© A.Deniaud/Tara Expeditions


Tara Mediterranée expedition: 7 scientific instruments

ACs – Spectrophotometer with flow-through high spectral resolution
This instrument continuously measures light absorption and scattering by particles at more than 80 wavelengths in the visible and near infrared. The data are used to calculate the concentrations of phytoplankton and their pigments, the concentration of other particles, and their relative size. The measurements are performed near the surface using the boat’s seawater circuit.

Alpha – spectrofluorometer with flow-through for measuring fluorescence of pigments
Measures the fluorescence of particles excited by blue and green lasers. The data are used to determine the concentrations of phytoplankton pigments and dissolved material.

BB3 – retro-diffusion meter
Measures the back-scattering of light at 3 visible wavelengths. Used to calculate the concentration of phytoplankton and other particles, and obtain information on their composition.

HTSRB – hyperspectral radiometer (measures visible optical properties)
This instrument is used to study incident light on the water, the relationship between  light emanating from the water towards space, and the optical properties of water. It is deployed every day around noon, the approximate time when satellites fly over the zone, and is used for calibration of satellite data.

TSG – Thermosalinograph for continuous measurements
The unit provides continuous data on salinity and temperature throughout the voyage. The results are used in circulation patterns and for identification of water masses.

CTD / fluorometer / retro-diffusion meter, vertical deployment
Similar to the TSG, this instrument measures salinity and surface temperature, but is vertically deployed using the ship’s winch. Besides salinity and temperature, it also measures back-scatter and chlorophyll fluorescence as a function of depth. This allows us to correlate the data recorded continuously near the surface with the vertical distribution of physical and optical properties.

Manta Net
A fishing net specifically designed for collecting living and non-living particles at the ocean’s surface. The Tara Mediterranean project will especially focus on floating plastic fragments smaller than 5cm.
The mesh size of the net is 1/3 of a millimeter.