Geologic controls on phytoplankton elemental composition
Shlomit Sharoni, Itay Halevy
Abstract
Significance The elemental composition of marine phytoplankton reflects their quality as a food source and regulates the flow of carbon, oxygen, and nutrients between the ocean, atmosphere, and rock reservoirs. Despite this importance, no systematic estimate exists of the geologic history of phytoplankton elemental composition, which is often regarded to have been constant through time, limiting our understanding of evolutionary patterns and global biogeochemistry. Here, using a biogeochemical model forced by geologic and evolutionary events (e.g., the colonization of the continents by plants), we find that the nutrient content of phytoplankton has increased over the last 550 million y of Earth history. This increase in the organic matter nutrient content has likely been important for the evolution of marine fauna.