100 likes | 362 Views
REWM 3500 Rangeland Plant Ecophysiology November 30, 2009 Human impact on the global nitrogen cycle – how will rangelands respond? Natural vs Anthropogenic Nitrogen Fixation Consequences of altered N biogeochemistry 1) Where is this nitrogen going?
E N D
REWM 3500 • Rangeland Plant Ecophysiology • November 30, 2009 • Human impact on the global nitrogen cycle – how will rangelands respond? • Natural vs Anthropogenic Nitrogen Fixation • Consequences of altered N biogeochemistry • 1) Where is this nitrogen going? • 2) Effects on plant populations and communities • 3) Effects on biodiversity • 4) Impacts on atmospheric chemistry and global warming
Anthropogenic production of reactive nitrogen Natural background rate From Galloway 2005
Human impacts on the global N cycle Atmospheric deposition of reactive N From Galloway 2005
Sinks Canyon, Fremont County, Wyoming Annual inorganic nitrogen deposition 1984-2007 http://nadp.sws.uiuc.edu
Human impacts on the global N cycle From Galloway 2005
Sources, feedbacks and impacts of enhanced N fixation From Galloway 2005
Atmospheric concentrations of nitrous oxide over the last 10,000 years and since 1750 (inset)
Terms and concepts to know: nitrogen fixation abiotically fixed N2 biologically fixed N2 anthropogenic N fixation Haber process mineralization nitrification denitrification nitrous oxide (N2O)