Methane-Oxidizer Ecology and the Efficiency of Methane Oxidation in Flooded Soils

EPA 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: Michaud, Jayne
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.

Supplemental Keywords:

fellowship, methane oxidation, phospholipid fatty acid analysis, PLFA, isotope fractionation, methane-oxidizer ecology, rhizosphere, nucleic acid probe hybridization, flooded soil, porewater methane, methane-oxidizing bacterial groups., RFA, Scientific Discipline, Air, Toxics, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Ecology, air toxics, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecosystem Protection, HAPS, Microbiology, Ecological Effects - Environmental Exposure & Risk, Environmental Microbiology, Habitat, Biochemistry, Biology, Engineering, Chemistry, & Physics, Ecological Indicators, model, soil , methane oxidizing bacteria, rice paddies, control, human impacts, flooded soils, methane emissions, modeling, agricultural environments, methane, methane , soil, agriculture, methane oxidation

Progress and Final Reports:

  • 1999
  • 2000
  • Final