Comparison of growth rate, biovolume, cellular contents, elemental ratio and CO₂ fixation rate of <i>C. watsonii</i> WH8501 cultivated under Fe-replete conditions (numbers in brackets represent standard deviation).

*<p>during light period.</p

Influence of Fe availability on the elemental composition of <i>C. watsonii</i>.

<p>Mean cellular content of C (A), N (B) and Chl <i>a</i> (C) related to dFe and Fe′ concentrations, in log scale. Error bars represent standard deviation; different letters correspond to statistically different means (<i>p</i><0.05) and the black bar indicates the region of expected Fe hydroxide precipitation.</p

Influence of Fe availability on N₂ and CO₂ fixation rates of <i>C. watsonii</i>.

<p>(A) Relative N₂ fixation rates and (B) relative CO₂ fixation rates of <i>C. watsonii</i> related to dFe and Fe′ concentrations, in log scale. Open and filled symbols correspond to the rates per cell and V-normalized rates respectively. Error bars represent standard deviation; different letters and different numbers of star correspond to statistically different means (<i>p</i><0.05) for cellular and V-normalized rates, respectively. The black bar indicates the region of expected Fe hydroxide precipitation.</p

Growth rate of <i>C. watsonii</i> related to dFe and Fe′ concentrations.

<p>Error bars represent standard deviation; different letters correspond to statistically different means (<i>p</i><0.05) and the black bar indicates the region of expected Fe hydroxide precipitation. The Monod regression, performed with dFe concentrations, is represented by the black line and standard deviation of regression by dotted lines.</p

Influence of Fe availability on V-normalized contents.

<p>Mean V-normalized contents of C (A), N (B) and Chl <i>a</i> (C) of <i>C. watsonii</i> related to dFe and Fe′ concentrations, in log scale. Error bars represent standard deviation; different letters correspond to statistically different means (<i>p</i><0.05) and the black bar indicates the region of expected Fe hydroxide precipitation.</p

Influence of Fe availability on <i>C. watsonii</i> biovolume.

<p>Scanning electron microscopy photography of <i>C. watsonii</i> growing in (A) Fe-replete condition (dFe = 403.3 nM) and (B) severe Fe-limited condition (dFe = 3.3 nM). (C) Mean biovolume of <i>C. watsonii</i> related to dFe and Fe′ concentrations, in log scale. Error bars represent standard deviation; different letters correspond to statistically different means (<i>p</i><0.05) and the black bar indicates the region of expected Fe hydroxide precipitation.</p

Influence of dFe concentrations in the cultures on surface∶volume ratio, elemental ratios, cellular and volume-normalized N₂ and CO₂ fixation rates of <i>C. watsonii</i> WH8501 (numbers in brackets represent standard deviation).

<p>ND : No data.</p