Infrastructure - Water

HydroFIA alkalinity meter

 The HydroFIA alkalinity meter is used to calculate the total alkalinity of a water sample. Alkalinity provides a "buffer" against major changes in the acidity of water. These changes can occur at the hands of industrial waste or climate change, among other things. Water alkalinity will therefore protect aquatic fauna and flora from fluctuations in acidity.

Hydro FIA alkaliniteitsmeter

Acoustic profile flow meter (ADCP) and speedlog

 An Acoustic Doppler Current Profiler (ADCP) or acoustic profile flow meter measures the vertical distribution of the velocity of water in the water column as well as the direction of flow. As the name of the ADCP suggests, its operating principle is based on the Doppler effect. Measuring currents is an important concept in oceanography. By determining how water masses move, researchers can relate this to how organisms, nutrients and other biological and chemical components are transported through the sea.

The speedlog is a device used to measure vessel speed. Both instruments are located in the hull of the RV Simon Stevin.


 A CTD is an acronym for a measuring instrument that contains sensors that measure ocean conductivity, temperature and depth. Despite its name, the CTD does not measure depth but pressure related to depth. VLIZ has added some additional sensors that measure the following chemical/biological parameters: photosynthetic active radiation (PAR), dissolved oxygen, turbidity, acidity, chlorophyll, and redox potential (ORP). Studying these parameters of seawater is important because they directly affect ocean life. Often the CTD is integrated into a carousel of Niskin bottles and set up from a research vessel.

Carousel with six Niskin bottles

 A carousel with six Niskin bottles is used to take water samples. The use of this device has the advantage that water samples can be taken at different depths by striking the individual release mechansims of the bottles. Often, along with the Niskin bottles, a CTD instrument is also mounted on the carousel. The water samples can be used to study plankton or to investigate the physical parameters of the seawater, or presence of contamination.

Automated Infra-Red Inorganic Carbon Analyzer (AIRICA)

 The "Automated Infra-Red Inorganic Carbon Analyzer" (AIRICA by MARIANDA), is designed to very accurately determine the amount of dissolved inorganic carbon (DIC) in both marine and pore water. DIC is the sum of all dissolved inorganic carbon (carbon dioxide, carboxylic acid, carbonate and bicarbonate ions).  It is one of the four parameters that characterizes the carbon system. Moreover, DIC is relevant to studies related to marine biogeochemistry, climate change and ocean acidification, among others.

Go-flo bottle

 A go-flo bottle is used for sampling water in function of examining plankton, nutrients, pigment particles, etc. A go-flo bottle is similar to a Niskin bottle with the difference that a go-flo bottle is designed to prevent contamination of the sample. A water sample taken with a Niskin bottle can be contaminated by a micro-layer present on the water surface that can be rich in organic matter, trace elements and fine dust.

Measuring buoy

 A measuring buoy is an anchoring floating object in which measuring instruments are placed. The VLIZ installed a measurement buoy at the level of the artificial reef in the C-Power wind farm, on the Belgian part of the North Sea. A CTD is mounted in the buoy for the continuous measurement of seawater temperature and salinity supplemented by sensors to determine turbidity, current, dissolved oxygen, acidity (pH) and seawater productivity. An acoustic telemetry-based receiver network to monitor the behavior and movement patterns of fish around the artificial reefs is also attached to the buoy. A C-POD, designed to detect the presence of toothed whales, was also attached to it.  The presence of a permanent monitoring station at a fixed point adds value to marine research.

Methane sensor

 The methane sensor allows on-site measurement of concentrations of methane dissolved in seawater. The sensor is suitable for long-term measurement of methane concentrations, e.g. tethered to an anchorage. VLIZ has optimized this sensor so that it can be connected to the seawater supply on board the RV Simon Stevin.

Multibeam sonar

 An instrument that uses sound to identify objects in the water column is called a SONAR (SOund NAvigation and Ranging). Active sonars themselves produce specific sound waves and then analyze the reflection (echosounders). This group includes the multibeam and singlebeam sonar. The multibeam sonar is used to visualize bottom topography.

Niskin bottle

 A Niskin bottle is a plastic cylinder with a cap at each end so that the bottle can be completely sealed. It is used to take water samples at the desired depth without danger of mixing with water from other depths. The water samples can be used, for example, to study plankton or to investigate the physical parameters of the seawater, or presence of contamination. A Niskin bottle can be used individually or in a carousel of six bottles along with a CTD instrument.

QuAAtro39 nutrient analyzer

 The QuAAtro39 is a 'segmented flow analyzer'(SFA) that can be used to determine the concentration of various nutrients in water. The knowledge of nutrient concentration is essential to determine the quality of the aquatic environment (which is under pressure from pollution and eutrophication) and its bio-geochemical status.

Scatter and transmittance meters LISST 100x/200x

 The scatter and transmittance meters LISST-200X, and its predecessor LISST-100X (LISST: Laser In-Situ Scattering and Transmissometry) are based on laser diffraction, a widely used technique to investigate detailed grain sizes and volume concentrations. This also allows the LISST to be used, for example, to measure the size and concentrations of oil droplets in the ocean or in studies of plankton distribution. The LISST-100X and 200X are often set up on a tripod and can be placed up to 300 m and 600 m deep, respectively.

Secchi disk

 A Secchi disk is used to measure the turbidity of the water. Connected to a rope, the disk is lowered into the water from a research vessel or from the shore until it is no longer visible. This "Secchi depth" is then used as a measure of the turbidity of the water. In general, white discs are used in the ocean and a disc with white and black quarters is used for lake surveys.

Underway data acquisition system aboard the RV Simon Stevin

 An underway data acquisition system has been installed in the dry lab, aboard the research vessel Simon Stevin. The pumped seawater, flows through a system of sensors that measures various characteristics of the seawater such as temperature, salinity, turbidity, oxygen, nutrients, surface pCO2 and fluorescence. The respective sensors are: a thermosalinograph, oxygen sensor, optical nitrate sensor, surface pCO2 sensor, flow cytometer, fluorimeter and a fast repetition rate fluorimeter. The data obtained by this flow-through system serves to support the marine science research conducted on board and adds value to the long-term marine series.