B1.6:Waste Materials and The Carbon Cycle

The cycle of elements:

• Living things are made of materials which are needed for growth and other life processes.
• Plants take elements such as carbon and oxygen from the soil or air and turn them into complex compounds (e.g. proteins) that make up living organisms.
• These compounds are passed through a food chain.
• They return back to the environment in waste products produced by the organisms or when they die.
• Materials decay because they are digested/broken down by microorganisms.
• Microorganism work best in warm, moist conditions as well as places with a lot of oxygen for respiration.
• Respiration produces heat which increases the temperature of their environment even further.
• The important elements are returned to the soil, used by new plants and put back into the food chain.
• In a stable community the materials taken out of the soil and used are balanced by those that are put back in.

Kitchen waste and garden waste can be made into compost.

Compost is decayed remains of animal and plant matter that can be used as a fertiliser to recycle nutrients back into the soil.

Compost bins rereate the ideal conditions for decay. Some features include:

• mesh sides - let oxygen in for respiration
• microoganisms - generate warmth
• lid - stops water vapour from escaping so keeps it moist

CARBON CYCLE - The continuous cycle of carbon from the air, through food chains and back into the air

Carbon is taken out of the air - carbon is removed from the air as carbon dioxide when green plants and algae use it for photosynthesis. They turn carbon dioxide into carbon compounds to make carbohydrates, proteins and fats.

Carbon moves through food chains - carbon is passed along the food chain when animals eat other organisms so the energy from photosynthesis is transferred up the food chain. Detrius feeders and microorganisms break down dead organisms and animal waste,which puts carbon back into the soil and are is taken up by plants as nutrients.

Carbon is returned to the air - carbon is put back into the air when green plants and algae respire. The combustion (burning) of products made by plants and animals and fossil fuels also puts carbon dioxide back into the air.