Kelps, algae of the order Laminariales, are important ecosystem engineers in temperate to Arctic coastal waters. They form marine forests that support complex communities by providing habitat for several taxa, they provide coastal defense and contribute significantly to climate change mitigation and adaptation by acting as carbon sink. However, these marine forests are threatened by impacts of anthropogenic-driven climate change. Hence, a better understanding of the acclimation mechanisms taking place in the sugar kelp Saccharina latissima across its life history stages is necessary to predict emerging environmental pressures, potential range shifts and, thus, future distributions. This study revealed novel insights into the molecular mechanisms of acclimation and adaptive responses of a keystone, but non-model species, for which only limited genomic information has been available previously. It also became evident that transcriptomic data do not necessarily match observations made on the physiological level, but are likely to reflect emerging constraints to cellular function and overall individual performance at an early stage. Furthermore, the differences in response towards environmental drivers across different latitudes, life history stages and sexes emphasize the need for integrative approaches in order to facilitate predictions on species performance in natural as well as aquaculture systems in the face of large-scale environmental change
