U. Riebesell1, R. G. J. Bellerby2,3, H.-P. Grossart4, and F. Thingstad5 1Leibniz Institute of Marine Sciences, IFM-GEOMAR, Duesternbrooker Weg 20, 24105 Kiel, Germany 2Bjerknes Centre for Climate Research, University of Bergen, Allégaten 55, 5007, Bergen, Norway 3Geophysical Institute, University of Bergen, Allégaten 70, 5007, Bergen, Norway 4Leibniz Institute of Freshwater Ecology and Inland F...