Describe the nutrient cycles for a forest ecosystem. Note where microbes could be important and how might they enhance nutrient uptake by plants?. Ecology

General model for nutrient cycles in a forest:

  • Inputs: rain, dust, biological fixation, rock weathering.
  • Outputs: stream water, gas emissions (fire and nitrification), loss to ground water
  • Transfer of nutrients between plants and the soil (leaching from leaves, decomposition of litter, root turn over, death, animals excretion)
  • Internal redistribution of mobile nutrients such as Nitrogen and Phosphorus (retranslocation)

Nutrient cycles in a forest:

  • Nitrogen and Phosphorus cycle:
  • Nutrient starts in the soil is up taken by trees (this is assisted by the mycorrhizal endosymbiosis in the roots of trees)
  • It returns to the soil by litter fall, leaching and decomposition. The decomposition of organic matter is assisted by microbes called detritivores, which returns the nutrients to the soil.
  • This cycle keeps repeating.

Microbes are important in:

  1. Assisting plants in nutrient poor soils (such as Australia soils) to uptake nutrients
  2. Breaking down organic matter to make nutrients available to the soil again
  3. Breaking down atmospheric nitrogen can only be done by algae such as cyanobacteria
Materials by theme: