Ab Grootjans worked at the University of Groningen between 1975 and 2016 and at the Radboud University Nijmegen between 2007 and 2017. His main field of expertise is eco-hydrology of wetlands. He dealt with projects ranging from eco-hydrological approaches on the landscape scale to very detailed research on the habitat scale. For example, he worked on the restoration of small dune wetlands along the Dutch and German coast and on developing new strategies for a more natural and dynamic coastal development. His work on the restoration of damaged peatlands helped improving restoration activities in various parts of the world including the former GDR, Slovakia, Latvia, Russia, Ireland, Tierra del Fuego, Japan, Australia and South Africa. He has also been active in the Dutch Knowledge network of researchers and managers (OBN) aimed at developing restoration projects in the Netherlands (1990-2015).