Transcript Nitrogen & Phosphorous

Nitrogen & Phosphorous
Group #3:
Neil Mehta
Misha Nelson
Tristan Jenkins
Jenna Colhouer
Brendon Esperancilla
Nitrogen
• Chemical Reactions
• Inorganic and organic reservoirs for the
element
• Pathway of movement
• Impact of human intervention on the cycle
Chemical Reactions
• Nitrogen: (N2) most abundant element in
atmosphere (78% of troposphere volume)
• Combines with atmospheric oxygen to
form nitrogen dioxide gas (NO2)
• (N2) cannot be metabolized as a nutrient
– Electrical discharges cause N2 & O2 to react
– Certain bacteria (Rhizobium, etc.) can fix
nitrogen for use by plants
Inorganic and organic reservoirs for
the element
• Inorganic:
– Atmospheric gas
• Organic:
– Plants are consumed by animals as a source
of nitrogen
– Detritus resulting from decomposition of
formerly living organisms
Pathway of movement
• Nitrification: ammonia converts to nitrite (NO2-) & nitrate
(NO3-)
• Assimilation: plant roots absorb inorganic ammonia,
ammonium ions, and nitrate ions
– Used for synthesis of DNA, proteins, etc.
• Ammonification: bacteria decompose dead matter into
constituent components, including ammonia and
ammonium salts
• Denitrification: bacteria convert ammonia and
ammonium back into nitrite and nitrate, then becoming
N2 and nitrogen oxide
Impact of human intervention on
the cycle
• When we burn any fuel, it adds large
amounts of nitric oxide
• Acid rain: formed by HNO3 (nitric
acid=atmospheric water and nitrogen
dioxide) and dissolves in rain or snow
• Farm animals release methane into
atmosphere
Phosphorous
• Chemical Reactions
• Inorganic and organic reservoirs for the
element
• Pathway of movement
• Impact of human intervention on the cycle
Chemical Reactions
• Very little P circulates in atmosphere
– At Earth STP, P is not usually gaseous and mostly mineral
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P is typically found in terrestrial rock and ocean sediment
Helps form structure of bones in animal skeletons
Often used in fertilizer
Composes ATP for nearly all cellular activities
Composes phospholipid bilayer of cell membranes
Most abundant form: orthophosphate (PO43-)
Inorganic and organic reservoirs for
the element
• Inorganic:
– Mineral formations
– Ocean sediment
• Organic:
– Aquatic and terrestrial plants
– Bones of terrestrial animal
Pathway of movement
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Starts in mineral form
Weathering deposits it in soils
Plants absorb from soil
Animals consume plants and their phosphorous
Reintegrated into soil after death of animal
Can run off into ocean
Ocean plants
ocean animals
Some settles into marine sediment
– Mined by humans for fertilizer
Impact of human intervention on
the cycle
• We harvest phosphorous from sediment to
make fertilizer
• Remove trees from tropical forests
– No plants, no absorption from soil
• No plant roots, no soil to begin with!
• Pollute aquatic environments
– Overabundance of P promotes algal bloom,
which helps bacteria thrive; bacteria consume
too much oxygen, and fish drown!?
HEY!