Q.20 Algal blooms impart a distinct color to water due to

1. their pigments

2. excretion of colored substances

3. formation of colored chemicals in water facilitated by the physiological degradation of algae

4. absorption of light by algal cell wall

Ans. (a) Algal bloom imparts distinct color to water due to their pigments. Pigment composition of several groups of algae.

Green algae - Chlorophyll-b
Brown algae - Chlorophyll-C, + Cạ fucOxanthin
yellow algae - Chlorophyll-C, +C2 fucOxanthin
Red algae - Phycoerythrin, phycocyanin
Blue algae - Phycoerythrin, phycocyanin