CTD

The CTD is an instrument used to profile the conductivity, temperature and depth (CTD) of the water column. Both 24 and 36 bottle CTDs can be deployed from from RV Investigator to depths of 10,000 m.

What it's used for

The CTD can be used to gather a range of ocean data including salinity, density and sound velocity. Extra sensors can also be added to the CTD to measure other variables such as phytoplankton, oxygen fluorescence and turbidity.

How it works

The CTD is deployed over the side of the vessel to depths of up to 10,000 m.

The CTD includes a frame/carousel, CTD instrument, various auxiliary sensors and water sample bottles (Niskin Bottles) that allow water to be collected for later analysis.

During ascent to the surface, the bottles on the CTD can be closed at predetermined depths, allowing scientists to collect water samples at regular intervals throughout the water column.

Key features

24 bottle carousel and frame

A cluster of 24 water sample bottles and sensors that is attached to a CTD.

36 bottle carousel and frame

A cluster of 36 water sample bottles and sensors that is attached to a CTD.

Trace metal CTD system

A specialised system that includes a trace metal clean winch with 12 bottle trace metal CTD. The system has a trace metal clean cable to 300 m which is connected to a cable that allows deployment to depths up to 6000 m.

CTD deployment boom

The CTD laboratory on RV Investigator is on the starboard side and uses a boom to deploy the CTD out through a vertically opening hatch.