On a research vessel, the top priority is to document EVERYTHING. Every step is written down so that later - back on land - you know what each sample belongs to and where it was taken and when. This is important for the analysis.

It is also very important that the programme on the computer is set to "Save data". You should always check this, because the programme looks exactly the same and also works completely normally if it is set to "do not save". So - don't forget to check!

The cable on which the probe is suspended contains a cable that can be used to transmit data in real time. It is also used to supply power to the CTD. This cable is called the lead-in cable. The CTD is lowered into the water. Some sensors send data directly to the computer (via the deck unit, of course). Other data is only obtained later from the water and the sediment samples that the CTD brings back on board. Sediments are loose materials that are also present in the water. They are tiny particles that have been formed by weathering and erosion, as well as sand, for example.¹

Using various methods, for example by filtering the sediment out of the water, we obtain samples that can be analysed for a wide variety of substances.

Did you know that the salt content in our oceans and seas is not the same everywhere? The salinity can vary greatly. This can be clearly seen in the illustration on the right.

Salinity is measured by the conductivity of the electric current. The more salts - and therefore charged ions - there are in the water, the higher the conductivity. And the higher the conductivity, the higher the salt content¹. More salt can dissolve in warm water than in cold water. This is how the different salt contents of the oceans come about. Ultimately, the researchers are interested in the salt content and not the conductivity.

Special programs/a special program is needed on the computers so that the large amounts of data can be recorded and displayed in an interpretable way.
One example of data visualisation is salinity as a function of depth. A corresponding graph is recorded directly as the probe is lowered. Anyone who can interpret these graphs is able to draw direct conclusions and does not have to look at the individual values first. You get a quick overview.