Thermosalinograph – Seabird SBE38 and SBE21 sensors

Chlorophyll and turbidity – WET Labs FLNTU-RT sensor package

The instruments are maintained in a ready state to be operated whenever the vessels are at sea.   Cleaning of the optical FLNTU-RT is scheduled daily and cleaning of the SBE21 on a post-cruise basis, with annual instrument calibrations and servicing at the manufacturers.   


While underway, the thermosalinograph pump is turned on. Water is pumped through pipework into the engine room and past a SBE38 sensor, which measures the temperature of the incoming seawater. The water continues to the deck unit containing the SBE21, which measures conductivity, and the water temperature to calculate salinity. Some water is diverted past the WET Labs FLNTU-RT, which is attached to the deck unit, and measures fluorescence and turbidity.

The SBE21 deck unit: