Kappaphycus alvarezii as semirefined carrageenan. "K. alvarezii" is affected by ice-ice, a disease that severely reduces its yield. This alga is an introduced species and a noxious aquatic weed in Hawaii. Kappaphycus alvarezii Kappaphycus alvarezii, the elkhorn sea moss, is a species of red algae. It is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Farming methods affect the character of the carrageenan that can be extracted from the seaweed. This alga grows to two meters long and is green or yellow in color. It is very fast-growing, known to double its biomass in 15
Red algae contain the sulfated polysaccharide carrageenan in the amorphous sections of their cell walls, although red algae from the genus Porphyra contain porphyran. They also produce a specific type of tannin called phlorotannins, but in lower amount than brown algae do. Complete genome sequences are only available for 6 species of red algae, including 4 published in 2013. One of the oldest fossils identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon. "Bangiomorpha pubescens", a multicellular fossil from arctic Canada, strongly resembles the modern red alga "Bangia" despite occurring in rocks dating