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?

(1) \(\frac{x}{10}(kacl \ m^{-2})yr^{-1}\)

(2) \(x(kacl \ m^{-2})yr^{-1}\)

(3) \(10x(kacl \ m^{-2})yr^{-1}\)

(4) \(\frac{100x}{3x}(kacl \ m^{-2})yr^{-1}\)

Answer 1

Correct option is (3) \( 10x(kacl \ m^{-2})yr^{-1}\)

NPP at first trophic level would be the GPP for second trophic level. NPP at second trophic level would be GPP for third trophic level. Therefore, 100x (kcal/m² /yr) would be GPP at second trophic level and 100x × 10% (kcal/m² /yr) i.e., 10x (kcal/m² /yr) energy would be GPP at third trophic level.