Radium inputs into the Arctic Ocean from rivers: a basin-wide estimate

Radium isotopes have been used to trace nutrient, carbon, and trace metal fluxes inputs from ocean margins. However, these approaches require a full accounting of radium sources to the coastal ocean including rivers. Here, we aim to quantify river radium inputs into the Arctic Ocean for the first ti...

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Bibliographic Details
Published in:Journal of Geophysical Research: Oceans
Main Authors: Bullock, Emma J., Kipp, Lauren, Moore, Willard, Brown, Kristina Brown, Mann, Paul, Vonk, Jorien E., Zimov, Nikita, Charette, Matthew A.
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2022
Subjects:
F700 Ocean Sciences
Arctic
Arctic Ocean
Climate change
Ice
permafrost
Online Access:https://nrl.northumbria.ac.uk/id/eprint/50000/
https://doi.org/10.1029/2022JC018964
https://nrl.northumbria.ac.uk/id/eprint/50000/9/JGR%20Oceans%20-%202022%20-%20Bullock%20-%20Radium%20Inputs%20Into%20the%20Arctic%20Ocean%20From%20Rivers%20%20A%20Basin%E2%80%90Wide%20Estimate.pdf
https://nrl.northumbria.ac.uk/id/eprint/50000/1/937430_1_merged_1660833012.pdf
Description
Summary:Radium isotopes have been used to trace nutrient, carbon, and trace metal fluxes inputs from ocean margins. However, these approaches require a full accounting of radium sources to the coastal ocean including rivers. Here, we aim to quantify river radium inputs into the Arctic Ocean for the first time for 226Ra and to refine the estimates for 228Ra. Using new and existing data, we find that the estimated combined (dissolved plus desorbed) annual 226Ra and 228Ra fluxes to the Arctic Ocean are 7.0 – 9.4 x 1014 dpm y-1 and 15-18 x 1014 dpm y-1, respectively. Of these totals, 44% and 60% of the river 226Ra and 228Ra, respectively are from suspended sediment desorption, which were estimated from laboratory incubation experiments. Using Ra isotope data from 20 major rivers around the world, we derived global annual 226Ra and 228Ra fluxes of 7.4 – 17 x 1015 and 15 – 27 x 1015 dpm y-1, respectively. As climate change spurs rapid Arctic warming, hydrological cycles are intensifying and coastal ice cover and permafrost are diminishing. These river radium inputs to the Arctic Ocean will serve as a valuable baseline as we attempt to understand the changes that warming temperatures are having on fluxes of biogeochemically important elements to the Arctic coastal zone.

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