2. ALGAE
• Algae are photoautotrophic that can prepare their own food
and they produce oxygen during photosynthesis.
• Algae are ubiquitous. Majority of algae are abundant in
stagnant waters.
3. 1. PRIMARY PRODUCERS
• Algae are the main oxygen producers in aquatic areas. They
are also useful in decreasing water pollution by releasing
oxygen.
• 10% of total photosynthesis carried out by plants is carried
out by the algae.
4. 2. ALGAE AS FOOD
• Algae species are used as food in
several countries and in several
forms.
• Algae species have proteins,
vitamins (A, B, C and E), lipids,
and minerals.
6. 3. ALGAE AS SOURCE OF IODINE
• The marine algae are rich in iodine and several other
important minerals.
• By feeding the milk cattle and hens with algae, iodine
quantity of the milk and eggs may sufficiently be
increased.
7. 4. AS ANTIBIOTIC AND MEDICINE
• Some algae yield antibiotics Chlorellin is obtained from green alga
Chlorella, that inhabits the growth of certain bacteria.
• Because of high iodine contents, brown algae is used in manufacture
of various goiter medicines.
• Spirogyra is used for cleaning of optical instruments.
8. 5. ALGAE IN SEWAGE DISPOSAL
• The effective disposal of sewage
requires oxygen and this oxygen is
brought about by the algal
members present in the sewage like
Chlamydomonas, Chlorella etc.
• The oxygenation by algae also
helps to avoid unpleasant odour
coming out of sewage bodies.
9. 6. ALGAE AS FERTILIZER
• Due to presence of P, K, Ca, and
some trace elements , the sea
weeds are used as fertilizers.
• Chara is used to overcome
calcium deficiency in the fields.
• Fucus is used as manure.
10. 7. ALGAE IN LAND RECLAMATION
• Algae act as binding agent.
• Algae help in reducing the pH of
alkaline soils and increasing the
water holding capacity of these
soils.
11. 8. USE OF ALGAE AS DIATOMITE
• Diatomite is fossilized remains of diatoms. Diatoms are
single-celled aquatic algae which are in the form of petri
dish.
• It is used in car paint, roof insulation, wall insulation,
cosmetics and bath products.
12. 9. USE OF ALGAE AS AGAR AGAR
• It is a jelly like substance
obtained from algae.
• It is used in desserts and other
cooking. It is also used to
thicken soups and sauces.
13. AGAR AGAR
• By using agar, microorganisms
can be cultured.
14. 10. ROLE IN NITROGEN FIXATION
• Algae plays in important role in
nitrogen fixation.
• A high rice yield has obtained
when the rice field were
inoculated by nitrogen fixation.
15. 11. SOURCE OF MINERALS
• Minerals obtained by Kelps are used in glass and soap
preparations.
• Sea-weeds are rich source of iron, zinc, copper,
manganese and boron.
16. 12. USE AS ALGIN
• Algin is obtained from different
algae.
• It is used in adhesive structure in
artificial silk.
• It is used in paints and many
pharmaceutical products.
• It is used in ice creams.
17. ALGAE AS ALGIN
• It is used in processing of
natural and synthetic rubbers.
19. 1. CONTAMINATION OF WATER RESERVOIRS
• The algae grows abundantly in water reservoirs meant for
domestic purposes.
• This affects the filtration process and brings bad taste to
water due to decay of dead algal plants.
• Such algae include members of cyanophyta and
chlorophyta.
20. 2. WATER BLOOMS
• Sometimes algal plants grow abundantly and form quit
apparent bodies called water blooms.
• These bodies deplete the oxygen contents of the water during
night time.
• Emit bad smell and secrete certain poisonous substances
harmful to aquatic animals.
22. 3. DEATH TO LIVING ORGANISMS
• Algae causes eutrophication in ponds and lakes. It causes
death of aquatic animals.
• The death of cattles occur by drinking the infected water.
• Due to thick layer of algae on surface of water,
photosynthesis does not occur.
23.
24. 4. DISEASES IN HUMAN BEINGS
• The contaminated water causes stomach disorder in
human beings.
• Similarly some algae are responsible for respiratory
disorders, skin diseases and other algae causes allergies.
25. 5. PARASITIC ACTIVITIES
• Some algae are parasites on other plants and animals
as well.
• Most of these belong to the Rhodophyta (red algae).