Fig. 7
The ISIP expression in metatranscriptome (MetaT) with respect to chlorophyll content. ISIPs in each Tara station were expressed as a percentage of the total value of ISIP1, ISIP2a, ISIP2b, and ISIP3 and normalized by the total diatom unigene expression, respectively. a Correlations between ISIPs expression in MetaT and chlorophyll content among various Tara stations. The station numbers are shown next to the circle and are colored according to the in situ measured iron concentration: red for 1.24–1.39 μmol iron/m3; orange for 0.98–1.13 μmol iron/m3; green for 0.13–0.30 μmol iron/m3; and blue for 0–0.05 μmol iron/m3. For Tara stations with in situ measured iron concentrations, the correlations between chlorophyll content and ISIP expression level were plotted in b, and c, d, and e follow suit. The Pearson correlation coefficients (Pearson r) and their statistical significance (p value) are indicated in each graph