Nutrient Cycles
Biosphere
Refers to the living layer of the Earth
It is a closed system: this means that every
part of it is recycled
Biospheres
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We call the Earth “Biosphere I”
Could we create a new closed biosphere?
Why would we want to do that?
Biosphere II
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Closed artificial biosphere built in Arizona
Held 3800 different species
Contains rainforest, grassland, desert & coral reef
After two years, many of the species had died out
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8 people lived here for 2 years (1991-1993)
They had to be entirely self-sufficient and
sustainable
Had to regulate their gas and nutrient
levels constantly
Atoms & Elements on Earth
● The atom is the simplest unit of matter on earth
● Elements are atoms of different types-- each has their
own chemical structure (number of protons, neutrons
and electrons) and each is different
● Each has a Chemical symbol (ie. oxygen is O, Mercury
is Hg)
Key Elements--- Nutrient Cycling
● On Earth, there are a few key elements that get used A
LOT and cycle through the hydrosphere, biosphere,
atmosphere and geosphere. This is called nutrient
cycling.
● These elements can be solids, liquids or gases and
combine to form different molecules (with other
elements)
● They are part of our bodies, our air, our soil and water
● We will look at 3-- Carbon (C), Nitrogen (N) and
Phosphorous (P)
The Carbon Cycle
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Where do you think most of the carbon is
on Earth?
−1.
−2.
−3.
−4.
−5.
−6.
−7.
The Carbon Cycle
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Where do you think most of the carbon is on
Earth?
−1.
Sedimentary Rock
−2. Marine Sediments
−3. Oceans
−4. Coal Deposits
−5. Soil and Organic matter
−6. Atmosphere
−7. Terrestrial vegetation
−8.Oil and gas deposits
Carbon Cycle Activity
The Nitrogen Cycle
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Nitrogen makes up 78% of the atmosphere
Like Carbon, nitrogen cycles through the
atmosphere, oceans, and soil.
It is the fourth most common element in
animals
Terms You'll Need To Know
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Nitrogen Fixation:
Nitrification:
Uptake:
Denitrification:
Terms You'll Need To Know
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Nitrogen Fixation:
Nitrification:
Uptake:
Denitrification:
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Humans and the Nitrogen Cycle
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Clearing land for lumber or agriculture
releases the nitrogen from the soil/plants
into the atmosphere
Humans and the Nitrogen Cycle
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Nitrates from factories react with water to
form HNO3(Nitric Acid) in the atmosphere
This acid returns to the Earth as acid rain
Humans and the Nitrogen Cycle
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Use of fertilizers have produced areas with
EXCESSIVE nitrogen called eutrophic
zones.
So much algae grows in these areas that
all the oxygen is consumed, a condition
called hypoxia.
No animals can live in these areas!
Nutrient Cycling video Short
Dead Zones on the West Coast
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Dead zones on the west
coast are natural
BUT
Run-off from major rivers
(Fraser, Columbia, etc)
are accelerating the
process
Dead zone videos--2
Phosphorus Cycle
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Phosphorus is
another element
which is critical to
plant growth
In animals,
phosphorus works
with calcium to
develop strong bones
Phosphorus Cycle
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Phosphorus DOESN'T exist in the
atmosphere, only in phosphates (PO43-)
that make up rocks and sediments
Plants absorb these phosphates
Animals get phosphates by eating the
plants
Phosphorus Cycle
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Excessive phosphorus (from fertilizers) flows
downstream into lakes and rivers
This can produce huge (and gross!) algae
blooms that use up all the oxygen
CBC - Save My Lake
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1 min → 10?
14 → 16
22 → 24
38 → 45