Radium 228 and Radium 226 in surface water of the Kara Sea and Laptev Sea, supplement to: Rutgers van der Loeff, Michiel M; Kühne, Stephan; Wahsner, Monika; Höltzen, Heike; Frank, Markus; Ekwurzel, Brenda; Mensch, Manfred; Rachold, Volker (2003): 228Ra and 226Ra in the Kara and Laptev seas. Continental Shelf Research, 23(1), 113-124

• Main Authors: Rutgers van der Loeff, Michiel M, Kühne, Stephan, Wahsner, Monika, Höltzen, Heike, Frank, Markus, Ekwurzel, Brenda, Mensch, Manfred, Rachold, Volker
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2003
• Subjects: Event label; Latitude of event; Longitude of event; Elevation of event; DEPTH, water; Salinity; Radium-226; Radium-226, standard deviation; Radium-228; Radium-228, standard deviation; Radium-228/Radium-226 activity ratio; Radium-228/Radium-226 activity ratio, standard deviation; δ18O, water; δ18O, standard deviation; River water percentage; Sampling by hand; Box corer; van Veen Grab; Water sample; Kasten corer RUS; Multiple investigations; Calculated; Gamma-ray spectrometry; Isotope ratio mass spectrometry; RU-Land_1999_Lena; DM49; ARK-IX/4; AWI Arctic Land Expedition; Dmitry Mendeleev; Polarstern; Laptev Sea System LSS; Marine Geochemistry @ AWI AWI_MarGeoChem; Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo; Permafrost Research Periglacial Dynamics @ AWI AWI_PerDyn; Quaternary Environment of the Eurasian North QUEEN; Arctic; Arctic Ocean; Kara Sea; Laptev Sea; Rus’; Van Veen; Yenisey; Baydaratskaya bay; laptev; permafrost
• Online Access: https://dx.doi.org/10.1594/pangaea.60021; https://doi.pangaea.de/10.1594/PANGAEA.60021

The surface water in the Transpolar Drift in the Arctic Ocean has a strong signature of 228Ra. In an earlier study of 228Ra in the open Arctic we showed that the major 228Ra source had to be in the Siberian shelf seas, but only a single shelf station was published so far. Here we investigate the sources of this signal on the Siberian shelves by measurements of 228Ra and 226Ra in surface waters of the Kara and Laptev Sea, including the Ob, Yenisey and Lena estuaries.In the Ob and Lena rivers we found an indication for a very strong and unexpected removal of both isotopes in the early stage of estuarine mixing, presumably related to flocculation of organic-rich material. Whereas 226Ra behaves conservatively on the shelf, the distribution of 228Ra is governed by large inputs on the shelves, although sources are highly variable. In the Kara Sea the maximum activity was found in the Baydaratskaya Bay, where tidal resonance and low freshwater supply favour 228Ra accumulation. The Laptev Sea is a stronger source for 228Ra than the Kara Sea. Since a large part of Kara Sea water flows through the Laptev Sea, the 228Ra signal in the Transpolar Drift can be described as originating on the Laptev shelf.The combined freshwater inputs from the Eurasian shelves thus produce a common radium signature with a 228Ra/226Ra activity ratio of 4.0 at 20% river water. The radium signals of the individual Siberian rivers and shelves cannot be separated, but their signal is significantly different from the signal produced on the Canadian shelf (Smith et al., in press). In this respect, the radium tracers add to the information given by Barium. Moreover, with the 5.8 year half-life of 228Ra, they have the potential to serve as a tracer for the age of a water mass since its contact with the shelves.