Kelps, brown algae of the order Laminariales, dominate rocky shores of cold-temperate regions. The distribution of kelps is constrained by abiotic factors like light including UV radiation, and temperature. Future global environmental changes could therefore have a potentially significant impact on geographic distribution patterns, vertical zonation, and primary productivity of kelp. We established a cDNA library of Saccharina latissima consisting of 400,503 ESTs, which were assembled to 28,803 contigs. Sporophytes of S. latissima were exposed in multifactorial experiments to combinations of light intensities, UV radiation and temperatures. Subsequently microarray hybridizations were performed to determine changes in gene expression patterns. S. latissima responds to abiotic stress with a multitude of transcriptional changes. Expression profile changes in several metabolic pathways included e.g. carbohydrate metabolism, lipid metabolism, and amino acid metabolism. Additionally several stress responses known from green plants like induction of ROS scavengers and induction of HSPs could be found. Another critical component of the molecular acclimation mechanisms to excessive light in Saccharina latissima is the induction of vitamin B6 biosynthesis.