Outline
n Phylum
Chlorophyta
n Phylum
Chromophyta
n Phylum
Rhodophyta
n Phylum Euglenophyta
n Phylum Dinophyta
n Phylum Cryptophyta
n Phylum Prymnesiophyta
n Phylum Charophyta
n Phylum Myxomycota
n Phylum Dictyosteliomycota
n Phylum
Oomycota
Features of Kingdom Protista
n All
members have eukaryotic cells.
n Individual
life cycles vary considerably, but reproduction is generally by cell division
and sexual processes.
n Most
multicellular members produce some motile cells.
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Phytoplankton...plankton..Greek for wanderer
meaning that they are passively transported. Nekton are those that swim. Size
categories of plankton:
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n ultraplankton:
less than 2 um
n nanoplankton:
2-20 um
n microplankton:
20-200 um
n macroplankton:
200-2000 nm
n megaplankton:
greater than 2 mm
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Types:
Holoplankton...spend entire life in open waters
Meroplankton...spends part of life as plankton and
part as a benthic or bottom dweller.
Tychopelagic...normally attached but break off and
can then be found in the plankton.
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Divisions
Cyanobacteria (Cyanophyta) Blue-green algae
(Monera)
n Chlorophyta
green algae
n Chrysophyta
golden algae/silicoflagellates
n Haptophyta-
coccolithophores
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n Xanthophyta
yellow-green algae
n Bacillariophyta
diatoms
n Dinophyta
(Pyrrophyta) dinoflagellates & zooxanthellae
n Cryptophyta cryptomonads
n Euglenophyta euglenas
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Division Cyanophyta/Cyanobacteria Blue green Algae
are prokaryotic cells specialized to carry on photosynthesis. Chlorophyll,
phycobilins, phycocyanin, beta-carotene and xanthophylls are the pigments so
color range is great..red, blue-green, black, olive, yellow, violet. The only
other prokaryotes that carry out photosynthesis are some autotrophic bacteria.
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There are hemosynthetic bacteria too that release
stored energy in chemical compounds (H2S) . Blue-green algae contain a bluish
pigment, PHYCOCYANIN. (Considered bacteria).
Photosynthesis occurs on folded membranes within
the cell (rather than chloroplasts).
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They do produce O2 etc. and probably played a role
in the oxygen in the atmosphere.
The presence of this ultraplankton is only being
discovered .
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Responsibilities of blue greens include forming
dark crusts along wave splashed zones , exploiting polluted sediments and even
forming a few types of red tides (Trichodesmium erythraea).(skin rashes).
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Blue-greens also carry out nitrogen fixation in
the ocean, converting N into nitrates to be converted to proteins. Some
blue-greens live on the surfaces of seaweeds and sea grasses (epiphites) and
some are known to lose their ability to photosynthesize, becoming heterotrophs.
Phylum Chlorophyta
n The
Green Algae
u Includes
about 7,500 species that occur in a rich variety of forms and occur in diverse,
widespread habitats.
« Greatest
variety found in freshwater lakes, ponds, and streams.
« Most
have a single nucleus.
« Most
reproduce both sexually and asexually.
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Chlorophyta..few marine planktonic reps. but lots
of macroscopic, benthic types
Phylum Chlorophyta
n Chlamydomonas
u Common
inhabitant of freshwater pools.
u Pair
of whip-like flagella on one end pull the cell through the water.
u Single,
cup-shaped chloroplast with one or two pyrenoids inside.
« Proteinaceous
structures thought to contain starch synthesis enzymes.
Chlamydomonas
n Asexual
Reproduction
u Nucleus
divides by mitosis, and cell contents become two daughter cells within the
cellulose wall.
« Develop
flagella and swim away.
Phylum Chlorophyta
n Ulothrix
u Thread-like
alga.
« Single
row of cylindrical cells forming a filament.
Basal
cell functions as a holdfast.
Phylum Chlorophyta
n Spirogyra
(Watersilk)
u Common
freshwater algae consisting of unbranched filaments of cylindrical cells.
« Frequently
float in masses at the surface of quiet waters.
u Asexual
Reproduction
« Fragmentation
of existing filaments.
u Sexual
Reproduction
« Papillae
fuse and form conjugation tubes.
Phylum Chlorophyta
n Oedogonium
u Epiphytic
filamentous green alga.
« Each
cell contains a large, netlike chloroplast that rolls and forms a tube around
and toward the periphery of each protoplast.
Phylum Chlorophyta
n Other
Green Algae
u Chorella
- Widespread green alga composed of tiny spherical cells.
« Reproduce
by forming either daughter cells or autospores through mitosis.
u Desmids
- Mostly free-floating and unicellular.
« Reproduce
by conjugation.
Phylum Chlorophyta
n Other
Green Algae
u Hydrodictyon
(Water Nets) - Net-like, tubular colonies with hexagonal or polygonal meshes.
« Asexual
reproduction as well as isogamous sexual reproduction.
u Volvox
- Colonial green algae held together in a secretion of gelatinous material
« Reproduction
asexual or sexual.
Phylum Chlorophyta
n Other
Green Algae
u Ulva
(Sea Lettuce) - Multicellular seaweed with flattened green blades.
« Isomorphic
reproductive structures.
u Cladophora
- Branched, filamentous green alga with species represented in both fresh and
marine waters.
« Mostly
multinucleate.MARINE PLANTS
« Green
Algae
CHLOROPHYTA. The great majority of green algae are
restricted to fresh water and terrestrial environments.
Only 10% are marine but they are dominant in
environments with wide variations in salinity such as bays and estuaries, tide
pools (sewage outfalls) .
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n These
are the stock from which land plants derived and in full agreement in regards
to pigment, starch, cellulose etc
n May
exist as single cells, simple or branched filaments, blades, organized into
tubes that are intertwined and usually grass green in color.
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n Few
green algae are as complex as the other groups but their pigments and food
reserve are the same as in higher plants. (evolved from green algae.)
n Chlorophyll
b in green and land but not other algaes).
n They
are unicellular, filamentous multicellular, shapes can vary in the same species
according to their environment.
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Enteromorpha is a thin hollow tube, Ulva, sea
lettuce is leafy-like, Valonia, forms huge spheres /clusters of them in
tropical waters., some branch and Caulerpa and Cladophora have tubes with many
nuclei, spongy, branching thallus Codium and segmented with deposits of calcium
carbonate in their walls to ward off predators but
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end up cementing the reef together in reef
areas...Halimeda... a Coralline green algae!
Life Histories of seaweeds involve an alternation
of gamete producing phase (gametophyte) and spore producing phase (sporophyte).
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Green algae...Ulva (sea lettuce) have two
identical phases. 1. Sporophyte (diploid) produces flagellated zoo spores
(haploid) (meiosis) and these 2. swim briefly and settle on the bottom and 3.
grow into a gametophyte phase (male or female) and produce motile gametes which
4. fuse to form zygotes (diploid).
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Codium, another green algae is more like animals
and produces gametes by meiosis which fuse and form a zygote and grows into the
familiar plant.
Phylum Chromophyta
n The
Yellow-Green Algae (Xanthophyceae)
u Mostly
freshwater organisms with a few marine and terrestrial representatives.
« Two
flagella of motile cells are oriented in opposite directions.
Aplanospores
formed during asexual reproduction.
Sexual reproduction rare.
Phylum Chromophyta
n The
Golden-Brown Algae (Chrysophyceae)
u Most
occur in the plankton of bodies of fresh water.
« Motile
cells have two flagella of unequal length inserted at right angles to each
other.
Photoreceptor
on short flagellum.
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Chrysophyta...golden/yellow color because in
addition to chlorophyll. a & c there is a dominant carotenoid, fucoxanthin
and many members have a cell covering of small siliceous scales. The
silicoflagellates have an internal glass skeleton. Rare today.Characterized by
star shaped internal skeleton made of silica and a single flagellum.
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Silicoflagellates are one of the lesser known
types of photosynthetic protists found in the oceans. They are prominent
because of their bizarre skeleton which consists of a rigid flattened basket
of hollow tubes. Two to 8 spines project radially from the central basket.
Because the construction of this skeleton is so robust, scientists can estimate
abundances of this organism fairly easily.
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PLANTS
Fossils of the skeleton indicate that the
diversity of silicoflagellates was once greater than the few species we have
today. The cell itself is a lumpy bag containing golden-brown bodies
(chloroplasts) that sits around the central part of the skeleton.
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Where do
they live?
Silicoflagellates are found in sun-lit zones of
the of the ocean and are generally more common in colder waters. During winter
they can be found closer to the tropics, but they retreat to cooler waters
again in the warmer months. The distribution of their fossilised skeletons is
used to help determine sea-temperatures in earlier ages
Phylum Prymnesiophyta
n The
Haptophytes
u Most
are unicellular, with two smooth flagella of similar length inserted at the
apex.
« Flagella
aid in food capture.
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Haptophyta.. or Coccolithophorids, flagellated
spheric cells covered with button like structures called coccoliths made of
calcium carbonate. This was broken off the above class because of different
types of flagella. Phaeocystis forms gelatinous clumps, visible and can effect
migration patterns of fish.
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n Coccolithophorales
n Emiliana
huxleyi - global distribution, bloom former, major player in marine
phytoplankton
n Thought
to be largest global producer of calcium carbonate, hence major sink for CO2.
n .
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Also, blooms long ago followed by anaerobiosis,
caused them to sediment and gave rise to oil deposits in the North Sea. The
coccolithophores have small calcareous plates covering them and the patterns go
way back in fossil records and are used by oil companies.
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Xanthophyta...like Chrysophyceae but have no
fucoxanthin pigment. The Xanthophyta include more than 600 species. Members of
this group are photosynthetic organisms which live primarily in freshwater,
though some are found in marine waters, in damp soil, or on tree trunks.
Euglenophyta...euglena..class contains only
unicellular flagellates, chlorophyll. A and B and a flexible cell covering...no
wall!
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Euglenophyta...euglena..class contains only
unicellular flagellates, chlorophyll. A and B and a flexible cell covering...no
wall!
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Bacillariophyta...diatoms...most important group
in terms of primary productivity. The characteristic yellow-brown color is due
to CAROTENOID pigments in addition to two types of chlorophyll (a and c). Half
of the 12,000 species are marine. The brownish scum in a fish tank consists of
millions of diatoms.
Phylum Chromophyta
n The
Diatoms (Bacillariophyceae)
u Among
best known and economically most important members of this phylum.
« Mostly
unicellular
Occur
in both fresh and salt water.
Particularly
abundant in colder marine habitats.
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n Diatom
Characteristics
n 1.
Usually unicellular but chains do occur
n 2.
Pigments chlorophyll. a & c and fucoxanthin (gold/brown)
n 3.
Food reserve is chrysolaminarin and oils (buoyant)
n 4.
Only flagellate cells in reproduction (uniflagellate.)
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n 5.
Walls made of glass called frustule.
n 6.
Looks like petri dish
7. Two symmetries..radial and bilateral which
divide diatoms into 2 sub-divisions..Centric & Pennates
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Reproduction...valve to valve...one product of the
division retains the parental epivalve (top) and the other the parental
hypovalve (bottom) which results in the bottom being slightly smaller than the
parent because a new inside always grows back.
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Continued vegetative reproduction reduces the size
until it gets to its smallest size and this diploid cell produces gametes which
fuse to form a full size zygote. Only the small cells will undergo sexual
reproduction and if they get too small, they can't even do that.
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Dinophyta /Pyrrhophyta or the Dinoflagellates
Mostly unicellular with 2 unequal flagella , one that wraps around a groove in
the middle of the cell, and the other that trails free, and include the
non-motile zooxanthellae (found in corals).
The are most abundant in warm waters and second to
diatoms in cold water.
Phylum Dinophyta
n The
Dinoflagellates
u Unicellular
u Contain
two flagella.
« One
trails behind the cell.
« Other
encircles the cell at right angles.
u Most
have disc-shaped chloroplasts.
« Contain xanthophyll pigments.
u Many
have tiny projectiles.
u Many
types of toxins produced. (Red Tides)
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Characteristics of Dinoflagellates
1. Most are marine
2. Chlorophyll a, c, peridinin. Starch, oils , but
can ingest food stuffs
3. Distinctive flagella pattern
4. Some without walls (naked) and others with
walls (Armor) with cellulosic plates fitting together like armor which may have
spines,
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5. Half are colorless, some heterotrophic,
sparophitic, phagocytic, parasitic and some photosynthetic. It is thought that
through
evolution they have gained the ability to function
as primary producers by "capturing" and using chloroplasts from other
algae.
6. some bioluminescent
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7. some responsible for red tides and 20 spp..
secrete toxins. They reproduce by simple cell division and form blooms that
often color the water red, reddish-brown, yellow or unusual shades.
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a. all toxic ones are photosynthetic
b. all are estuarine or neritic forms
c. all probably produce benthic, sexual resting
stages
d. all capable of producing monospecific blooms
(suggest competitive advantages through exclusion
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e. all produce bioactive-watersoluable or lipid
soluble toxins that are hemolytic, or neurotoxic in activity. (NSP, PSP, Dsp)
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The Zooxanthellae are a variety of dinoflagellates
which have developed a close association with an animal host. The hosts range
from sponges to giant clams but the most important are the ones in the stony
corals.
They help fix carbon through photosynthesis,
release organic matter to be used by the coral, help in formation of the coral
skeleton.
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It was once believed that all zooxanthellae were
the same species, Symbiodinium microadriaticum (Rowan and Powers, 1991).
However, recently, zooxanthellae of various corals have been found to belong to
at least 10 different algal taxa.
Phylum Euglenophyta
n The
Euglenoids
u Spindle-shaped.
u No
cell wall, thus changes shape as it moves.
« Sub-membrane
strips and membrane form pellicle.
u Contains gullet.
u Contains
red eyespot.
u Reproduction
by cell division.
Phylum Cryptophyta
n The
Cryptomonads
u Asymmetrical,
unicellular marine and freshwater algae with two flagella.
« Single
two-lobed chloroplast with starch granules surrounding a central pyrenoid.
« Distinctive
nucleomorph
« Gullet
« Ejectosomes
« Reproduction
by mitosis
Phylum Charophyta
n The
Stoneworts
u Primarily
aquatic organisms of shallow, freshwater lakes and ponds.
u Often
precipitate calcium salts on their surfaces.
u Axil
with short lateral branches in whorls.
u Sexual
reproduction is oogamous.
Human and Ecological Relevance of Algae
n Diatoms
u Oils
are sources of vitamins.
u Diatomaceous
Earth
« Filtration
« Polishes
« Reflectorized
Paint
n Other
Algae
u Chlorella
« Potential
human food source.
Human and Ecological Relevance Algae
n Algin
u Produced
by giant kelp.
« Ice
Cream, Salad Dressing
« Latex Paint, Textiles, Ceramics
« Regulates
water behavior.
n Agar
u Produced
by red alga Gelidium.
« Solidifier
of nutrient culture media for growth of bacteria.
Phylum Myxomycota
n The
Plasmodial Slime Molds
u Totally
without chlorophyll and are incapable of producing their own food.
« Distinctly
animal-like during much of life cycle, but fungus-like during reproduction.
Plasmodium
converts into separate small sporangia (each containing spores) during times of
significant environmental changes.
Phylum Dictyosteliomycota
n The
Cellular Slime Molds
u About
two dozen species of cellular slime molds are not closely related to the other
slime molds.
« Individual
amoebalike cells feed independently, dividing and producing separate new cells
periodically.
u Human
and Ecological Relevance
« Break
down organic particles to simpler substances.
Phylum Oomycota
n The
Water Molds
u Often
found on dead insects.
u Range
in form from single spherical cells to branching, threadlike, coenocytic
hyphae.
« Coenocytic
hyphae may form large thread masses (mycelia).
Review
n Phylum
Chlorophyta
n Phylum
Chromophyta
n Phylum
Rhodophyta
n Phylum Euglenophyta
n Phylum Dinophyta
n Phylum
Cryptophyta
n Phylum
Prymnesiophyta
n Phylum
Charophyta
n Phylum
Myxomycota
n Phylum
Dictyosteliomycota
n Phylum
Oomycota
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n Members
include seaweeds, sea grasses, mangroves, marsh grass, microscopic algae.
n they
are eukaryotic
n contain
organelles enclosed by a membrane
n photosynthesis
takes place in chloroplasts--green,brown, or red organelles.
n lack
flowers, roots stems and leaves.
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n While
most are referred to as plants, some have flagella and show animal
characteristics...and some are actually claimed by both botanists and
zoologists as theirs!
n Taxonomically,
a compromise has placed them in the Kingdom Protista
the unicellular forms.
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n Seaweeds...dominant
marine plants containing chlorophyll and additional pigments from blue to red.
n Seaweeds
are all eukaryotic and most are multicellular.
n
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n But
some that are unicellular or simple filaments are considered seaweed because
the classifications of seaweeds is based not only on structure,
n but
also on other features such as types of pigments and food storage products.
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n Classification
characteristics used to classify are;
1.
form which starch is stored
2.
composition of cell wall
3.
presence of motile with flagella
4.
level of complexity
n 5.
sometimes, reproductive patterns (reds)
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n Red
Algae is Rhodophyta
n Green
Algae is Chlorophyta
n Brown
Algae is Phaeophyta
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n Algae
are Thallus, meaning they lack true roots, stems, and leaves, fruits,
connecting tissue etc. and
n
photosynthesis occurs throughout the plant, not just the leaves.
n Parts:
Holdfast, stipe, blade, air bladders (pneumatophores).
n (list
functions)
Phylum Chromophyta
n The
Brown Algae (Phaeophyceae)
u Relatively
Large
u Most
Marine
u Non-Unicellular
or Colonial
u Many
have a thallus differentiated into a holdfast, a stipe, and blades.
« Blades
may have gas-filled bladders.
u Sargassum
- Floating Brown Seaweed
u Fucus
- Common Rockweed
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n Brown
Algae.
n Phaeophyta..microscopic
to 60' make up the largest and structurally most complex.
n Colors
range from olive green to dark brown, due to yellow pigments fucoxanthin
dominance over chlorophyll.
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n Pigments
are xanthophyll and carotene and chlorophyll.
n The
simplest brown algae have a finely filamentous thallus as in Ectocarpus.
n There
is the fan shaped Padina.
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n Many
species of brown alga are found in the intertidal zone and known as rockweeds
and in deeper areas of the cool coastal zones are the kelps, the largest and
most complex of all brown algaes.
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As mentioned before, kelp plays an important in
the coastal production with many organisms finding homes around the kelp beds.
Some kelps consist of a single blade, Laminaria,
which are harvested for food.
Kelps have been estimated to grow up to 50 cm (20
inches) per day.
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Alginic Acid, a gummy, slimy layer in cell wall,
is used as an emulsifying agent (algin)..(Know uses) (algae Readings)
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Brown algae...Nereocystis (bull kelp). The kelp is
the sporophyte or diploid phase and
1. certain areas of the fronds (sori) become
darker
2. meiosis occurs and haploid zoo spores are
formed.
3. They settle to the bottom and grow into
microscopic gametophytes.
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4. The female produces eggs but holds them and the
male produces sperm which are released and
5. attracted to eggs, fertilize them and
6. zygotes are formed which germinate into the
sporophyte plant.
Kelp (how are chances for fertilization
increased?) ....Fucus, another brown algae or rockweed, is again, like animals where
the
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1. diploid plant forms gametes through meiosis
2. fertilization occurs
3.the zygote immediately germinates back to the
sporophyte
Gametes are produced in cavities called
CONCEPTACLES.
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n Red
Algae
n Rhodophyta
has more species of these than green and brown combined.
n It
has the highest commercial value, and don't get as large as brown algae.
absence
of flagellate stages
presence
of other pigments mainly phycobilins
Phylum Rhodophyta
n The
Red Algae
u Most
species are seaweed.
u Tend
to occur.
u Numbers
of species produce agar.
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Floridean
starch as food reserve (scattered throughout cells)
Existence
of special female cells (carpogonia) and male gametes (called spermatia) for
sexual reproduction.
Cell
walls with inner rigid component and outer mucilage or slime layer. This is
like the alginates and very valuable.
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n The
structure of the thallus of red algae does not show the wide variation in
complexity and size that is observed in brown algae.
n Most
reds are filamentous but thickness, width and arrangement of the filaments vary
a great deal.
n There
are many variations in the shapes, sizes and colors of the reds.
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n One
important in marine environments are the red alga Corallines.
n These
are characterized by deposits of calcium carbonate around their cell walls.
n These
can be encrusting on the rocks or articulated, branching plants, with colors
from light to reddish pink-white when dead.
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n Warm
water corallines are active in reef development.
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1. Sporophyte produces tetrasporangia (site of
meiosis) which produce 4 haploid tetraspores.
2. Gametophytes grow from the spores and their
gametes (spermatia and carpogonia) fuse and
3. are retained and develop into a special mass of
diploid cells (the carposporophyte)
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4. which breaks up into many carpospores (diploid)
and
5. these grow into a sporophyte generation which
resembles the gametophyte (isomorphic) and..(go to 1)
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Red algae Porphyra or Nori is a valuable food
source but has an atypical life history with the gametophyte being the large
leafy plant and the sporophyte being the tiny "conchocelis" found
living in discarded shells. The Typical red cycle is that of Polysiphonia.
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THE IMPORTANCE OF CORALLINE ALGAE
Corallines as carbon stores
Coralline algae take up carbon for use in the
process of photosynthesis, as do most plants, but they have an additional
mechanism of carbon uptake, the calcification process.
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Calcium is deposited in the cell walls of
coralline algae in the form of calcium carbonate.
Coralline algae may be one of the largest stores
of carbon in the biosphere.
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Non-geniculate corallines are of particular
significance in the ecology of coral reefs, where they provide calcareous
material to the structure of the reef, help cement the reef together, and are
mportant sources of primary production. Coralline algae are especially important
in reef construction, as they lay down calcium carbonate as calcite.
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Although they contribute considerable bulk to the
calcium carbonate structure of coral reefs, their more important role in most
areas of the reef, is in acting as the cement which binds the reef materials
together into a solid and sturdy structure.
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An area where corallines are particularly
important in constructing reef framework is in the algal ridge that
characterizes surf-pounded reefs in both the Atlantic and Indo-Pacfic regions.
Algal ridges are carbonate frameworks that are constructed mainly by
nongeniculate coralline algae (after Adey 1978).
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They require high and persistent wave action to
form, so are best developed on the windward reefs in areas where there is
little or no seasonal change in wind direction. Algal ridges are one of the
main reef structures that prevent oceanic waves from striking adjacent
coastlines, and they thus help to prevent coastal erosion.