Royal Netherlands Institute for Sea Research

Sonja van Leeuwen

Research Assistant
Phone number
+31 (0)222 369 423
Research Assistant


  • European riverine nutrient loads
  • Numerical modelling of hydrodynamics and biogeochemistry of marine environment
  • Linking lower to higher trophic level models (end-to-end modelling)
  • Stressor response studies of the marine ecosystem using numerical modelling
  • Ecohydrodynamic regions

Research interests

As a marine ecosystem modeller my research interests span everything from European riverine nutrient loads, hydrodynamics, marine chemistry, lower trophic levels, higher trophic levels all the way to ecosystem services. I have worked at CEFAS, Lowestoft, UK (a governmental research institute) for 12 years looking at eutrophication, low oxygen zones, deep chlorophyll maxima, ecohydrodynamic regions and combined stressor effects (nutrient loads, climate change, acidification, fishing pressure) in combined lower and higher trophic level models, mainly with a focus on the European Shelf but occasionally further away (Barents Sea, Patagonia, Mediterranean). Though simulations of the marine environment rarely capture the variability observed in nature they do provide information at spatial and temporal scales that observations cannot match, and allow for future and past projection over long time scales (decades to centuries). The latter provides insights into long-term combined stressor response and possible management actions. I have a particular interest in understanding marine biogeochemical processes (including benthic-pelagic coupling), combining bottom-up and top-down pressures in system response and end-to-end modelling.

Although I work mainly with so-called hydrobiogeochemical models, especially GETM-ERSEM-BFM (the joint NIOZ/CEFAS model), I also have experience with size-structured models (representing higher trophic levels, i.e. fish, marine mammals), particle tracking models, the Phytoplankton Index (formerly known as the Phytoplankton Community Index or PCI), linking of lower and higher trophic level models (including 2-way coupling), end-to-end modelling and Fe cycling. I am also the official keeper of the OSPAR ICG-EMO (Intersessional Correspondence Group on Eutrophication MOdelling) riverine load database, consisting of daily flow and nutrient load values for rivers exiting onto the European Shelf. This database is freely available upon request.





Previous key-publications

Van Leeuwen, S.M., le Quesne, W., Parker, E.R. Potential future fisheries yields in shelf waters: a model study of the effects of climate change and ocean acidification, Biogeosciences, 13, p.441-454, 2016 doi: 10.5194/bg-13-441-2016

Van Leeuwen, S.M., Tett, P., Mills, D.K., van der Molen, J. Stratified areas in the North Sea: long-term variability and biological and policy implications, Journal of Geophysical Research - Oceans, Vol. 120 (7), pp 4670-4686, 2015, doi: 10.1002/2014JC010485

Jickells, T., Andrews, J., Barnard, S., Tett, P., van Leeuwen, S.M. Natural Sciences Modelling in Coastal and Shelf Seas, in Coastal Zones Ecosystem Services, K. Turner and M. Schaafsma (eds.), in series Studies in Ecolological Economics, 9, Springer International Publishing Switzerland, 2015, ISBN 978-3-319-17214-9, doi:10.1007/978-3-319-17214-9

Van Leeuwen, S.M., van der Molen, J., Ruardij, P., Fernand, L., Jickells, T. Modelling the contribution of Deep Chlorophyll Maxima to annual primary production in the North Sea, Biogeochemistry, Vol. 113 (1), pp 137—152, 2013, DOI: 10.007/s10533-012-9704-5

Lenhart, H-J., Mills, D.K., Baretta-Bekker, H., van Leeuwen, S.M., van der Molen, J., Baretta, J.W., Blaas, M., Desmit, X.,  Kühn, W.,  Los, H.J.,  Ménesguen, A.,  Neves, R., Proctor, R.,  Ruardij, P.,  Skogen, M.D., Vanhoutte-Brunier, A., Villars, M.T., Wakelin, S. Predicting the consequences of nutrient reduction on the eutrophication status of the North Sea, Journal of Marine Systems, Vol 81,pp 148-170, 2010

Publications since starting at NIOZ

Capuzzo, E., Lynam, C.P., Barry, J., Stephens, D., Forster, R.M., Greenwood, N., McQuatters-Gollop, A., Silva, T., van Leeuwen, S.M., Engelhard, G. H., 2017, A decline in primary production in the North Sea over twenty‐five years, associated with reductions in zooplankton abundance and fish stock recruitment, Global Change Biology, DOI: 10.1111/gcb.13916


Professional education



Awards and Prized