MARINE PLANTS
nMembers include seaweeds, sea grasses, mangroves, marsh grass,
microscopic algae.
nthey are eukaryotic
ncontain organelles enclosed by a membrane
nphotosynthesis takes place in
chloroplasts--green,brown, or red organelles.
nlack flowers, roots stems and leaves.
MARINE PLANTS
nWhile 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!
nTaxonomically, a compromise has placed them in the Kingdom
Protista…the unicellular forms.
MARINE PLANTS
nSeaweeds...dominant marine plants containing
chlorophyll and additional pigments from blue to red.
nSeaweeds are all eukaryotic and most are multicellular.
n
• MARINE PLANTS
nBut some that are unicellular or simple filaments are
considered seaweed because the classifications of seaweeds is based not only on
structure,
nbut also on other features such as types of
pigments and food storage products.
MARINE PLANTS
nClassification characteristics used to classify are;
•1. form which
starch is stored
•2. composition
of cell wall
•3. presence of
motile cells with flagella
•4. level of
complexity
n5. sometimes, reproductive patterns
(reds)
MARINE PLANTS
nRed Algae is Rhodophyta
nGreen Algae is Chlorophyta
nBrown Algae is Phaeophyta
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nAlgae 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.
nParts: Holdfast, stipe, blade, air bladders (pneumatophores).
n(list functions)
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nBrown Algae.
nPhaeophyta..microscopic to 60' make up the largest and
structurally most complex.
nColors range from olive green to dark brown, due to yellow
pigments fucoxanthin dominance over chlorophyll.
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nPigments are xanthophyll
and carotene and chlorophyll.
nThe simplest brown algae have a finely filamentous thallus as in Ectocarpus.
nThere is the fan shaped Padina.
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nMany 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.
MARINE PLANTS
As mentioned before, kelp plays an important role 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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nRed Algae
nRhodophyta has more species of these than green and
brown combined.
nIt has the highest commercial value, and don't get as large as
brown algae.
•absence of flagellate stages
•presence of other pigments mainly phycobilins
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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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They can also deposit calcium carbonate (lime) into the
walls of some species (Coralline algae) (Coralline algae)
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nThe structure of the thallus
of red algae does not show the wide variation in complexity and size that is
observed in brown algae.
nMost reds are filamentous but thickness, width and arrangement
of the filaments vary a great deal.
nThere are many variations in the shapes, sizes and colors of
the reds.
MARINE PLANTS
nOne important in marine environments are
the red alga Corallines.
nThese are characterized by deposits of calcium carbonate
around their cell walls.
nThese can be encrusting on the rocks or articulated, branching
plants, with colors from light to reddish pink-white when dead.
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nWarm 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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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) .
MARINE PLANTS
nThese are the stock from which land plants derived and in full
agreement in regards to pigment, starch, cellulose etc
nMay exist as single cells, simple or
branched filaments, blades, organized into tubes that are intertwined and
usually grass green in color.
MARINE PLANTS
nFew 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.)
nChlorophyll b in green and land but not
other algaes).
nThey are unicellular, filamentous multicellular, shapes can
vary in the same species according to their environment.
MARINE PLANTS
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).
MARINE PLANTS
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.
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Marine Angiosperms (flowering plants)...few occur in
the marine environment but those that do are usually very productive and
adapted for their lifestyle. Of the 3 groups, mangroves, marsh grass and
seagrass, only the sea grasses are adapted to live completely submerged
in water. Pollination occurs under water.
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Seagrasses are not grasses, and thrie closest relatives are
probably lilies. Pollen is carried by water currents and seeds are dispersed by
water currents and feces of fish and other animals that browse of the plants.
Eel Grass (Zostera) is the most widely distributed of the 50 species and found
in shallow, well-protected coastal waters such as bays and estuaries.
MARINE PLANTS
It has distinct flat ribbon like leaves. Surf grass
(Phyllospadix) is on rocky coasts exposed to waver
action. Turtle grass (Thalassia) is common in the keys. (
Manatee Grass (Halophila)).
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Mangroves..80 unrelated species of
flowering plants adapted to various ways to survive in the salty environment.
Mangroves have a special root system using aerial roots to ventilate the
system below the substratum (especially in anaerobic mud and under water).
MARINE PLANTS
The three
types of mangroves found in Florida include the Red Mangrove (Rhizophora
mangle), the Black Mangrove, (Avicennia germinans) and White
Mangrove, (Laguncularia racemosa). These are found along the estuaries,
canals, and form islands.
MARINE PLANTS
The term
"Mangrove" is applied to a diverse group of tropical salt tolerant
trees which are abundant in south Florida and the Florida Keys. These trees
have been able to successfully occupy coastal environments where they have
little or no competition from other species of plants.
MARINE PLANTS
In
order to do this, the mangrove trees have had to cope with a number of problems
including soft, oxygen-poor soil, periodic flooding of their root zones and a
highly saline environment.
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Some genera have seeds that germinate on the parent
plant and drop as seedlings rather than seeds.
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Saltmarsh plants, true members of the
grass family, usually consists of succulent shrubs and herbs and grass-like species which
can tolerate large salinity fluctuations. Cord grass inhabits the zone
above the mud flats and can be submerged, and have salt glands to get rid of
excess salt. Halophytes are found in higher levels of the marsh (pickleweed).
MARINE PLANTS
Phytoplankton...plankton..Greek for wanderer
meaning that they are passively transported. Nekton
are those that swim. Size categories of plankton:
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nultraplankton: less than 2 um
nnanoplankton: 2-20 um
nmicroplankton: 20-200 um
nmacroplankton: 200-2000 nm
nmegaplankton: 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.
MARINE PLANTS
Divisions
Cyanobacteria (Cyanophyta) Blue-green algae (Monera)
nChlorophyta green algae
nChrysophyta golden algae/silicoflagellates
nHaptophyta- coccolithophores
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nXanthophyta yellow-green algae
nBacillariophyta diatoms
nDinophyta (Pyrrophyta) dinoflagellates & zooxanthellae
nCryptophyta cryptomonads
nEuglenophyta euglenas
MARINE PLANTS
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.
MARINE PLANTS
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).
MARINE PLANTS
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).
MARINE PLANTS
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.
MARINE PLANTS
Chlorophyta..few marine planktonic
reps. but lots of macroscopic, benthic types
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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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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
MARINE PLANTS
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.
MARINE PLANTS
nCoccolithophorales
nEmiliana huxleyi - global distribution, bloom former,
major player in marine phytoplankton
nThought 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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Fungi There are at least 500 species of marine fungi, most
which are decomposers of dead organic matter. Some are parasites causing
diseases in fish , shellfish, seaweed and sponges.
Also some form associations with algae forming lichens and marine lichens may
be found as thick, dark-brown/black or even orange patches on the wave splashed
zones on rocky shores.
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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.
MARINE PLANTS
nDiatom Characteristics
n1. Usually unicellular but chains do occur
n2. Pigments chlorophyll. a & c
and fucoxanthin (gold/brown)
n3. Food reserve is chrysolaminarin and oils (buoyant)
n4. Only flagellate cells in reproduction (uniflagellate.)
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n5. Walls made of glass called frustule.
n6. 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.
MARINE PLANTS
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.
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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.
MARINE PLANTS
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.
MARINE PLANTS
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.
MARINE PLANTS
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.
MARINE PLANTS
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.