RT Journal Article SR Electronic T1 A Universal Phase Transition in Plankton Trait Dynamics JF bioRxiv FD Cold Spring Harbor Laboratory SP 679209 DO 10.1101/679209 A1 Jenny Held A1 Tom Lorimer A1 Ruedi Stoop A1 Francesco Pomati A1 Carlo Albert YR 2019 UL http://biorxiv.org/content/early/2019/06/24/679209.abstract AB Key ecological traits, like cell size, often follow scale-free or self-similar distributions. This indicates that these systems might operate near a critical (i.e. second-order) phase transition where macroscopic system behaviour is largely decoupled from microscopic system details, allowing an extremely simple, yet accurate and robust mathematical system characterisation. However, how trait-distribution scaling results from a critical transition has not yet been explicitly demonstrated. Here, we demonstrate that a generic class of cell growth and division models exhibits a critical transition from a growth-dominated to a division-dominated phase. We find experimental evidence for this transition, both in the population dynamics and in the moment scaling of chlorophyll distributions, for prokaryotic and eukaryotic phytoplankton growth under different light intensities. Our approach offers testable predictions of the response of unicellular trait-distributions to perturbations.