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Cycles of Matter
Bio Chapter 3-3
Energy
Energy -essential in an ecosystem and to
organisms but they also need:
Water, minerals, and other compounds to
survive
In most organisms more than 90% of body is
made of four elements:
Oxygen
Nitrogen
Hydrogen
Carbon.
Recycling in the
Atmosphere
Energy flows in one direction
Only 10 % is available to each tropic level
above it
Matter is recycled and flows within and
between ecosystems continuously.
Biogeochemical Cycles
A Biogeochemical cycle is when: elements,
compounds and matter are passed from one
organism to another and from one ecosystem
to another
Biogeochemical cycles connect all:
biological, geological and chemical aspects
of the biosphere.
Matter
Matter cannot be used up, but can be
transformed.
Biogeochemical cycle passes the same
molecules around again and again.
You are breathing oxygen that dinosaurs
might have inhaled millions of years ago.
Earth's biosphere can be thought of as a
sealed container into which nothing new is
ever added except the energy from the Sun
Example
Matter can be reused and assembled into living tissue in
the body or passed out as waste
Example
You are a carbon atom in a molecule of carbon dioxide.
You are floating in air. The leaf of a blueberry bush
absorbs you during photosynthesis. You then become part
of a carbohydrate molecule used to make fruit. The fruit is
eaten by an animal and within a few hours you are passed
out through waste. Then a beetle eats you up. Then an owl
eats the beetle that ate you. Then you are released back
into environment when owl exhales the carbon dioxide
that you are part of. Then the cycle starts again
Nutrient Cycle
Nutrients- all chemical substances an
organism needs to live. Our bodies “building
blocks”
Producers obtain nutrients from simple
inorganic molecules in the environment
Consumers obtain nutrients from eating
other organisms
Every living organism needs nutrients to
carry out life functions. Similar to water,
nutrients are passes between organisms and
the environment through biogeochemical
cycles.
The Water Cycle
Water moves between: ocean-atmosphere- land
Water molecule enter atmosphere as water vapor in
air
Water that leaves oceans and other bodies of water
and travels into atmosphere is called Evaporation
If it comes off leaves of plants then its called
transpiration
Cont.
During the day the sun heats the atmosphere. As warm
damp air rises it cools down. Water vapor eventually turn
into tiny droplets of water that form clouds. This is called
condensation
When water droplets become large enough they return to
earth and this is called precipitation: rain, snow, sleet, hail.
Rain can also seep into soil and become ground water.
This then enters plants through roots and water cycle
begins again. Water run-off travels along earth until it
reaches oceans or lakes
The Carbon Cycle
Carbon is the key ingredient in all living organisms
However only about 1% of all carbon in the world
circulates within the biosphere
Where is the rest?
There are many ways carbon
cycles
Biological processes:
Photosynthesis
respiration
Decomposition of plants and animals
Geochemical Processes
release of carbon by volcanoes
There are many ways
carbon cycles
Mixed biogeochem processes
Burying carbon rich dead organisms and
conversion into petroleum(fossil fuels)
Human activity
mining
burning of fossil fuels
cutting or burning of forests
The Nitrogen Cycle
All organisms need nitrogen to make amino
acids= proteins
Different types of nitrogen found in the world:
Nitrogen gas (N2) makes up 78% of earth’s
atmosphere.
Only bacteria in soil and roots can use
nitrogen gas
They convert gas into ammonia through
nitrogen fixation..
Nitrogen cycle cont.
Other bacteria in soil convert ammonia into nitrates
and nitrites
producers can then use nitrates/nitrites to make
proteins.
Consumers then eat the producers and reuse the
nitrogen to make their own proteins
Cont.
When organisms die decomposers return
the nitrogen to the soil as ammonia.
The ammonia is then taken up again by
producers.
Soil bacteria convert the nitrates into
nitrogen gas in a process called
denitrification.
The process releases nitrogen into the
atmosphere again.
The Phosphorus Cycle
Important in DNA and RNA so it’s essential to living
organisms.
It is not very common in the biosphere
Remains mostly in rock and soil minerals and in
ocean sediment
Doesn’t enter the atmosphere like carbon, oxygen and
nitrogen.
Cont.
As rocks gradually wear down phosphorus is released.
On land it washes into rivers and streams where it is
dissolved.
If it makes it way to oceans marine organisms can
use it.
Some phosphate stays on land and cycles between
organisms and the soil.
Plants absorb the phosphate from soil/water, plants
bind phosphate into inorganic compounds. Organic
phosphate moves through food web from producers
to consumers and to the rest of the ecosystem.
Nutrient Limitation
Primary productivity- the rate at which organic
matter is created by producers
Amount of available nutrient scan control primary
productivity
Limiting nutrient- when an ecosystem is limited by a
single nutrient that is scarce or cycles very slowly
Cont.
In oceans nitrogen is often the limiting nutrient
In streams, lakes, freshwater environments phosphorus is often
the limiting nutrient
Farmers often fertilize their field to boost productivity because
of limiting nutrients.
When an aquatic system receives a large input of a limiting
nutrient- say from runoff of a heavily fertilized field. The result
is an immediate increase in producers and algae. This is called
an algae bloom. This happens because more nutrients mean
more opportunity to grow and reproduce. If there are not
enough consumer this can result in algae covering the surface
and can upset the health of the environment.