Statsraad Lehmkuhl slowed to a full stop, and a sleek instrument was lowered into the sea. The first research stop was underway.
Statsraad Lehmkuhl is something truly unique – a fully equipped sailing research vessel. On board are instruments that allow scientists to study both the seawater the ship sails through and the water far beneath it.
A rosette of cylinders
To collect water from the depths, the ship comes to a complete stop, and a CTD is carefully lowered into the sea. CTD is short for Conductivity, Temperature, and Depth, and is built as a rosette of cylinders, suspended from a cable. As it descends through the water column, it records how the ocean is layered and changing.
It is fitted with sensors to measure salinity, temperature, pressure, oxygen levels, and biological indicators such as fluorescence, which is microalgae concentration. And it measures the light penetration in the water. It also collects water samples for further analysis, including environmental DNA and oxygen isotopes.
On their own
On its way from Shetland to Tromsø Statsraad Lehmkuhl paused for its first scientific stop. For the Research coordinators Lucie Cassarino and Natacha Fabregas lowering the sleek frame of the CTD into the sea marked the transition from training and preparation to real-time ocean science.
– We lowered the rosette down to 1000 meters to collect water and record physical parameters, says Lucie.
This deployment was significant not only because it marked the scientific start of the journey, but because the team was on their own for the first time.
So how did it go?
– It went very well, to be honest. We were very happy. Stressed, obviously. That was the first time without the specialist and technician who put it on board. So, yeah, we had to stay focused, but it went very well, Lucie says.
The operation requires care. The CTD must float for one full minute just below the surface to trigger properly, while the crew keeps the instrument clear of the ship’s hull.
– That’s the critical moment, Lucie explains. The rosette is fragile. You don’t want it to hit the boat. It could be damaged. And during that one-minute surface pause, everyone holds their breath.
Breathing out oxygen, or breathing in
Here, in the Atlantic, the researchers want to see where the water masses are coming from, how much life is in the ocean, and how the ocean breathes.
– Data from the sensors tells us about the structure of the ocean, Lucie says. We can spot the differences in water coming from the Arctic and from the North Atlantic for example, and at what depth water from the different origins are. We can also find out how much biomass there is present, indicating how much oxygen that is produced. Is the ocean breathing out oxygen or breathing in oxygen? A very important question.
With that first launch completed successfully, the team is now confident they can repeat the procedure. Looking ahead, they hope to perform a CTD stop every three days, conditions permitting - and each adding to a growing body of data that will help scientists understand the ocean and how it is changing.
– Of course, everything depends on the weather, Lucie says, but now we’re on our way!
