13.5 Cycling of Matter
Energy flows from the sun to the earth and back out
again into space creating an open system for earth
• Matter on the other hand on earth is a closed system?
– Why?
Hint: Law of Conservation of matter
– Give an example or two!
Oxygen
Carbon
Water
Nitrogen
– What 4 elements make up 96% of the human body?
COHN
13.5 Cycling of Matter
KEY CONCEPT
Matter cycles in and out of an ecosystem.
13.5 Cycling of Matter
Water cycles through the environment.
• The hydrologic, or water, cycle is the circular pathway of
water on Earth.
• Organisms all have bodies made mostly of water.
13.5 Cycling of Matter
About 326 million trillion gallons of water on earth.
• If all that water could fit in a 1 gallon container just 3
teaspoons would represent all the available water for life
– Rest salty and locked in ice
13.5 Cycling of Matter
Elements essential for life also cycle through
ecosystems.
• A biogeochemical cycle is
the movement of a
particular chemical through
the biological and
geological parts of an
ecosystem.
• The main processes
involved in the oxygen
cycle are photosynthesis
and respiration.
13.5 Cycling of Matter
• Oxygen cycles indirectly through an ecosystem by the
cycling of other nutrients. Ex. Break down of limestone by
acid rain
oxygen
photosynthesis
respiration
carbon
dioxide
13.5 Cycling of Matter
• Carbon is the building block of life.
– The carbon cycle moves carbon from the atmosphere,
through the food web, and returns to the atmosphere.
– Carbon is emitted by the burning of fossil fuels.
– Other sources include rocks (limestone), bicarbonate,
CO2 in air, Dead stuff
– Some carbon is stored for long periods of time in areas
called carbon sinks. Ex Trees
13.5 Cycling of Matter
Carbon Cycle
13.5 Cycling of Matter
• The nitrogen cycle mostly takes place underground.
– Some bacteria convert gaseous nitrogen into ammonia
through a process called nitrogen fixation.
– Some nitrogen-fixing bacteria live in
nodules on the
nitrogen in
atmosphere
roots of plants;
animals
others live
freely in
the soil.
plant
nitrogen-fixing
bacteria in
decomposers
roots
ammonification
nitrogen-fixing
ammonium
bacteria in soil
nitrifying
bacteria
nitrates
nitrifying
bacteria
nitrites
denitrifying
bacteria
13.5 Cycling of Matter
– Ammonia released into the soil is transformed into
ammonium.
– Nitrifying bacteria change the ammonium into nitrate.
– Nitrogen moves through the food
web and returns nitrogen in
atmosphere
to the soil during
animals
decomposition.
plant
nitrogen-fixing
bacteria in
decomposers
roots
ammonification
nitrogen-fixing
ammonium
bacteria in soil
nitrifying
bacteria
nitrates
nitrifying
bacteria
nitrites
denitrifying
bacteria
13.5 Cycling of Matter
• The phosphorus cycle takes place at and below ground
level.
– Phosphate is released by the weathering of rocks.
– Phosphorus moves through the food web and returns to
the soil during
decomposition.
rain
geologic uplifting
– Phosphorus leaches
into groundwater
weathering of
phosphate from rocks
from the soil and
runoff
plants
is locked in
sediments.
animalsphosphate
phosphate in solution
in soil
– Both mining and
leaching
agriculture add
sedimentation
phosphorus into
decomposers
forms new rocks
the environment.