In an ecosystem if the Net Primary Productivity (NPP) of first trophic… | Energy Flow and the Ten Percent Law across Trophic Levels

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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?

A $10x\ (kcal\ m^{-2})\ yr^{-1}$

B $\frac{100x}{3x}\ (kcal\ m^{-2})\ yr^{-1}$

C $\frac{x}{10}\ (kcal\ m^{-2})\ yr^{-1}$

D $x\ (kcal\ m^{-2})\ yr^{-1}$

The answer is A.

Solution

Only about 10% of energy is transferred from one trophic level to the next (10% law). As per the solution in the source: GPP of the third trophic level $= \frac{NPP\ of\ first\ trophic\ level}{10} = \frac{100x}{10} = 10x\ (kcal\ m^{-2})\ yr^{-1}$

Concept Applying 10% energy transfer rule across trophic levels

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?

Solution

Ecosystem in past papers

Practice

Free resources

Platform

At the institute