Algal blooms impart a distinct colour to water due to:
a. their pigments
b. excretion of coloured substances
c. formation of coloured chemicals in water facilitated by physiological degradation of algae.
d. absorption of light by an algal cell wall.
The answer is the option (a) their pigments
Explanation: If green algae are prevalent, they impart green color to water. Red algae impart red color and brown algae impart brown color.