conditions; 3) Determine if diurnal cycles affect soil respiration and soil VOC efflux; and 4) Determine if VOCs can uniquely indicate below ground root production of biomass. This exploratory study has the potential to create a method that greatly improves the measurement of autotrophic and heterotrophic respiration as well as reduce the efforts required to determine these important fluxes. As a result, this work could increase the possible number of measurements that can be made and ecosystems monitored. Ultimately, the proposed study will improve our understanding of terrestrial carbon cycle processes and provide better predictions regarding the effect of climate change on soil organic matter pools.