Which of the following ecosystem has the highest gross primary productivity :-

Options

A. mangrove
B. rain forest
C. grassland
D. coral reef

Answer

To determine which ecosystem has the highest gross primary productivity (GPP) among mangroves, rainforests, grasslands, and coral reefs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Gross Primary Productivity (GPP)**:
- GPP is the total amount of organic matter (biomass) produced by photosynthetic organisms in a given area over a specific time period. It reflects the total energy captured by photosynthesis before any is used by the plants for respiration.

2. **Identify the Ecosystems**:
- The ecosystems in question are:
- Mangroves
- Rainforests
- Grasslands
- Coral Reefs

3. **Compare GPP of Each Ecosystem**:
- **Mangroves**: These ecosystems are productive but generally have lower GPP compared to tropical rainforests.
- **Rainforests**: Tropical rainforests are known for their high biodiversity and dense vegetation, leading to a very high GPP due to optimal conditions for photosynthesis.
- **Grasslands**: Grasslands have moderate productivity, primarily due to the type of vegetation and climatic conditions.
- **Coral Reefs**: While coral reefs are highly productive in terms of biomass, their GPP is generally lower than that of tropical rainforests when considering the total area.

4. **Conclusion**:
- Based on the information, tropical rainforests have the highest GPP among the listed ecosystems. Therefore, the correct answer is **Rainforest**.

### Final Answer:
The ecosystem with the highest gross primary productivity is the **Rainforest**.

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