The mooring (bottom diagram), initially planned with two lines, one for production (left) and one for sediment traps (right), was deployed at the start of each long station, but independently for the “production” and “trap” lines. Sampling with the CTD-rosette was systematically carried out close to the “trap” mooring during the time the stations were occupied.
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“PRODUCTION” LINE : AQUAMOUT
The first mooring corresponds to the launch of the AQUAMOUT, made up of 9 different levels (adaptable to within 5 m) and representing the depths where we find 75, 54, 36, 19, 10, 2.7, 1, 0.3 and 0.1% of incident light. As an order of magnitude, this represents between 5 m and 180 m at station LD C, west of the gyre.
At each level, the various bottles used to measure carbon, oxygen and nitrogen production are moored for 24-h incubation (figure below). Initially, samples were taken from the rosette of Niskin bottles at the desired depths, then the various tracers were added before installing the bottles and launching the mooring system. At the end of incubation, the line is recovered and the samples analyzed. This operation is repeated 3 times at each long duration station.
“TRAPS” LINE
The “trap” line is launched at the start of the station and recovered at the end of the station, and only in the case of long-duration stations. Falling material is quantified every 24 hours, thanks to a system of rotating recovery buckets. Analyses are carried out well after return to the laboratory by INSU’s “traps” unit.
The attached document presents the planned immersion depths for the various devices on the “trap” mooring.
The initially planned drift trap scheme was finally split into two independent lines.
