Photosynthetic Capacity of Fucus vesiculosus Linnaeus, 1753 (Phaeophyta: Fucales) in the Barents Sea during the Tidal Cycle

During the tidal cycle, Fucus vesiculosus L. lost moisture (up to 30% of wet weight) and was characterized by a sinusoidal pattern in photosynthetic activity. Three peaks in the photosynthesis capacity were observed at the beginning and middle of low tide and at the beginning of high tide. There were no structural changes in the photosynthetic apparatus. When analyzing the curves of CO2 gas exchange, the processes of photosynthesis in the algae exposed to the air was limited by the activity of the light and dark phases of photosynthesis. The increase in the content of lipid peroxidation products, catalase activity, and accumulation of proline in F. vesiculosus thalli indicated the presence of reversible oxidative stress during low tide.