Marine Algae
By: Mike Dedio, Christian Bailey,
Alex Zimm, Arianna Dean
Algae Basics
• Algae are Eukaryotic meaning that their
cells have a nucleus-classified under the
kingdom of protista
• They are autotrophs, producing their own
food from photosynthesis
• Algae and marine plants produce upwards
of 70% of the oxygen for terrestrial life
Algae Basics Continued…
• Many algae species form symbiotic
relationships with other species supplying
organic substances and receiving
protection
• Used as fertilizer, engergy source, food
source, for pigments, pollution control, and
medicinal purposes
Seaweeds
• Seaweeds are multicellular algae that live
in the sunlit waters of the ocean.
• Ulva- A common tissue thin seaweed that
contains chloroplasts.
• Some marine animals eat alga for the
nutrients it provides while others filter the
nutrients from the water such as barnacles
Seaweeds
Reproductive Cycle of Algae
• Thallus- The leafy part of seaweed.
• Ulva use asexual reproduction.
• Specialized cells at the end of the Thallus
produce spores called sporophyte thallus
which is diploids.
• Spore- A repoductive cell that contains the
organisms number of chromosomes.
Reproductive Cycle of Algae
continued.
• Spores have flagella that move back and forth,
the spores will at some point reach the ocean
floor.
• They land on a suitable substrate each develop
into a leafy thallus that produces gametes.
• Gametes- Are reproductive cells that contqain
the haploid number of chromosomes necessary
for sexual reproduction.
Reproductive Cycle of Algae
Continued
• The life cycle of Ulva is composed of two
separte stages or generations- the
sporophyte and gametophyte gernerations
• The succession of two types of
generations is called alternation of
generations.
Brown Algae
• Classified in the phylum Phaeophyta
• Brown or olive green in color, the color
results from mixtures of pigments in the
cells of the algae
• Mostly the green pigment chlorophyll and
the yellow pigment xanthophyll, the
blending of these pigments result in a
brown color.
Brown Algae
Brown Algae Continued..
• Provide shelter and/or nutrients for other organisms, and
are used materials people find valuable.
• For example, the sea palm which grows on rocks and
resembles a tiny palm tree can be eaten raw or cooked.
• Rockweed attaches to rocks in the intertidal zones along
the Atlantic, Pacific, and Gulf coasts.
• The rockweed’s holdfast, anchors the algae to rocks, it is
a tough, fibrous pad of tissue, and it also prevents the
algae from being dislodged from his holding from strong
currents and waves for example.
Brown Algae Continued..
• The largest seaweeds in the ocean are
called kelp which falls under the category
of brown algae.
• Laminaria, a type of kelp, thrives in the
color waters of the temperate zone, mainly
concentrated of the coasts of Maine and
California.
• They grow rapidly from the seafloor to the
surface of the water.
Brown Algae Continued…
• Giant kelps, like the Nereocystis and
Macrocystis, can reach a length of more than 60
meters.
• Fish, shellfish, sea urchins, sea lions, sea
otters, and sharks all live around giant kelp for
food and shelter.
• A chemical in algae called algin, is used in many
different industries for food preparations,
medicines, paints, and paper products.
Brown Algae Continued….
• One type of brown algae that is not
anchored to a substrate is the Sargassum,
floats on the waters surface in places such
as South Atlantic Ocean and in some seas
off the coasts of Asia.
Red Algae
• Most abundant of the marine algae
• Classified in phylum Rhodophyta
• Found in intertidal to subtidal zone
and some species at great depths of
ocean
• Contains red pigment phycoerythin
and the blue pigment phycocyanin
• These two pigments allow for
photosynthesis to occur at much
deeper waters to carry out
photosynthesis
Red Algae continued
• types of red algae include Coralline Algae,
Irish Moss, Porphyra, and Lithothamnion
Coralline Algae
(Corallinia)
• Hard and brittle red algae with calcium
carbonate in the cell walls
• Found attached to rocks in lower intertidal
zone
• Many are epiphytic (growing on other
algae and marine angiosperms) or epizoic
(grow on animals)
• Used as soil conditioners and in medicine
Irish moss
(Chrondrus Crispus)
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•
•
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Short, bushy, spongy red algae
Found in lower intertidal and subtidal zones
Found carpeting rocks
Contains a chemical called carrageean which is
used as a binding agent in ice cream, puddings,
and toothpaste
• Others like this contain a chemical called agar
that is used to make food, medicinal products as
well as a medium for growing bacteria
Porphyra
• Thin and delicate, sheetlike red algae
• Also called Nori
• Grows in intertidal zone usually attached
to rocks
• Is the most commonly eaten seaweed
• There are 60-70 species of porphyra found
world wide
Lithothamnion
• Known as encrusting stony red algae
• Grows on rocks and is often found on the
shells of hermit crabs
• Adorns shells with a bright red color