Leonie Esters, University of Bonn, Institute of Geosciences, Meteorology, Bonn, Germany, Mariana Ribas Ribas, Carl von Ossietzky Universität Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Wilhelmshaven, Germany and Carola Lehners, Carl von Ossietzky Universität Oldenburg, Institute for Chemistry and Biology of the Marine Environment, Wilhemshaven, Germany