2.2.1 Cultures and radiocarbon labeling of zooplankton
The zooplankton rotifer B .plicatilis was raised in a 30-L polyethylene tank containing 15 L 0.22-µm filtered seawater (FSW) at a temperature of 25 ± 1°C under illumination of 120 μmol photons/m/s with a 14:10 h light/dark cycle.Chlorella sp. algal cells (with a final density of 105–106 cells/mL) at the exponential growth phase were used to feed the rotifer on a daily basis. One-third of the seawater in the tank was renewed each day.
The rotifers were fed14C-labeled algae Chlorella sp. (see details in Text S1) once per day as described above. One week later, the rotifers were considered to be uniformly labeled with 14C (12.9–28.4 Bq/µg C).