The pigments of kelps (Ochrophyta) as part of the flexible response to highly variable marine environments

Macroalgae drive the biodiversity and functioning of many shallow benthic ecosystems. Besides their key role in coastal ecosystems, they are rich sources of a wide variety of unique molecules with high impact in food science, pharmaceutical industry and public health. Carotenoids and chlorophylls present in three kelp species-Laminaria ochroleuca, Saccharina latissima and Saccorhiza polyschides-were determined by high-performance liquid chromatography coupled to a diode array detector. The effect of different harvesting times, depths and growth conditions (wild vs. aquaculture) on pigment qualitative and quantitative profiles was assessed. Stipes, blades and whole macroalgae were studied. In spite of the considerable variability observed amongst all samples, fucoxanthin was evidently the main carotenoid. Overall, the relative contents of carotenoids were significantly higher than those of chlorophylls. In addition, the cultivation of macroalgae in an integrated multi-trophic aquaculture system appears to increase pigment levels. Altogether, the results demonstrate the complexity of the influence of species-specific and environmental factors on pigment composition and reinforce that macroalgae cultivation systems may provide an interesting approach to optimize the production of some valuable metabolites.