The Western Antarctic Peninsula is one of the regions most affected by stratospheric ozone depletion and global climate warming, resulting in an increased UVB radiation and a fast glacier retreat. During the last 10 years intensive studies on the seaweed communities and the physiology of single species were conducted at Potter Cove. It was found that UVB radiation can decrease the diversity of the seaweed community by direct and indirect effects (exerting negative effects on the grazers). A higher sediment inflow into the water column due to the melting glaciers is decreasing the light availability for photosynthesis, changing the lower depth distribution of the seaweeds. Additional laboratory and field experiments on the physiological performance and recruitment success of seaweed spores showed a strong species specific susceptibility to UV and photosynthetically active radiation. Altogether the seaweed community at Potter Cove is strongly shaped by the changes of their abiotic environment.