Dataset: Series 3B: bubble expt flow cytometry

Experiments were conducted to investigate the impact of bubbling gas through cultures of Thalassiosira pseudonana CCMP 1014 grown in Multicultivator MC-1000 OD culture tubes. TP1014 stock cultures were maintained in artificial seawater (Kester et. al 1967), enriched as with f/2 media (Guillard 1975). For the experiment, 5 ml of the TP1014 stock cultures were inoculated into 75 ml of ASW in eight tubes. The tubes were incubated in a Multicultivator MC-1000 OD unit (Qubit Systems), at 25 deg C and 400 µmol photons * m-2 * sec-1, set at a 12:12 day:night cycle for four days. Three tubes had no aeration (T1, T2, and T3); three tubes were bubbled with air at 60 ml·min-1 through a 0.2 µm stainless steel “carbonating stone” (T4, T5, and T6); and two tubes were bubbled with air at 120 ml·min-1 through a 0.2 µm stainless steel “carbonating stone” (T7 and T8). Samples were collected from each tube at the start of the experiment (day-0), and 5 hours after the start of the light phase each day (i.e. at 24-hour intervals) after that for four days. Samples were always collected 5 hours after the start of the light phase.

1 ml of each sample was fixed with buffered formalin (1% final conc. v/v), and stored at 4 deg C. At the end of the experiment, all fixed samples were run through a Guava easyCyte HT Sampling Flow Cytometer. TP1014 cells were identified based on their chlorophyll content (red fluorescence * cell-1), and size (forward scatter). A minimum of 300 cells was counted in each sample (except in one tube, where the culture did not grow well).