Cycling of Matter in Ecosystems
When living things use or lose energy, it gets constantly replaced by the sun, but,
the amount of matter on earth is fixed.
All living things on earth use and reuse the same matter over and over again.
THE CARBON CYCLE
Organic Matter- substances that contain atoms of Carbon (C) bonded with
Hydrogen (and often Oxygen and Nitrogen)
For Example- protein Sugar and fats
Inorganic Matter- substances that do not contain Carbon bonded with Hydrogen
For Example- CO2, H2O and NH3 (ammonia)

Carbon is found in the atmosphere as a gas- Carbon Dioxide (CO2) and
is used by plants during photosynthesis (inorganic to organic)
CO2
+
Carbon dioxide
H2 O
+
water
ENERGY
light
=
C6H12O6
+
carbohydrate(sugars)
O2
oxygen

To balance everything, carbon is released back into the environment
through cellular respiration by plants and animals (organic to inorganic)
C6H12O6
+
O2 =
CO2
+
H2O
+
ENERGY
carbohydrate(sugars)
oxygen
Carbon dioxide
water
light

Plants have carbon and when herbivores eat plants and carnivores eat
meat, they are consuming carbon!

To balance everything, when organisms die, decomposers break down
the organic material and return carbon and other nutrients back to
plants.

Sometimes, organic matter doesn’t decay very quickly. This matter can
collect deep in rock to make fossil fuels (e.g., coal, petroleum and
natural gas).

Two ways that this carbon can be returned to the cycle are, mining or
weathering AND burning of fossil fuels.

The ocean contains a huge amount of dissolved carbon dioxide. This CO2
is used by plants (e.g. algae) for photosynthesis.

Herbivores and carnivores in the ocean also get carbon.

This CO2 is returned when plants perform cellular respiration and
animals respire (breathe out).
CARBON HAS 3 MAIN SINKS
 Atmosphere (smallest)
 Oceans (biggest)
 Earth’s crust and rocks
GREATEST CARBON RETURN
 Cellular respiration (opposite of photosynthesis)
 Burning matter or fuel
 Decomposition
 Deforestation