Royal Netherlands Institute for Sea Research

Wadden Sea

A unique coastal tidal environment and one of the main research areas

The UNESCO World Heritage Wadden Sea, stretching from the Netherlands to Denmark, is one of the main NIOZ research areas. Our Wadden Systems Research Centre offers easy access to our ongoing research projects and other regional activities.

UNESCO World Heritage

UNESCO has chosen the international Wadden Sea between Den Helder in the Netherlands and Esbjerg in Denmark as a natural world heritage area because of its unique characteristics.

For NIOZ, the Wadden Sea with its large and characteristic tidal fluctuations with drained intertidal flats at low tide, has been a main research area since the institute was founded in 1876. For our Texel location, the Wadden Sea is in fact our backyard.

Sea level rise

The input and transport of sand and suspended material through the tidal inlets of the Wadden Sea is essential to keep up the tidal flats with the rise in sea level, which has been going on for the last decades. If the transport and sedimentation on the tidal flats become too low, the Wadden Sea as we currently know it will end up drowning, with large consequences for present coastal communities including fish and birds.

Primary production

The NIOZ has a coastal observatory which use a suite of automated sensors which are positioned on the Ferry crossing the Marsdiep area and on the sampling jetty behind the institute. In this way we monitor with high temporal resolution changes in water quality parameters, sediment transport and primary production. All these data will give us information about the effects of climate change and human induced changes (e.g. reduction in nutrient loads, fresh water discharge) the potential carrying capacity in the western Dutch Wadden Sea

Nursery areas for fish

The development of fish populations shows a negative trend in the Wadden Sea ecosystem. The catch in the NIOZ fyke near Texel in the western Wadden Sea has decreased by more than 90% since the early 1970s. We are currently investigating why the Wadden Sea’s nursery function for fish has diminished so much during the past decades.

The Wadden Sea ecosystem has also seen many new immigrants, mainly imported by ballast water from ships or by animal transport for aquaculture. Examples are the American comb jelly Mnemiopsis leidyi and the Pacific oyster Crassostrea gigas, along with their ‘native’ parasites. An important research question is how these ‘newcomers’ find their way in the Wadden Sea ecosystem.

Feeding grounds for birds

The plants and animals living in the Wadden Sea are adapted to rapid changes of sea level, temperature and salinity. For millions of migrating birds belonging to a multitude of species, the fauna living on or below the surface of the tidal flats is the fuel for the second part of their migration routes between their breeding areas in the Arctic and their wintering grounds in the tropics.

Other bird species use the Wadden Sea as a wintering area, or use the chain of islands and the coastal areas to breed and nourish their young at low tide in the Wadden Sea. At the top of the food web, thousands of resting and fishing harbour and grey seals can be found in the Wadden Sea (although they often swim through the tidal inlets into the North Sea to feed).

Research foci

Our current research foci for the Wadden Sea are movement ecology (from larvae to migratory birds) and tropic interactions within coastal food webs (including plankton, benthos, parasites, fish, birds and mammals) in an environment where hydrodynamics and sediment transport are at the basis of many biological processes.

Wadden Systems Research Centre

Eager to know more? Then have a look on the pages of our Wadden Systems Research Centre. Contact persons are dr. ir. Katja Philippart or dr. ir. Henk W. van der Veer.

News and updates

Tuesday 22 May 2018
Over zeespiegelstijging, bodemdaling en sedimentatie in de Nederlandse Waddenzee
Tijdens het nationaal congres ‘Waddenzee Wereldklasse’ op 17 mei jl. in Leeuwarden ging de korte film ‘Over zeespiegelstijging, bodemdaling en sedimentatie in de Nederlandse Waddenzee’ in première.
Friday 18 May 2018
Wetenschappers bieden onderzoeksagenda aan voor Waddengebied
Als gevolg van klimaatverandering en door menselijk ingrijpen verandert er veel in de Waddenzee. Internationale monitoring van het Waddengebied en een gezamenlijk onderzoeksplan om veranderingen in het rijke gebied te verklaren zijn daarom van…
Saturday 28 April 2018
WADfilm: Mosselen luiden het voorjaar in van de Waddenzee
De lente is begonnen en daarmee breekt voor veel dieren en organismen in de Waddenzee de paringstijd aan. Wanneer het zeewater de 10 graden bereikt, is dat voor de mossel hét teken om te gaan ‘kuitschieten’. Een vrouwelijke mossel kan wel een miljoen…
Saturday 21 April 2018
WADfilm: De vissentrek naar de rijke Waddenzee
Nu het lente is en het water opwarmt, komen er allerlei vissen naar de voedselrijke Waddenzee. Ook komen de larven van schol, bot en haring op dit moment met miljoenen tegelijk naar binnen op zoek naar kleine schelpjes en wormen en andere kleine…

Linked Projects

Impact of human activities on sediment composition
Henk van der Veer
Project duration
1 Jun 2017 - 31 Oct 2017
EMODnet_The European Marine Observation and Data Network - part biology
Karline Soetaert
European Community
Project duration
19 Apr 2017 - 18 May 2019
INNOPRO_INNOvation and return improvement of mussel PROduction
Tjeerd Bouma
Project duration
24 Jan 2017 - 31 Dec 2019
Vegetable Biomass from Sea
Klaas Timmermans
Provincie Noord-Holland
Project duration
1 Jan 2017 - 1 Oct 2018

Linked publications

  • 2016
    Buiter, R.; Govers, L.; Piersma, T.; Metawad Team (2016). Knooppunt Waddenzee. Metawad/NIOZ: [s.l.]. ISBN 978-90-5615-378-6. 141 pp.