(Table 2) Annual mass fluxes, 230Th composition and organic geochemistry of sediment trap samples in the South Altantic, supplement to: Walter, Hans-Jürgen; Geibert, Walter; Rutgers van der Loeff, Michiel M; Fischer, Gerhard; Bathmann, Ulrich (2001): Shallow vs. deep-water scavenging of 231Pa and 230Th in radionuclide enriched waters of the Atlantic sector of the Southern Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 48(2), 471-493

DOI

The scavenging of 231Pa and 230Th was investigated in the Atlantic Sector of the Southern Ocean by combining results from sediment trap and in situ filtration studies. We present the first high-resolution profile of dissolved 230Th and 231Pa in surface waters across the ACC, showing a dramatic southward increase of both radionuclides around the southern ACC Front at 533S. High dissolved 231Pa/230Th ratios combined with low 230Th/231Pa fractionation factors (F) in these surface waters result in extremely high 231Pa94/230Th94 ratios of material collected in the shallow traps. Particulate 231Pa94/230Th94 ratios in a shallow trap near Bouvet Island increase continuously during the productive period in austral summer, and drop back in the low flux period. This behavior, following the Rayleigh fractionation principle, is interpreted to be due to an increase in the dissolved 231Pa/230Th ratio in the euphotic zone resulting from preferential scavenging of 230Th relative to 231Pa, even in opal-dominated regions. In the post-bloom stage, the depleted radionuclide concentrations are replenished by upwelling of Circumpolar Deep Water. The high particulate 231Pa94/230Th94 signal is weakened during downward transport of the bloom particles in the water column by incorporation of deep suspended particles, which have a lower 231Pa94/230Th94 ratio. It is shown that under the special hydrographic conditions in the Southern Ocean scavenging from the upper water column significantly influences the budgets of 230Th and 231Pa in the sediment. Nevertheless, the budgets are still made up primarily by scavenging from the large standing stock of deep suspended particles.

Identifier
DOI https://doi.org/10.1594/PANGAEA.57910
Related Identifier https://doi.org/10.1016/S0967-0637(00)00046-7
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.57910
Provenance
Creator Walter, Hans-Jürgen; Rutgers van der Loeff, Michiel M
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2001
Funding Reference Fourth Framework Programme
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Size 231 data points
Discipline Earth System Research
Spatial Coverage (-57.528W, -65.605S, 5.833E, -50.127N); Weddell Sea; Bouvet Island, Southern Ocean (Atlantic sector); Polar Front
Temporal Coverage Begin 1983-12-01T00:00:00Z
Temporal Coverage End 1992-05-15T00:00:00Z