OOS 42 - Microbial Responses to Moisture Availability: Scaling up from Physiology to Ecosystem-Level Processes

Thursday, August 11, 2011: 1:30 PM-5:00 PM
12A, Austin Convention Center
Organizer: Stephanie N. Kivlin
Co-organizers: Claudia M. Boot and Sean M. Schaeffer
Moderator: Bonnie G. Waring
The overarching goal of this session is to synthesize knowledge gained from model simulations, laboratory incubation experiments, and field studies, to produce a more coherent framework with which to link microbial ecophysiology to ecosystem level processes. While it is recognized that soil microbes play a critical role in mediating the flux of carbon between plants, soils and the atmosphere, many carbon cycling models do not include an explicit role for decomposer or mycorrhizal microorganisms. Therefore, there is a considerable effort underway aimed at understanding the physiological mechanisms which constrain microbial activity in soil, particularly with respect to the effects of water availability. When scaled up to the ecosystem level, such research would enhance our understanding of seasonal and geographical patterns in soil respiration, as well as soil and plant feedbacks to global climate change. The session will begin with a discussion of microbial physiological responses to changes in environmental conditions, focusing on recent carbon cycling models which explicitly incorporate the role of microbial physiology. Speakers will then discuss microbial community responses to both experimentally imposed drought stress and natural inter-annual climate variability, considering the physiological mechanisms which might underlie such community shifts. Finally, speakers will address the ways in which changes in microbial physiology and community structure might affect ecosystem processes, such as soil respiration and nutrient mineralization. Our speakers span a range of perspectives and experimental approaches, from simulation-based modeling studies to large-scale ecosystem manipulations. Ultimately, in a time of rapid global change, this holistic approach is required for a predictive framework that links individual microbial functions to ecosystem level processes.
1:30 PM
The surprising role of extracellular enzymes in soil microbial responses to altered precipitation patterns
Matthew D. Wallenstein, Colorado State University; Sarah Evans, University of California Irvine; J. Megan Steinweg, Oak Ridge National Laboratory
1:50 PM
The interaction of substrate concentration and moisture level in decomposition
Donovan P. German, University of California, Irvine; Steven D. Allison, University of California
2:10 PM
Seasonal drought, microbial threshold responses, and biogeochemical cycles in Mediterranean ecosystems
Sean M. Schaeffer, University of Tennessee, Knoxville; Claudia M. Boot, Colorado State University; Dad Roux-Micholett, University of California Santa Barbara; Joshua P. Schimel, University of California, Santa Barbara
2:30 PM
Physical vs. physiological controls on water-stress in soil microbial communities
Stefano Manzoni, Swedish University of Agricultural Sciences; Joshua P. Schimel, University of California, Santa Barbara; Amilcare Porporato, Duke University
2:50 PM
The role of hydraulic lift on mycorrhizal-mediated dynamics
Michael F. Allen, University of California
3:10 PM
3:20 PM
Uncovering the mechanistic basis for soil microbial community response to altered precipitation patterns
Nicholas J. Bouskill, Lawrence Berkeley National Laboratory; Ulas Karaoz, Lawrence Berkeley National Laboratory; Benjamin Bowen, Lawrence Berkeley National Laboratory; Richard Baran, Lawrence Berkeley National Laboratory; Trent R. Northen, Joint Genome Institute; Eoin Brodie, Lawrence Berkeley National Laboratory
3:40 PM
Microorganisms, molecules, and moisture: Drought induced soil community dynamics and their impact on ecosystem function
Mark A. Williams, Virginia Tech University; M. Kakumanu, Mississippi State University; D. Beard, Mississippi State University
4:00 PM
Effects of drying and rewetting cycles on microbial community composition and C and N mineralization
Joshua P. Schimel, University of California, Santa Barbara; Claudia M. Boot, Colorado State University; Corey Lawrence, University of Colorado; Xuyong Li, State Key Laboratory of Urban and Regional Ecology; Dad Roux-Michollet, Bren School; Sean M. Schaeffer, University of Tennessee, Knoxville; Martin Wetterstedt, Swedish University of Agricultural Sciences
4:20 PM
Abiotic controls on community structure and function of nitrogen cycling microorganisms in wetland ecosystems
Ariane L. Peralta, Indiana University; Jeffrey W. Matthews, Illinois Natural History Survey; Eric Johnston, Georgia Institute of Technology; Sarah Ludmer, University of Illinois at Urbana-Champaign; Angela D. Kent, University of Illinois at Urbana-Champaign
See more of: Organized Oral Session
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