Species in high latitude are assumed to be more sensitive to environmental changes because temperate regions are subject to larger seasonal changes than tropical regions. These changes are increased frequencies of shading events in coastal systems caused by anthropogenic global change. Therefore, algae in temperate regions are presumably better able to acclimate to changes in light supply than their tropical counterparts. It can be assumed that this ability makes algae in temperate regions also more robust towards short-term fluctuations in light supply than tropical algae.

We conducted experiments with macroalgae at 3 temperate and 3 subtropical/tropical sites. Algae were subjected to different light intensities as well as to fluctuating light supply. We found that temperate brown algae can acclimate to changes and tropical red algae don’t show this capability and suffered strongest from lack of light. None of the tested algae showed reduced fitness under fluctuating condition. We conclude that short-term fluctuations condition doesn’t seem to affect distribution patterns of macroalgae.