Which organisms is responsible for red surface of sea?

Options

A. Euglena
B. Gonyaulax
C. Amoeba
D. Paramecium

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which organism is responsible for the red surface of the sea, commonly referred to as "red tides."

2. **Identifying the Phenomenon**: Red tides are a phenomenon that occurs when there is a rapid increase in the population of certain types of algae in marine and freshwater environments.

3. **Recognizing the Organisms Involved**: The organisms primarily responsible for red tides are a group of algae known as dinoflagellates.

4. **Specific Dinoflagellate**: Among the dinoflagellates, a specific genus called **Gonyaulax** (or Gonyaulax species) is often associated with red tides. These organisms can produce toxins that affect marine life and humans.

5. **Understanding the Impact**: The accumulation of these dinoflagellates leads to the red or brown coloration of the water, which can have harmful effects on marine life, particularly shellfish, and can pose health risks to humans.

6. **Conclusion**: Therefore, the organism responsible for the red surface of the sea is the **dinoflagellate Gonyaulax**.

**Final Answer**: The organism responsible for the red surface of the sea is the dinoflagellate Gonyaulax.

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