What is It?
Red algae are marine multicellular organisms that have no cell specialization. In other words, there are no different tissues although red algae are highly branched.
They are completely sessile and have no way to move around other than the movement of the water.
Most have a reddish or purplish tint, due to the phycobillin pigments they have.
Red algae have a very unique reproductive cycle, consisting of two diploid stages and one haploid one. Red algae gametes, just like those of most diploid organisms, are haploid. Once the gametes are fertilized, instead of forming a zygote, a diploid carposporophyte is formed. These spores are then emitted and develop into another diploid generation, known as a tetrasporophyte. This is called an isomorphic alternation of generations.
Red algae can grow very deep because the phycobillin pigments can absorb a different wavelength of light for photosynthesis.
Depending on the species, red algae cells can have more than one nucleus.
Use in the Human World
Red algae is used in nori, the seaweed used in many sushi dishes.
Carrageenan is a gel-like product made from red algae that is used in many things, from ice cream to toothpaste.
“Rhodophyta.” Columbia Encyclopedia. January 27, 2009
“Life Cycles and Reproduction.” Botanical Gardens Trust. January 27, 2009