Fig. 3: Viral induced bloom demise changes the composition of organic matter recyclers.
a Analysis of predicted eukaryotic traits plotted per phase of the E. huxleyi bloom. Relative abundance of autotrophy, mixotrophy, and heterotrophy, defined through literature search (left). Trophic modes within heterotrophy, as defined by72 (right). b Absolute abundance of thraustochytrids throughout the mesocosm experiment on the 2–20 μm size fraction, measured by ddPCR. Points and error bars show the mean and standard deviation across n = 3 replicates. c Thraustochytrid to bacteria biomass ratios throughout the experiment duration (see Methods and Supplementary Data 1–4 for detailed calculation). d Correlation between total viral load and growth rate during demise phase of thraustochytrids (2–20 μm) and bacteria (for the free-living fraction measured by flow-cytometry and for 2–20 μm fraction measured by qPCR). Symbols indicate the mean, error bars the standard deviation between parameters obtained from n = 3 fits with shifted (by ±0.5 days) start times. e Exponential rate of change of the biomass ratio of thraustochytrids to bacteria (combining biomasses from free-living and 2–20 μm size fraction) plotted as a function of total viral load, per bag (see Methods). Symbols and error bars represent the mean and standard error for parameter estimates of the nonlinear fits in (c). f Concentration of thraustochytrids measured by ddPCR, E. huxleyi cells measured by qPCR, and bacterial production using leucine incorporation46, in three phases of an open ocean E. huxleyi bloom infection. Transparent symbols are individual measurements; bars, solid, and error bars represent means and standard error of n = 4 samples (n = 2 for second “early” phase of infection). Source data are provided as a Source Data file.
