Earth’s eccentric orbit paced the evolution of marine phytoplankton

Variations in Earth’s orbit might help to determine the evolution of marine phytoplankton. Researchers analysed fossils of coccolithophores that lived in the Pleistocene period (from 2.6 million to 11,700 years ago) alongside deviations in the circularity of Earth’s annual orbit, which cycles approximately every 100,000 and 400,000 years. They found that the diversity of plankton species increased during periods of high eccentricity of Earth’s orbit, when the seasons vary more in equatorial regions.