The research interests of my working group in “Chemical Paleoceanography” are focusing on the reconstruction of ocean circulation and its relationships to the climate of the past on different time scales. In addition, the relationships between erosional inputs from the continents, nutrient utilization, biological productivity, and the climate are subject of our investigations. For these reconstructions geochemical and isotopic proxy indicators are developed, improved and applied. Our interests are centred around radiogenic (Nd, Pb, Hf, Sr), stable (i.e. Si, Fe, Ba, Mo), and cosmogenic (10Be) isotope systems, as well as element distributions (i.e. rare earth elements, REEs). Besides the extraction of these proxy signatures from marine archives (sediments, manganese/iron crusts and nodules) a particular focus is the understanding of the processes controlling these proxies in the present day water column. For this we actively participate in the detailed investigations of the internationally coordinated research programme GEOTRACES in order to calibrate these proxies for their application to reconstruct the past. Our groups runs a state of the art clean laboratory and operates a MC-ICP mass spectrometer, and in collaboration with other groups at GEOMAR further techniques and methods are applied in order to achieve comprehensive multi proxy data sets.