MACROSCOPIC ALGAE (SEAWEEDS) 9 



ine. Some algae have also been shown to contain nucleic acids, and some 

 various water-soluble peptides. 57 - 60 



The lipid content of macroscopic algae may vary from zero to 3 or 

 4 per cent. Of the fatty acids identified, the commonest are the unsaturated 

 ones with 16, 18, and 20 carbons. These are present in most algae, with 

 the exception of Alaria crassifolia, which has over half its fatty acids in 

 saturated forms. The predominant algal fatty acid is the 16-carbon palmitic 

 acid. Besides these fats, there are varying small quantities of such lipoid 

 substances as photosynthetic pigments, sterols, and hydrocarbons. 61 " 63 



The mineral ash content varied from 5.0 to 38.9 per cent in a number 

 of reported studies. The water-soluble ash exceeded the insoluble frac- 

 tion by as much as four or five times. One investigation of kelps 64 listed 

 identified substances and their percentage of the total ash as shown in 

 Table I. 



TABLE I 



Sulfates 6.14—11.24% 



Calcium oxide 3.35 — 4.46 



Magnesium oxide 1.99 — 4.34 



Phosphates (as P 2 5 ) 2.52— 5.60 



Potassium 9-40—10.43% 



Sodium 10.51—13.57 



Chlorine 27.62—32.59 



Iodine 0.06— 0.09 



Bromine Trace 



The seaweeds containing the most iodine are Laminaria digitata, 

 Laminaria saccharina, Fucus vesiculosus, and Saccharina bulbosa. The 

 richest in bromine is Fucus serratus. 



Vitamins in good quantity have been found in some varieties of 

 seaweed investigated. 47 Vitamin A has been demonstrated in the sea 

 lettuce Viva lactuca, Laminaria digitata, and Codium tomentosum, as well 

 as in ground meal prepared from Pacific coast kelps. This vitamin is even 

 more abundant in phytoplankton, which will be discussed later. 



Freudenthal 65 in 1949 conducted biological investigations on three 

 species of algae from the coast of Denmark — Furcellaria fasti giata, Fucus 

 serratus, and Fucus vesiculosus. He reported that they possessed a growth- 

 promoting and anti-xerophthalmic vitamin activity (in Wistar rats) ex- 

 ceeding that of the best Danish summer butter. He also claimed that 

 feeding these algae prevented the epithelial dysplasia and rickets that 

 developed in animals maintained on vitamin- deficient diets. Freudenthal, 

 incidentally, takes issue with the common belief that rickets is related 

 to Vitamin D deficiency; he feels that the disease is "the retarded, in- 



