Work

Cerium occurs as cerium-phosphate clusters around bioapatite nanocrystals in deep-sea sediments

Year: 2025

Type: article

Abstract: Deep-sea mud is rich in rare-earth elements, primarily found in fluorapatite, a mineral deposit that forms over hundreds of thousands to millions of years through the accumulation of fish remains. After fish die, biogenic apatite captures rare earth elements from seawater on the seafloor and from pore waters during the diagenesis process. The conventional model for rare earth element enrichment suggests that they are incorporated into the bioapatite crystal structure through solid-state diffusion. However, our data reveal that cerium atoms are instead precipitated within an amorphous layer surrounding bioapatite nanocrystals, as shown by high-energy-resolution X-ray absorption spectroscopy and transmission electron microscopy. Computational simulations further support this finding, predicting that cerium atoms cluster on the surface of fluorapatite. These results suggest that the fluorapatite-water interface plays a crucial role in the enrichment of cerium, as well as other rare earth elements, in marine sediments. Cerium atoms are not incorporated into the crystal structure of bioapatites as host grains, but precipitate on the surface, according to high-energy-resolution X-Ray absorption spectroscopy data from bioapatites of fish bones and teeth recovered in deep-sea sediments, and computational simulations.

Source: Communications Earth & Environment

DOI: 10.1038/s43247-025-02439-2