Transcript Marine Algae - davis.k12.ut.us

Marine Algae
Marine Biology Unit #2
Unicellular Algae
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The unicellular algae show plant-like and
animal-like characteristics.
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Algae are eukaryotic, photosynthetic
organisms.
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Unicellular algae are included in the Kingdom
Protista.
Unicellular Algae
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Diatoms:
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Diatoms are efficient photosynthetic factories,
producing much-needed food, as well as oxygen for
other forms of life.
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They are very important
open water primary
producers in temperate
and polar regions.
Unicellular Algae
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Dinoflagellates:
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They are more common in the tropics.
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Responsible for huge blooms called red tides.
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Dinoflagellates are also
noted for the production
of bioluminescence.
Multicellular Algae
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Commonly called “Seaweeds.”
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More complex than unicellular algae.
Being algae, seaweeds lack the true
leaves, stems, and roots of the
higher plants. Body is a thallus.
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Three types of seaweeds are the
green, brown, and red algae.
Seaweed Structure

The general structure of seaweed is analogous to land
plants, but being algae, seaweed lack the true leaves,
stems, and roots.

Blades –
 huge surface are for photosyntesis
Pneumatocysts –
 gas-filled bladders for bouyancy
Stipes –
 growth and flexibility
Holdfast –
 anchorage to substrate
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Seaweed Structure
Division Chlorophyta
Green Algae (major oxygen producers)
 Mostly freshwater and terrestrial
 Most are unicellular and filamentous
 Some marine species are multicellular
 Found in shallows
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Division Rhodophyta
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Red algae.
Grow deeper than other algae.
There are more species of marine
red algae than of green and
brown algae combined.
Coralline red algae deposit calcium
carbonate which helps form and
develop coral reefs.
Division Phaeophyta
Brown Algae (commonly called “Kelp”)
 Almost all marine.
 Major primary producers
on temperate rocky coasts.
 Macrocystis – “giant kelp”
 Form kelp forests.

Division Phaeophyta
Kelp Forests
Kelp Forests

Enormous primary productivity, analogous to a terrestrial
tropical rain forest in their complexity.

Kelp forests are the basis of recreation and fisheries on
North America’s west coast.
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In the colder waters of the north and south Atlantic and
Pacific Oceans, kelp beds, or forests are formed when
many plants, each with many fast-growing and
intertwined stripes form dense and very productive
regions.
Kelp Forests
Kelp Forests
Uses for Seaweeds
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Harvested seaweed is used in many ways. The most
obvious is as a food source.
The farming, or mariculture, of seaweed is big business in
China, Japan, and Korea.
Alginates (from brown algae)
Carrageenan (from red algae)
These compounds are used as stabilizers and emulsifiers

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ice cream, cheese, and topping
shampoo, shaving cream and cosmetics
plastics and pesticides