The productivity of the oceans is approximately ....the annual net primary productivity of the whole biosphere .

Options

A. half
B. one third
C. one fifth
D. one fourth

Answer

To solve the question regarding the productivity of the oceans in relation to the annual net primary productivity of the whole biosphere, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Net Primary Productivity (NPP)**: This is the amount of organic matter produced by photosynthetic organisms (like plants) after accounting for the energy used in respiration.
- **Whole Biosphere NPP**: This refers to the total NPP of all ecosystems on Earth.

2. **Know the Values**:
- The annual net primary productivity of the whole biosphere is approximately **170 billion tons** of organic matter per year.
- The annual net primary productivity of the oceans is approximately **55 billion tons** of organic matter per year.

3. **Set Up the Comparison**:
- We need to compare the ocean's productivity to that of the whole biosphere. This can be done by calculating the ratio of ocean productivity to biosphere productivity.

4. **Calculate the Ratio**:
- To find how the ocean's productivity compares to the whole biosphere, we calculate:
\[ \text{Ratio} = \frac{\text{NPP of Oceans}}{\text{NPP of Whole Biosphere}} = \frac{55 \text{ billion tons}}{170 \text{ billion tons}} \]

5. **Perform the Calculation**:
- Simplifying the ratio:
\[ \text{Ratio} \approx \frac{55}{170} \approx 0.3235 \]
- This value can be approximated to **one-third** (since 0.3235 is close to 0.33).

6. **Conclusion**:
- Therefore, the productivity of the oceans is approximately **one-third** of the annual net primary productivity of the whole biosphere.

### Final Answer:
The productivity of the oceans is approximately **one-third** of the annual net primary productivity of the whole biosphere.