Fig. 1: Overview of the initial conditions for the four experiments (E1–E4). | Nature Communications

Fig. 1: Overview of the initial conditions for the four experiments (E1–E4).

From: Short-term acidification promotes diverse iron acquisition and conservation mechanisms in upwelling-associated phytoplankton

Fig. 1: Overview of the initial conditions for the four experiments (E1–E4).The alt text for this image may have been generated using AI.

a Map of experiment locations with satellite-derived chlorophyll a. The chlorophyll a data was obtained from the NOAA Coastwatch Browser as a 14-day average centered on August 22, 2020 which falls between Experiments 2 and 3 (Table 1). b Dissolved iron concentrations (dFe, nmol L−1). Nitrate (NO3, µmol L−1) to dissolved iron (dFe, nmol L−1) ratios (c) before and (d) after macronutrient addition at the start of each experiment. The horizontal dashed line indicates the threshold for potential iron limitation (8 µmol:nmol)53,122. Ratios were derived and standard deviations were propagated from the average values of field replicates presented in Figs. 1a and 2a. e Siex proxy for diatom iron limitation within each experimental treatment. Initial time point (T0) values reflect the Siex value following macronutrient addition. Negative values indicate iron stress or limitation due to preferential uptake of silicic acid (H4SiO4) relative to nitrate (NO3)53,122. Error bars represent the standard deviation of the mean (n = 3 biologically independent samples or field replicate samples for T0). For dissolved iron concentrations at Experiments 1 and 4 and macronutrient data at T0 of Experiment 2, n = 2.

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