The Gersmehl Cycles (Nutrient Cycles)

The model of the nutrient cycle was first developed in 1976, by P.F. Gersmehl, who attempted to show differences between ecosystems. It regards nutrients, transferred and stored between three areas.

- Plants take in those nutrients where they are built into new organic matter.

- Nutrients are taken up when animals eat plants

- They are returned to the soil when animals die and the body is broken down by decomposers.

In all, nutrient cycles there are interactions between the atmosphere and soil and many food chains are involved.

Nutrient cycles vary greatly between ecosystems, as the rate of nutrient transfer is dependent on the amount of moisture, heat, vegetation and the length of the growing season.

Key words to note:

Nutrients - chemical elements and compounds needed for organisms to grow and function.

Nutrient stores - 3 types

Soil - mineral material on the immediate surface of the Earth

Litter - amount of organic matter, including humus and leaf litter

Biomass - total mass of living organisms, mainly plant tissue.

Challenge Questions to answer:

• What are the stages in the nutrient cycle?

• Can the same nutrient cycle be applied to all situations?

• Define nutrients, soil, litter and biomass?