My main research interest is how phytoplankton and benthic microalgae acclimate to varying environmental conditions, especially with regard to the interplay between light and nutrient conditions, and if regulation patterns are partly dictated by taxonomic affiliation. As acclimation to fluctuation and excess irradiances involve quite a variety of quickly operating processes my research depends a lot of variable fluorescence techniques like Fast Repetition Rate fluorometry (FRRF) and PAM-fluorescence combined with other techniques to measure photosynthesis like 14C or 13C uptake and oxygen techniques like the Membrane Inlett Mass Spectrometry (MIMS) which allow to measure oxygen uptake in the light.
I'm a firm believer that in order to understand the functioning of an aquatic ecosystem knowledge of primary production is a must. We substantiated this view in the OSPAR project EcApRHA where primary production is now accepted as candidate indicator. Unfortunately, measurements of primary production are declining globally, certainly as year-round monitoring activity. Being an optical technique, FRRF seems an ideal tool to replace the conventional 14C-technique, as it can be automated and measurements can be carried out autonomously. We are pioneering this at two location: at the NIOZ jetty in the Wadden Sea where photosynthetic activity is monitored continuously and in the MONEOS program, where we monitor primary production using an automated FRRF in the Westerschelde estuary during the monitoring campaings carried out by Rijkswaterstaat (RWS, Ministry of Infrastructure and Environment). Applying this technique requires knowledge of the electron requirement for C-fixation, and understanding this relationship is a main part of my research.
In 1983 I completed my MSc in Biology at the University of Amsterdam. I continued my PhD there in the group of Prof. dr. Luuc Mur where I received my PhD in 1987 on a study of the mechanisms and kinetics of buoyancy regulation in two freshwater cyanobacteria. I continued this study, adding some molecular biology into gene expression studies as a postdoc in the Lab of Prof. Anthony Walsby at the Univeristy of Bristol (UK). In 1989 I moved to the Delta Institute, which became the Center for Estuarine and Marine Ecology of the Netherlands Institute of Ecology. The CEME which merged in 2012 with the NIOZ.