Fig. 3: Temporal evolution of the pH and Mg (µM), Si (µM), and Fe (µM) concentration and the Mg/Si and Fe/Si concentration ratios of the olivine dissolution experiments.

a The pH remained stable during the experiment and was slightly lower for the melanin-deficient Δpks1 and Δpks1/Δphd1 mutants at the end of the experiment. b, c The Mg and Si concentrations (µM) increased during the experiment and were highest for the Δsdh1 mutant. d The Fe concentration (µM) increased for the Δsdh1, Δpks1, and Δpks1/Δphd1 mutants and was highest for the former. The Fe concentration of the WT, Δphd1 mutant, and abiotic control was lower and stayed constant during the experiment. e Stoichiometric dissolution is illustrated by the dotted line at Mg/Si = 1.856: all set-ups showed a stoichiometric Mg/Si release. f For Fe/Si, stoichiometric dissolution is not shown, lying at Fe/Si = 0.1726. Fe/Si release was far below this ratio for all set-ups, indicating the removal of Fe from the solution. However, the Δsdh1, Δpks1, and Δpks1/Δphd1 mutants had significantly higher Fe/Si ratios than the abiotic control, WT, and Δphd1 mutant, indicating their ability to keep iron in solution. Error bars represent either twice the analytical uncertainty or twice the standard error of three biological replicates, whichever was highest. For the concentration ratios, they represent twice the combined propagated uncertainties of either Mg and Si (for Mg/Si) or Fe and Si (for Fe/Si). If the error bars are not visible they are smaller than the symbol.