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 Brown Algae
Kingdom Chromista - Phylum Phaeophyta
99% of the brown algae species are found in the marine environment.
Characteristics exhibit a wide range of reproductive strategies,
from simple, asexual cell division to complex forms of sexual
reproduction known as "Alteration of generations."
The thallus (or body) of the brown kelp algae, is made of:
- Holdfast - base used to attach to rock or bottom
- Stipe - flexible and used for flotation - most without
vascular tissue so not the same as the stem of a land plant
- Pneumatocyst - air bladder to help blades float at
surface
- Blade - leaf like structure that floats on surface
to collect sunlight for photosynthesis and energy.
Pigments: Chlorophyll a, c + fucoxanthin
Cell Walls: Cellulose and algin.
Carotenoids are usually red, orange, or yellow pigments,
and include the familiar compound carotene, which gives carrots
their color. Carotenoids cannot transfer sunlight energy directly
to the photosynthetic pathway, but must pass their absorbed energy
to chlorophyll. For this reason, they are called accessory pigments.
One very visible accessory pigment is fucoxanthin the brown pigment
which colors kelps and other brown algae as well as the diatoms.
Macrocystis pyrifera, or giant brown kelp algae, flourishes
in the Pacific Oceans of the west coasts of North American.
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