Growth rates of six coccolithophorid strains as a function of temperature

We determined growth rates of six coccolithophorid strains (five species) as a function of temperature. We grew four strains (three species: Emiliania huxleyi, Gephyrocapsa oceanica, and two strains of Calcidiscus leptoporus) at six temperatures between 6 degrees C and 25 degrees C, Coccolithus braarudii at four temperatures, and Syracosphaera pulchra at two temperatures. The growth rates were to a large extent consistent with the biogeographical distributions of these species. C. braarudii grows relatively fast at low temperatures, the two strains of C. leptoporus have temperature optima of 12 degrees C and 20 degrees C, E. huxleyi has an optimum at 20 degrees C, and the growth rate of G. oceanica (and S. pulchra) increases up to the highest tested temperature of 25 degrees C. This shows that maximum growth rate is an important factor in controlling distribution in the ocean, but it is not the only one.