An ecologist studying productivity in a sample of grasses measures gross primary productivity as 1000 kcal/m2/yr and autotrophic respiration as 100 kcal/m2/yr.Based on these calculations,the net primary productivity would be
A)10 kcal/m2/yr.
B)900 kcal/m2/yr.
C)1100 kcal/m2/yr.
D)10,000 kcal/m2/yr.

Question

Quizplus · Accepted Answer

Net primary productivity (NPP) is calculated by subtracting the energy used by the plant for its own metabolism, known as autotrophic respiration, from the gross primary productivity (GPP).

NPP = GPP - autotrophic respiration

In this case, 
NPP = 1000 kcal/m2/yr - 100 kcal/m2/yr 
NPP = 900 kcal/m2/yr

Therefore, the answer is B) 900 kcal/m2/yr.

An Ecologist Studying Productivity in a Sample of Grasses Measures