In their variable environments, marine macroalgae rely on efficient photoacclimatory and -protective mechanisms in order to minimize oxidative stress-induced cellular damages. Thereby, adjustments in photosynthetic pigments (also xanthophyll cycle), phlorotannins and antioxidants were confirmed to feature a high significance. Further, it was indicated that modulations in fatty acid composition (degree of saturation, chain length) might also form part of photoacclimation and -protection, both along vertical and seasonal gradients. The latter acclimation response might not only help the algae to optimize their membrane fluidities, but also to create ideal environments for the functioning of the xanthophyll cycle under variable environmental conditions. Generally, adjustments in fatty acid profiles were shown to be highly species-specific, with both light and temperature having a strong impact on this response variable. The findings of this dissertation might help to predict macroalgal responses towards challenging environmental conditions, which is crucial under ongoing climate change, and might be useful for commercial applications
