Hydrogen isotope fractionation in lipids as a function of growth rate in E. huxleyi chemostat cultures.

(A) Fractionation factors (α) decreased, indicating greater 2H/1H fractionation between lipids and extracellular water, as growth rates increased by 44‰ (div d-1)-1 for brassicasterol, and 79‰ (div d-1)-1 for myristic acid (C14:0), 52‰ (div d-1)-1 for palmitic (C16:0), and 32‰ (div d-1)-1 for stearic acid (C18:0). (B) Fractionation factors (α) decreased, indicating greater 2H/1H fractionation between alkenones and extracellular water, as growth rates increased by 38‰ (div d-1)-1 for C37:2, and 25‰ (div d-1)-1 for C37:3, 24‰ (div d-1)-1 for C38:2, and 33‰ (div d-1)-1 for C38:3.