The western Weddell Sea along the northward branch of the Weddell Gyre is undergoing dramatic changes due to the breakup of ice shelves along the Antarctic Peninsula, however, its perennial sea ice cover is among the thickest on Earth and thus make it hard accessible. During the interdisciplinary Weddell Sea Ice (WedIce) project, carried out in spring 2019, in-situ snow and ice sampling including biodiversity and biogeochemical studies were carried out. Although there was rotten ice below a solid, ~30 cm thick surface-ice layer, pronounced gap layers, were rare and high algal biomass, dominated by Phaeocystis, was only found north of the Antarctic Sound. However, diatom dominated standing stocks of integrated sea ice algae biomass were among the highest found in Antarctica. Despite high macro-nutrient concentrations, the biomass of the flagellate dominated phytoplankton was negligible for primary production in the entire region. It thus can be concluded that despite changing light condition for the phytoplankton, sea ice derived carbon represents an important control variable for higher trophic levels in this region.