Wednesday, November 7, 2007 - 10:55 AM
289-6
Linking Process Level Function and Beta-Ammonia Oxidizer Community Dynamics across Varying Soils Following Manure Application.
Ann-Marie Fortuna1, C. Wayne Honeycutt1, Terence L. Marsh2, Timothy Griffin1, Robert Larkin1, Zhongqi He1, Brian Wienhold3, Karamat Sistani4, Stephan Albrecht4, Bryan Woodbury5, H. Allen Torbert4, J. Mark Powell6, Robert K. Hubbard7, Roger A. Eigenberg8, and Robert Wright4. (1) USDA-ARS-NEPSWL, University of Maine, Orono, ME 04469-5753, (2) Dept. of Microbiology & Molecular Genetics, MI State Univ., 6171 BIOMED PHYS SCI, East Lansing, MI 48824-4320, (3) East Campus, UNL, USDA-ARS, 120 Keim Hall, Lincoln, NE 68583-0934, (4) USDA-ARS, USDA-ARSNat'l Prog. Staff, 4740 Frederick Avenue, Shady Side, MD 20764, (5) USDA, PO Box 166, State Spur 18d, Clay Center, NE 68933, (6) 1925 Linden Drive, USDA-ARS, University of Wisconsin-Madison, USDA-ARS Dairy For. Research Ctr., Madison, WI 53706, (7) Southeast Watershed Research Laboratory, USDA-ARS, 2390 Rainwater Rd. P.O. Box 748, Tifton, GA 31793, (8) U.S. Meat Animal Research Center, PO Box 166, Clay Center, NE 68933
Our research links a process level nutrient transformation, nitrification to changes in beta-ammonia oxidizer community dynamics, organic N inputs and soil type. Different cluster groups of nitrifiers have been shown to vary in energy efficiency and generation time. Therefore, shifts in nitrifier community dynamics have short and long-term effects on N cycling. Samples were collected at USDA-ARS sites on eight soil series in a variety of ecoregions. Each soil was used in a 30-d incubation containing a dairy slurry (300 kg N ha-1) amended soil and a soil control. Sub samples were removed at 5 time intervals for analyses of nitrification potentials and community structure of beta-ammonia oxidizers via denaturing gradient gel electrophoresis (DGGE). Soil type had a significant influence on nitrification potentials and microbial community structure. DGGE migration patterns relative to cluster controls indicated that some cluster groups of beta-ammonia oxidizers varied between soil series. Excised DGGE bands will be sequenced. Manure additions affected the rate of nitrification but not the microbial community structure. Dairy slurry may have increased nitrification by providing substrate to static cells of beta-ammonia oxidizers. Nitrifiers are slow growing and may require greater than 30 d to experience a shift in community structure.