Alexandra Kraberg1 1 Biologische Anstalt Helgoland, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, 27498 Helgoland, Germany 2 Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine [...] University of Hamburg, Germany, florian.mundt@uni-hamburg.de Harms, L., Scientific Computing, Alfred Wegener Institute, Bremerhaven, Germany Heinrich, S., Department Molecular Plant Genetics, University [...] Federal Ministry on Research and Education (BMBF) / Hemholtz Center for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, Germany Multiyear studies on phytoplankton showed decreasing trends in