Question

Find out what do the terms red-tides signify.

Answer 1

Red tides are caused by red dinoflagellates (Gonyaulax) that multiply rapidly. Due to their large numbers, the sea appears red in colour. They release large amounts of toxins in water that can cause death of a large number of fishes.

Answer 2

1. The abrupt and frequently poisonous growth of marine phytoplankton, especially dinoflagellates, is what causes red tides. The high concentration of photosynthetic accessory pigments in the sea gives the water a red, brown, or yellowish hue.
2. Certain dinoflagellates, including Gonyaulax, secrete strong poisons that can either kill fish and other invertebrates instantly or build up in the food chain, endangering people who consume shellfish and other seafood.
3. These phytoplanktonic blooms are caused by the activation of cyst-like structures on the ocean floor, which may be a result of nutrient-rich inputs from the land or upwelling marine waves.