Recycling Flashcards
What is carbon?
Carbon is one of a number of elements that are found in living organisms.
Why does Carbon need to be recycled?
Carbon needs to be recycled so it can become available again to other organisms.
What does feeding do?
Feeding passes carbon compounds along a food chain or web.
How is carbon dioxide removed from the air?
Carbon dioxide is removed from the air by photosynthesis in plants.
Carbon dioxide is released into the air by:
- Plants and animals respiring
- Soil bacteria and fungi acting as decomposers.
- The burning of fossil fuels (combustion).
Why are oceans often called carbon sinks?
Because carbon dioxide can be locked up in limestone for a long time.
What is carbon dioxide also absorbed by?
Carbon dioxide is also absorbed from the air by the oceans. Marine organisms make shells of carbonate, which become limestone rocks.
How does the carbon in limestome return to the air?
The carbon in limestone can return to the air as carbon dioxide during volcanic eruptions or weathering.
What happens in the nitrogen cycle?
- Plants take in nitrogen as nitrates from the soil to make proteins for growth
- Feeding passes nitrogen compounds along the food chain or web
- The nitrogen compounds in dead plants and animals are broken down by decomposers and returned to the soil.
A number of microorganisms are responsible for the recycling of nitrogen:
- Decomposers are soil bacteria and fungi and they convert proteins and urea into ammonia.
- Nitrifying bacteria convert the ammonia to nitrates
- Denitrifying bacteria convert nitrates to nitrogen gas.
- Nitrogen-fixing bacteria living in root modules (or in the soil) fix nitrogen gas - this also occurs by the action of lightning.
What do decomposers need to breakdown dead material in soil?
- They need oxygen and a suitable pH.
- Decay will therefore be slower in waterlogged soils as there will be less oxygen
- Acidic conditions will also slow down decay.
