3. Algae
Algae are a diverse group of aquatic organisms that have the ability to conduct
photosynthesis. Certain algae are familiar to most people; for instance, seaweeds (such as
kelp or phytoplankton), pond scum or the algal blooms in lakes.
4. Algae characteristics
Photosynthetic pigments: They possesses brown colored
photosynthetic pigments fucoxanthin and β-carotenoids
in addition to chlorophyll a and c.
Habitat: They are almost marine, very few are fresh
water
Thallus: they are multicellular brown algae
6. Plankton is a primary food source for many animals, and
consists of bacteria, protozoans, certain algae
7. a narrow channel dug at the
side of a road
Brackish water (less commonly brack water)
is salt water and fresh water mixed together.
of little depth.
Distribution and habitat of algae
18. Algal nutrition
From the view point of their nutrition the algae are
autotrophic.
They synthesize their food from inorganic materials
(Inorganics include salts, metals, substances made
from single elements and any other compounds that
don't contain carbon bonded to hydrogen) such as
carbon dioxide, water and minerals by means of
photosynthesis.
This way, the process of nutrition in algae is quite
similar to that of ordinary green plants.
19. Algal nutrition
Iodine and other marine minerals. Algae can absorb and contain marine
minerals such as iodine, magnesium, potassium, calcium, and magnesium.
Consuming iodine from dietary sources such as seaweed is essential for the
maintenance of good health, particularly for thyroid health.
dietary sources -It is usually of plant or animal origin, and
contains essential nutrients, such as carbohydrates, fats,
proteins, vitamins, or minerals.
21. Diatom
Diatoms are a major group of microalgae, and are among the most
common types of phytoplankton.
Diatoms are unicellular, although they can form colonies in the
shape of filaments or ribbons, fans, zigzags, or stars.
23. • Green algae, members of the division Chlorophyta, comprising between 9,000
and 12,000 species. The photosynthetic pigments (chlorophylls a and b,
carotene, and xanthophyll) are in the same proportions as those in higher
plants.
• The typical green algal cell, which can be motile or nonmotile, has a central
vacuole, pigments contained in plastids that vary in shape in different species,
and a two-layered cellulose and pectin cell wall.
• Food is stored as starch in pyrenoids (proteinaceous cores within the
plastids). Green algae, variable in size and shape, include single-celled
(Chlamydomonas, desmids), colonial (Hydrodictyon, Volvox), filamentous
(Spirogyra, Cladophora), and tubular (Actebularia, Caulerpa) forms.
• Sexual reproduction is common, with gametes that have two or four flagella.
Asexual reproduction is by cell division (Protococcus), motile or nonmotile
spores (Ulothrix, Oedogonium), and fragmentation.
24. • Most green algae occur in fresh water, usually attached to submerged rocks and wood or
as scum on stagnant water; there are also terrestrial and marine species. Free-floating
microscopic species serve as food and oxygen sources for aquatic organisms.
• Green algae are also important in the evolutionary study of plants; the single-celled
Chlamydomonas is considered similar to the ancestral form that probably gave rise to land
plants.
33. Brown algae
The Phaeophyceae or brown algae, are a large group of
mostly marine multicellular algae, including many
seaweeds located in colder Northern Hemisphere waters.
They play an important role in marine environments,
both as food and as habitats.
40. Red algae
The red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The
Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000
currently recognized species.
47. Characteristical for Red algae is that no motile
stage occurs during the entire life cycle.
The spores and gametes are transported by
the water in a passive manner.
In the sexual reproduction only oogamy is
observed. ...
In red algae the egg cell develops in a female
gametangium, called carpogonium.
Reproduction in Red Algae
48. Microalgae
Microalgae or microphytes are microscopic algae, typically
found in freshwater and marine systems, living in both the
water column and sediment. They are unicellular species
which exist individually, or in chains or groups.
49. The different divisions include:
Euglenophyta (Euglenoids)
Chrysophyta (Golden-brown algae and Diatoms)
Pyrrophyta (Fire algae)
Chlorophyta (Green algae)
Rhodophyta (Red algae)
Paeophyta (Brown algae)
Xanthophyta (Yellow-green algae)
