Question

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100x(kcal m⁻²) yr⁻¹, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

Options

• 10x(kcalm⁻²)yr⁻¹

• `(100x)/(3x) ("Kcalm"^(-2))"yr"^-1`

• `x/10("Kcalm"^(-2))"yr"^-1`

• x(kcalm2)yr-1

Answer 1

10x(kcalm⁻²)yr⁻¹

Explanation:

The trophic level energy transfer efficiency, which is normally approximately 10%, can be used to determine the Gross Primary Productivity (GPP) of the third trophic level from the Net Primary Productivity (NPP) of the first trophic level. GPP of the third trophic level is equal to NPP of the first trophic level divided by the energy transfer efficiency of the trophic level.

Given: NPP of the first trophic level = 100x(kcalm⁻²)yr⁻¹ Trophic level energy transfer efficiency = 10% = 10

So, GPP of the third trophic level = `(100x)/10` = 10x(kcalm⁻²)yr⁻¹