Algae are aquatic plants that lack the leaves, stem, roots, vascular systems, and sexual organs of the higher plants. They range in size from microscopic phytoplankton to giant kelp 200 feet long (Shalaby 2011). They live in temperatures ranging from hot spring to arctic snows, and they come in various colors, mostly green, brown and red. There are about 25,000 species of algae compared to 250,000 species of land plants. Algae make up in quantity what they lack in diversity, for the biomass of algae is immensely greater than that of terrestrial plants (Lowenstein 1986).