4. Sampling principles for the Tara Oceans expedition

For each of the 210 stations on the Tara Oceans expedition (figure 3 ), sampling was carried out at two depths. The first is the surface water layer (SUR), defined as the layer three to seven meters below the surface. The second is the so-called deep chlorophyll maximum (DCM), which corresponds to the zone of maximum abundance of photosynthetic plankton, determined by measuring chlorophyll concentration using fluorimetry.

For each station, several size fractions of organisms were sampled. The plankton sampled during the Tara Oceans expedition covered six orders of magnitude in terms of size, corresponding to...