Oxygen optode calibration workshop at the Max Planck Institut in Bremen (9.-11.12.09)

The Max Planck Institute for Marine Microbiology in Bremen (MPI, www.mpi-bremen.de) hosts a three-day workshop on the calibration of macro oxygen optodes. These sensors, that are manufactured by the Aanderaa Data Instruments in Norway (AADI; www.aadi.no), determine dissolved oxygen concentrations based on the changes in optical properties of an oxygen sensitive fluorophor. Due to their outstanding long-term stability and their insensitivity to pressure, macro oxygen optodes have become a standard tool for long term monitoring of dissolved oxygen in the water column and will be the main sensor type used for oxygen monitoring in HYPOX. The main goal of the workshop is to test a simplified procedure for the calibration of these sensors. This is done by exposing optodes of unknown or outdated calibration (“test optodes”) and known calibration (“reference optodes”) to a large variety of temperatures and oxygen partial pressures in a big airtight calibration vessel. Different partial pressures are established when water temperature (and, hence, oxygen solubility) is changed in the vessel. By running a temperature gradient at several oxygen concentrations the entire range of environmentally relevant temperatures and oxygen partial pressures can be covered with a reasonable effort. The workshop was attended by eight people from the Gothenburg University, the MPI, and AADI.


The workshop participants (Photograph: M. Schloesser, MPI)


Close up of the optodes in the calibration vessel (Photograph: M. Schloesser, MPI)


M. Holtappels and F. Janssen filling the calibration vessel (Photograph: M. Schloesser, MPI)