Oxygen measurement and community production
Laure Chirurgien is responsible for measuring dissolved oxygen in seawater and community production. Here she describes the various instruments she uses, some of which have been specially developed at the MIO.
Laure Surgeon.
OCEANOGRAPHERS' INSTRUMENTS - Laure Chirurgien is an instrumentation and experimental engineer at the Institut Méditerranéen d'Océanologie (MIO) in Marseille, France. In BioSWOT-Med, she is responsible for measuring dissolved oxygen in seawater and community production.
What are your research interests outside BioSWOT-Med?
I develop experimental devices and installations. In recent years, I have worked mainly with Dominique Lefèvre on the development of calibration baths for dissolved oxygen sensors.
During the BioSWOT-Med cruise, you will be responsible for measuring oxygen. What instruments will you use to do this? How do they work?
On the CTD, there is a dissolved oxygen sensor that needs to be corrected for potential drift and accuracy errors. Therefore, every day I take samples from the CTD at different depths and measure the oxygen concentration at these depths using the chemical reference methodology: the Winkler method. These reference values allow us to correct the sensor calibration parameters in order to provide the community with more accurate values.
To carry out this measurement, I use a single-wavelength spectrophotometer called Endpoint, which we developed in collaboration with the Centre de Physique des Particules de Marseille (CPPM) and the Technical Division of the Institut National des Sciences de l'Univers (DT INSU).
You are also responsible for measuring Community production. How do you go about this and what instruments do you use?
To study the production of communities, I use two different instruments. Firstly, a mass spectrometer that measures the Oxygen/Argon (O2/Ar) ratio. This instrument uses the continuous supply of seawater to balance the O2/Ar ratio in the seawater into a gas phase which is then measured by the mass spectrometer.
Secondly, I'm responsible for an in-house system developed by Dominique Lefevre that measures O2-based community net production as a function of light during a 24-hour incubation period.
All the data from these two experiments will enable us to study the community's net production.
Contact us: Tosca Ballerini
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