[Behind the scenes in oceanography (2/12)]. Caroline Le Bihan is a technician in the Technical Department for In-Situ Observations atIfremer‘sPhysical and Spatial Oceanography Laboratory (LOPS). She works in particular on the acquisition and processing of salinity, temperature, pressure and oxygen data to support the work of researchers.
Each month, océans connectés goes to meet the men and women who make oceanography work. They are laboratory technicians, topographers, engineers, sailors or meteorologists, and they are all essential to the smooth running of marine research. In this second episode, we delve into the day-to-day life between sea and land of Caroline Le Bihan, a technician in oceanic data.
By Maud Lénée-Corrèze
Cover photo : Caroline Le Bihan © M.Lénée-Corrèze
Hammers, screwdrivers, drills… you wouldn’t think you were in the workshop of an oceanography laboratory. The measuring instrument on the floor against a wall and the map of the Ovide research programme in the North Atlantic give us some clues. This is indeed the workshop of the Technical Department for In-Situ Observations of the Physical and Spatial Oceanography Laboratory (LOPS, a joint CNRS/IRD/Ifremer/UBO research unit) where Caroline Le Bihan, a technician specialising in CTD (salinity, temperature, pressure) and dissolved oxygen measurements, works.
Caroline Le Bihan graduated from Lannion with a DUT in physical measurements and joined Ifremer’s test basin in 2002, as part of the Research and Technological Development unit, which develops instrumentation for marine research. She was then taken on in the metrology laboratory, still within this unit, working mainly on calibration, accumulating experience over fifteen years which then led her to LOPS in December 2019. Before embarking on two years of Master’s studies, she looks back on her career as a Physical and Chemical Measurements technician.
What does your job entail in practical terms?
Generally speaking, the technician assists the researcher or research engineer with any experimentation project, whether on land or at sea, from the choice of equipment to be used or the set-up to data acquisition. Personally, I trained in conductivity, temperature, depth and dissolved oxygen data. With the whole of the team in the technical service for in-situ observations, we manage a range of instruments for LOPS, including CTD sensors, the rosette that we put in the water for sampling purposes, and a chemistry container. The latter is a bit like our mobile laboratory, enabling us to take reference measurements of salinity and oxygen at sea and on land, and to be completely autonomous in this respect.
At sea, on land, what’s your daily routine?
Most of my work is on land – I’m at sea for about a month a year – because I look after the maintenance of our container, to make sure that all the measuring equipment is working properly. I recently had the air conditioning changed, for example. Another part of my day-to-day work is adjusting the data collected on previous missions before sending it on to the researchers. I do some of this at sea, but I don’t necessarily have the time to look at everything in detail. And still with a view to guaranteeing the quality of the data, every year I take part with other laboratories [IRD, SHOM, IUEM, etc., editor’s note] in a water sampling at the môle Saint-Anne, just below Ifremer, to analyse the dissolved oxygen. We compare our results and this enables us to validate our oxygen analyses for all our measurements the following year.
Caroline Le Bihan at her desk in the In-Situ Observations Technical Department workshop. Part of her work on land involves processing the data collected at sea ©Ifremer
And at sea ?
It’s all about recovering data and processing it the first time. We have our rosette, which we put in the water a certain number of times a day. On this rosette, we have a probe capable of producing a CTD and dissolved oxygen profile directly as the rosette descends in depth. We check the salinity and oxygen profile data by taking water samples in bottles attached to the bathysonde, which are opened on descent and closed again on ascent to different depths depending on what we have observed on the probe profile. These samples are then warmed up in our container and analysed twenty-four hours later, following a well-defined protocol. The sampling bottles are then emptied and ‘rearmed’ for the next station. For temperature and pressure, we have other sensors on the rosette whose data we will compare with that of the probe profile.
My role is to prepare the samples for analysis: I check in the container that all the equipment is working properly and is correctly calibrated, particularly the salinometer. As we use the Winkler method to measure dissolved oxygen, I have to calibrate the thiosulphate, which is a necessary preamble to the analysis. Then, while the analysts come to work on the samples, I process the data from the previous day, adjusting it for the first time before passing it on to the researchers.
What are the challenges of your job?
Adaptation would be my watchword. You have to realise that nothing always goes according to plan at sea. You also have to adapt to the arrival of new sensors or new parameters to measure. For some time now we’ve been seeing the emergence of robotics, with more and more drones entering the oceanography market. This is a real turning point for us, and we need to take it on board, bearing in mind that these drones, whether surface, airborne or underwater, autonomous or piloted, must provide our scientists with usable, high-quality data. These new technologies are a real opportunity to supplement what a campaign at sea or one-off analyses can offer.
AUVs (Autonomous Underwater Vehicles) are being used more and more in oceanography. Here, Caroline Le Bihan launches the YUCO from Seaber during deployment tests in the Bay of Seine ©Ifremer
What do you think of the development of science under sail?
I know that at Ifremer, this is something that is being discussed more and more. Argo floats have been successfully launched and recovered under sail, and a colleague is working on sailboats as vessels of opportunity for surface measurements of salinity and temperature, in particular certain racing boats, such as skipper Fabrice Amedeo ‘s boat, which has a sensor on board to measure these two parameters as well as microplastics… It’s under development, but for the moment, sailing doesn’t seem to me to be enough, for example, to launch equipment or machinery that requires energy and major lifting equipment. Mission times might also be longer, bearing in mind that people already spend more than a month on board ocean-going vessels… That said, I’ve never yet tested science under sail, and I’d be very keen to do so.