The Santander standard section sampling program was originally designed for day-long coastal surveys carried out with small research vessels. As a result, its initial focus was primarily on the continental shelf. However, thanks to the close proximity of the continental slope off Santander (in the southeastern Bay of Biscay), monthly sampling extending into mid-waters became possible as early as the 1990s at the outermost stations. Sampling was limited to 1000 meters until the end of 2007, then it was extended to 1500 and since 2014, after the construction of a larger regional vessel that is in charge of sampling, it covers the total depth of 2500 m. The deep station (S7), which is regularly sampled from the surface to the seafloor, forms the core oceanographic station of the SATS observatory — providing continuous, high-quality data from the upper ocean to ocean floor.