Which one of the following has the highest measure of net primary productivity?
The total measure of the energy stored in the producers after meeting the cost of respiration is called as the net primary productivity (NPP). NPP is the biomass or energy avaiable for the heterotrophs in an ecosystem. In terms of NPP per unit area the most productive ecosystems in the world are estuaries, swamps and marshes, followed by the tropical rain forests, coral reefs, temperate deciduous forests and grasslands. The tundras, open oceans and deserts are the least productive. In coral reef, an underwater ecosystem has the highest number of producers (zooxanthallae algae in symbiosis with coral reefs).