Nutrient Cycling Flashcards
(7 cards)
Carbon Cycle
Plants absorb CO2 from atm and synthesise carbohydrates during photosynthesis
From carbs, plants produce lipids, proteins and nucleic acids (all containing C)
Molecules consumed by animals - entering their bodies following digestion
Both p and a release CO2 via respiration
Decomposers use DOM for food - some used in resp
Fossil fuels release CO2 into atmosphere when burnt
Carbon Cycle Diagram
Nitrogen Cycle
Plants absorb nitrate ions NO3- from soil
Plants use N in ions to synthesise amino acids - and so proteins, nucleotides and so nucleic acids
Molecules consumed by animals
Undigested matter egested as faeces
Animals prod nitrogenous waste products - ammonia and urea - excreted
Decomposers use DOM, faeces and urea for food
Protein and Nucleic Acid broken down and N released as ammonia or ammonium
Ammonia used by nitrifying bacteria and oxidised to nitrate ions - nitrates released when animals die
Nitrogen Fixing Bacteria
Add to the nitrogen available in plants
Some species Inhabit root modules of legumes
Are able to utilise gaseous nitrogen to synthesise organic nitrogen-containing compounds
Denitrifying Bacteria
Reduce N available to plants
Live in waterlogged and oxygen-deficient soils
Use nitrate and convert it to gaseous N which is returned to atm
How does removing crops for silage effect N cycle
Removed some primary production - less available to any grazing food chain
Means N containing cmpnds within plants are removed so that soil becomes depleted in nitrate - unless added in organic or inorganic fertilisers
Nitrogen Cycle Diagram
