Chondrus crispus

Chondrus crispus, known under the common name Irish moss, or carrageen moss (Irish carraigín, "little rock"), is a species of red alga which grows abundantly along the rocky parts of the Atlantic coast of Europe and North America. In its fresh condition the plant is soft and cartilaginous, varying in colour from a greenish-yellow, through red, to a dark purple or purplish-brown. The principal constituent of Irish moss is a mucilaginous body, made of the polysaccharide carrageenan of which it contains about 55%; the plant also has nearly 10% of protein and about 15% of mineral matter, and is rich in iodine and sulfur. When softened in water it has a sea-like odour, and because of the abundant cell wall polysaccharides it will form a jelly when boiled, containing from 20 to 100 times its weight of water.

Description

Chondrus crispus is a relatively small red alga little more than 20 cm long growing from a discoid holdfast and branching in a dichotomous, fan-like manner four or five times. The morphology is very variable, especially the broadness of the thalli. The branches are 2 - 15 mm broad, firm in texture and dark reddish brown in colour bleaching to yellowish in sunlight. The gametophytes (see below) often show a blue iridescence and fertile sporophytes show a spotty pattern. Mastocarpus stellatus (Stackhouse) Guiry is a similar species which can be readily distinguished being strongly channelled and often somewhat twisted. The cystocarpic plants of Mastocarpus show reproductive papillae quite distinctively different from Chondrus.^[1] When washed and sun-dried for preservation it has a yellowish translucent horn-like aspect and consistency.

Distribution

Chondrus crispus is found growing on rock from the middle intertidal zone downwards. It is common all around the shores of Ireland and Great Britain and can also be found along the coast of Europe from Iceland, the Faroe Islands ^[2] western Baltic Sea to southern Spain.^[1] It is found on the Atlantic coasts of Canada^[1]^[3] and recorded from California in the United States to Japan.^[1] However, any distribution outside the Northern Atlantic needs to be verified. There are also other species of the same genus in the Pacific Ocean, for example, C. ocellatus Holmes, C. nipponicus Yendo, C. yendoi Yamada et Mikami, C. pinnulatus (Harvey) Okamura and C. armatus (Harvey) Yamada et Mikami.^[4]

Uses

Chondrus crispus is a source of carrageenan, which is commonly used as a thickener and stabilizer^[5] in milk products such as ice cream^[6] and processed foods including lunch meat. In Europe it is indicated as E407 or E407b. It may also be used as a thickener in calico-printing and for fining beer or wine. Irish moss is frequently mixed with Mastocarpus stellatus (Gigartina mammillosa), Chondracanthus acicularis (G. acicularis) and other seaweeds with which it is associated in growth. Carrageenan and agar-agar are also used in Asia for gelatin-like deserts such as almond jelly. Presently the major source of carrageenan is tropical seaweeds of the genera Kappaphycus and Eucheuma.

Irish moss is also used to make a beverage popular in the Caribbean. The beverage is made by boiling the Irish moss for about an hour in water. A flavouring, such as vanilla or strawberry, may be added, and finally milk or sweetened condensed milk, rum and spices are added. It is usually served chilled, is very thick and is sometimes thought to have aphrodisiac qualities. It is also now available ready made, tinned. The Irish Moss used in the Caribbean is most often Gracilaria spp.

In parts of Scotland, where it is known as (An) Cairgean in Scottish Gaelic, it is boiled in milk and strained, before sugar and other flavourings such as vanilla, cinnamon, brandy or whisky are added.^[7] The end-product is a kind of jelly similar to tapioca or blancmange.^[8]

Life history

Chondrus crispus undergoes an alternation of generation life cycle common in many species of algae (see figure below). There are two distinct stages: the sexual haploid gametophyte stage and the asexual diploid sporophyte stage. In addition there is a third stage- the carposporophyte, which is formed on the female gametophyte after fertilization. The male and female gametophytes produce gametes which fuse to form a diploid carposporophyte, which forms carpospores, which develops into the sporophyte. The sporophyte then undergoes meiosis to produce haploid tetraspores (which can be male or female) that develop into gametophytes. The three stages (male, female and sporophyte) are difficult to distinguish when they are not fertile; however, the gametophytes often show a blue iridescence.

Names in various languages

Scientific interest

Chondrus crispus is, compared to most other seaweeds, well-investigated scientifically. It has been used as a model species to study photosynthesis, carageenan biosynthesis, and stress responses.

References

^ ^a ^b ^c ^d P. S. Dixon & L. M. Irvine (1977). Seaweeds of the British Isles. Vol. 1 Rhodophyta Part 1: Introduction, Nemaliales, Gigartinales. ISBN 0-565-00781-5.
^ F. Börgesen (1903). "Marine Algae of the Faröes", Botany of the Faröes based upon Danish investigations Part II (Copenhagen Reprint 1970), 35. ISBN 0-90-6105-011-1.
^ W. R. Taylor (1972). Marine Algae of the Northeastern Coast of North America. University of Michigan Press, Ann Arbor. ISBN 0-472-04904-6.
^ Hu, Z., Critchley, A.T., Gao T, Zeng X, Morrell, S.L. and Delin, D. 2007 Delineation of Chondrus (Gigartinales, Florideophyceae) in China and the origin of C. crispus inferred from molecular data. Marine Biology Research, 3: 145-154
^ Roeck-Holtzhauer, Y.de 1991. Uses of seaweeds in Cosmetics. in Guiry, M.D. and Blunden, G. 1991 Seaweed Resources in Europe: Uses and Potential. John Wiley & Sons ISBN 0 471 92947 6
^ Stegenga, H., Bolton, J.J., and Anderson, R.J. 1997. Seaweeds of the South African West Coast. ed. Hall, A.V. Bolus Herbarium Number 18 Cape Town. ISBN 0 7992 1793 X
^ Feum à Feamainn (DVD, Scottish Gaelic), Comhairle nan Eilean Siar
^ [1] Lusan a' Chladaich(Western Isles Council, Scottish Gaelic site)

Contents