The TAN concentration of –N treatments aimed to supply the seaweeds withNH4+ -N fluxes (at an average of 3.3 lM NH4+ -N per hour)similar to the lowest levels supplied in the integrated cultivation system (see below). Preliminary experiments showed thatthe TAN in the –N treatments was depleted after 8 h, whereasin the +N vials, between 40 and 60 lM of TAN was still presentafter 24 h. Two vials of each N treatment were aerated withambient air ()C), while in the four remaining vials, the aeration was enriched with gaseous CO2 (+C) during the light period (14 h). The pH of the water enriched with CO2 wasbetween 7 and 7.5 (-2.9 mM DIC) during the light period,thus providing nonlimiting CO2 conditions for Asparagopsis photosynthesis (see Mata et al. 2007). In the vials with ambientaeration, the pH varied between 8.3 and 8.5 during the lightperiod. The water of each vial was exchanged every day, and theexperiment was run for 7 d. Biomass growth was calculated asthe weight difference of the algae at the end and beginning ofthe experiment. The algae were rinsed in a paper beforeweighing to remove excess water. At the end of the experiment,half of the biomass in each vial was frozen at )20C for analysisof bromoform and dibromoacetic acid contents (see below),and the other half was oven-dried (48 h; 60C) to determinethe tissue N and C content in an elemental analyzer (ThermoFinnigan, Flash EA 1112, Thermo Fisher Scientific, Walthman,MA, USA).