During a cruise on James Cook in April the observatory was serviced so that data are now produced every few hours on the meteorology, biology, physics and chemistry of the upper water column much of this being transmitted immediately by satellite to land. Downward flux of particles is measured using sediment traps at 3000m depth and the underlying seabed is observed using a time lapse camera system.

During the cruise the main equipment used will be zooplankton nets (MultiNet and WP2), video plankton recorder, CTD rosette sampler, marine snow catchers, PELAGRA drifting sediment trap, turbulence probe and gliders. Two of the PELAGRAs have been modified to take high resolution photographs of the particles entering the traps to derive size spectra and sinking rates.

We also hope to deploy a device to listen for whales and dolphins, fastened to one of our PELAGRAs. This device was designed and built by Douglas Gillespie and his team at St Andrews.

Find out more about the CTD package

CTD package


A large instrument package called a CTD is the standard workhorse of oceanographers for acquiring water column profiles. It is called a CTD because as a minimum it measures electrical Conductivity, Temperature, and Depth (pressure). The conductivity measurement can be corrected with temperature to give salinity or how salty the seawater is. With just these three measurements, a good picture can be gained of the physics of the ocean along a section.

Find out more about the PELAGRA trap


Pelagra is a free-floating, or more precisely, neutrally buoyant sediment trap that sinks to a certain depth and remains there for several days collecting falling particles in the open ocean. The name PELAGRA comes from 'Particle Export measurement using a LAGRAngian trap'.

The Pelagra sediment trap is designed and built by the Mechanical Engineers at NOC Southampton.

Marine Snow Catcher (Snatcher)

The Marine Snow Catcher is lowered to a pre-determined depth in the water column and closed. This traps 100L of sample inside it, which after being brought back onboard the ship, is left to settle for 3 hours. The marine snow particles settle to the bottom of the chamber, the top 95litres of water is removed and the lower 5litre section separated along with the deposited particles.. This chamber can then be isolated and the settled particles taken away for detailed analysis.


Underwater gliders are a type of robotic underwater vehicle that uses an engine to change the buoyancy of the vehicle rather than drive a conventional propeller as in our Autosub family of vehicles.

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