Dataset: Grazing experiment 4: pCO2

The phytoplankton Rhodomonas sp. CCMP 755 was grown semi-continuously in atmosphere controlled chambers at three different CO2 treatment concentrations; Ambient (400ppmv), Moderate (750ppmv), and High (1000ppmv). Cultures were diluted daily starting day 4 with pre-equilibrated media containing f/50 nutrients. Some of the culture removed was used to evaluate chemical parameters. Samples for pH were filtered through a GFF to remove cells and loose coccoliths both of which increase optical scatter.  Samples were warmed to 25°C in a water bath and run within three hours of sampling.  pH was analyzed spectrophotometrically with m-cresol dye on an Agilent 8453A UV-VIS Diode Array Spectrophotometer.  Samples for total alkalinity were taken on growth days 5, 7 and 10.  Alkalinity was measured by gran titration using a Titrando 888, and 0.1 N HCl titrant, in a temperature controlled titration vessel (+/1 5 ueq/kg).  Other parameters were calculated with CO2sys.