The geological story of marine diatoms and the last generation of fossil fuels
Abstract The analysis of the sedimentary record enables to reconstruct the evolutionary history of marine diatoms and evaluate their significance as a sink for atmospheric carbon dioxide. Here I analyze the timing and causes that led marine diatoms to become one of the most prominent primary producers on Earth today. Enhanced continental weathering and the ensuing ocean fertilization facilitated the ecological success of diatoms in marine ecosystems over the last 40 million years and gave rise to the last generation of marine fossil fuels. The rise of diatoms to ecological prominence occurred at the expense of calcareous phytoplankton, chiefly coccolithophores. This evolutionary change decreased the biological coupling of organic and inorganic carbon burial fluxes, and increased the role of organic productivity in the removal of carbon from Earth’ surficial reservoirs. The extent to which marine diatoms contributed to reduce atmospheric carbon dioxide levels deserves further investigation.