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.

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

News and updates

Monday 16 April 2018
WAD; overleven op de grens van water en land | Kanoeten
In de Waddenzee leven alle dieren, vogels, planten het zand, het weer en de seizoenen in één adembenemende film. Ruben Smit, maker van de Nieuwe Wildernis, legde het leven in de Waddenzee vast voor zijn nieuwe natuurfilm: 'WAD; overleven op de grens…
Tuesday 20 March 2018
WAD; overleven op de grens van water en land | Kiezelwieren
In de Waddenzee leven alle dieren, vogels, planten het zand, het weer en de seizoenen in één adembenemende film. Ruben Smit, maker van de Nieuwe Wildernis, legde het leven in de Waddenzee vast voor zijn nieuwe natuurfilm: ‘WAD; overleven op de grens…
Friday 27 October 2017
Exotische Japanse oester vriend en vijand van Waddenzeebewoners
Exoten vormen wereldwijd een bedreiging voor mariene ecosystemen. Deze invasieve soorten die door menselijk handelen (aquacultuur, scheepsvracht) in een nieuw gebied komen, gaan de strijd aan met inheemse soorten: ze vreten ze op of overwoekeren…
Tuesday 18 July 2017
Algae living on mudflats are the solar panels that fuel the Wadden Sea food web
What fuels the Wadden Sea food web? One of the largest ecological research projects in the Netherlands, the recently finalized ‘Waddensleutels’ program, revealed that the most important energy source for the majority of animals higher up the food…
Wednesday 10 May 2017
Rapport Waddenvereniging: wadden kunnen nog deze eeuw verdrinken
De Waddenzee kan nog deze eeuw verdrinken. Dit is de conclusie van het rapport 'Toekomst van de Waddenzee: een stijgende zeespiegel over een dalende bodem' van de Waddenvereniging, waaraan ook het NIOZ, de TU Delft en de Universiteit Utrecht…
Tuesday 04 April 2017
Theunis Piersma geridderd
Prof. Theunis Piersma benoemd tot Ridder in de Orde van de Nederlandse Leeuw.
Tuesday 28 March 2017
Hoe zeegras omgaat met stress door bio-bouwen in zijn eigen omgeving
Zeegrasvelden zijn uiterst productieve bio-bouwers die in kustgebieden over de hele wereld hun eigen leefomgeving vormen. Het areaal van deze belangrijke gebieden daalt momenteel drastisch, onder andere door watervervuiling. Om zeegrasvelden in de…
Thursday 16 March 2017
NIOZ software opens new avenue for animal migration research
This week, a NIOZ-made software program for the R statistical environment was introduced. ‘FLightR’ enables refined and statistically validated analyses of animal movement data acquired with solar data loggers. The possibilities of the programme are…
Saturday 11 February 2017
Diepwatermosselen zijn watjes vanwege kalme jeugd
Het wilde maar niet lukken om mosselbanken in de Waddenzee terug te brengen. Welke technieken de terreinbeheerders van Natuurmonumenten en Staatbosbeheer en de onderzoekers van Rijksuniversiteit Groningen en NIOZ ook probeerden, de mosselen die…

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.