Quantitative studies on brown algal phenols IV. Ultraviolet spectrophotometry of extracted polyphenols and implications for measuring dissolved organic matter in sea water

Abstract

Poor correlation exists between levels of total phenols and of ultraviolet-absorbing materials in extracts of the brown algae Ascophyllum nodosum (L.) Le Jol. and Fucus vesiculosus L. The uv extinction sp coefficient of a major exuded polyphenol fraction increases rapidly and markedly in sea-water solution. Consequently, uv spectrophotometry cannot provide a useful measure of either total polyphenols or total organic matter in extracts or exudates from these brown algae. Moreover, considerable errors may be introduced when uv spectrophotometry is used to estimate dissolved organic matter in sea water which receives significant exudation from brown macrophytes.