Three groups of seaweeds Red algae phylum(division) Rhodophyta
Brown algae phylum(division) Phaeophyta Green algae
phylum(division) Chlorophyta
Slide 4
Rhodophyta
Slide 5
Slide 6
Irish Moss - Rich in protein and minerals
Slide 7
Corallines Secrete a calcium carbonate shell that bond coral
colonies together (holds the coral reef structure together)
Slide 8
Nori - Rich in protein and minerals
Slide 9
Slide 10
Phylum Rhodophyta Red Algae Corallines Secrete a calcium
carbonate shell that bond coral colonies together (holds the coral
reef structure together) Irish Moss Rich in protein and minerals
Nori Rich in protein and minerals
Slide 11
Phylum Rhodophyta Biochemistry Chlorophylls a, d Phycoerythrin
(red pigments) Allow some red algae to live much deeper than any
other algae As deep as 200 m (656 ft)
Slide 12
Phylum Rhodophyta Ecological Roles Seasonal food for
herbivores, grazers Some form turfs and reef sediments Some
stabilize reef sediments
Slide 13
Phylum Rhodophyta Commercial uses Agar Used in medicine and
research for culturing microorganisms Carrageenan Desserts, ice
cream, milk shakes, sweetened condensed milks, puddings, sauces:
gel to increase viscosity thickener : Shampoo and cosmetic
creams.
Slide 14
Red Algae Phylum Rhodophyta Primarily marine (98%) The highest
diversity among seaweeds Mostly benthic in distribution Some
species are epiphytes (plant living on plant) Coraline red algae-
helps to cement loose coral together
Slide 15
Important commercial uses Agar culturing bacteria Carrageenan
thickening agent Source of food for human consumption, animal feed,
and used in fertilizer
Slide 16
Phylum Phaeophyta Brown Algae Kelp Sargassum Rockweed
Slide 17
Slide 18
Phylum Phaeophyta Biochemistry Chlorophylls a, c Pigment
fucoxanthin
Slide 19
Slide 20
Phylum Phaeophyta Ecological Roles Long term food for
herbivores, grazers very productive the Giant Kelp is the
foundation for many temperate coastal ecosystems: California, the
Mediterranean, and New Zealand Kelp form massive undersea forests
Habitat for diversity of marine animals Sea urchins, fishes,
crustaceans, molluscs, sea lions, sea otters
Slide 21
Phaeophyta
Slide 22
Brown Algae Phylum Phaeophyta Rockweeds, kelps, and sargassum
Almost exclusively marine (99.7%) Most are benthic except for
Sargassum Range in size from microscopic to the giant kelps
Olive-brown color is due to pigment fucoxanthin (also found in
diatoms)
Slide 23
Brown Algae Blades of brown algae usually have gas-filled
bladders that help them to stay afloat to get maximum exposure to
sunlight The stipe is attached to the bottom by a holdfast
Slide 24
Slide 25
Ecological roles of Sargassum Sargassum forms floating mats in
the North Atlantic Ocean in an area known as the Sargasso Sea
Habitat to a variety of organisms unique to the sargassum Massive
mats of sargassum support a complex and diverse community Several
species of fish and invertebrates live only in this ecosystem
Slide 26
Slide 27
Slide 28
Slide 29
Phylum Phaeophyta Commercial uses Brown algae is used as a food
resource Seaweeds and algae make up 10% of the Japanese diet The
commercial product algin is used in food processing, salad
dressing, ice cream, paint, and abrasives Food and chemical
industries use about $250 million worth of algin annually
Slide 30
Commercial products from Brown Algae The alginates of some
brown algae are harvested for commercial use as thickening agents
in the textile, dental, cosmetic, and food industries Brown algae
are used as food, and as cattle feed
Slide 31
Chlorophyta
Slide 32
Phylum Chlorophyta Green Algae Sea lettuce
Slide 33
Phylum Chlorophyta Biochemistry Chlorophylls a, b Carotenoids
Chlorophyta share the same pigments as land plants Evolutionarily
significant, indicates that land plants evolved from green
algae
Slide 34
Phylum Chlorophyta Ecological Roles Seasonal food for
herbivores, grazers Manatees eat sea lettuce Some form turfs and
reef sediments
Slide 35
Phylum Chlorophyta Commercial uses Can be used as a compost
material and as fertilizer
Slide 36
Green Algae Phylum Chlorophyta Contain the same types of
pigments that are found in land plants (a,b) Few marine species
(13%), most are freshwater and phytoplankton
Slide 37
Distribution of Seaweeds Most species of seaweed are benthic
Fouling communities live on pilings, bulkheads, boat hulls... The
environmental factors most influential in distribution Light and
temperature
Slide 38
Structure of Seaweeds Thallus The seaweed body Blade Flattened
part of the thallus Holdfast Attaches the thallus to a surface
Stipe Stem-like region between the holdfast and the blade
Slide 39
Photosynthetic pigments Chloroplasts in all seaweeds have
chlorophyll a Green algae also has chlorophyll b Brown algae
chlorophyll c Red algae chlorophyll d
Slide 40
Composition of cell walls Primarily composed of cellulose
Calcareous algae may also have calcium carbonate
Slide 41
Reproduction in Seaweeds Both asexual and sexual Asexual
Fragmentation Thallus breaks into pieces and each piece grows into
a new plant Spore formation Sporophyte produces spores Sexual
Gametes are produced and zygote is formed Gametophyte produces
gametes Alternation of generations Asexual sporophyte and sexual
gametophyte in same plant