Transcript Biogeochemical Cycling

Biogeochemical Cycling
Earth Science Standards
7 a,b,c,d
• Energy flows thru the ecosystem
• Nutrients is vital to life are constantly being
recycled.
• Biogeochemical cycling: the cycling of
nutrients thru the ecosystem.
• They move nutrients (elements) from the
nonliving to living then back again.
• The earth contains a fixed amount of
elements: so they have to be recycled.
4 major Cycles
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Carbon Cycle
Nitrogen Cycle
Oxygen cycle
Phosphorous cycle
Carbon Cycle
• Carbon (C) is the base of all life.
• Comes from atmosphere, CO2.
• Plants use CO2 to complete the Photosynthesis
process:
6CO2 + 6 H20
C6H12O6 + 6O2
• Carbon is used to make glucose by plants and
algae.
• Glucose energy gets stored as starch in plant.
• Animal eats plant and the cycle continues
Pathways for Carbon Cycle
• Cellular Respiration: the breakdown of
glucose so plants can use it for energy.
The CO2 is present in the atmosphere
from humans exhaling.
Marine Organism
• CO2 is used to combine with calcium to
make hard limestone shells. These
limestone shells over million of years
become sediments settled = carbon
reservoirs.
Carbon into Fossil Fuels
• The bodies of plants and animals buried
for million of years, exposed to Earth’s
heat and pressure result in fossil fuels.
fuel get burned = CO2 back into
atmosphere.
Carbon and/or CO2 released
• Plate tectonics = volcanic eruption (gas)
• Weathered materials like limestone
• Food chain waste returned to the soil
where the organic molecules can be
utilized and turned back to atmosphere as
CO2.
• Also involves the creation of methane gas.
– Methane a hydrocarbon molecule that is
produced by anaerobic bacteria ( without air)
as a byproduct of their feeding process.
• Cows digestive tract
• Mud of rice paddies
Student activity objective
• Students will create a diagram that
illustrates all the sources from which
Carbon is created and recycled back into
the ecosystem.
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Identify all 7 sources of carbon production (7 points)
Use pictures to help explain the diagram (7 points)
Label the sources and title the diagram (8 points)
Use arrows to illustrate how the cycle continues within
the ecosystem. (3 points)
• Total 25 point assignment due tomorrow!
Oxygen Cycle
• Most abundant element in the Earth’s crust. 45%
• Second most abundant gas in the atmosphere
21%
• Can make up 63% of the human body
• Some oxygen combined with other elements to
form earth minerals and rocks.
• Dissolved in water, where marine organisms
utilize O for respiration.
• Ozone layer high in the stratosphere is made up
of oxygen and helps block ultraviolet rays.
Oxygen
• Part of the photosynthesis and respiration
process.
– Photosynthesis: O2 is a by-product.
– Respiration: O2 used to break down glucose
(plant food) to produce energy for plant
growth processes.
Nitrogen
• Important element (N) that is part of the
DNA molecule.
• Also a component of protein molecules.
• 5% of the human body is composed of
nitrogen.
• The source of nitrogen for the ecosystem
is the atmosphere.
• Earths atmosphere is 78% nitrogen
– Diatomic form n2
Nitrogen Cycle
• Begins when microscopic bacteria located
in the soil and in the roots of legumes
combines atmospheric nitrogen with other
atoms to form nitrogen compounds=
nitrification useable form of nitrogen by
plants.
• Plants use the useable form to produce
proteins.
• Plants containing nitrogen become part of
the food chain.
• Then waste expelled containing nitrogen
returning compounds back to the
environment and soil.
• Then decomposed by detritivores
decomposing organisms.
– Bacteria change back to N2 diatomic nitrogen
Human activity creating
Nitrogen
• Burning fossil fuels, causes atmospheric
nitrogen.
– Nitrogen combines with oxygen forming
nitrogen oxides.
• Can mix with water H2O and produce nitric
acid(acid rain).
Phosphorus (P)
• A macronutrient for plants. (P)
• Also part of DNA molecules of living
organisms.
• Individual cells use phosporus-containg
molecules, as an energy source.
• Major source NOT found in the
atmosphere, but rather in rocks.
• Weathered rocks is the main source for
the ecosystem.
Phosphorous Cycle
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Found in rocks
Phosphorous gets weathered
Phosphorous gets taken up by plants
Plants get eaten by animals
Animals waste transfers phosphorous
back into the earth.
• Limited in supply= limiting factor
• Complete Cornell notes and the unit
summary for biogeochemical notes. Must
be 8-10 sentences long.