Biogeochemistry of the rare-earth elements in aquatic macrophytes of Linsley Pond,North Branford,Connecticut

Aquatic plants, water, lake mud, soils and rocks from Linsley Pond were analyzed for all the naturally occurring elements of the periodic table which could be detected by optical and X-ray emission spectroscopy. In the course of this study, it was noted that all the rare earths of even atomic number were detected; of the odd-numbered members of the group only La and Pr were found. The others were presumably present in amounts below detection. These elements relative to their concentration in the soils and rocks of the basin are absorbed by plants, giving an enrichment of about one hundred fold relative to Al on a dry weight basis. Samarium is present in excess of Nd in the rooted emergent plants but not in the submerged rooted or rootless ones. There is some suggestion of a fractionation of the rare earths in different parts of the plants. A comparison of the relative accumulation of trace elements with their content in the sediment suggests that Y, La, Ce, Pr, Sm, Dy, Er and Yb may be essential trace elements.