HR: 16:45h
AN: B54B-04    [Abstracts]
TI: Effects of long-term increases in atmospheric CO₂ concentration, precipitation, temperature and N deposition on gross N mineralization and nitrification rates in California annual grassland soil
AU: Hungate, B A
AF: Department of Biological Sciences, Northern Arizona University PO Box 5640, Flagstaff, AZ 86011, United States
AU: Gurwick, N P
AF: Department of Global Ecology, Carnegie Institution 260 Panama Street, Stanford, Ca 94305, United States
AU: * Dijkstra, P
EM: Paul.Dijkstra@nau.edu
AF: Department of Biological Sciences, Northern Arizona University PO Box 5640, Flagstaff, AZ 86011, United States
AB: We have studied the effects of long-term increases in atmospheric CO₂ concentration, precipitation, temperature and N deposition on soil inorganic N content, and gross and net N transformation rates in Californian grassland. We sampled soil (0-10 cm) from the Jasper Ridge Global Change Experiment plots in February and April 2005, and determined the gross N mineralization and nitrification rates using the 15N isotope dilution methodology. Statistical analysis revealed significant interactions between multiple climate change factors, making mechanistic interpretations difficult. Consistent effects of N deposition and an interaction between atmospheric CO₂ concentration and temperature treatments on N cycling were observed. These results demonstrate the importance of studying interactions between multiple climate change factors in order to provide realistic predictions of C and N cycling under realistic future environmental conditions.
DE: 0428 Carbon cycling (4806)
DE: 0469 Nitrogen cycling
DE: 0486 Soils/pedology (1865)
DE: 1600 GLOBAL CHANGE
SC: Biogeosciences [B]
MN: 2007 Fall Meeting