Classification of algae:
Based on the various pigments found in them, algae are classified into different classes as follows:
Blue Green algae:
blue green algae.jpg
Ocillatoria, Nostoc
Green algae:
green algae.jpg
Chara, Chlamydomonas and Spirogyra
Brown algae:
brown algae.jpg
Sargassum, Laminaria
Red algae:
red algae.jpg
Polysiphonia, Gelidium
Economic importance of algae:
Algae as food:
  • Algae such as Chlorella, Spirulina and Ulva are used as food supplements by humans.
  • These are mostly consumed as food by the people in Japan, England and India.
  • Algae such as Laminaria, Ascophyllum are used as food by domestic animals.
  • In food industries, algae such as the Gelidium and Gracilaria are used in preparing ice creams and jellies.
Algae in agriculture:
Some of them, such as blue-green algae, are organisms that fix the atmospheric nitrogen into the soil. This fixation of atmospheric nitrogen increases the fertility of the soil.
Red algae such as Gelidiumand Gracillariaare used to extract Agar-Agar which is further used to prepare growth medium in laboratories and make ice creams and jellies in food industries.
It is obtained from brown algae like Laminaria.
Space travel:
Chlorella pyrenoidosa is used in space travel to get rid of the carbon dioxide and decompose the human waste.
Single Cell Protein (SCP):
Single-cell algae such as blue-green algae are used in the production of protein.
Example: Chlorella and Spirulina.