Presentation about the red algae . Includes the introduction and some brief knowledge about some red algae like thalus Reproduction and its importance.

1. RED ALGAE

2. 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 with
taxonomic revisions ongoing.
RHODOPHYTA

3. The red algae form a distinct group characterized by having
eukaryotic cells
without flagella and centrioles, chloroplasts that lack
external endoplasmic reticulum and contain unstacked
(stroma) thylakoids, and use phycobiliproteins as accessory
pigments, which give them their red color. Red algae store
sugars as floridean starch, which is a type of starch that consists
of highly branched amylopectin without amylose, as food
reserves outside their plastids.

4. Most red algae are also multicellular, macroscopic, marine,
and reproduce sexually. The red algal life history is typically
an alternation of generations that may have three generations
rather than two.The coralline algae, which secrete calcium
carbonate and play a major role in building coral reefs, belong here.
Red algae such as dulse (Palmaria palmata) and laver (nori/gim) are
a traditional part of Europeanand Asian cuisines and are used to
make other products such as agar, carrageenans and other food
additives.

5. Some examples of red algae
Habitat – You can find dulse on most rocky
shores at any reasonably low tide, but you
do need to ensure the tide is fully out to
make gathering easy. Grows either from a
small discoid holdfast on the rock or
epiphytically on other seaweeds, notably the
large stalks of forest kelp (laminaria
hyperborea).
1.Dulse
Rhodymenia
palmata

6. Thallus —The thallus is flattened and usually dichotomously
branched. It grows in the intertidal zone and at low-water mark,
attached to rocks or to other seaweeds by a discoid holdfast.
Reproduction —Dulse can reproduce sexually, by the joining of
specialized male and femalereproductive cells, called gametes. After
they are released from the sporophyte, the spores settle and grow
into male and female plants called gametophytes. Dulse can
also reproduce asexually through fragmentation or division.
Importance —Dulse can act as a natural alternative to
supplements due to its significant B12 content. Whilst
the benefits of dulseobviously include its high calcium and
potassium levels, the algae also contains substantial levels of
beta-carotene. It's this nutrient which allows the algae to
improve eyesight.

7. Habitat: Inlets, tide pools, and
lowerintertidal zone.
Seasonal appearance: All year. Irish
moss is a red seaweed with flattened
blades that fork off from a short stalk to
form fingers with round, blunt tips. The
blades taper towards disk-shaped
holdfasts, which are actually root-like
anchoring structures.
2.Irish moss
Chondrus
ocellatus

8. Thallus —Irish moss is a relatively small sea alga, reaching up to a little
more than 20 cm in length. It grows from a discoid holdfast and branches
four or five times in a dichotomous, fan-like manner. The morphology is
highly variable, especially the broadness of the thalli.
Reproduction —Irish moss normally has a life cycleconsisting of three phases: male,
female and a spore- producing phase. All phases are similar in size and shape. The
primary mode of reproduction is by the sexual production of spores that then form
small plants.
Importance —Rich in potassium chloride, Irish moss can work wonders for
congestion and mucous and holds anti-bacterial and anti-viral properties. It's
also thought to be good for dry skin and for skin conditions ranging from eczema
to psoriasis, making it a valued ingredient for lotions and moisturizers

9. Habitat —Red coralline algae can
be found in most marine habitats.
Articulated corallines grow mostly
in low intertidal and subtidal
coastal areas.
Crustose corallines have been
found in depths up to 500 feet
(152 m).
3.Coralline algae
Coralline

10. Thallus —Coralline algae are red algae in the order Corallinales.
They are characterized by a thallusthat is hard because
of calcareous deposits contained within the cell walls. The colors of
these algae are most typically pink, or some other shade of red, but
some species can be purple, yellow, blue, white, or gray-green.
Reproduction —crustose coralline algae reproduce by releasing gametes
into the water column, where they form propagules which drift until
competent to settle. The planktonic phase of algal gametes in in the order of
4-11 days in laboratory conditions but may be much longer in the sea.
Importance —Crustose coralline algae play a variety ofimportant roles in
many marine ecosystems, particularly coral reefs. We call them coral reefs
because their three-dimensional structures are built by stony coral animals,
which produce limestone as they grow ever upwards towards the sun.

11. 4.Gelidium
Habitat: Pools in lower
intertidal and subtidal,
generally in shaded situations,
southern and western shores,
frequent. Similar
species: Gelidium pulchellum
which does not have strongly
flattened main axes and
occurs higher on the shore.
Gelidium
amansii

12. Thallus —It is a stiff cartilaginous pinnately branched agar yielding
red alga that is attached to the substratum by a number of rhizoids.
Appearance is lace-like. Gelidium is the major source of agar which is
obtained from cell wall.
Reproduction —The vegetative plants occur only in the period coinciding with
the start of the rainy season. The success of vegetative growth is closely
correlated with the success of their sexual reproduction and asexualpropagation.
The triphasic reproductioncycle of Gelidium is apparently similar to that of other
red algae.
Importance —This algae is used to make agar, whose components are the
polysaccharide agarose and agaropectin, from the large amount of algin
which is located in the algae's cell wall, as well it is sometimes served as part
of a salad, puddings, jams, and other culinary dishes in producing regions.

13. Habitats —Lemanea is a genus
of freshwater red algae, in the
order Batrachospermales.
Bothspecies are considered to
be widespread in the northern
hemisphere. Although placed
in the Rhodophyta (red algae) it
in fact is green in colour.
5.Lemanea
Lemanea fluviatilis

14. Thallus —Lemanea is a stiff bristle-like branched or unbranched alga
similar to a coarse horsehair. Close inspection show it to have small
swellings at more or less regular intervals along its length. It grows
to 40 cm in length, in bunches in freshwater. It is blue-green to olive
in colour when young.
Reproduction—They have evolved mechanisms of reproductive isolation to
ensure that their offspring will continue to use separate habitats. Limnetic adults
prefer to mate with limnetic adults and benthic adults prefer to mate with benthic
adults (Rundle et al., 2000). Primary producers compete for nutrients and light.
Importance—important for phytoplankton in terms of
photosynthesis, zinc concentrations above 0.05 mg l−1 are often
considered toxic and impair photosynthesis.

15. Habitat —More specifically, it
belongs to red algae phylum of
laver species (from which comes
laverbread), comprising
approximately 70species. It
grows in the intertidal zone,
typically between the upper
intertidal zone and the splash
zone in cold waters of temperate
oceans.
6.Porphyr
a
Porphyra sp.

16. Thallus —Porphyra thalli appear in nature as free-living organisms, and their
microscopic filaments bore into calcium carbonate substrates such as oyster
shells. Porphyrablades may be from circular to linear in outline, and from a few
centimetres to over a metre in length.
Reproduction —Porphyra displays a heteromorphic alternation of generations.
The thallus we see is the haploid generation; it can reproduce asexually by forming
spores which grow to replicate the original thallus. It can also reproduce sexually.
Both male and female gametes are formed on the onethallus.
Importance —The marine red alga Porphyra has been cultivated extensively in many
Asian countries as an edible seaweed used to wrap the rice and fish that compose the
Japanese food sushi and the Korean food gimbap. In Japan, the annual production of
Porphyra species is valued at 100 billion yen (US$1 billion).

17. Habitats —Polysiphonia is
commonly found as an epiphyte
on plants and lithophyte on rocks in
brackish estuaries in the intertidal
and sublittoral regions.
Most species prefer quiet waters
whereas some are found in rough or
even polluted waters.
7.Polisiphoniya
Polysiphonia
elongella

18. Thallus —The thallus is filamentous, red or purple red in colour. The thallus is multi-
axial and all cells are connected by pit connections hence, the name given is
Polysiphonia. Due to continuous branching and re-branching the thallus has feathery
appearance (Fig. 1A). The thalli may reach the length of about 30 cm.
The thallus is heterotrichous and is differentiated into a basal prostrate system and
erect aerial system.
Reproduction—Sexual Reproduction: Sexual reproduction is oogamous type and plants are
dioecious i.e., male and female sex organs are produced on different male and female
gametophytic plants. Male Gametophyte: The male sex organs, spermatangia or antheridia
develop on fertile trichoblasts present on tips of male gametophytic plant.
Importance —The ends of the rhizoids are flattened into lobed discs called haptera, which
assist the penetration of the host tissue (Polysiphoniaparasitic form) or confirm
attachment to substrata. The branches may be of determinate and indeterminate growth.

19. Habitat —Thorea is a genus of
freshwater algae in the Phylum
Rhodophyta (red algae). Thorea is a
small alga with filaments up to 200 cm
long, dark green in colour and not red
as are marine Rhodophyta. The
filaments have only as few secondary
branches. Thorea is distributed
throughout temperate and tropical
regions.
8.Thorea
Thorea hispida

20. Thallus —Thorea thalli are dark brown and robust, with pro
fusely branched structure. Filaments are multiaxial, with an
obvious outer assimilatory and inner medullary layers . Algae
filaments are surrounded by a mu mucilaginous envelope.
Reproduction —Thorea is distinguished by having assimilatory filaments not
contained in a common gelatinous matrix withreproductive structures (carpogonia,
spermatangia, carposporangia and monosporangia) at their base, whereas in
Nemalionopsis they are embedded in a gelatinous matrix with reproductive
structures at their apex
Importance —It helps in maintaining the health of the marine ecosystem
because algae are naturally absorbent of carbon dioxide and also provide oxygen
to the water. 4. Fertilizer: Algae are rich in minerals and vitamins. So they also
used as liquid fertilizer which helps in the repairing level of nitrogen present in the
soil

21. Habitat —Bangia grows in
freshwater or in marine habitats,
usually forming dense clumps or
mats, and occur throughout the
intertidal area and subtidally to the
maximum depth at which
benthic algae occur.
9.Bangia
Bangia fuscopurpurea

22. Thallus — Bangia is a red alga that arises from a discoid holdfast and short
stipe consisting of the extensions of rhizoidal cells. Bangia has
unbranched, erect thalliforming initially uniseriate filaments becoming
multiseriate at maturity.
Reproduction— Species ofBangia undergo a heteromorphic alternation of
generation life cycle in which the haploid generation is
dominant. Reproduction can be either sexual or asexual; sexual plants
occur mainly during the cold season of the year, while at other times the
thalli often bear monosporangia only.
Importance—Used as a food source for
organisams , a fodder, in fish farming, as a
fertilizer. also use in a variety of commercial
products etc.

23. Porphyra umbilicalis
10.Laver (nori)
Habitat —Porphyra is a
coldwater seaweed that grows
in cold, shallow seawater. More
specifically, it belongs to red
algae phylum of laver species
(from which
comes laverbread), comprising
approximately 70 species.[2]It
grows in the intertidal zone,
typically between the upper
intertidal zone and the splash
zone in cold waters of
temperate oceans.

24. Thallus —Laver species exhibit an alternation of generations in their life cycles.
The haploidthallus, a sheet of one or two layers of cells embedded in a thin
gelatinous stratum, varies in colour from deep brown or red to pink.
Reproduction —The sexual reproductive structures are borne at the margin of
the thallus, and many species can also reproduce asexually by spores. The
diploid stage, known as the conchocelis, is usually microscopic and consists of
branched filaments of cells.
Importance —It grows best in cold nitrogen-rich water.Laver is harvested, dried, and
used as food in greater amounts than any other seaweed, giving it significant
economic importance. It is also used as a soup base, as a flavouring for other food,
and as a covering for rice-filled sushi.

25. Thank you