Marine biodiversification in response to evolving phytoplankton stoichiometry

Diversification of the marine biosphere is intimately linked to the evolution of the biogeochemical cycles of carbon, nutrients, and primary productivity. Analysis of the ratio of carbon-to-phosphorus buried in sedimentary rocks during the past 3 billion years indicates that both food quantity and, critically, food quality increased through time as a result of the evolving stoichiometry (nutrient content) of eukaryotic phytoplankton.