According to diverse model predictions Arctic seaweed systems are proposed to alter structure and composition due to global change in future. Two major factors that will influence these systems are (1) ocean warming and (2) increased glacier melting leading to a reduction in ice cover and ice-scouring and changing light quantity and quality as well as substrate characteristics. In 2012 / 13 we investigated a polar kelp system along a depth transect off Hansneset, Kongfjorden (Svalbard) and compared these data with a baseline study performed at the same site in 1996/98. Probably as a consequence of continuously ice-free winters since 2006, biomass and biodiversity changes were observed. Concurrent laboratory studies revealed the susceptibility of kelp recruitment towards a combination of increased sedimentation, warming and grazing. Furthermore we will report on ecotypic differentiation and first calculations of carbon budgets for the kelp system