Nitrogen
Mrs. Nolan
APES
ž  Matter
cannot be created or destroyed.
ž  It is recycled through natural cycles.
ž  Matter
= all things that have mass and take
up space.
ž  Matter exists as solid, liquid or gas.
ž  Water
moves between the atmosphere and
the Earth.
ž  Example: When you leave a glass of water
out a few days what happens?
ž  It has evaporated!!!
ž  Water from lakes and oceans evaporates.
ž  This
water vapor will condense, or come
together, and make clouds.
ž  Eventually, after more condensation water
droplets form.
ž  This water falls to earth as rain, ice or snow
(precipitation).
ž  Plants and animals need water vapor to
live!!!
ž 
Plants take water in through their roots. Water leaves
plants through their leaves. This process is called
transpiration.
ž 
90% of water that reaches
atmosphere is from transpiration.
Animals take in water (by drinking it). They breathe out
water vapor in every breath.
ž  Animals also urinate (which returns water to the
environment).
ž 
ž  Water
flows into streams, lakes and oceans
called runoff.
ž 
ž 
Is an atmospheric cycle.
All life on Earth is based on the element carbon.
ž 
Autotrophs harvest the sun’s energy and change carbon dioxide
gas into sugar by the process called photosynthesis.
ž 
Carbon is required for formation of organic compounds in living
things.
C in carbon dioxide in atmosphere and in water is moved to C in
glucose by photosynthesis by producers.
ž 
ž  C
in glucose (C6H12O2) is moved to C in
carbon dioxide (CO2) by cellular respiration.
ž  C in glucose is moved to C in organic
molecules by synthesis reactions in living
things.
ž  Heterotrophs
autotrophs.
get carbon from eating
ž  C
in organic molecules is moved to C in
carbon dioxide by combustion (The burning
of fossil fuels- oil, coal, natural gas).
ž  C in organic molecules in organisms is moved
to C in fossil fuels over millions of years by
pressure, heat, and bacterial action.
ž  C
in limestone (CaCO3) is released slowly to
C in carbon dioxide when exposed to oxygen
and/or water.
ž  Largest
reservoir or sink of carbon sedimentary rocks (limestone)
ž  When
autotrophs die, decomposers release
carbon dioxide back into the atmosphere.
ž  Volcanoes
release carbon dioxide into the
atmosphere. (Ex. Mt. Saint Helens).
ž  Carbon
sinks/reservoirs: Where you store
more carbon dioxide than is released.
¡  Ocean-
producers in the ocean take in and store
carbon dioxide and release oxygen, CO2 dissolved
in water. Second largest reservoir of carbon.
ž  In water: CO2 + H2O à HCO3-(bicarbonate ions) +
CO32-(carbonate ions)
Ca2+ + CO32- à CaCO3(calcium carbonate) in shells/
skeletons of aquatic organisms
ž  CaCO3 buried, long period of time, pressureà
limestone
¡  Forests- trees take in and
store carbon dioxide.
ž  Removal
of vegetation reduces absorption of
carbon dioxide for photosynthesis from
atmosphere. Increases atmospheric CO2.
ž  Burning of fossil fuels increases atmospheric
CO2.
ž  Increase in atmospheric CO2 leads to
increased Greenhouse Effectà Global
Warming.
Carbon dioxide in atmosphere Respira2on Photosynthesis Animals (consumers) Diffusion Burning fossil fuels Forest fires Plants (producers) Deforesta2on Transporta2on Respira2on Carbon in plants (producers) Carbon dioxide dissolved in ocean Carbon in animals (consumers) Decomposi2on Marine food webs Producers, consumers, decomposers Carbon in limestone or dolomite sediments Carbon in fossil fuels Compac2on Process Reservoir Pathway affected by humans Natural pathway Fig. 3-19, p. 70
N2 (nitrogen gas) is in our atmosphere. (78%)
Plants and animals cannot use free nitrogen gas in the
atmosphere. They must have nitrogen in "fixed" form.
Nitrogen is required for proteins, nucleic acids in living things.
¡ 
ž 
ž 
ž 
Free N2 in atmosphere is "fixed" by nitrogen-fixing bacteria to NH3
(ammonia): N2 +3H2 à 2NH3
¡  Nitrogen
fixing bacteria live in the nodules on
the roots of leguminous plants.
¡  What kind of relationship do the nitrogen-fixing
bacteria have with leguminous plants?
MUTUALISM.
¢  Plants benefit because they get nitrogen.
¢  Bacteria is happy because it gets carbohydrates.
¢ 
¡  How
¢ 
do we get nitrogen?
From eating broccoli, lettuce, corn, soybeans, peas,
clover, alfalfa etc…
ž 
Water in the soil reacts with ammonia to form NH4+
(ammonium ion)- a form plants can use J
ž 
Another species of bacteria can perform nitrification once
ammonium has formed: NH4+ à NO2_ (nitrite; toxic) à
NO3-(nitrate; plant nutrient)
ž 
Assimilation - absorption of ammonia, ammonium ion,
nitrate for use by plants to make nucleic acids, proteins.
ž 
Animals get fixed nitrogen by eating plants or other
animals.
ž 
Plants and animals are broken down by still other bacteria
that convert nitrogen- containing organic molecules in
organisms to an inorganic form of nitrogen (ammonia or
ammonium ion) = ammonification
ž 
Once this ammonia has formed, still another group of
bacteria can perform denitrification:
NH3 or NH4+ à NO2_ and/or NO3- à N2 and N2O (nitrous
oxide)
ž  Nitrogen
is often limiting factor in plant
growth because ammonia, ammonium ion,
nitrate are water-soluble: can be leached
from soil.
ž  In
the atmosphere: N2 + O2 à 2NO (nitric oxide)
produced when burning fuel or forests. (Heat
combines N2 and O2 present in atmosphere)
ž  NO + O2 à NO2 (nitrogen dioxide gas)
ž  NO2 + H2O à HNO3 (nitric acid - dissolved in
water causes acid deposition)
ž  N2O(nitrous oxide) released from decomposition
of fertilizer and waste.
ž  Excess nitrogen added to aquatic systems by
runoff of artificial fertilizer ,farm waste,
discharge of sewage. This stimulates growth of
algae. Breakdown of algae by aerobic
decomposers depletes water of oxygen.
Process Denitrifica2on by bacteria Nitrogen in atmosphere Reservoir Nitrifica2on by bacteria Pathway affected by humans Natural pathway Nitrogen oxides from burning fuel and using inorganic fer2lizers Nitrogen in animals (consumers) Electrical storms Volcanic ac2vity Nitrogen in plants (producers) Nitrates from fer2lizer runoff and decomposi2on Decomposi2on Uptake by plants Nitrate in soil Nitrogen loss to deep ocean sediments Nitrogen in ocean sediments Bacteria Ammonia in soil Fig. 3-20, p. 71
ž  Phosphorus
is required in the form of
phosphate ions for nucleic acids, ATP,
phospholipids in cell membranes, bones,
teeth, shells of animals.
ž  PO43- = Phosphate
ž  Is a sedimentary cycle - does not include the
atmosphere.
ž  Plants get phosphorus from the soil.
ž  Animals get phosphorus from eating plants.
ž  When animals die, phosphorus returns to the
soil.
ž  Phosphate
on land and in ocean sediment
released by weathering into water and taken
up by plants. Can be limiting factor for plant
growth - is present in artificial fertilizer.
ž  Decomposition changes organic molecules
with phosphorus back into phosphate which
dissolves in water which returns the
phosphorus to ocean sediment or deposited
as rocks.
ž  Mining
of phosphate for fertilizers and soap
causes disruption to ecosystems.
ž  Removal of phosphorus from ecosystems by
cutting down of vegetation.Most of
phosphorus is taken up as biomass.
ž  Excessive phosphate in runoff from fertilizer,
discharge of sewage,farm waste causes
growth of algae, etc. (same problem as
nitrogen).
Process Reservoir Pathway affected by humans Natural pathway Phosphates in sewage Phosphates in mining waste Phosphates in fer2lizer Runoff Runoff Sea birds Runoff Erosion Animals (consumers) Phosphate dissolved in water Plants (producers) Plate tectonics Phosphate in rock (fossil bones, guano) Phosphate in shallow ocean sediments Ocean food webs Phosphate in deep ocean sediments Bacteria Fig. 3-21, p. 73
ž  Is
an atmospheric cycle.
ž  H2S(hydrogen sulfide) and SO2 (sulfur dioxide)
released into atmosphere from natural
(volcanoes) and non-natural sources.
ž  H2S +O2 à SO2
ž  SO2 + O2 à SO3 (sulfur trioxide) or
ž  SO2 + H2O à H2SO4 (sulfuric acid) à acid
deposition, sulfur returned to water and soil,
taken up by plants, animals.
ž  Sulfur
containing coal, when burned,
releases SO2
ž  Refining oil to make gasoline and heating oil
ž  Extracting Cu, Pb, Zn from sulfur containing
compounds in rocks mined for these metals.
Sulfur dioxide in atmosphere Smel2ng Burning Refining coal fossil fuels Sulfur in animals (consumers) Dimethyl sulfide a bacteria byproduct Sulfur in plants (producers) Mining and extrac2on Sulfur in ocean sediments Process Reservoir Pathway affected by humans Natural pathway Sulfuric acid and Sulfate deposited as acid rain Uptake by plants Decay Decay Sulfur in soil, rock and fossil fuels Fig. 3-22, p. 74