The annual net primary productivity of the whole biosphere is approximately 170 billion tonnes. Of this, the productivity of all land-based ecosystems is about ____ billion tonnes.

Step-by-step solution

The annual net primary productivity of the whole biosphere is approximately 170 billion tonnes (dry weight) of organic matter. Despite occupying about 70 percent of the Earth's surface, the productivity of the oceans is only 55 billion tonnes. The productivity of all land-based ecosystems is the remaining amount. Productivity of land-based ecosystems = 170 - 55 = 115 billion tonnes. Answer: 115