The seasonal variation in chemical composition of some of the littoral seaweeds common to scotland. Part I.Ascophyllum nodosum

✍ Scribed by Black, W. A. P.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1948
• Weight: 345 KB
• Volume: 67
• Category: Article
• ISSN: 0368-4075
• DOI: 10.1002/jctb.5000670905

✦ Synopsis

Abstract

The ash, iodine, crude protein, mannitol, laminarin and alginic acid contents of samples of Ascophyllum nodosum taken at monthly intervals from April, 1945, to March, 1947, have been determined. The samples were taken from three different habitats in the neighbourhood of Oban in order to show the effect of varying exposure.

In general, the loch samples are lower in iodine, total ash, crude proteins, and higher in laminarin and mannitol than the open sea or medium exposed samples. An increase in the mannitol and laminarin contents is accompanied by an increase in the dry weight content and a decrease in the total ash content. The graphs for the mannitol, laminarin and dry weight contents show three distinct peaks in the year, which agree with those in samples of the laminariacea already examined. The drop in mannitol and laminarin which occurs in the laminariaceae in July/August, and is at present the subject of investigation, also occurs in Ascophyllum nodosum.

Ascophyllum nodosum is appreciably lower in mannitol and laminarin than the laminariaceae, but laminarin is present throughout the year, whereas it is absent for periods in the laminariaceae so far investigated. This alga is higher in alginic acid than any of the laminariaceae examined. The very slight variations in mannitol, laminarin and alginic acid, throughout the year, enable this alga to be harvested for any particular constituent at any time of the year.