Terrestrial Carbon Sequestration Studies
EMSL Project ID
25706
Abstract
One of the approaches to minimizing the possible effects of climate change stemming from the recent increases in atmospheric CO2 levels involves storing C as biomass in terrestrial ecosystems. Of the possible terrestrial reservoirs for C storage one of the most promising is organic matter in soil. This matter, termed humus, contains about twice as much C as is in the atmosphere. Conversion of biomass to charcoal by pyrolysis techniques also offers a very promising way to obtain energy and sequester C at the same time. In contrast to humus, the biochar produced by this approach is stable for thousands of years and provides an easily verifiable and leakage-free way of removing C from the atmosphere. Historically, our research has focused on understanding the fundamental enzymatically driven process by which humus is created (i.e., humification) and extending this knowledge to enhance the rate of humification. As soil enzyme activity depends on structural conformation, and longevity depends on protection from microbial predation, we are examining the nature of enzyme attachment to soil particles and the impact of physical properties such as pore size on activity and longevity. The presence of incompletely burned coal in fly ash (and presumably biochar) can have a significant positive impact on the humification reaction, presumably by providing an organic surface where humic monomers preferentially accumulate and consequently react. Accordingly, a strong focus of our current research is on further understanding the role of black C on humification. Our experimental approach involves identifying key soil-chemical parameters that can be manipulated to enhance the net rate of humification in soils associated with a switchgrass field site near Milan, Tennessee as part of the DOE-funded CSiTE project. Soils from this site will be characterized by other members of the project for basic soil properties. Our focus will be on determination of existing black-C content, C stability, oxidase/hydrolase activities, and fungal activity. Soils will be subjected to two types of experiments to determine the impact of chemical properties on humification rates. The first experiment will focus on determining the differences in the oxidase and hydrolase enzyme activities as chemical properties vary. The second experiment will involve incubations of soil microcosms after addition of fresh C or biochar. Of particular importance will be our determinations of the impact of biochar amendments on greenhouse gas emissions. We will be monitoring these emissions from our microcosms and also from gas collection systems at the field site. Another activity will develop a way to measure the humification status of a soil quickly, reliably, and inexpensively either by enzymatic analyses or resistance to persulfate oxidation. This project will enhance our understanding of the factors controlling the formation and stability of soil organic C, which is the largest terrestrial soil C pool. We will explore the possible role and utility of bio-char in both promoting soil organic C sequestration, and acting as a sequestration agent itself. The information provided will be of key importance as decisions are made about the best ways to combat climate change.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-24
End Date
2010-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Amonette JE, JL Barr, LM Dobeck, K Gullickson, and SJ Walsh. 2010. "Spatio-temporal changes in CO2 emissions during the second ZERT injection, August-September 2008." Environmental Earth Sciences 60(2):263-272. doi:10.1007/s12665-009-0402-0
Amonette JE, JL Barr, RL Erikson, LM Dobeck, JL Barr, and JA Shaw. 2013. "Measurement of advective soil gas flux: Results of field and laboratory experiments with CO2." Environmental Earth Sciences 70(4):1717-1726. doi:10.1007/s12665-013-2259-5
Bader, Sydney . "Soil Composition and its Effect on Carbon Sequestration." Science and Enginering Symposium. EMSL, Pacific Northwest National Laboratories. 9 Aug. 2012. PowerPoint Presentation.
Joseph S, M Camps-Arbestain, Y Lin, PR Munroe, CH Chia, JM Hook, L Van Zweiten, SW Kimber, AL Cowie, BP Singh, JC Lehmann, N Foidl, R Smernik, and JE Amonette. 2010. "An investigation into the reactions of biochar in soil." Australian Journal of Soil Research 48(7):501-515. doi:10.1071/SR10009