Errata and re-visitation of “What is the limit for photoautotrophic plankton growth rates?” (Flynn and Raven, 2017)

Abstract

Abstract An error in our original work prompts a revisitation of factors constraining photoautotrophic plankton growth rates (μmax). Ribulose-1,5-bisphosphate Carboxylase-Oxygenase does not itself provide that constraint, but we identify other factors that result in our previously suggested value of ~2 doublings per day still likely being representative of the maximum for most photoautotrophs. μmax likely evolves to balance the advantage of possessing a high competitive value while minimizing the stresses incurred when the organism is incapable of routinely achieving a higher μmax due to various limiting factors. Organisms with extreme high μmax are thus expected to grow under conditions that provide the necessary environment (stable pH, non-limiting nutrients and light) for sufficient time that the evolution of higher μmax becomes advantageous. Conditions in nature allowing the evolution of higher μmax include the exploitation of an exceptional opportunity and then entering stasis (e.g. desert microalgae), or a situation where high grazing pressures match high phytoplankton growth, thus maintaining non-limiting nutrient and light conditions. The latter, however, conflicts with the paradox of enrichment, as only under resource limitation would the necessary stability be attained in the predator–prey dynamic. Ultimately, ecology, not biophysics, constrains phototroph μmax.