Activity #18:
Cycles of Matter
EQ
• How do Earth’s biotic and abiotic factors
interact to shape ecosystems and affect the
survival of organisms over time?
• Why is the cycling of matter important to life
on earth?
Challenge Question
• Describe how matter cycles through an ecosystem.
Vocabulary
• Biogeochemical cycle
• Denitrification
• Nitrogen fixation
Four Main Elements of
Living Things:
• CHON
• Make up:
o
o
o
o
o
Water
Carbs
Lipids
Nucleic acids
Proteins
Energy & Matter
• Energy flows in a one way direction starting from the
sun
o It is not recycled
• Matter is recycled through the biosphere
Matter is Recycled Within and
Between Ecosystems
• This is different than the one-way flow of energy
through an ecosystem
• Biogeochemical Cycles- process in which elements,
chemical compounds (water and nutrients), and
other forms of matter are passed from one
organism to another and from one part of the
biosphere to another
Processes in Biogeochemical
Cycles can be…
• Biological- cellular respiration,
photosynthesis, decomposition, nitrogen
fixation, etc.
• Geological- erosion, rock formation, heat
and pressure from the earth
• Chemical- formation of clouds/precipitation
• Physical- flow of running water
• Human Activity- logging, deforestation,
burning fossil fuels, wastes, fertilizers
Energy and Matter
• Energy powers the cycles of matter
• Matter is transformed, never created or destroyed
The Water Cycle
• Water moves between oceans, atmosphere, and
land
• Can be inside or outside of organisms
How does water vapor
enter the atmosphere?
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•
•
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Evaporation
Transpiration
Combustion
Respiration
Once water vapor is in the
atmosphere…
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Condensation
Precipitation
Runoff
Groundwater
Also use evaporation
Nutrient Cycles
• The cycling of carbon, nitrogen, and phosphorus
through organisms and the environment are
especially important
The Carbon Cycle
• Carbon is a major
component of all
organic compounds
• Found in some
inorganic
compounds
o Example: calcium
carbonate (CaCO3) –
molecule that is part of
animal skeletons
o Example: carbon dioxide
(CO2) - major part of the
atmosphere and
necessary for
photosynthesis
Carbon & Oxygen
• Oxygen often cycles with carbon through the
biosphere, particularly due to photosynthesis and
cellular respiration.
Fossil Fuels
• Fossil Fuels: Energy rich fuels (coal, oil, and natural
gas) created from carbon-containing compounds
of ancient, dead forests, marine organisms, or other
animals have been buried and transformed by
pressure and heat.
Reservoirs
• Major reservoirs (locations of large
amounts) of carbon in the biosphere
include the:
o
o
o
o
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Atmosphere
Oceans
Rocks
Fossil Fuels
Forests
Video
• bromothymol blue 3:20
The Nitrogen Cycle
• Nitrogen is required to make amino acids and
nucleic acids
Forms of Nitrogen
• Different forms of nitrogen occur naturally in the
biosphere
• Nitrogen gas (N2)makes up 78% of earth’s
atmosphere
• Ammonia (NH3), nitrate ions (NO3-), nitrite ions (NO2-)
are found in soil, in the wastes produced by many
organisms, and in dead and decaying organic
matter.
• Dissolved nitrogen exists in several forms in the
ocean and other large water bodies
Nitrogen gas is the most abundant
form of nitrogen on Earth
• Only a handful of organisms – certain types of
bacteria – can use this form directly
• They “change” (=fix) the nitrogen into usable forms
• The usable forms can then be used by other
organisms
• Thus, nitrogen-fixing bacteria are an essential part
of the nitrogen cycle
Nitrogen Fixation
• Nitrogen Fixation: The conversion of Nitrogen Gas
(not usable) into Ammonia, Nitrates, and Nitrites
(usable) by bacteria
• Some of these bacteria live in the soil whereas
others live on the roots of certain plants called
legumes (ex. peanuts, peas, soybeans)
• Bacteria are the driving force of the nitrogen cycle!
Available Nitrogen
• Once these forms of nitrogen are available, primary
producers can use them to make proteins and
nucleic acids.
• Consumers eat the producers and reuse nitrogen to
make their own nitrogen-containing compounds
(and so on through the food web).
Nitrogen Cycle
Fertilizers Contain
Nitrogen & Phosphorus
• Eutrophication:
excess growth of
algae due to
increased levels of
fertilizers in the
water
o Creates an algal bloom
o Algae takes oxygen from
other organisms and may
release toxins