Fightoplankton: A low-cost automatic sampler for the study of phytoplankton cell cycle

The latitudinal shift in phytoplankton range due to climate change can have important repercussions for bloom dynamics and assemblages. The effect of seasonal variations in day lengths on the growth and division of phytoplankton is little known. This study investigates how growth and division in a tropical strain of Picochlorum sp., responds to varying light regimes using high resolution sampling data collected through the creation of a low-cost automatic water sampler – the Fightoplankton. The automatic sampler was designed to sample cultures at regular user-programmed intervals, store samples at 4°C in the dark, and prevent cross contamination through purging systems. Three experimental conditions of 16:8, 12:12, and 8:16 light:dark cycles were set up with at least three replicates per group. Each culture was maintained for a period of 4 - 7 days and sampled hourly over a period of 24 h. Cellular parameters were analysed through flow cytometry and processed using R. The results of this study indicate that the timing of division is unaffected by light regime conditions, but that growth is coupled directly to light availability. Validation of the Fightoplankton’s sampling accuracy and preservation of samples at 4°C suggests that low-cost do-it-yourself equipment could help research in this field. In this study alone, over 200 manhours were saved through the use of the Fightoplankton.