Royal Netherlands Institute for Sea Research

Research Facilities

Research Vessels

For research in the shallow Wadden Sea two research vessels are available: RV Navicula and RV Stern.

contact: Thomas de Greef    +31(0)222 369 375 / Erica Koning   +31(0)222 369 441 

Mobile Bird Observatory

The Wadden Pontoon "De Richel" is used mainly for bird research. In spring the pontoon is hauled to De Richel, a sandbank in the Wadden Sea just off the eastern tip of Vlieland, where it remains until late autumn. The pontoon is extremely well suited for bird watching and accommodates up to four researchers.

contact: Anne Dekinga     +31 (0) 222 369 486

Automated Monitoring Platform

The NIOZ pier extends 45 m into the Marsdiep, the westernmost tidal inlet of the Wadden Sea. The pier is equipped with automated sensors, which measure a suite of abiotic and biotic parameters such as water temperature, salinity, water height, hyper-spectral light conditions, chlorophyll-a and primary productivity. The pier has two cabins with mains power (220V), heating, potable water and access to seawater by means of a screw pump. Water samples are taken regularly to calibrate the sensors. The pier, with a working platform of 3 by 10m, has easy acces to the waterfront and two winches to lower equipment into the water. It is located close to the NIOZ laboratories, workshops and harbour. It offers the possibility to test all kinds of equipment and other seagoing materials in turbid and turbulent coastal waters.

contact: Eric Wagemaakers     +31 (0) 222 369 376

The Fyke

Since 1959 fish monitoring has been conducted with a fyke in the Marsdiep at the head of Texel. While the fyke is present, between March and October, it is checked upon every day. Caught fish are identified and measured at NIOZ. Thus, the fyke provides long-term monitoring data about seasonal and yearly abundances of fish stocks. 

contact: Henk van der Veer     +31 (0) 222 369 575

Shorebird Experiment Facility

The Shorebird Experiment Facility is an intertidal, climatized indoor arena for testing field-generated hypotheses. Inside the facility are 7 holding facilities of approximately 4m long, 2m wide and 2.5m high, with a supply of running fresh water in a tray. The floor is made of easily cleaned material and is covered by running salt water for hygienic purposes. In 5 out of the 7 cages is a small mudflat with running salt water where the birds can probe the sediment.

The experimental arena is an aviary of approximately 8m long, 7m wide and 3m high filled with a layer of sand. In this aviary we are able to simulate the tidal cycle by raising and lowering the water level. Adjacent the aviary and opposite each other are two aviaries of 4m long, 1.6m wide and 2.5m high. Before a trial the birds can acclimatize in one of these aviaries from where they are released into the experimental arena using sliding doors.

contact: Anne Dekinga    +31 (0) 222 369 486


The NIOZ offers a suite of state-of-the-art facilities and high quality operational procedures for the analyses of various biological and non-biological parameters of wadden systems. The Molecular Biology Laboratory, for example, facilitates DNA and RNA targeted approaches to study any marine organism or community: from viruses in coastal phytoplankton to harbour seals. The Sediment Lab analyses natural radio-isotopes, such as 234Th en 210Pb as well as man-made isotopes such as 137Cs, which are often used for dating sediments. Some isotopes can be measured directly using a HR ICP-MS, whereas other isotopes can be detected by alpha and beta spectrometric techniques. Both ICP-MS and spectrometry are available. Specific metabolic and chemical process rates, be it of cultures or natural wadden communities, can be assayed using radio-active nutrients, energy sources or oxidants. These substrates may be labelled with 3H, 14C, 32P, 33P, or 35S radio-isotopes. Some typical examples of activity measurements include bacterial amino acid uptake rate as a measure for bacterial production and 14C incorporation rates as a measure for primary production. Analyses of these radio-isotopes can be performed by the Radio-Isotope Lab. The Benthic Fauna and Plankton Lab are well equipped to determine biomass, species composition and production rates of pelagic and benthic flora and fauna in wadden systems world-wide.

contact: Biem Trap    +31 (0) 222 425

Thermo-controlled laboratories

The NIOZ provides a number of thermo-controlled laboratories for experimental studies and cultivation. Most laboratories have access to artificial and natural seawater of various salinities. Some laboratories enable testing of complete sediment cores (up to 4000 kg), which can be transported from a lorry to the climate room by means of a heavy-duty elevator and crane. One of these laboratories can be used for experiments under quarantine conditions.

contact: Biem Trap    +31 (0) 222 369 425

Automated Weighing Machine

The automated weighing machine, that was designed and built at NIOZ, has the capacity to weight 9000 crucibles a day, with a precision of a tenth of a milligram. It plays a pivotal role in the SIBES project that covers more than 5000 sampling stations across the Dutch Wadden Sea, including parts of the German Wadden Sea. The samples are weighed three times: dry weight, ash-free dry weight and finally the empty weight of the crucible. Comparisons of these values yield energy values. Procedures are explained in an instruction video.

contact: Sander Holthuijsen     +31 (0) 222 369 490   

Valve Gape Monitor

Bivalve shellfish filter water to obtain food and oxygen by keeping their valves open and generate a water current over their gills. They response to disturbance or a change in environmental conditions by changing the degree to which the valves are opened. Briefly stated: if a shellfish (e.g. a mussel) is happy, it’s valves are more often and wider open. Monitoring the mutual valve position of a clam over a prolonged time provides insight in the environment the shellfish is in. The request of the biologists was to develop a valve gape monitor for eight bivalves which can run and store data autonomously for months on only a few alkaline batteries. A further request was that the method was minimally intrusive. The solution chosen for the measurement is to measure the electric field between to micro coils. This meant that two small coils with wires need to be glued to the valves. Experiments showed that these wires didn’t disturb the normal behaviour of different shellfish species which were tested (jack-knife clam, blue mussel, cockle). The Valve Gape Monitor (VGM) design functions already perfect for several years. The only real wear of the system concerns the wires. The system now uses 16 wires (2 per shellfish). A new system that only uses 8 wires is now under development while at the same time a researchers’ wish to be able to extract the collected data wireless is taken into account. This new design is planned to be fully tested operational before the end of this year.

contact (scientific): Rob Witbaard    +31 (0) 113 577 462 / +31 (0) 222 368 537

contact (technical): Walther Lenting    +31 (0) 222 368 342 / +31 (0) 650 286 741

Bird tracking techniques

Advanced technologies in bird tracking with loggers and transmitters enable us to study behaviour of mobile animals such as birds on large scales in time and place. We have applied several techniques to increase our understanding about habitat use of birds: Automated Radio Tracking systems (ARTS) and Time Difference of Arrival Techniques (TDOA). TDOA was invented at Cornell Lab of Ornithology, and further developed at NIOZ.  While ARTS and TDOA require local receiver stations, the latest techniques allow communication with Argos satellites. Technicians are continually working to reduce the size and increase the capabilities of avian satellite transmitters. Nowadays not only gulls are tracked, but even red knots. Satellite tracking occurs in close collaboration with UvA-BiTS (gulls, bar-tailed godwits, crab plovers), and Microwave Telemetry Inc. (red knots).

contact: Job ten Horn +31 (0) 222 369 460