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Methane-Oxidizer Ecology and the Efficiency of Methane Oxidation in Flooded SoilsEPA Grant Number: U915340
Title: Methane-Oxidizer Ecology and the Efficiency of Methane Oxidation in Flooded Soils
Investigators: Macalady, Jenn
Institution: University of California - Davis
EPA Project Officer: Broadway, Virginia
Project Period: September 1, 1998 through September 1, 2001
Project Amount: $63,580
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology and Ecosystems
The objective of this research project is to identify physical, chemical, and biological factors controlling the efficiency of methane consumption by methane-oxidizing bacteria in flooded soils.
Weekly methane flux measurements, soil porewater methane concentrations with depth, soil temperature, soil pH, and plant growth characteristics will be compared throughout the growing season at several field sites in California, including rice paddies farmed using contrasting agricultural practices and adjacent natural wetlands. The distribution and activities of the two major types of methane-oxidizing bacteria (Types I and II) in intact soil cores and in plant root/rhizosphere samples will be measured using phospholipid fatty acid analysis and nucleic acid probe hybridization. The extent of in situ methane oxidation (methane oxidation efficiency) will be calculated from measured 13C values of porewater methane and emitted methane using an isotope fractionation model. Trends in methane oxidation efficiency will be compared with soil physical and chemical parameters with the population sizes of methane-oxidizing bacterial groups. The data will be used to generate specific hypotheses about which factors control the extent of methane oxidation in flooded soils. These hypotheses will be tested using data from subsequent field seasons at the same sites.