The West Antarctic Peninsula is the most rapidly warming region in the Southern hemisphere, with glacial retreat and ice shelf collapse causing major changes in the marine environment. We will make a systematic investigation of iron, aluminium, manganese and related bio-essential trace metals Co, Ni, Cu, Zn in the water column and the sea-ice of Marguerite Bay throughout two complete annual cycles. This study will serve as a first assessment of the distribution and cycling of iron and the other trace metals in relation to the ice/water cycle and the biological cycle. We will test the working hypothesis that the annual collapse of the bloom of large diatoms at the end of the summer is due to depletion of dissolved iron by the bloom itself. This first study will serve as the baseline for future assessment of changes in relation to the major climate changes at the West Antarctic Peninsula.