controlTwo RASs, each consisting of three tanks, were located at Ifremer(Palavas les Flots Station, Montpellier, France). The experimentalsystem, in which ORP was elevated by ozone injection into a skim-mer, was called RAS-O3. The control system was referred to asRAS-C. Details of the construction of the systems and of the ORPcontrollers were reported in Li et al. (2014).