Royal Netherlands Institute for Sea Research

Dr. Marcel Wernand

Senior Scientist
Phone number
+31 (0)222 369 417
Senior Scientist


  • Bio-optical variability of estuaries, seas and oceans, long-term monitoring
  • Design and development of multi-spectral ocean colour instrumentation
  • Long-term changes of ocean colour in relation to global change
  • Polytechnics, remote sensing
  • Marine-optical science history

Research interests

Since 1978 I am working as a marine-optics expert at NIOZ.  Besides the main theme of the physical department, the study of hydrodynamic processes in the marine environment, also the leader of marine-optical research. Colour observations of natural waters are based on multi- and hyper-spectral measurements performed in the field and from space. A simpler approach to determine the colour of natural waters is by means of the Forel-Ule colour comparator scale. This scale has been applied globally and extensively by oceanographers and limnologists since the 19th century. A new method for Forel-Ule colour classification, through participatory science, i.e. with the help of a smartphone and dedicated App operated by the public, has been developed within the Citclops project. The App facilitates the need to connect present oceanographic data with the past.

My main research interests combine: the design and development of multi-spectral ocean colour instrumentation; bio-optical variability of estuaries, seas and oceans, long-term monitoring of coastal colour; the development of water quality algorithms for application in coastal optical remote sensing; long-term changes of ocean colour in relation to global change; marine-optical science history. Interests and sports: Drama, playwright, poetry, tennis, golf and mouth- harp.



From 1977: Senior Scientist at Royal Netherlands Institute for Sea Research (NIOZ), The Netherlands, department of Physical Oceanography (marine optics and remote sensing)

1974-1977: Designing physical experiments for bachelor students at the Free University Amsterdam (VUA), The Netherlands



Wernand M.R. , van der Woerd HJ, Gieskes WWC, 2013. Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide. PLoS ONE 8(6): e63766. doi:10.1371/journal.pone.0063766,

Wernand, M. R., Hommersom, A., and van der Woerd, H. J., 2013. MERIS-based ocean colour classification with the discrete Forel–Ule scale, Ocean Sci., 9, 477-487, doi:10.5194/os-9-477-2013.

Wernand, M.R., 2010. On the history of the Secchi disc" J. Europ. Opt. Soc. Rap. Public. 5, 10013s, 1-6. 321-2074.pdf

Wernand, M.R. and van der Woerd, H.J., 2010.Spectral analyses of the Forel-Ule ocean colour comparator scale. J. Europ. Opt. Soc. Rap. Public. 5, 10014s, 1-7. 322-2179.pdf

Wernand, M.R. and van der Woerd, H.J., 2010. Ocean colour changes in the North Pacific since 1930. J. Europ. Opt. Soc. Rap. Public. 5, 10015s, 1-6. 325-2186.pdf

Please find my list of publications at the bottom of this webbpage. You can download all my publications on ResearchGate. See also PhD thesis.



Professional education

2011: PhD Physics University of Utrecht 

1974: Polytechnics in Math and Physical engineering, COVALU, Utrecht 


Awards, prized and funded

2012-2015: Citizens’ Observatory for Coast and Ocean Optical Monitoring (Citclops) EC-funded 3-years project, started October 2012 and is focused on retrieving, through crowdsourcing, data on three main optical properties related to sea-water quality: colour, transparency and fluorescence. Novel technologies will be developed to retrieve these properties based on citizens’ measurements with common mobile devices (3.8 M€)

2004: Best speaker award, winner of the Golden Bell, during Ocean Optics XVII Conference, Fremantle, Australia, October 25-29, 2004



Wernand, M.; Novoa, S.; van der Woerd, H.; Gieskes, W. (2014). A Centuries-long History of Participatory Science in Optical Oceanography: from observation to interpretation of natural water colouring. Histor. Meereskd. Jahrb. 19: 61-90. In: Historisch-meereskundliches Jahrbuch = History of Oceanography Yearbook. Deutschen Meeresmuseums (DMM): Stralsund. ISSN 0943-5697.

Wernand M.R., Oct. 2013, Chapter: The history of subsea optics (ca. 50 p) in Subsea optics and imaging, Edited by J Watson, University of Aberdeen, UK and O Zielinski, University of Oldenburg, Germany, ISBN 0 85709 341 X, ISBN-13: 978 0 85709 341 7, October 2013, 608 pages, hardback, Woodhead Publishing Series in Electronic and Optical Materials No. 46.

Wernand, M.R., and W. Gieskes, 2011, Ocean Optics from 1600 (Hudson) to 1930 (Raman), shifting interpretation of natural water colouring. Union des Océanographes de France, Paris, ISBN: 978-2-9510625-3-5 (book).



WadCam (realtime)
NIOZ-jetty live monitoring Wadden Sea -COLOURS-
Marsdiep data day variables-Chlorofyll a, Total Suspended Matter and Forel-Ule


With the Citclops/EyeonWater app you will…

  • be more informed about the sea and its colour,
  • be environmentally active doing coast-watching,
  • enjoy more your favorite water activities.


1993: Wernand, M.R, Editor (initiator), WOIRS 1993, European Workshop on Optical Ground Truth Instrumentation for the Validation of Space-Borne Optical Remote Sensing Data of the Marine Environment, Netherlands Institute for Sea Research, Texel, The Netherlands, Nov. 23 - 24, 1993, ISSN 0923-3210.


2008: Coordinating author: Ian S. Robinson. Contributing authors, David Antoine, Miroslaw Darecki, Patrick Gorringe, Lasse Pettersson, Kevin Ruddick, Rosalia Santoleri, Herbert Siegel, Patrick Vincent, Marcel R. Wernand, Guy Westbrook, Giuseppe Zibordi, Jan-BartRemote Sensing of Shelf Sea Ecosystems, State of the Art and Perspectives, Position Paper 12, Marine Board, ESF, February 2008. Series Editor: Niamh Connolly, Editorial support: Nicolas Walter.

1996: Ir. P.J.F. Geerders (P. Geerders Consultancy), Ir. J.M.M. Kokke (MD/RWS), M. Wernand (NIOZ), 1996. Feasibility study european intercalibration facility for marine optical data, nrsp96-37, Final report. BCRS project 6.3/IS-54.

NIOZ publications