Data and code from: Growth strategies of a model picoplankter depend on social milieu and pCO2

<p><span><span><span><span><span><span><span><span><span><span><span>Aquatic microbial primary producers exist in genetically diverse populations, but are often studied as single lineages, so that interpreting single lineage studies relies critically on understanding how microbial growth differs with social milieu. The properties of lineages grown alone often fail to predict the growth of these same lineages in the presence of conspecifics, and this discrepancy points towards an opportunity to improve our understanding of how multilineage assemblages of a species are shaped. We demonstrate that different lineages of a marine picoplankter modulate their lineage growth rate in response to the presence of non-self conspecifics, even when resource competition is effectively absent. This explains why growth rates of lineages in isolation do not reliably predict their growth rates in mixed culture, or the lineage composition of assemblages. The diversity of growth strategies observed are thus consistent with lineage-specific energy-allocation that depends on social milieu. Since lineage growth is only one of many traits determining fitness in natural assemblages, we propose that in all but the poorest quality environments where allocating maximum energy to growth is the only viable strategy, we should expect intraspecific variation in growth strategies, with more strategies possible in ameliorated environments, such as high CO₂ for many marine picoplankton. </span></span></span></span></span></span></span></span></span></span></span></p>