Genoveva Esteban is a Professor of Microbial Ecology at Bournemouth University (UK). She received her PhD from Universidad Complutense de Madrid (Spain) in 1989 and carried out two post-doctoral positions: one at the National Scientific Research Council in Spain (1990-1991), and the second (1992-1995) at the Institute of Freshwater Ecology (The Ferry House, Windermere, UK). She then became employed as a senior scientist at the Natural Environment Research Council (NERC, UK) until 2007. That same year, she moved to the university sector to work at Queen Mary University of London (2007-2011). She has published over 110 original articles and book chapters. Her research expertise is centered on free-living microbial eukaryotes.Tom Fenchel is Emeritus Professor of Marine Biology at the University of Copenhagen (Denmark). He received his Ph.D. in 1965 and became employed at the Marine Biological Laboratory as lecturer. From 1970-1987 he became FullProfessor at the University of Aarhus and he returned to the University of Copenhagen in 1987 until formal retirement in 2010. He has published about 200 original papers on microbial ecology and population biology and has authored or co-authored five books.