Red sea is red due to

Options

A. red tides by Protistans
B. red alga like Sargassum
C. blue green alga like Trichodesmium
D. iron salts in Gonyaulax

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why the Red Sea appears red. We need to analyze the options provided to find the correct reason.

2. **Evaluating the Options**:
- **Option A**: Red algae - This option suggests that red algae are responsible for the color. However, this is not correct.
- **Option B**: Red algae like Sargassum - This option also refers to red algae, which is incorrect.
- **Option C**: Blue-green algae like Trichodesmium - This option mentions blue-green algae, which are known to cause blooms in the Red Sea.
- **Option D**: Iron salts - This option suggests that iron salts contribute to the color, which is not the case.

3. **Identifying the Correct Answer**:
- The blue-green algae, specifically **Trichodesmium erythraeum**, are commonly found in the Red Sea.
- These algae produce a pigment called **phycoerythrin**, which gives the water a reddish appearance when they bloom.

4. **Conclusion**: Based on the analysis, the correct answer is **Option C: Blue-green algae like Trichodesmium**.

**Final Answer**: The Red Sea is red due to blue-green algae like Trichodesmium.

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