Research ships

Research ships

Scientists regularly go to sea onboard oceanographic vessels to measure water properties at key locations, or to deploy and recover sensors. These ships are high tech floating laboratories which allow the scientists to carry out a wide variety of measurements and experiments.

Measure the seawater properties

The oceanographic cruises allow measuring the seawater from the surface to the bottom at a given moment in time. Properties like temperature, salinity, fluorescence, dissolved oxygen or the nutrient concentrations can thus be measured with precision.

Several experiments are carried out onboard


Conductivity Temperature Depth Rosette.

Deployment of the CTD Rosette

A CTD Rosette is a suite of sensors which measure the Conductivity, Temperature and Depth. It is an essential piece of oceanographic equipment and provides a profile of physical and chemical data through the water column. The sensors are attached to a metal frame called a rosette, or carousel, along with numerous water sampling bottles. These bottles are deployed open during the descent, and closed up (`fired`) at chosen depths to sample the seawater in a vertical profile. The salinity of seawater is difficult to measure directly. It is therefore determined by simultaneously measuring the temperature and the electrical conductivity of a sample volume.

(Extract from the PAP Cruise 2009 diary)

For more details on the CTD Rosette :
www.classroomatsea.net
oceanexplorer.noaa.gov
www.whoi.edu


Plankton nets


A plankton net.

To catch the plant and animal plankton drifting in the upper layers of the oceans, scientists deploy nets with a fine mesh. Given that plankton ranges in size from a few centimetres to a few micrometres, scientists can adapt the net mesh to the species they want to sample. Trawls are either done vertically below the stationary ship, or horizontally at a chosen depth while the ship is moving at low speed. Once collected, the plankton is analysed under a magnifying glass to identify the species present.

PAP Cruise 2009

For more details on plankton sampling :
oceanexplorer.noaa.gov/technology/tools/trawl/trawl.html

Sediment traps


Sediment traps.

A sediment trap is an upward-facing funnel moored between 1000 and 4000 m of depth in the ocean. It collects the sinking particles of organic and inorganic matter from the surface, and allows the estimate of flux to the ocean depths. Under the funnel a rotating system of cups samples the particles for a predefined time period. The cups are then sealed from the ambient water until the trap recovery (up to one year later).

PAP Cruise 2009

For more details on sediment traps :
www.whoi.edu/instruments/

Argo drifters

Argo drifters can also be deployed during oceanographic cruises.

For more details on argo drifters :

See how to observe the global ocean with argo drifter

Maintenance of the devices at sea

Open ocean observatories are a collection of sensors attached to a mooring. Certain instruments can transmit data to the scientist via a satellite link, while others collect and stock samples and recordings. The observatories can remain deployed for several years, but need regular maintenance or replacement of the sensors. Once serviced, the moorings are again ready to record ocean properties for several years.

For more details on other devices used during oceanographic cruises

The "Megacorer"

The Bathysnap

The Acoustic Doppler Current Profiler (ADCP)

The Remote Operated Vehicles (ROV)

Observation Tools

Ocean Instruments