Eucheuma

Eucheuma, commonly known as gusô, is a seaweed algae that may be brown, red, or green in color. Eucheuma species are used in the production of carrageenan, an ingredient for cosmetics, food processing, and industrial manufacturing, as well as a food source for people in Indonesia and the Philippines. Eucheuma cottonii – cultivated in the Philippines – is the particular species known as gusô. Other species include Betaphycus gelatinae, Eucheuma denticulatum, and several species of the genus Kappaphycus, including K. alvarezii. Since the mid-1970s, Kappaphycus and Eucheuma have been a major source for the expansion of the carrageenan industry. Though commercially significant, species of Eucheuma are difficult to identify without the aid of close scientific examination, as different species may have similar morphologies. Some eighteen to twenty species alone fall within the genus Eucheuma, represented by the groups Cottoniformia, Gelatiformia, and Anaxiferae. Gusô is listed in the Ark of Taste international catalogue of endangered heritage foods of the Philippines by the Slow Food movement. Eucheuma are naturally found within the range of 20 degrees either side of the Equator in the Indo-Pacific region from eastern Africa to Guam, and are most concentrated in Southeast Asia. A few species are found on Lord Howe Island and in southwestern Australia. As a commercial crop, Eucheuma has since been distributed to many regions away from their original natural habitats, including Japan, Hawaii, and island nations in the South Pacific. Eucheuma are typically found below the low tide mark to the upper subtidal zone of a reef, growing on sand to rocky seafloor areas along a coral reef, where water movement is slow to moderate. Their growth is similar to terrestrial plant species, where Eucheuma have a growing tip, or apical meristem, which is also capable of dividing to form new growing branches. They also show a triphasic life cycle, consisting of a gametophyte (n) (dioecious), carposporophyte (2n), and the sporophyte (2n). Both the gametophyte and the more robust sporophyte stage are significant to the development of the seaweed, where their characteristics allow for increased vegetative regeneration. Commercial growth of Eucheuma is an important source of income for people living in developing nations, where the production of the low-valued seaweed can be a sustainable source of income with lower environmental costs compared to other sectors of aquaculture. As Eucheuma are some of the most common and fastest growing species of seaweeds, their commercial aspects are visible by large quantities grown and harvested over short periods of time, possessing the ability to reach ten times their mass in some 45 to 60 days in warm tropical settings. Once harvested, the product can be dried, packaged, and then transported to areas ready for carrageenan extraction or used as a food supply.