As the Arctic Ocean gets warmer sea-ice extent is rapidly reduced. This will influence the habitats of phytoplankton at the base of the Arctic food web. When the ice melts, an influx of freshwater will lower salinity levels in the surface and light availability will increase. The picophytoplankton Micromonas polaris is an Arctic species that is dominating the Arctic Ocean. Knowledge of how M. polaris responds in a warming Arctic Ocean is therefore important. In this study, the growth of M. polaris in different salinities (20, 25, 30, 33 and 35 ppt) and light conditions (8-9, 15-17, 32-35 and 50-60 mE m-2 s-1) were tested separately. Primary production was also assessed using a photosynthesis-irradiance (P-E) curve. It was found that M. polaris was able to grow in all the tested salinities and had highest growth rate in 20 ppt. The growth was also highest at the highest tested irradiance (50-60 mE m-2 s-1). The P-E curve showed that a photoinhibition of M. polaris is reached at 152 mE m-2 s-1. These results indicates that M. polaris will continue to thrive as the Arctic ice melts. Both when it comes to lower salinity and light availability.