Meike Vogt, Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland, Riikka Tauriainen, Bern University of Applied Sciences, Bern Academy of the Arts, Bern, Switzerland and Marta Musso, Technical University of Denmark, National Institute of Aquatic Resources, Centre for Ocean Life, Kgs Lyngby, Denmark