Two moorings will be deployed during the cruise and recovered after 1 year during the Bicose 2 cruise scheduled for 2018. These two moorings will be positioned to cross the hydrothermal plume of the active site TAG. They will collect samples of plume particles at regular intervals and measure the currents in the hydrothermal plume.
The Ifremer mooring is composed of:
- a dead weight,
- a system of two acoustic releasers to disconnect the instruments from the dead weight.
- a sediment trap, positioned at 50 m above the seafloor. The trap is composed of a funnel, a rotation plate and 24 sampling bottles. The bottles are attached to the rotating plate. Every 2 weeks, an engine ensures the plate rotation that connect a sampling bottle to the funnel. Each bottle collects the polymetallic sulfide particles in suspension in the hydrothermal plume.
- a float mounted with an ADCP (Doppler instrument) oriented to the seafloor to measure the bottom currents
- a second float mounted with 2 ADCP positioned 120 meters above the first ADCP. The first one is pointing down, the second one up. They are positioned in the center of the plume.
- an aluminum frame with two floats, a flashing beacon, a radio antenna, and an Argos beacon. These 3 instruments help to locate the mooring at the surface when released after 1 year of measurements.
The base of the mooring is the same as the Ifremer mooring: a dead weight, a double acoustic releaser system, a sediment trap with 24 sampling bottles, an aluminum frame with floats and beacons. The mooring also includes:
- an inclinometer fixed on the sediment trap to measure its movements
- an “Aquadopp”, similar to an ADCP, positionned under the sediment trap. It is oriented to the seafloor to measure the currents between the trap and the bottom.