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

• Main Authors: Tang, Yi, Castrillejo, Maxi, Roca-Marti, Montserrat, Masqué, Pere, Lemaitre, Nolwenn, Stewart, Gillian
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2018
• Subjects: North Atlantic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000295319; http://hdl.handle.net/20.500.11850/295319

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 100m, and it was closer to unity in the mesopelagic (100–1000m). 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 (1–53µm) and large ( > 53µm) 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 ... : Biogeosciences, 15 (17) ...