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.’
‘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.’
‘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 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 +
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.
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
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)