nutrient cycles

• what is the chemical formula for ammonia?

  NH4
• in what form do plants get phosphorus?

  in the form of phosphate ions
• what reservoir does phosphate ions come from?

  sedimentary rocks
• describe the phosphate cycle?

  1.weathering and erosion of sedimentary rocks causes phosphate to dissolve into phosphate ions

  2.plants absorb phosphate ions and use it to create phosphate containing compounds such as ATP

  3.animals eat plants ect. and then produce phosphate containing compounds

  4.then animal and plants die or exctrete, which are broken down by saprobionts back into phosphate ions

  5.these are either reabsorbed or travel in the water within soil back to the sea

  6.thousand of years later new rocks form and the cycle continues
• where is nitrogen obtained from initially and in what form?

  the air - nitrogen gas
• what form is nitrogen absorbed in?

  nitrates
• what are the different forms for how nitrogen goes from a gas to nitrates?

  nitrogen → ammonium ions → nitrites → nitrates
• what is the stage called when nitrogen is converted from nitrogen to ammonia?

  nitrogen fixation
• explain nitrogen fixation?

  • nitrogen is converted into ammonia by nitrogen fixating bacteria
  • mutualistic nitrogen fixating bacteria convert nitrogen into ammonia and the plant absorbs it as ammonia in return for carbohydrates
  • free living nitrogen fixating bacteria convert nitrogen into ammonia which dissolved in the soil to ammonium ions which are then absorbed
• where do mutualistic nitrogen fixing bacteria live?

  on the plant roots
• whats after nitrogen fixation?

  nitrification
• describe nitrification?

  -

  • nitrification is the conversion of ammonium ions → nitrites → nitrates
  • ammonium ions are converted to nitrites using nitrifying bacteria
  • nitrites are converted into to nitrates using nitrifying bacteria
  • nitrifying bacteria rely on oxygen as they use it to aerobically respire and because its used in nitrification so the soil needs to be well aerated
• after nitrification, the nitrates are absorbed by plants then animals, the dead animals and exctretions are broken down by saprobionts, whats the next step called?

  ammonification
• what is ammonification?

  -ammonification is when the saprobionts break down the nitrogen containing compounds such as dna to ammonia

  -the ammonia is then converted into ammonium ions
• describe the role of saprobionts (2marks)

  1.saprobionts break down nitrogen-containing compounds such as DNA

  2.then produce ammonia which then turn into ammonium ions
• what step is after ammonification? kind of...

  denitrification
• what is dentrification?

  -dentitrification is when denitrifying bacteria converts nitrates into nitrogen gas

  -dentrifying bacteria respire anaerobically
• what are the two forms plant can absorb nitrogen?

  ammonia and nitrates
• what is mycorrhizae

  the relationship between the roots of plant and fungi
• what are the two benefits of mycorrhizae?

  1.increases surface area for water and mineral uptake

  2.fungi act as a sponge and holds onto water

  this is a mutal relationship in return for the products of photosynthesis such as carbohydrates
• what is the equation of net production of consumer:

  N = I - F + R
• why cant nitrogen be absorbed ?

  because it has a triple bond
• what are the units for for rates of productivity?

  Kj ha^-1 year^-1