The seasonal variation in chemical constitution of some of the sub‐littoral seaweeds common to scotland. Part I. laminaria cloustoni

Abstract

AbstractIt is well known that seaweed, vast quantities of which grow around the coast of Scotland, undergoes wide seasonal variation in chemical constitution, and it is important that this variation be known so that the weed can be harvested at the appropriate period. Monthly samples of Laminaria cloustoni have been collected at a definite spot and at a constant depth over a period of two years, the plants divided into stipe and frond and analysed separately for total ash, organic nitrogen, iodine, mannitol, laminarin and alginic acid. The results show that the wide seasonal variations in composition, previously recorded, are due almost entirely to variations in the composition of the fronds. Samples have also been taken at depths of 1/2 to 61/2 fathoms (L.W.) and the variation in composition with depth of immersion studied.