Net Primary Productivity (NPP) is expressed as

Options

A. GPP+R
B. GPP-R
C. GPP `xx` R
D. `GPP"/"R`

Answer

**Step-by-Step Solution:**

1. **Understanding Productivity**:
- Productivity refers to the rate of biomass production in an ecosystem. It indicates how much organic matter is produced in a given area over a specific time period.
- **Hint**: Remember that productivity is about the rate of biomass production.

2. **Defining Primary Production**:
- Primary production is the amount of biomass or organic matter produced per unit area over a time period, specifically during photosynthesis.
- **Hint**: Focus on the role of photosynthesis in primary production.

3. **Gross Primary Productivity (GPP)**:
- GPP is the total rate of organic matter production by photosynthesis in an ecosystem. It represents the overall biomass produced before any losses due to respiration.
- **Hint**: GPP is the total production before accounting for any losses.

4. **Net Primary Productivity (NPP)**:
- NPP is defined as the amount of organic matter or biomass available after subtracting the respiration losses from GPP. The formula is:
\[ NPP = GPP - R \]
- Here, \( R \) represents the respiration losses.
- **Hint**: NPP is what remains after considering the energy lost through respiration.

5. **Units of Measurement**:
- NPP is typically expressed in units such as grams per square meter per year (g/m²/year) or kilocalories per square meter per year (kcal/m²/year).
- **Hint**: Remember the common units used for measuring productivity in ecosystems.

6. **Conclusion**:
- Therefore, Net Primary Productivity (NPP) is expressed as the rate of biomass production available for consumption after accounting for respiration losses, typically in units like g/m²/year or kcal/m²/year.

**Final Answer**: Net Primary Productivity (NPP) is expressed as grams per square meter per year (g/m²/year) or kilocalories per square meter per year (kcal/m²/year).

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