Open AccessNd isotopic constraints on the origin of suspended particles in the Atlantic Sector of the Southern Ocean
Author(s) -
Hegner E.,
Dauelsberg H. J.,
Rutgers van der Loeff M. M.,
Jeandel C.,
de Baar H. J. W.
Publication year - 2007
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2007gc001666
Subject(s) - polar front , oceanography , geology , geotraces , circumpolar star , terrigenous sediment , circumpolar deep water , detritus , peninsula , thermohaline circulation , front (military) , antarctic intermediate water , antarctic bottom water , ocean current , phytoplankton , north atlantic deep water , seawater , geochemistry , sedimentary rock , nutrient , paleontology , geography , archaeology , chemistry , organic chemistry
In the nutrient‐rich Southern Ocean, Fe is a vital constituent controlling the growth of phytoplankton. Despite much effort, the origin and transport of Fe to the oceans are not well understood. In this study we address the issue with geochemical data and Nd isotopic compositions of suspended particle samples collected from 1997 to 1999 in the South Atlantic Sector of the Southern Ocean. Al, Th, and rare earth element (REE) concentrations as well as 143 Nd/ 144 Nd isotopic ratios in acetic acid‐leached particle samples representing the lithogenic fraction delineate three major sources: (1) Patagonia and the Antarctic Peninsula provide material with ɛ Nd > −4 that is transported toward the east with the polar and subpolar front jets, (2) the south African shelf, although its influence is limited by the circumpolar circulation and wind direction, can account for material with ɛ Nd of −12 to −14 adjacent to South Africa, and (3) East Antarctica provides material with ɛ Nd of −10 to −15 to the eastern Weddell Sea and adjacent Antarctic Circumpolar Current. For this region we interpret the Nd isotopic evidence in combination with oceanographic/atmospheric constraints as evidence for supply of significant amounts of terrigenous detritus by icebergs.