Digital Action of Diatom Biological Pump II: Metal silicate complex in seawater and theory for the incorporation of REEs in diatom opal, to explain REE distribution in oceans.

Abstract

Despite diatoms contributing most to primary production, the role of diatom opal has not been considered in the circulation of trace elements due to the difficulty in determining their original composition. Rare earth element (REE) composition of original diatoms was for the first time estimated by applying a dissolution kinetics model to settling particles in an area of extremely high diatom productivity. The estimated concentration of REEs in diatom opal was much lower than that in terrigenous matter, but released sufficient REEs to explain the observed concentration increase in deep water. This study elucidates the hitherto unexplained significant surface concentration of REEs by attributing it to REE-silicic acid complex formation.