Chemical Characteristics of Humic Compounds Isolated From Some Decomposed Marine Algae

Abstract

The chemical and spectroscopic characteristics of humic compounds isolated from decomposed thalli of Fucus vesiculosus and Laminaria digitata, seaweed exudate, and dissolved organic matter in river water show that, in spite of several differences, their gross structural features are similar to those of humic compounds isolated from marine sediments or soils. Dominant functional groups are carboxyl and carbonyl but phenolic and alcoholic hydroxyl groups are also present in small proportions. Between 20 and 40% of humic acids are represented by fractions having molecular weight greater than 200,000, whereas the fulvic acids do not exceed 10,000. Carbon and nitrogen contents show a direct relation with molecular weight whereas the oxygen is inversely related.