biochemical cycles

• haber process

  Atmospheric nitrogen is removed via the Haber Process and fixed into ammonia which is then used in fertiliser production

  This creates a flow from the atmospheric store to the lithospheric store, when fertiliser is applied to the soil
• • nitrate fertilisers can increase flow of nitrogen from lithosphere to hydrosphere - nitrates leached from soil by infiltrating water + end up in rivers or lakes where they can cause eutrophication
  • Planting legumes may increase levels of nitrogen compounds in soil, due to nitrogen fixing root nodule bacteria 
  • Digging drainage ditches aerates the soil, increasing the number of nitrifying bacteria + reducing the number of denitrifying bacteria 
  • Soil disturbance also aerates the soil,

  Soil disturbance also increases the rate of decomposition which releases more NOx into the atmosphere
• phosphorus store
• phosphorus cycle-

  • Phosphorus is not found in a gaseous phase
  • Only added to into an ecosystem by the weathering of rocks, which is a very slow process
  • Phosphate ions are also not as soluble as ammonium or nitrate ions, so they are always in shorter supply in soil water or in rivers / lakes / oceans
• Mycorrhizal fungi-

  Mycorrhizas are beneficial fungi growing in association with plant roots, and exist by taking sugars from plants ‘in exchange’ for moisture and nutrients gathered from the soil by the fungal strands. The mycorrhizas greatly increase the absorptive area of a plant, acting as extensions to the root system.
• • The phosphate in fertilisers often comes from guano (bird or bat faeces) which is rich in phosphoric acid or from ground up animal bones
  • Adding phosphate fertilisers to the soil increases transfer to the hydrosphere via leaching

  This increases eutrophication (in the same way that nitrates do)
• pollution-

  • Grey water is water that has been used domestically for cleaning
  • Grey water contains detergent (washing powder, soap, washing-up liquid) which has high levels of phosphates

  When grey water is released into the sewage system if it is not treated correctly (by phosphate stripping) it can get into the hydrosphere and cause eutrophication
• ionisation- processes such as lightning and meteor trails provide the energy for atmospheric nitrogen and oxygen to react to produce nitrates of oxygen
• fixation- some micro-organisms can chemically reduce nitrogen to ammonia. They may be free-living bacteria in the soil or they may live symbiotically in the root nodules of legumes.
• food chains- nitrogen passes between organisms as amino acids and proteins in food
• nitrification- nitrification involves the oxidation of ammonium ions to nitrites then to nitrates by nitrifying bacteria in the soil
• denitrification- the chemical reduction of nitrates in soil to nitrogen and nitrogen oxide gases by denitrifying bacteria in the soil reduces soil fertility. this normally occurs under anaerobic conditions
• leaching- the high solubility of nitrates means they are easily leached from the soil into water bodies where they act as nutrients for aquatic plants and algae
• root absorption- plants absorb nitrogen as soluble ions, mainly as nitrates but also as ammonium ions
• ammonification- the amino groups in proteins are released as ammonium ions by the action of bacteria, fungi and detrivores as they decompose dead organic matter
• phosphorus cycle

  1. Weathering:rocks break down due to weathering processes l releasing phosphorus into the soil and water.
  2. Absorption by Plants: Plants absorb phosphorus from the soil through their roots.
  3. Consumption and Trophic Transfer: Animals get phosphorus by eating plants or other animals that have already taken in phosphorus.
  4. Decomposition: When plants +animals die, decomposer organisms like bacteria and fungi break down their remains.
  5. Sedimentation and Geological Processes:
  6. Leaching and Runoff: