Changes in marine fossilization conditions may explain a significant increase in diatoms--phytoplankton with silica shells--in the Cenozoic Era, according to a study. Diatoms are primary producers that became ecologically dominant during the Cenozoic Era, a development previously interpreted as representing a critical shift in the cycling of silica in the ocean. Sophie Westacott and colleagues built a model of the effect of sedimentation rate and ocean temperature on the burial efficiency of biogenic silica, using known Cenozoic marine conditions and assuming a constant population of diatoms over the past 66 million years. The results revealed that around 5-20 million years ago, biogenic silica preservation conditions improved, a trend that produced the observed increase in diatom abundance in the fossil record. According to the authors, the rise of grasslands and baleen whales, previously tied to diatoms' impact on the silica cycle, may have instead been caused by the same global cooling trend that drove diatom preservation.
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Article #21-03517: "Revisiting the sedimentary record of the rise of diatoms," by Sophie Westacott, Noah J. Planavsky, Ming-Yu Zhao, and Pincelli M. Hull.
MEDIA CONTACT: Sophie Westacott, Yale University, New Haven, CT; tel: 607-281-9502; email: < sophie.westacott@yale.edu >
Proceedings of the National Academy of Sciences