1. Secondary productivity is defined as the rate of formation of new organic matter by consumers.
2. It is the rate of assimilation of food energy by the consumers.
3. This amount of energy available to consumer for transfer to the next trophic level.
4. The annual net primary productivity of the whole biosphere is approximately 170 billion tonnes (dry weight) of organic matter. Of 170 billion tonnes, the oceans create about 55 billion tonnes, and rest is by land ecosystems.
