Sun is the only source of energy for the given ecosystems except

Options

A. deep sea hydrothermal ecosystem
B. savannah ecosystem
C. shallow lake ecosystem
D. mangrove ecosystem

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which ecosystem does not rely solely on the sun as its energy source. We need to analyze the options provided.

2. **Analyzing the Ecosystems**:
- **Option A: Deep Sea Hydrothermal**: This ecosystem is located deep in the ocean where sunlight cannot penetrate. Instead of relying on sunlight, organisms here utilize chemical energy through a process known as chemosynthesis.
- **Option B: Savannah**: This is a grassland ecosystem that receives ample sunlight, making the sun the primary energy source for the plants and animals living there.
- **Option C: Shallow Lake Ecosystem**: In shallow lakes, sunlight can penetrate, allowing photosynthesis to occur in aquatic plants and algae, thus relying on the sun for energy.
- **Option D: Mangrove Ecosystem**: Mangroves are coastal ecosystems that also receive sunlight, supporting photosynthesis and making the sun a key energy source.

3. **Identifying the Exception**: After analyzing each ecosystem, it is clear that the deep sea hydrothermal ecosystem is the only one that does not depend on sunlight. Instead, it relies on chemical energy from hydrothermal vents.

4. **Conclusion**: Therefore, the answer to the question is **Option A: Deep Sea Hydrothermal**.