Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9566
Senior Scientist
  • Physics
  • Oceanography
  • Hydrodynamics, sediment transport, morphodynamics
  • Biogeochemistry and planktonic ecosystem dynamics
  • Numerical Modelling

Dr. Ir. Johan van der Molen

Senior Scientist

Calculating how humans influence the sea

Oceanographer Johan van der Molen calculates how humans influence the sea. ‘To do that, I simulate the sea using mathematical models. I split the sea surface and the water column into small cubes, and within these cubes, I assign values to things like water levels, flow rates, wave heights and the amount of sediment in the water. Besides these physical characteristics, I also convert biochemical characteristics, such as the quantity of nutrients, into numbers.’

From currents to fish larvae

‘Using models like these, I can for example calculate what happens to eggs released by fish. Currents carry these eggs to another area where they will hatch. Subsequently, the larvae are transported by the water to another area. Similarly, nutrients from rivers or from the depths of the ocean also spread in the water and fuel algal growth, which can then feed fish and other animals.’

Virtual Experiments

‘Although mathematical models are only an approximation of reality, they do provide understanding. In my digital reality, I can carry out “experiments” that could never be done at sea. For example, what happens if you put a large wind farm somewhere, or if you put long ropes in the water to grow seaweed? How does that change the currents and all the other phenomena that depend on them?’

Models in development

‘Models are being developed continuously. Following the many, still relatively small offshore wind parks that have been built, there are now plans to generate solar energy at sea. Thus, we have to adapt the models to answer new questions. Of course, that is absolutely worth the effort. After all, we want to stay ahead of the game when making radical changes at sea. Models allow us to look into the future and can warn us about the effects of our actions.’

Read more +

Research interests

I started at NIOZ as Senior Scientist in Coastal and Biophysical Oceanography in September 2017 after working at Cefas, a governmental research laboratory in Lowestoft, UK for 13 years. At Cefas, I created hydrodynamical model setups for GETM, restructured and extended the particle tracking model for GETM, developed a suspended sediment model for the coupled physical-biogeochemical model GETM-ERSEM, and contributed to the development of ERSEM. I applied these models to address scientific and managerial questions. I also gave scientific guidance to a team of numerical modellers. Before that, I worked as a post-doc at IMAU, Utrecht University on sediment transport and morphodynamics, and as visiting research fellow at Manchester Metropolitan University on wave-induced sediment resuspension.

My research interests are in modelling physical and biological material transport, biogeochemistry and ecosystem dynamics in shelf seas, in response to natural and anthropogenic influences.



2011-2017: Principal Ecosystem Modeller (Cefas). Scientific project development and coordination, model development and application

2008–2011: Senior Ecosystem Modeller (Cefas). Managing Cefas parallel computing cluster, model development and application

2004–2008: Modeller/Oceanographer (Cefas). Development and application of hydrodynamics, sediment transport, Individual Behaviour, and ecosystem models

2003–2004: Research Fellow (Manchester Metropolitan University, The Leverhulme Trust). Development of a morphodynamical model of cross-shore coastal profile evolution

2003–2001: Postdoc (Insitutute for Marine and Atmospheric Research, Utrecht University, The Netherlands). Modelling basin-scale morphodynamics of the North Sea

1996–2001: Postdoc (Netherlands Organisation for Scientific Research, based at IMAU, Utrecht University, The Netherlands). Modelling Holocene hydro-dynamics and sand transport in the North Sea, and relating to the evolution of the Dutch and Belgian coasts



Predicting the consequences of nutrient reduction on the eutrophication status of the North Sea HJ Lenhart, DK Mills, H Baretta-Bekker, SM Van Leeuwen, J der Molen, ... Journal of Marine Systems 81 (1), 148-170.

The influence of tides, wind and waves on the net sand transport in the North Sea J Van der Molen Continental Shelf Research 22 (18), 2739-2762.

Holocene tidal conditions and tide-induced sand transport in the southern North Sea J Van der Molen, HE De Swart Journal of Geophysical Research, Oceans 106, 9339-9362.

Dispersal patterns of the eggs and larvae of spring-spawning fish in the Irish Sea, UK J van der Molen, SI Rogers, JR Ellis, CJ Fox, P McCloghrie Journal of Sea Research 58 (4), 313-330.

Modelling marine ecosystem response to climate change and trawling in the North Sea J van der Molen, JN Aldridge, C Coughlan, ER Parker, D Stephens, ... Biogeochemistry 113 (1-3), 213-236.

Please find my list of publications at the bottom of this webpage or on Google Scholar


Professional education

1992-1995: Ph.D., Earth Sciences, 04/1997. Thesis: Tides in a salt-marsh. Vrije Universiteit, Amsterdam, The Netherlands

1986-1991: M.Sc, Applied Physics. Thesis: Automatische optimalisatie van de veldhomogeniteit van een NMR spectrometer. Delft University of Tecnology, Delft, The Netherlands

1980-1986: VWO, Han Fortmann College, Heerhugowaard


Awards and prizes

2016: CASE partner, NERC CASE PhD studentship, Increasing understanding of changes in dissolved oxygen concentrations in UK waters (Lead insitute: Plymouth Marine Laboratory)

2014: CASE partner, NERC CASE PhD studentship. Shelf-sea variability: using annually resolved records and bioegeochemical models to identify 'good environmental status' (Lead institute: University of Exeter)

2014: Cefas Principal Investigator, NERC Marine Ecosystems Research Programme, Module 6, Biogeochemical modelling

2013: Cefas Principal Investigator, NERC Shelf Seas Biogeochemistry Programme, Work Package 4: Integrative Modelling for Shelf Seas Biogeochemistry

2003: Visiting Researcher Fellowship grant, The Leverhulme Trust, Dalton Research Institute, Manchester Metropolitan University, Manchester, UK

2001: Large-scale morphodynamics of shelf seas, NWO, 93 kEuro, IMAU, Utrecht



2015-2017: Member of the Executive Committee of the National Partnership for Ocean Prediction

From 2014: Deputy President, Ocean Science Division, European Geosciences Union

From 2009: Secretary for Coastal and Shelf Seas, Ocean Science Division, European Geosciences Union

From 2008: Convener Open Session on Coastal and Shelf Seas, EGU annual assemblies

From 2006: Member organising group OSPAR International Correspondence Group for Ecosystem Modelling (ICG-EMO)


Linked news

Tuesday 30 May 2023
ANEMOI - Towards minimal chemical pollution of offshore wind farms
Offshore wind energy offers many advantages: next to the primary aim of renewable energy production, offshore wind farms (OWFs) also offer opportunities to nature conservation and aquaculture activities. There are multiple research projects into the…
Friday 29 July 2022
How coastal seas help the ocean in absorbing carbon dioxide from the atmosphere
The biologically productive North Sea impacts the global climate through exchange of carbon and nutrients with the Atlantic Ocean. A Dutch consortium of scientists will investigate how big this role of the North Sea really is. Under the leadership of…
Tuesday 22 March 2022
Four years research into the effects of sand extraction in the North Sea
In the coming years, a broad consortium of research institutes and companies will be working on the ecological optimisation of sand extraction in the North Sea. "The aim is to keep the marine ecosystem healthy", says Karline Soetaert, researcher at…
Thursday 11 November 2021
Oceans of Energy will build 1 MW offshore solar off the coast of Scheveningen
Scheveningen, The Netherlands; November 11, 2021 - Today Oceans of Energy and partners & observers announce the upscaling of the world's first offshore solar farm system 20 times and expand it to 1 MW (MegaWatt). In the coming years, the company…
Wednesday 20 May 2020
Four NWO grants boost NIOZ North Sea and fishery research
The Dutch Research Council (NWO) has awarded grants to NIOZ scientists Johan van der Molen and Karline Soetaert for research into the effects of future offshore wind farms on marine life, sediment, and underwater sand waves in the North Sea. The…

NIOZ publications

  • 2023
    Brandao, I.L.S.; van der Molen, J.; van der Wal, D. (2023). Effects of offshore wind farms on suspended particulate matter derived from satellite remote sensing. Sci. Total Environ. 866: 161114.
    van Leeuwen, S.M.; Lenhart, H.-J.; Prins, T.C.; Blauw, A.N.; Desmit, X.; Fernand, L.; Friedland, R.; Kerimoglu, O.; Lacroix, G.; van der Linden, A.; Lefebvre, A.; van der Molen, J.; Plus, M.; Ruvalcaba Baroni, I.; Silva, T.H.; Stegert, C.; Troost, T.A.; Vilmin, L. (2023). Deriving pre-eutrophic conditions from an ensemble model approach for the North-West European seas. Front. Mar. Sci. 10: 1129951.
  • 2022
    van der Molen, J.; Groeskamp, S.; Maas, L.R.M. (2022). Imminent reversal of the residual flow through the Marsdiep tidal inlet into the Dutch Wadden Sea based on multiyear ferry-borne acoustic Doppler current profiler (ADCP) observations. Ocean Sci. 18(6): 1805-1816.
    van der Molen, J.; Pätsch, J. (2022). An overview of Atlantic forcing of the North Sea with focus on oceanography and biogeochemistry. J. Sea Res. 189: 102281.
  • 2021
    Foekema, E.; van der Molen, J.; Asjes, A.; Bijleveld, A.; Brasseur, S.; Camphuysen, K. (C.J.); Van Franeker, J.A.; Holthuijsen, S.; Kentie, R.; Kühn, S.; Leopold, M.; Kleine Schaars, L.; Lok, T.; Niemann, H.; Schop, J. (2021). Ecologische effecten van het incident met de MSC Zoe op het Nederlandse Waddengebied, met focus op microplastics. NIOZ-rapport, 2021(03). NIOZ Royal Netherlands Institute for Sea Research: Texel. 98 pp.
    Lenhart, H.; Blauw, A.; Desmit, X.; Fernand, L.; Friedland, R.; Heyden, B.; Kerimoglu, O.; Lacroix, G.; Van der Linden, J.; van der Molen, J.; Plus, M.; Prins, T.; Ruvalcaba, J.L.; Stegert, C.; Thewes, D.; Troost, T.; Vilmin, L.M.; van Leeuwen, S. (2022). ICG-EMO report on model comparison for historical scenarios as basis to derive new threshold values. ICG: [s.l.].
    van der Molen, J.; Soetaert, K. (2021). Potential ecosystem effects of large upscaling of offshore wind in the North Sea: Recommendations for further work. NIOZ-rapport, 2021(02). NIOZ Royal Netherlands Institute for Sea Research: Texel. 13 pp.
    van der Molen, J.; van Leeuwen, S.M.; Govers, L.L.; van der Heide, T.; Olff, H. (2021). Potential micro-plastics dispersal and accumulation in the North Sea, with application to the MSC Zoe incident. Front. Mar. Sci. 8: 607203.
    van Duren, L.A.; Zijl, F.; van Kessel, T.; van Zelst, V.T.M.; Vilmin, L.M.; van der Meer, J.; Aarts, G.M; van der Molen, J.; Soetaert, K.; Minns, A.W. (2021). Ecosystem effects of large upscaling of offshore wind on the North Sea - Synthesis report. Deltares: [s.l.]. 42 pp.
  • 2020
    Karpouzoglou, T.; Vlaswinkel, B.; van der Molen, J. (2020). Effects of large-scale floating (solar photovoltaic) platforms on hydrodynamics and primary production in a coastal sea from a water column model. Ocean Sci. 16: 195-208.
    Legge, O.; Johnson, M.; Hicks, N.; Jickells, T.; Diesing, M.; Aldridge, J.; Andrews, J.; Artioli, Y.; Bakker, D.C.E.; Burrows, M.T.; Carr, N.; Cripps, G.; Felgate, S.L.; Fernand., L.; Greenwood, N.; Hartman, S.; Kröger, S.; Lessin, G.; Mahaffey, C.; Mayor, D.J.; Parker, R.; Queirós, A.M.; Shutler, J.D.; Silva, T.; Stahl, H.; Tinker, J.; Underwood, G.J.C.; van der Molen, J.; Wakelin, S.; Weston, K.; Williamson, P. (2020). Carbon on the northwest European shelf: Contemporary budget and future influences. Front. Mar. Sci. 7(article 143).
    Luisetti, T.; Ferrini, S.; Grilli, G.; Jickells, T.D.; Kennedy, H.; Kröger, S.; Lorenzoni, I.; Milligan, B.; van der Molen, J.; Parker, R.; Pryce, T.; Turner, R.K.; Tyllianakis, E. (2020). Climate action requires new accounting guidance and governance frameworks to manage carbon in shelf seas. Nature Comm. 11: 4599.
    Philippart, C.J.M.; Dethmers, K.E.M.; van der Molen, J.; Seinen, A. (2020). Ecological engineering for the optimisation of the land-based marine aquaculture of coastal shellfish. International Journal of Environmental Research and Public Health 17(19): 7224.
    Tidbury, Hannah; Taylor, Nick; van der Molen, J.; Garcia, Luz; Posen, Paulette; Gill, Andrew; Lincoln, S.; Judd, A.; Hyder, K. (2020). Social network analysis as a tool for marine spatial planning: Impacts of decommissioning on connectivity in the North Sea. J. Appl. Ecol. 57(3): 566-577.
  • 2019
    García-García, L.M.; Sivyer, D.; Devlin, M.; Painting, S.; Collingridge, K.; van der Molen, J. (2019). Optimizing monitoring programs: a case study based on the OSPAR eutrophication assessment for UK waters. Front. Mar. Sci. 5: 503.
  • 2018
    Beraud, C.; van der Molen, J.; Armstrong, M.; Hunter, E.; Fonseca, L.; Hyder, K. (2018). The influence of oceanographic conditions and larval behaviour on settlement success—the European sea bass Dicentrarchus labrax (L.). ICES J. Mar. Sci./J. Cons. int. Explor. Mer 75(2): 455–470.
    van der Molen, J.; García-García; Whomersley, P.; Callaway, A.; Posen, P.E.; Hyder, K. (2018). Connectivity of larval stages of sedentary marine communities between hard substrates and offshore structures in the North Sea. NPG Scientific Reports 8: 14772.
    van der Molen, J.; Ruardij, P.; Mooney, K.; Kerrison, P.; O'Connor, N.E.; Gorman, E.; Timmermans, K.; Wright, S.; Kelly, M.; Hughes, A.D.; Capuzzo (2018). Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15(4): 1123-1147.
    Whomersley, P.; van der Molen, J.; Holt, D.; Trundle, C.; Clark, S.; Fletcher, D. (2018). Modeling the dispersal of spiny lobster (Palinurus elephas) larvae: Implications for future fisheries management and conservation measures. Front. Mar. Sci. 5: 58.
  • 2017
    Ford, D.A.; van der Molen, J.; Hyder, K.; Bacon, J.; Barciela, R.; Creach, V.; McEwan, R.; Ruardij, P.; Forster, R. (2017). Observing and modelling phytoplankton community structure in the North Sea. Biogeosciences 14(6): 1419-1444.
    Townhill, B.L.; van der Molen, J.; Metcalfe, J.D.; Simpson, S.D.; Farcas, A.; Pinnegar, J.K. (2017). Consequences of climate-induced low oxygen conditions for commercially important fish. Mar. Ecol. Prog. Ser. 580: 191-204.
    van der Molen, J.; Ruardij, P.; Greenwood, N. (2017). A 3D SPM model for biogeochemical modelling, with application to the northwest European continental shelf. J. Sea Res. 127: 63-81.

Linked projects

NoSE_North Sea Atlantic Exchange
Matthew Humphreys
Netherlands Organization for Scientific Research
Project duration
1 Oct 2022 - 31 Dec 2027