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. 2016 Feb 4;7:10543. doi: 10.1038/ncomms10543

Figure 4. The inhibitory effects of Ge are dependent on the Ge/Si ratio.

Figure 4

(a) C. braarudii cells were treated with 0, 2, 5 or 20 μM Ge for 48 h in seawater containing 2 μM Si. Effects on coccolith morphology were determined by counting the mean number of discarded liths relative to the cell density. Specific growth rate (per day) and photosynthetic efficiency (the quantum yield of photosystem II, Fv/Fm) were also determined. *P<0.05 and **P<0.01 denote treatments that differ significantly from the 0 μM Ge control (one-way ANOVA with Holm–Sidak post hoc test, n=3). Error bars denote standard errors. (b) C. braarudii cells treated as in a but in seawater containing 20 μM Si. (c) C. braarudii cells treated as in a but in seawater containing 100 μM Si. Ge had a much lower impact on coccolithophore physiology at higher Si concentrations, suggesting that Ge acts competitively with Si.