Question

The annual net primary productivity of the biosphere is approximately:

• A. 170 billion tons
• B. 55 billion tons
• C. 170 million tons
• D. 55 million tons

Hint:

Understanding productivity is crucial for ecosystem management and sustainability.

Answer 1

The Correct Option is A

The annual net primary productivity of the biosphere is approximately 170 billion tons.

(A) 170 billion tons - Correct: Represents global biomass production (mostly from oceans and tropical forests).

(B) 55 billion tons - Incorrect: Too low for total productivity (close to just terrestrial contribution).

(C) 170 million tons - Incorrect: Underestimates by 1000-fold.

(D) 55 million tons - Incorrect: Vastly underestimates global productivity.

The correct answer is (A) 170 billion tons, as measured in dry organic matter per year.

Answer 2

Net Primary Productivity (NPP) is the amount of energy captured by photosynthetic organisms (like plants) in a given area after accounting for the energy they use for their own metabolic activities.

The NPP of the biosphere is estimated to be around 170 billion tons annually, which is the total amount of organic matter produced by plants and algae globally.

Option (A) is correct because 170 billion tons is the widely accepted estimate of the NPP of the biosphere.