Rare earth elements oceanic distributions

Tachikawa K., Jeandel C., and Dupre B. (1997) Distribution of rare earth elements and neodymium isotopes in settling particulate material of the tropical Atlantic Ocean (EUMELl site). Deep-Sea Res. I Oceanogr. Res. Pap. 44(11), 1769-1792. 

Although the oceanic distributions of rare earth elements somewhat resemble those of nutrients, their behaviors are clearly different in that they are not actively taken up by photoplankton but passively scavenged by particles. Elemental reactivity with suspended particles, which controls, together with sinking of particle aggregates, the mean oceanic residence times of not only REEs but also a number... 

The distribution of ruthenium and rhodium traces in the ocean has been investigated by RIS -VETA. Both elements are rare and their distribution is of great geological and geochemical importance. The abundance of Ru and Rh in the Earth s crust is estimated to be 1-100 pg/g and can not be directly measured by current analytical techniques. The fire assay method and concentration by polymer sorbents were used prior to RIS analysis. Concentrations of Ru varied from 1.3 pg/mL in ocean water to 7.6 ng/g in Red Sea sediments. Concentrations of Rh in ocean water were 3- lOpg/mL. 

Table 19.1 shows the distribution of elements in the earth s crust, oceans, and atmosphere. The major element is, of course, oxygen, which is found in the atmosphere as O2, in the oceans in H2O, and in the earth s crust primarily in silicate and carbonate minerals. The second most abundant element, silicon, is found throughout the earth s crust in the silica and silicate minerals that form the basis of most sand, rocks, and soil. The most abundant metals, aluminum and iron, are found in ores in which they are combined with nonmetals, most commonly oxygen. One notable fact revealed by Table 19.1 is the small incidence of most transition metals. Since many of these relatively rare elements are assuming... 

---