Terrestrial Nitrogen Cycle

Directions

  1. Draw an landscape showing the reservoirs. Label the reservoirs.
  2. Use arrows to represent the fluxes that connect reservoirs. Label the arrows.
  3. When finished, check that you have correct number of reservoirs and fluxes.

Reservoirs :

Where nitrogen and its compounds are stored or retained.

  1. Animals (rabbits)
  2. Atmosphere
  3. Decomposers (bacteria and fungi) in soil.
  4. Denitrifying bacteria in soil.
  5. Nitrifying bacteria in soil.
  6. Nitrogen-fixing bacteria living in plant root nodules.
  7. Nitrogen-fixing bacteria living in soil.
  8. Plants (alfalfa)
  9. Soil

Fluxes

Movement of nitrogen.

  1. Animals (rabbits) eat the plants (alfalfa) and convert it to animal tissue. Label = consumption.
  2. Decomposers (bacteria and fungi) in soil convert dead animals and their droppings into NH4+ that stays in soil. Label = ammonification.
  3. Denitrifying bacteria in soil convert NO3- to atmospheric N2. Label = denitrification.
  4. Nitrifying bacteria convert NH4+ in soil to NO3- that stays in soil. Label = nitrification.
  5. Nitrogen-fixing bacteria living in alfalfa root nodules take atmospheric N2 and convert it to NH4+ for use by the alfalfa. Label = nitrogen fixation.
  6. Nitrogen-fixing bacteria living in soil take atmospheric N2 and convert it to NH4+ that stays in soil. Label = nitrogen fixation.
  7. Plants (alfalfa) use NH4+ from nodules to make plant tissue. Label = uptake.
  8. Plants (alfalfa) use NO3- in soil to make plant tissue. Label = uptake.