The effect of acidic polysaccharides on the biogeochemistry of iron in the marine environment [Elektronische Ressource] / Sebastian Steigenberger

PHD THESIS “THE EFFECT OF ACIDIC POLYSACCHARIDES ON THE BIOGEOCHEMISTRY OF IRON IN THE MARINE ENVIRONMENT” SEBASTIAN STEIGENBERGER SUPERVISORS: D. WOLF-GLADROW (AWI, UNI HB), V. SMETACEK (AWI, UNI HB) , U. PASSOW (AWI) AND P. CROOT (IFM-GEOMAR) ALFRED WEGENER INSTITUT FÜR POLAR- UND MEERESFORSCHUNG, BREMERHAVEN UNIVERSITÄT BREMEN APRIL 2008 Acknowledgements I would like to thank a number of people, who made this work possible and enjoyable during the past three years. A big thanks to my primary supervisors Uta Passow and Peter Croot, as well as to Christoph Völker, Victor Smetacek and Dieter Wolf-Gladrow. Thanks also to Marta Plavsic (RBI, Croatia) and Peter Statham (NOCS, UK) for providing excellent opportunities to work at different institutes and their great collaboration. The MARMIC PhD program also offered valuable teaching opportunities and key skills training. This work was funded by the DFG and partly by the European Union under the Sixth Framework Marie Curie Actions. Special thanks also to Martha Valiadi, my friends and my family for their guidance and invaluable support. 1. Introduction 1 2. The role of polysaccharides and diatom exudates in the redox cycling of Fe and the photoproduction of hydrogen peroxide in coastal seawaters. 6 3. Identifying the processes controlling the distribution of H O in surface waters 2 2along a meridional transect in the Eastern Atlantic. 39 4.