Knowra Brown algae Brown algae Brown algae are mostly marine, multicellular algae in the class Phaeophyceae. Their brown color comes chiefly from fucoxanthin, which masks chlorophyll.
Fucoxanthin : A brown carotenoid pigment that absorbs blue-green light and contributes to the color of brown algae. This pigment gives brown algae their characteristic color and broadens their usable light spectrum.
Oogamy : A form of sexual reproduction in which a large, nonmotile egg is fertilized by a smaller, motile sperm. Oogamy is common among brown algae, including kelps.
Kelp forest : A coastal marine ecosystem formed by dense stands of large kelps attached to the seafloor. Kelp forests are prominent ecosystems built by brown algae.
Red algae : A diverse group of mostly marine algae in the phylum Rhodophyta, often containing the pigment phycoerythrin. Red algae differ in pigments, storage products, and evolutionary history.
Stramenopile : A major eukaryotic lineage that includes brown algae, diatoms, and oomycetes. Brown algae are part of this lineage, despite their plant-like appearance.
Alginic acid : A polysaccharide in brown-algal cell walls and extracellular material, widely used as a thickener and stabilizer. Its salts form the alginates that make kelp tissues flexible and commercially useful.
Isogamy : A form of sexual reproduction in which the fusing gametes are similar in size and form. Some brown algae use isogamy rather than the egg-and-sperm pattern common in kelps.
Alginate : A family of salts of alginic acid used to thicken, stabilize, or form gels in products and materials. Brown-algal cell walls are the main commercial source of alginate.
Green algae : A diverse group of algae containing chlorophylls a and b, including lineages closely related to land plants. Green algae share photosynthetic ancestry with plants, unlike brown algae.
Archaeplastida : A eukaryotic supergroup that includes land plants, green algae, and red algae. Brown algae are not members of Archaeplastida, the lineage containing plants and their closest algal relatives.
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