Progress 12/01/07 to 11/30/12
Outputs
OUTPUTS: The overarching objectives of this proposal were to understand how microbial communities and ecosystem processes change in response to precipitation variability. Activities: 1) Microbial community responses to precipitation variability. We developed a stable isotope probing technique (SIP) that uses heavy water (H218O) to identify soil bacteria that are metabolically active following precipitation events. We successfully extracted isotopically labeled DNA and RNA from both pure cultures of bacteria and from soil samples in different land use treatments at the Kellogg Biological Station's (KBS) Long Term Ecology Research site. Until recently, much of the laboratory work had done on Michigan State University's (MSU) main campus. Our lab is now equipped with a benchtop ultracentrifuge, which helped us refine the SIP methodology. 2) Ecosystem responses to precipitation variability. We developed and applied real-time sensor technology to measure soil responses to natural and manipulated precipitation variability. The sensors measured CO2, soil moisture, and temperature at 30 minute intervals. We deployed the sensors in different land use treatments at KBS, which were configured to transfer data wirelessly to our laboratory for monitoring and analysis. We analyzed the sensor data using time series regression modeling and maximum likelihood analysis. PARTICIPANTS: Jay T. Lennon - PI, Michigan State University, Kellogg Biological Station Zach Aanderud - Postdoc, Michigan State University, Kellogg Biological Station Brent Lehmkuhl - Research Technician, Michigan State University, Kellogg Biological Station Cathy McMinn - Research Technician, Michigan State University, Kellogg Biological Station Ben Phillips - Undergraduate Research Technician, Michigan State University, Kellogg Biological Station Donald Schoolmaster - Collaborator, State University, Kellogg Biological Station TARGET AUDIENCES: Results from this proposal will be targeted primarily towards the academic audience. We will also make an effort to disseminate our results to local and state agencies interested in soil properties. Some of our research may also dovetail with a recently funded DOE Bioenergy proposal, which has significant extension opportunities. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
1) Microbial community responses to precipitation variability. We have extracted DNA and RNA samples for phylogenetic analysis. Specifically, we have taken advantage of new 454 pyrosequencing technology at MSU and UC Boulder. We are still in the process of analyzing these data and will be able to evaluate which members of the soil microbial community are responsible for elevated activity following precipitation events. 2) Ecosystem responses to precipitation variability. We have generated and analyzed data from field experiments that address how plants mediate CO2 responses to precipitation variability. Our field scale manipulation documented how plant removal in different land use treatments affected soil moisture, temperature, nitrogen, carbon, methane and nitrous oxide flux. On top of this experimental template we documented significant changes in CO2 responses to investigator-imposed precipitation regimes. Our results suggest that plant communities have the ability to dampen fluctuation in soil moisture and thus reduce the amount and variability of CO2 flux from Midwestern agricultural landscapes.
Publications
- No publications reported this period
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