INTERVIEW – Laure Chirurgien is in charge of measuring oxygen dissolved in seawater and community production. Here she describes the different instruments she uses, some of which especially developed at MIO.
THE INSTRUMENTS OF OCEANOGRAPHERS – Laure Chirurgien is an instrumentation and experimental technical engineer at the Mediterranean Institute of Oceanography (MIO) in Marseille, France. In BioSWOT-Med she is charge to measure oxygen dissolved in seawater and community production.
Q: Your affiliation
A: I have joined the MIO in 2011. I’m an instrumentation and experimental technical engineer.
What are your research interests besides BioSWOT-Med
I develop experimental devices and setup. In the last few years, I have mainly worked with Dominique Lefèvre, on the development of calibration baths for dissolved oxygen sensors.
In the BioSWOT-Med cruise you will be responsible for measuring oxygen. What instruments do you use to do so? How do they work?
On the CTD, there is dissolved oxygen sensor that needs to be corrected for potential drift and exactitude errors. Therefore, every day, I will take samples from the CTD at different depths and measure the oxygen concentration at these depths using the chemical reference methodology: the Winkler method. With these reference values we are able to correct the calibration parameters of the sensor to provide the community with more accurate values.
To make this measurement I use a one-wavelength spectrophotometer, called Endpoint, which we developed in collaboration with the Marseille Particle Physics Centre (CPPM) and the Technical Division of the National Institute of Sciences of the Universe (DT INSU).
You are also responsible for measuring community production. How do you do so and what instruments do you use?
To study community production, I use two different instruments. First, a mass spectrometer that measures the Oxygen/Argon ratio (O2/Ar). This instrument is using the continuous underway seawater supply to equilibrated the O2/Ar in seawater to a gas phase which is then measured by the mass spectrometer.
Secondly, I am responsible of a homemade system developed by Dominique Lefevre which allows to measure O2based net community production versus light during 24 hours incubation.
The whole of the data resulting from these two experiments will enable us to study the net community production.
Contact: Tosca Ballerini (firstname.lastname@example.org)