3 Answers
Algal bloom
Algal bloom refers to an increase in the population of algae or blue-green algae in water, resulting in discoloration of the water body. This causes an increase in the biological oxygen demand (BOD), resulting in the death of fishes and other aquatic animals.
Red-tides
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.
A rapid increase in the population of microscopic algae in an aquatic habitat is called algal bloom. The algal bloom involving the dianoflagellates is called the ‘red tide’ because of its red hue. Red tide can be harmful for other aquatic life forms.
Algals usually form huge colonies and are called ‘Algal bloom’ formed by their multiplying in a rapid rate. Dinoflagellate have different colours based on pigments. “Algal bloom” of Red dinoflagellate gives a red appearance to the part of sea in which it is present, hence called ‘Red Tide’.