1. Tardigrade
  2. Question
  3. Biology
  4. The annual total primary earth surface production amounts to (dry weight) of organic matter.

Q. The annual total primary earth surface production amounts to (dry weight) of organic matter.

 130  152 NTA AbhyasNTA Abhyas 2020 Report Error

Solution:

Net primary productivity is defined as gross primary productivity minus respiration loss (R).
NPP = GPP - R
Net primary productivity is the available biomass for the consumption of heterotrophs i.e., both herbivores and decomposers.
Whittaker and Leith have compiled data regarding the net productivity of the major ecosystems of the world. The annual NPP of the whole biosphere is approximately 170 billion tonnes (dry weight) of organic matter. Of this, despite occupying about 70 % of the surface, the productivity of oceans is only 55 billion tonnes and of the terrestrial system is 115 billion tonnes.