Section 13-5

“Cycles”

13.5 Cycling of Matter

KEY CONCEPT:

Matter cycles in and out of an ecosystem.

Fill in details as we

go through the notes

13.5 Cycling of Matter

The hydrologic cycle, or water cycle, is

the circular pathway of water on Earth. precipitation condensation

transpiration

evaporation

water storage

in ocean

surface

runoff

lake

groundwater

13.5 Cycling of Matter

Key terms for the water cycle:

• Precipitation: moisture that falls to the

ground (rain, snow, sleet, hail)

• Evaporation: changing from liquid to

gas (water to water vapor)

• Transpiration: plants give off water

vapor from their leaves to the air

• Condensation: changing from gas to a

liquid (little water droplets form on the

outside of a cold glass of lemonade - that’s

condensation)

13.5 Cycling of Matter

• Oxygen Cycle:

• Plants make food by photosynthesis

–They use carbon dioxide (CO2) to

make oxygen (O2)

• Animals breathe out carbon by

respiration

–They use oxygen (O2) and breathe

out carbon dioxide (CO2)

–By the way … humans are animals

too

13.5 Cycling of Matter

Oxygen Cycle:

oxygen

respiration

carbon

dioxide

photosynthesis

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 also emitted by the

burning of fossil fuels (like wood,

oil, gasoline, and coal)

13.5 Cycling of Matter

13.5 Cycling of Matter

nitrogen in

atmosphere animals

denitrifying

bacteria

nitrifying

bacteria

nitrifying

bacteria

ammonium

ammonification

decomposers

nitrogen-fixing

bacteria in soil

nitrogen-fixing

bacteria in

roots

nitrates

nitrites

plant

The nitrogen cycle mostly takes place underground.

The Nitrogen Cycle

13.5 Cycling of Matter

The Nitrogen Cycle

Nitrogen-fixing bacteria convert nitrogen gas in

the atmosphere into ammonia.

Ammonification: Decomposers break down

animal excretions, dead animal and plant matter

and convert nitrogen into ammonium.

Nitrifying bacteria change the ammonium into

nitrate.

Denitrifying bacteria use nitrates as an oxygen

source and release nitrogen gas into the

atmosphere.

13.5 Cycling of Matter

nitrogen in

atmosphere animals

denitrifying

bacteria

nitrifying

bacteria

nitrifying

bacteria

ammonium

ammonification

decomposers

nitrogen-fixing

bacteria in soil

nitrogen-fixing

bacteria in

roots

nitrates

nitrites

plant

The Nitrogen Cycle

Some nitrogen fixing bacteria live in nodules on roots of plants

such as beans and peas; others live freely in soil.

13.5 Cycling of Matter

nitrogen in

atmosphere animals

denitrifying

bacteria

nitrifying

bacteria

nitrifying

bacteria

ammonium

ammonification

decomposers

plant

nitrogen-fixing

bacteria in soil

nitrogen-fixing

bacteria in

roots

nitrates

nitrites

– Nitrogen moves through the food web and returns

to the soil during decomposition.

13.5 Cycling of Matter

13.5 Cycling of Matter

The Phosphorus Cycle

• Begins when phosphate is released by the weathering of

rocks.

• Phosphorus moves from producers to consumers through

the food web.

• Decomposers break down dead organisms which release

phosphorus back into the soil or water for producers to use.

• Some phosphorus leaches into groundwater from the soil

and settles at bottom of bodies of water such as lakes; over

thousands of years the phosphorus in the sediments

eventually become rock again, and the cycle continues.

13.5 Cycling of Matter

Both mining and

agriculture runoff

also add

phosphorus into

the environment.