Pyramid of energy in aquatic ecosystem is

Options

A. Always upright
B. Always inverted
C. Bell-shaped
D. None of these

Answer

### Step-by-Step Solution:

1. **Understanding the Pyramid of Energy**: The pyramid of energy represents the flow of energy through different trophic levels in an ecosystem. It illustrates how energy is transferred from producers to various levels of consumers.

2. **Identifying the Trophic Levels**:
- **Level 1 (Producers)**: At the base of the pyramid, we have producers (like phytoplankton in aquatic ecosystems) that convert sunlight into energy through photosynthesis. They form the foundation of the energy pyramid.
- **Level 2 (Primary Consumers)**: The next level consists of primary consumers (such as zooplankton) that feed directly on producers, obtaining energy from them.
- **Level 3 (Secondary Consumers)**: Above primary consumers, we have secondary consumers (like small fish) that eat primary consumers to gain energy.
- **Level 4 (Tertiary Consumers)**: At the top of the pyramid are tertiary consumers (like larger fish or marine mammals) that feed on secondary consumers.

3. **Energy Transfer Efficiency**: As energy moves up the pyramid from producers to consumers, there is a significant loss of energy at each trophic level due to metabolic processes, heat loss, and incomplete digestion. This results in a decrease in available energy.

4. **Shape of the Pyramid**: The pyramid of energy is always upright, meaning that the energy available decreases as you move from the base (producers) to the top (tertiary consumers). For example, if producers have 1000 units of energy, primary consumers might only have 100 units, secondary consumers might have 10 units, and tertiary consumers might have just 1 unit.

5. **Conclusion**: The pyramid of energy in an aquatic ecosystem is always upright, indicating that energy decreases as you ascend through the trophic levels.

### Final Answer:
The pyramid of energy in an aquatic ecosystem is always upright.

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