1. (a) (c) (b) (d) (e) Supplemental Fig. 1 Supplemental Figure 1. Changes in intracellular (a) carbon, (b) nitrogen, and (c) phosphorus concentrations, and (d) surface area normalized silicon, and (e) intracellular chlorophyll-a concentrations of Thalassiosira weissflogii grown under different pCO 2 and iron conditions. Solid lines in (a), (b), (c), and (e) represents the regression between pCO 2 and intracellular C, N, P, and chlorophyll a concentrations, respectively. Statistics are shown in Tables 2 and 3.

2. (a) (c) (b) (d) (e) Supplemental Fig. 2 Supplemental Figure 2. Change in net (a) carbon, (b) nitrogen, (c) phosphorus, (d) silicon, and (e) chlorophyll-a production of Thalassiosira weissflogii grown under different pCO 2 and iron conditions. Solid lines in (b) and (c) represent the significant regression between pCO 2 and net N and P production, respectively. Statistics are shown in Tables 2 and 3.

3. RQ C RQ N RQ P RQ Si Supplemental Figure 3. Relative cell quota of carbon (RQ C ), nitrogen (RQ N ), phosphorus (RQ P ), and silicon (RQ Si ) between iron-limited and -replete conditions. Error bars represents the range of duplicate bottles. Supplemental Fig. 3