REWM 3500

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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) Impa
cts on atmospheric chemistry and global warming
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Connectivity
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Anthropogenic production of reactive nitrogen
Natural background rate
From Galloway 2005
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Human impacts on the global N cycle Atmospheric
deposition of reactive N
From Galloway 2005
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(No Transcript)
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Sinks Canyon, Fremont County, Wyoming Annual
inorganic nitrogen deposition 1984-2007
http//nadp.sws.uiuc.edu
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Human impacts on the global N cycle
From Galloway 2005
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Sources, feedbacks and impacts of enhanced N
fixation
From Galloway 2005
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Atmospheric concentrations of nitrous oxide over
the last 10,000 years and since 1750 (inset)
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Terms and concepts to know nitrogen
fixation abiotically fixed N2 biologically fixed
N2 anthropogenic N fixation Haber
process mineralization nitrification denitrificati
on nitrous oxide (N2O)