Practicing Success
How much of the total annual net primary productivity of the biosphere is contributed by the oceans? |
170 billion tons 115 billion tons 70 billion tons 55 billion tons
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55 billion tons
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The correct answer is Option (4) –55 billion tons Primary productivity depends on the plant species inhabiting a particular area. It also depends on a variety of environmental factors, availability of nutrients and photosynthetic capacity of plants. Therefore, it varies in different types of ecosystems. The annual net primary productivity of the whole biosphere is approximately 170 billion tons (dry weight) of organic matter. Of this, despite occupying about 70 per cent of the surface, the productivity of the oceans are only 55 billion tons. Rest of course, is on land. |