1. Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg; 26129 Oldenburg Germany
2. Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego; La Jolla CA 92037 USA
3. Laboratoire d'Oceanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls sur mer; Sorbonne Universités, UPMC; France