Since 2007, thorium-230 (230Th) concentrations decreased significantly over the entire water column, particularly between 300 and 1,500 m in the Amundsen Basin, Arctic Ocean. As is often the case with 230Th, this decrease could reflect either ventilation of 230Th-depleted water or removal of this particle reactive tracer by scavenging intensification. Valk and co-workers (2020, see reference below) demonstrate that the later hypothesis is likely explaining 230Th-depletion in intermediate layers of the Amundsen basin. They also hypothesize that the scavenging intensification occurs at the “source” and during the transport of these waters, along the Siberian shelves.
1. Valk, O., Rutgers van der Loeff, M. M., Geibert, W., Gdaniec, S., Moran, S. B., Lepore, K., Edwards, RL., Lu, Y., Puigcorbé, V., Casacuberta, N., Paffrath, R., Smethie, W. Roy-Barman, M. (2020). Decrease in 230Th in the Amundsen Basin since 2007: far-field effect of increased scavenging on the shelf? Ocean Science, 16(1), 221–234. DOI: https://doi.org/10.5194/os-16-221-2020
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