Fig. 2: Phycosphere pH of marine diatoms Coscinodiscus wailesii CCAP 1013/9 (~50 µm radius). | The ISME Journal

Fig. 2: Phycosphere pH of marine diatoms Coscinodiscus wailesii CCAP 1013/9 (~50 µm radius).

From: Phycosphere pH of unicellular nano- and micro- phytoplankton cells and consequences for iron speciation

Fig. 2: Phycosphere pH of marine diatoms Coscinodiscus wailesii CCAP 1013/9 (~50 µm radius).

a A photo of C. wailesii and the arrows showing the measurement positions which correspond to the letters given in the b. b The measured pH at different surface sites of an illuminated diatom. Bulk seawater pH = 7.76, HCO3− = 0.4 mM. c The pH changes when the pH probe was approaching or moving away from an illuminated cell. Bulk seawater pH = 7.97. d pH at different distances from an illuminated cell. The numbers alongside the dots indicate the distance to the cell (µm). Bulk seawater pH = 8.00. e The decrease of H+ concentration in the phycosphere (i.e. pH increase) at seawater pH 7.78 was significantly higher than that at bulk pH = 8.10 (n = 53–71, p = 0.000) while the difference in ΔH+ of the phycosphere between seawater 8.40 and 8.10 was insignificant (n = 47–53, p = 0.920). f The thickness of the pH boundary layer at seawater pH 7.78 was significantly larger than that at bulk pH 8.00 (n = 2, p = 0.014).

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