48 MARINE PRODUCTS OF COMMERCE 



(carrageenin) and algin, the two most important seaweed products developed in 

 the Western Hemisphere. 



The third of the three seaweed products of prime importance, agar, is still 

 produced in greatest quantity in Japan, where it originated centuries ago. How- 

 ever, it appears that with World War H the Japanese permanently lost their global 

 monopoly on this product. War-generated agar factories developed in the United 

 States (both Atlantic and Pacific coasts), Australia, and New Zealand. Since the 

 factories in all three nations are still producing agar, they may not yet have been 

 eflFected by the low prices and saturated market resulting from competition and 

 economic pressure. At the same time their prospects are aided by new types of 

 agar, by the many new uses that have been developed, and by improvements in 

 production processes. The agar factories of Australia and New Zealand appear to 

 have fared better since the war than those of the United States. 



Classification of Algae 



Plants included in the Algae group have long been classified as a subdivision of 

 the phylum Thallophyta on the basis of the theory that Algae and Fungi (the 

 other subdivision of Thallophyta) developed from a common ancestor. Recent 

 work, which takes physiological characteristics into account, indicates that Fungi 

 were derived from Protozoa, not from the Algae by degradation as the old classifi- 

 cation assumes. Furthermore, most classes of the old sub-division Algae are now 

 believed to have developed along separate phylogenetic lines, as suggested by the 

 morphology of reproductive cells, pigmentation, and physiology. Wide acceptance 

 of this view relegates the term Algae to the status of a purely artificial group and 

 has established seven separate phyla of plants formerly included in the Algae 

 group (Smith, 1938). All these phyla reproduce by means of single-celled spores 

 and do not have flowers, fruits, or seeds. The conspicuous marine algae include the 

 following four phyla: 



Cyanophyta, the blue-green algae, are widely distributed in the ocean, in fresh 

 water, and in soil. The individual plants are miscroscopic and are not commer- 

 cially utilized. 



Chlorophyta, the green algae, are most abundant in fresh water, but are also 

 widely distributed in the ocean, with the greatest variety of marine species in 

 tropical waters. They are of little or no economic value; however, some species 

 are used as food in Hawaii, Japan, and the South Pacific. 



Phaeophyta, the brown algae, are almost entirely marine and are characteristic 

 of cold waters throughout the world although they occur in tropical waters as 

 well. The giant kelps and abundant intertidal rockweeds of our northern coastal 

 waters are of great economic importance as a source of alginates. They are 

 considered in detail in Chapter 6. 



Rhodophyta, the red algae, occur in greatest variety in tropical waters, but 

 are also abundant in cold oceans. Of all the seaweeds certain genera of this group, 

 from which agar and agaroids are obtained, have the greatest economic value, 

 although the importance of the brown algae is rapidly increasing. While all of the 

 red algae contain a characteristic red pigment, phycoerythrin, they often range in 

 color from yellow-green to purplish black because of the chlorophyll (green) and 

 other pigments present in them. Of approximately 2500 known species only about 

 50 are found in fresh water. 



