Seasonal variations in the chemical composition of Arctic brown macroalgae

The dynamics of White Sea macroalgae chemical composition during the growing season (June-September) was analysed. The study revealed an increase in the content of polyphenols (from 5.35%dw-6.02%dw to 14.66% dw-16.80%dw), a high level of pigments (chlorophyll a (up to 0.134%dw), carotenoids (up to 0.036%dw)), and saturated fatty acids (up to 3.206%dw (90%rel)), which is most likely due to solar, photosynthetic activity, as well as elevated seawater temperature. The optimal month to collect macroalgae, with the maximum content of valuable chemical compounds of lipophilic fractions, carbohydrates and proteins is August. Priority species have been identified for the selective production of individual fractions of algae biomass components. Fucaceae (Ascophyllum nodosum, Fucus vesiculosus) species are preferable for the isolation of lipophilic components and minerals, Laminariaceae (Laminaria digitata, Saccharina latissima) species are preferable for the isolation of carbohydrates (alginates, mannitol, cellulose). A comparative analysis of the content of the main groups of Arctic brown algae biomass with macroalgae from Europe, the Far East, and Southeast Asia was carried out. It is shown that the White Sea species have high potential as a promising new source of lipophilic substances (polyphenols, pigments, fatty acids), as well as cellulose.

Automated summary

The study analysed the changes in chemical composition of macroalgae in the White Sea during the growing season. It found increased levels of polyphenols, pigments, and saturated fatty acids, likely due to solar activity, photosynthesis, and higher seawater temperature. August was identified as the optimal month to harvest macroalgae with valuable chemical compounds, and specific species were recommended for isolating different components. Compared to macroalgae from Europe, the Far East, and Southeast Asia, the White Sea species showed high potential as a new source of lipophilic substances and cellulose.