5.4 Nutrient Cycles Flashcards
What cycles have nutrients recycled
Nitrogen and Phosphorus Cycles
What is the recylcing of nutrients (phosphorus and nitrogen) dependant on
Bacteria
What are saprobionts
- Organisms that decompose dead organic matter
- By secreting digetive enzymes extracellulary
- Hydrolysisng polymers into monomers
What is the role of Mycorrihizae
Facilitates the uptake of water and inorganic ions by plants
Nitrogen Cycle Stage: Nitrogen gas in atmosphere to ammonia
Nitrogen Fixation
Nitrogen Cycle Stage: Ammonia to nitrites then nitrates
Nitrification
Nitrogen Cycle Stage: Nitrites then nitrates to nitrogen gas in atmoshpere
Denitrification
Nitrogen Cycle Stage: Dead organic matter to amino-acids
Saprobioitc Nutrition
Nitrogen Cycle Stage: Amino-acids to ammonia
Ammonification
What carries out nitrogen fixation and where
- Nitrogen fixing bacteria
- In soil
- Root nodules of legumes
What carries out nitrification and where
Nitrifying bacteria in the soil
What carries out denitrification
Denitrifiying bacteria
What sort of process is denitrification
Anaerobic
What carries out sapreobiotic nutrition
Saprobionts
What carries out ammonification
Saprobionts
In what conditions does denitfification occur in
Water-logged soil
What is the purpose of fertilisers
- Replace minerals lost (nitrates and phosphates) from the soil
- By harvesting plants and removing livestock
Point of comparison for natural vs artificial fertilisers
- Natural need to be decomposed by saprobionts, so are longer lasting
- Artificial are absorbed quicker
Describe leaching
When mineral ions dissolve in the water from rain, and run-off into watercourses
Describe how farmers could increase the productivity of crops
- Fertilisers
- Selective breeding
- Crop rotation, for pest reduction
- Plough the soil to aerate it, reducing denitrification and increasing nitrification
Describe the process of eutrophication
- Higher concentration of mineral ions in the water due to leaching
- Rapid algal growth occurs, and an algal bloom, covering the surface of the water
- Algae blocks sunlight, so aquatic plants cannot photosynthesise
- Aquatic plants die
- Saprobionts decompose dead aquatic plants
- This increases the bacterial poppulation, that are respiring aerobically
- Oxygen concentration in water falls
- Causes death of aquatic animals
