Dissolved rare earth elements in the Southern Ocean: Cerium oxidation and the influence of hydrography

• Published in: Geochimica et cosmochimica acta 1995-04, Vol.59 (8), p.1551-1558
• Main Authors: German, C.R., Masuzawa, T., Greaves, M.J., Elderfield, H., Edmond, J.M.
• Format: Article
• Language: English
• ISSN: 0016-7037; 1872-9533
• DOI: 10.1016/0016-7037(95)00061-4

Analysis of dissolved REE distributions in the southeastern Atlantic Ocean has revealed that progressive oxidative removal of dissolved Ce from deepwater ( >1 km) occurs over the mixing time of the oceans. Ce-anomaly (Ce/Ce∗) values measured in deep-waters from the southeastern Atlantic are similar to, but slightly higher than, those from deep-ocean stations throughout the Indian and Pacific oceans, typically falling in the range 0.08Ce ≤ Ce∗ ≤ 0.12. Only deepwater samples from the North Atlantic exhibit values greater than Ce/Ce ∗ ∼ 0.12, with the exception of southeastern Atlantic bottomwaters which are influenced by Antarctic Bottomwater. Covariation of dissolved REE concentrations with salinity and/or dissolved Si concentrations at this site has allowed dissolved REE compositions for various Southern Ocean water masses to be predicted. End-member concentrations for Antarctic Bottom Water (AABW) derived in this way indicate high dissolved REE concentrations, similar to average Pacific Deep Water, but with significantly enhanced dissolved Ce concentrations and less pronounced HREE enrichment. This result is consistent with the proximity of our study site to active AABW deepwater formation and evolution of that water mass during transport to the Pacific Ocean.