Using Lipidomics to Investigate the Predator–Prey Dynamics of Emiliania huxleyi and Oxyrrhis marina

Phytoplankton drive roughly half of Earth’s oxygen production and sit at the base of the marine food web, where single-celled protist grazers exert powerful control over their populations. For my master’s thesis, I used lipidomics — the large-scale study of an organism’s lipids — to explore the chemical dynamics between the coccolithophore Emiliania huxleyi (prey) and the dinoflagellate Oxyrrhis marina (predator). Using principal component analysis, PLS-DA, and presence/absence analysis in MetaboAnalyst, I identified lipid classes and individual lipid biomarkers linked to calcification state, ploidy level, and grazing stress. I found that E. huxleyi strains share a core lipidome but respond to grazing in strain-specific ways, and that O. marina’s lipid profile shifts predictably with feeding — including a striking wax-ester response to one poorly digestible prey strain. This work points to candidate biomarkers that could one day reveal the state of predation in wild ocean samples.