Distributions of total and size-fractionated particulate 210Po and 210Pb activities along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise

Type Article
Date 2018-09
Language English
Author(s) Tang Yi1, 2, Castrillejo Maxi3, 4, Roca-Martí Montserrat3, Masqué Pere3, 5, Lemaitre Nolwenn6, Stewart Gillian1, 2
Affiliation(s) 1 : Earth and Environmental Sciences, the Graduate Center, City University of New York, New York, USA
2 : School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, USA
3 : Institut de Ciència i Tecnologia Ambientals & Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
4 : Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, Zürich, 8093, Switzerland
5 : School of Science and Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, Western Australia, Australia
6 : Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH Zurich, Zürich, Switzerland
Source Biogeosciences (1726-4170) (Copernicus GmbH), 2018-09 , Vol. 15 , N. 17 , P. 5437-5453
DOI 10.5194/bg-15-5437-2018
WOS© Times Cited 11
Note Special issue GEOVIDE, an international GEOTRACES study along the OVIDE section in the North Atlantic and in the Labrador Sea (GA01)
Abstract

Vertical distributions of total and particulate polonium-210 (210Po) and lead-210 (210Pb) activities in the water column were measured at 11 stations in the North Atlantic during the GEOTRACES GA01 transect: GEOVIDE cruise in May–June 2014. Total 210Po activity was on average 24 % lower than 210Pb activity in the upper 100 m, and it was closer to unity in the mesopelagic (100–1000 m). The partitioning coefficients (Kd) along the transect suggest the preferential association of 210Po relative to 210Pb onto particles. The prominent role of small particles in sorption was confirmed by the observation that over 80 % of the particulate radionuclide activity was on small particles. To account for the observed surface water 210Po ∕ 210Pb disequilibria, particulate radionuclide activities and export of both small (1–53 µm) and large (>53 µm) particles must be considered. A comparison between the GEOVIDE total particulate 210Po ∕ 210Pb activity ratios (ARs) and the ratios in previous studies revealed a distinct geographic distribution, with lower particulate ARs in the high-latitude North Atlantic (including this study) and Arctic in relation to all other samples. For the samples where apparent oxygen utilization (AOU) was calculated at the same depth and time as the 210Po ∕ 210Pb AR (40 stations including this study), there was a two-phase correlation between the total particulate AR and AOU, likely reflecting the nature of the particles and demonstrating the forces of remineralization and radionuclide decay from particles as they age.

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How to cite 

Tang Yi, Castrillejo Maxi, Roca-Martí Montserrat, Masqué Pere, Lemaitre Nolwenn, Stewart Gillian (2018). Distributions of total and size-fractionated particulate 210Po and 210Pb activities along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise. Biogeosciences, 15(17), 5437-5453. Publisher's official version : https://doi.org/10.5194/bg-15-5437-2018 , Open Access version : https://archimer.ifremer.fr/doc/00485/59671/