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Cycles of Matter
MATTER CYCLES
Each of the elements that is vital for life exists
on Earth in a closed loop of cyclical changes.
From a systems point of view, Earth is
essentially a closed system with respect to
matter.
ENERGY FLOWS
The functioning of our planet relies on a constant input of energy from
the sun. This energy leaves Earth in the form of heat flowing to outer
space. From a systems point of view, Earth is an open system with
respect to energy.
LIFE WEBS
A vast and intricate network of relationships connects all Earth's
organisms with each other and with the cycles of matter and the flows of
energy. From a systems point of view, Earth is a networked system with
respect to life.
Recycling in the Biosphere
• Recycling in the
Biosphere
– Energy and matter
move through the
biosphere very
differently.
Recycling in the Biosphere
• Recycling in the
Biosphere
– Energy and matter
move through the
biosphere very
differently.
– Unlike the one-way
flow of energy,
matter is recycled
within and between
ecosystems.
• Elements, chemical compounds, and other forms of
matter are passed from one organism to another and
from one part of the biosphere to another through
biogeochemical cycles.
• Matter can cycle because biological systems do not
use up matter, they transform it.
• Matter is assembled into living tissue or passed out of
the body as waste products.
The Water Cycle
• Water moves between the ocean, atmosphere, and land.
• Let’s review some of the terms of that cycle!
• The process by which water changes from a
liquid form in the ocean or other bodies of water
into an atmospheric gas is called evaporation.
• Water can also enter the atmosphere by
evaporating from the leaves of plants in the
process of transpiration.
• Water vapor condenses into tiny droplets that
form clouds (condensation), and then returns
to Earth’s surface as precipitation (rain).
• Water enters streams or seeps into soil where it
enters plants through their roots to start the
cycle all over again!
Nutrient Cycles
• Nutrient Cycles
– All the chemical substances that an organism
needs to sustain life are its nutrients.
– Every living organism needs nutrients to build
tissues and carry out essential life functions.
– Similar to water, nutrients are passed between
organisms and the environment through
biogeochemical cycles.
Nutrient Cycles
• Primary producers, such as plants, usually
obtain nutrients in simple inorganic forms from
their environment.
• Consumers obtain nutrients by eating other
organisms.
Carbon Cycle
•Carbon is a
key ingredient
of living tissue.
CO2 in
Atmosphere
•Biological
processes, such
as
photosynthesis,
respiration, and
decomposition,
take up and
release carbon
and oxygen.
Photosynthesis
feeding
Respiration
Decomposition
•Geochemical
processes, such
as erosion and
volcanic activity,
release carbon
dioxide to the
atmosphere and
oceans.
Volcanic
activity
Human
activity
Erosion
CO2 in Ocean
Respiration
Uplift
Deposition
Photosynthesis
Fossil fuel
feeding
Deposition
Carbonate
Rocks
•Biogeochemical
processes, such
as the burial and
decomposition
of dead
organisms and
their conversion
under pressure
into coal and
petroleum (fossil
fuels), store
carbon
underground.
Carbon Cycle
CO2 in
Atmosphere
Photosynthesis
feeding
Respiration
Decomposition
•Human
activities, such
as mining,
cutting and
burning forests,
and burning
fossil fuels,
release carbon
dioxide into the
atmosphere.
Volcanic
activity
Human
activity
Erosion
CO2 in Ocean
Respiration
Uplift
Deposition
Photosynthesis
Fossil fuel
feeding
Deposition
Carbonate
Rocks
Nitrogen Cycles
– The Nitrogen Cycle
• All organisms require nitrogen to make
proteins.
• Although nitrogen gas is the most abundant
form of nitrogen on Earth, only certain types of
bacteria can use this form directly.
• Such bacteria live in the soil and on the roots of
plants called legumes. They convert nitrogen
gas into ammonia in a process known as
nitrogen fixation.
• Other
bacteria in the
soil convert
ammonia into
nitrates and
nitrites.
• Once these
products are
available,
producers
can use them
to make
proteins.
• Consumers
then eat the
producers
and reuse the
nitrogen to
make their
own proteins.
• When organisms
die,
decomposers
return nitrogen
to the soil as
ammonia.
• The ammonia
may be taken up
again by
producers.
• Other soil
bacteria convert
nitrates into
nitrogen gas in a
process called
denitrification.
• This process
releases
nitrogen into the
atmosphere
once again.
Nitrogen Cycle
N2 in
Atmosphere
Synthetic fertilizer
manufacturer
Uptake by
producers
Bacterial
nitrogen fixation
Decomposition
Reuse by
consumers
Decomposition
excretion
NH3
Atmospheric
nitrogen fixation
Uptake by
producers
Reuse by
consumers
Decomposition
excretion
NO3 and
NO2
• Phosphorus is essential to
organisms because it helps
forms important molecules
like DNA and RNA.
• Most phosphorus exists in the
form of inorganic phosphate.
Inorganic phosphate is
released into the soil and
water as sediments wear
down.
• Organic phosphate moves
through the food web and to
the rest of the ecosystem.
• Phosphate, eventually enters
the ocean, where it is used by
marine organisms.
• Some phosphate stays on
land and cycles between
organisms and the soil. Plants
bind the phosphates into
organic compounds.
Phosphorus
Cycle
Organisms
Land
Ocean
Sediments
Nutrient Limitation
• The primary productivity of an ecosystem is the rate at which organic
matter is created by producers.
• One factor that controls the primary productivity of an ecosystem is the
amount of available nutrients.
• If a nutrient is in short supply, it will limit an organism's growth.
• When an ecosystem is limited by a single nutrient that is scarce or cycles
very slowly, this substance is called a limiting nutrient.
• When an aquatic Nutrient
ecosystem receives a
large input of a
limiting nutrient—such
as runoff from heavily
fertilized fields—the
result is often an
immediate increase in
the amount of algae
and other producers.
• This result is called
an algal bloom.
• Algal blooms can
disrupt the equilibrium
of an ecosystem.
Limitation
Nutrient Cycles
CO2 in
Atmosphere
Photosynthesis
feeding
Volcanic
activity
Respiration
Decomposition
Human
activity
Erosion
CO2 in Ocean
Respiration
Uplift
Deposition
Photosynthesis
Fossil fuel
feeding
Deposition
Carbonate
Rocks
– Transpiration is part of the
•
•
•
•
water cycle.
carbon cycle.
nitrogen cycle.
phosphorus cycle.
– Carbon is found in the atmosphere in the
form of
•
•
•
•
carbohydrates.
carbon dioxide.
calcium carbonate.
ammonia.
– Biologists describe nutrients as moving through
cycles because the substances
• start as simple organic forms that plants need.
• provide “building blocks” and energy that organisms
need.
• are passed between organisms and the environment
and then back to organisms.
• are needed by organisms to carry out life processes.
– The only organisms that can convert
nitrogen in the atmosphere into a form
useful to living things are nitrogen-fixing
•
•
•
•
plants.
bacteria.
detritivores.
animals.
– When an aquatic ecosystem receives a
large input of a limiting nutrient, the result
is
•
•
•
•
runoff.
algal death.
algal bloom.
less primary productivity.