Cycling of Matter in Ecosystems

Recycling Matter

• All life on Earth requires water and nutrients• These particles of matter don’t remain in your body

forever• Every part of every cell in your body is replaced over

time• We are like living recycling machines• Nutrients from food are used to repair and renew

all the cells in our body

• Approximately 2 million blood cells are replaced every second in your body.

• You are a fantastic recycling machine!!

Biogeochemical Cycles• As matter cannot be created or destroyed, it must be

produced or obtained from chemicals that already exist in the environment.

• Therefore biogeochemical cycles involve movement of matter (cycles) through the biotic and abiotic environment on earth.

• These cycles are: 1. Water Cycle2. Carbon Cycle3. Nitrogen Cycle

The Water Cycle

The series of processes that cycle water through the environment

Condensation

Precipitation

Collection

Evaporation

• Liquid water evaporates forming water vapour that travels through the atmosphere

• Water that is taken in by plant roots is released by leaves through transpiration

Transpiration & Evaporation

• The vapour eventually condenses• It forms liquid water or ice crystals in the

atmosphere

Condensation

• Vapour returns to the Earth as rain, hail or snow• Water falling on land and melting snow move across the

surface (runoff) and enter bodies of water• If this doesn’t occur it will enter the soil and groundwater

instead

Precipitation and Runoff

The Carbon Cycle

• All living things contain carbon.

• Carbon is found in the atmosphere and dissolved in the oceans as carbon dioxide (CO2)

• Carbon, from the atmosphere, is used by plants to make carbohydrates through the process

of photosynthesis

• Carbon is returned to the environment through the process of cellular respiration.

• Decomposers can release the carbon found in dead organisms and waste through cellular respiration as well.

• Carbon dioxide can dissolve in water to form carbonic acid, which can be used by water plants as a source of carbon.

• Most of the earth’s carbon is stored in carbon rich deposits• Fossil fuels are the most valuable carbon deposits• It is also stored in limestone from millions of years of dead

marine organisms• Carbon sinks are contained in plant tissues and dissolved in

oceans

Carbon Deposits

• Humans increase the concentration of carbon dioxide in the atmosphere through burning fossil fuels

• This causes climate change and alters average temperatures disrupting ecosystems

• Deforestation reduces the amount of photosynthesis needed for absorption of carbon dioxide

Human Activities and the Carbon Cycle

The Nitrogen Cycle

• The atmosphere is composed of 78% nitrogen gas, N2 but plants cannot use nitrogen in this form, it must be supplied in other forms:

• ammonium ion (NH4+)

• nitrate ion (NO3-)

Making Nitrogen UseableNitrogen Fixation• The process of converting N2 gas into usable

sources, such as ammonium (NH4+)

• This accomplished by bacteria or lightning.• Without bacteria, movement of nitrogen would

almost STOP completely!

Denitrifying Bacteria: • The process of converting nitrates (NO3

-) back into nitrogen gas (N2)

Class/Homework

• WS “Cycling of Matter”• Pg. 51 #5, 7 - 10