Gross primary productivity minus respiration losses of an ecosystem is

Options

A. Primary productivity
B. Net Productivity
C. Net primary productivity
D. Secondary productivity

Answer

To solve the question "Gross primary productivity minus respiration losses of an ecosystem is", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Gross Primary Productivity (GPP)**: This is the total amount of organic matter (biomass) produced by photosynthetic organisms (producers) in an ecosystem over a specific time period.
- **Respiration Losses**: This refers to the amount of energy or biomass that is used by producers for their own metabolic processes, which is not available for growth or storage.

2. **Identify the Relationship**:
- The relationship between GPP and respiration losses is crucial. When we subtract the respiration losses from the GPP, we are left with the amount of biomass that is available for growth and storage.

3. **Define Net Primary Productivity (NPP)**:
- **Net Primary Productivity (NPP)** is defined as the amount of biomass produced by the producers after accounting for the energy lost through respiration. Mathematically, it can be expressed as:
\[ NPP = GPP - \text{Respiration Losses} \]

4. **Evaluate the Options**:
- Given the definitions:
- **Primary Productivity**: General term for productivity in ecosystems.
- **Net Primary Productivity (NPP)**: Specifically defined as GPP minus respiration losses.
- **Secondary Productivity**: Refers to biomass produced by consumers, not relevant here.
- The correct answer to the question is **Net Primary Productivity (NPP)**.

5. **Conclusion**:
- Therefore, the answer to the question is that gross primary productivity minus respiration losses of an ecosystem is **Net Primary Productivity (NPP)**.

### Final Answer:
The answer is **Net Primary Productivity (NPP)**.