Decrease in 230Th in the Amundsen Basin since 2007: far-field effect of increased scavenging on the shelf? ...

• Main Authors: Valk, Ole, Rutgers van der Loeff, Michiel M., Geibert, Walter, Gdaniec, Sandra, Moran, S. Bradley, Lepore, Kate, Edwards, Robert L., Lu, Yanbin, Puigcorbé, Viena, Casacuberta, Núria, Paffrath, Ronja, Smethie, William, Roy-Barman, Matthieu
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2020
• Subjects: amundsen basin; Arctic; Arctic Ocean
• Online Access: https://dx.doi.org/10.3929/ethz-b-000402040; http://hdl.handle.net/20.500.11850/402040

This study provides dissolved and particulate 230Th and 232Th results as well as particulate 234Th data collected during expeditions to the central Arctic Ocean (GEOTRACES, an international project to identify processes and quantify fluxes that control the distributions of trace elements; sections GN04 and GIPY11). Constructing a time series of dissolved 230Th from 1991 to 2015 enables the identification of processes that control the temporal development of 230Th distributions in the Amundsen Basin. After 2007, 230Th concentrations decreased significantly over the entire water column, particularly between 300 and 1500 m. This decrease is accompanied by a circulation change, evidenced by a concomitant increase in salinity. A potentially increased inflow of water of Atlantic origin with low dissolved 230Th concentrations leads to the observed depletion in dissolved 230Th in the central Arctic. Because atmospherically derived tracers (chlorofluorocarbon (CFC), sulfur hexafluoride (SF6)) do not reveal an ... : Ocean Science, 16 (1) ...