Dataset: Comparison of abundance-based growth rate predictions

See complete methodology in Franzè and Menden-Deuer, 2020.

Clonal cultures of Oxyrrhis marina (CCMP 3375), Gyrodinium dominans (SPMC 103), and Protoperidinium bipes were established from single-cell isolation. Herbivorous protists were acclimated to each target temperature before growth rates were measured. Due to the wide temperature range tested (0−22°C), cultures were moved from the initial temperature of 15°C through gradual transitions limited to at most 3°C. The experimental Day 0 (D0) was defined as the first day on which acclimated growth rates were measured. To determine predator and prey abundance, samples were preserved in acid Lugol at a 2% final concentration (Menden-Deuer et al. 2001) and enumerated using a Sedgewick-Rafter slide (1 ml volume) and a Nikon Eclipse E800 light microscope equipped with phase contrast. Herbivore biovolume was calculated based on linear dimensions obtained from ≥35 cells measured at each time point and temperature treatment using an image analysis system consisting of a high-resolution digital camera (Allied Vision, Stingray F45) and ImageJ software (version 1.5i).

Growth rates of the 3 herbivorous species were determined at 7 incubation temperatures: 0, 2, 5, 10, 15, 18, and 22°C. Changes in O. marina, G. dominans, and P. bipes abundance and biomass were determined over 24 h incubations of the triplicate 150 ml bottles and used to calculate growth rates (μ d−1) assuming exponential growth: μ = ln(Nt/N0)/t, where: N0 and Nt are the initial and final cell abundance (or biomass) respectively, and t is the experiment duration in days. Measurements were made at Day 0 and again after 10 and 30 days.