Question

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 algal cell wall

Answer 1

The correct option is A Their pigments

Algal blooms occur when environmental conditions allow explosive growth of phytoplankton that create very dense clouds of these organisms (blooms) which can change the colour of ocean water.

All photosynthetic phytoplankton have chlorophyll as their primary pigment, which explains why researchers measure chlorophyll concentrations to figure out how much phytoplankton there are in a certain region. Phytoplankton also has accessory pigments that allow them to use different wavelengths of sunlight for cellular growth and nourishment. There are three kinds of ”red” tides: red, brown, and green.

So the answer is 'Their pigments'.