An overaccumulation of dinoflagellates causes a red tide, which can contaminate shellfish and make them unfit for human consumption.
The Correct Answer and Explanation is:
Correct Answer: True
Explanation
A red tide is a phenomenon caused by the overaccumulation of dinoflagellates, a type of microscopic algae that lives in marine and freshwater environments. Under certain conditions—such as warm water temperatures, high nutrient levels (often from agricultural runoff), and calm seas—these algae can reproduce rapidly, resulting in what scientists call a harmful algal bloom (HAB).
Dinoflagellates are named for their two flagella (tail-like structures) that help them move through the water. Not all dinoflagellates are harmful, but some species produce powerful toxins. During a red tide, the water may appear discolored—often reddish-brown—due to the large concentration of these pigmented organisms. However, the color is not always red, and discoloration may not always be visible.
The real danger lies in the toxins that some dinoflagellates release. These toxins can accumulate in shellfish such as mussels, clams, oysters, and scallops, which filter large amounts of water to feed. As they do this, they ingest the dinoflagellates and store the toxins in their tissues without being harmed themselves.
When humans consume shellfish contaminated with these toxins, it can lead to serious health problems such as:
- Paralytic Shellfish Poisoning (PSP)
- Neurotoxic Shellfish Poisoning (NSP)
- Amnesic Shellfish Poisoning (ASP)
Symptoms can range from nausea and dizziness to more severe effects like paralysis and, in rare cases, death.
Because of the risk to public health, fisheries and health departments closely monitor red tides and often issue warnings or bans on shellfish harvesting during blooms. Shellfish from affected areas are considered unfit for human consumption until tests confirm they are safe.
In conclusion, the statement is true: An overaccumulation of dinoflagellates does cause red tides, which can contaminate shellfish and make them unsafe to eat.
