Overview of the Carbon Cycle
Energy enters an ecosystem as sunlight and leaves as heat (linear)
The flow of nutrients through an ecosystem is not linear, but cyclic. Simple cycle:
> Nutrient taken up by producers (plants) as a simple inorganic molecule
>Producer incorporates the nutrient into complex organic molecules
>When consumers (animals) eat the producer, the nutrient is passed on
>Then passed along food chain when these animals are eaten by other consumers
>When producers and consumers die, their complex molecules are broken down by saprobiotic microorganisms (decomposers) that release the nutrient in its original simple form.
The main source of carbon is from carbon dioxide in the atmosphere. Photosynthetic organisms remove it from the air to build it up into macromolecules. All organisms then return it to the air through respiration.