Environmental changes in the Arctic Ocean are occurring now!

This is what reveals the first full transarctic section of radium-228 (228Ra) in surface waters measured during Arctic cruises along GEOTRACES transects GN04 (cruise PS94) and GN01 (cruise HLY1502) proposed by Rutgers van der Loeff and colleagues (2018, see reference below). 228Ra activities in the central Arctic have increased from 2007 through 2011 to 2015 (Kipp, et al. 2018), reflecting increased 228Ra input attributed to stronger wave action on shelves resulting from a longer ice-free season (in other words to climate change). However, the authors are going further, associating thorium-228, iodine-129, SF6, thorium-234 and polonium-210 data to their own Ra results to better disentangle the vertical (mostly biogenic) from the advected fluxes. They estimate a ventilation time of 480 years for the deep Makarov-Canada Basin, in good agreement with previous estimates using other tracers.

18 RutgersFigure: Two GEOTRACES expeditions in 2015 provided together a full section across the Arctic Ocean, crossing in surface waters the Transpolar Drift (TPD) identified by the high fraction of river water derived from Siberian rivers. 228Ra is added to the TPD from the sediments on the wide Siberian shelves. 228Ra data in surface waters measured on Healy (GN01, blue) and Polarstern (GN04, red) are in good agreement and show that 228Ra in the TPD has about doubled since earlier sections in 2011 (black circles, track in black) and 2007 (GIPY11, black squares, track not shown). Click here to view the figure larger.


Rutgers van der Loeff, M., Kipp, L., Charette, M. A., Moore, W. S., Black, E., Stimac, I., Charkin, A., Bauch, D., Valk, O., Karcher, M., Krumpen, T., Casacuberta, N., Rember, R. (2018). Radium Isotopes Across the Arctic Ocean Show Time Scales of Water Mass Ventilation and Increasing Shelf Inputs. Journal of Geophysical Research: Oceans, 123(7), 4853–4873. DOI : http://doi.org/10.1029/2018JC013888

Kipp, L.E., Charette, M.A., Moore, W.S., Henderson, P.B., Rigor, I.G., 2018. Increased fluxes of shelf-derived materials to the central Arctic Ocean. Science Advances 4, DOI: http://dx.doi.org/10.1126/sciadv.aao1302

You can also read the EOS.org magazine Editors’ highlight “Increased Release Rates of Radium Isotopes on Arctic Shelves”: https://eos.org/editor-highlights/increased-release-rates-of-radium-isotopes-on-arctic-shelves

Latest highlights

Science Highlights

Icebergs as sources of trace metals to the ocean: which impact?

Earth’s Ice Sheets are known to release significant quantities of lithogenic particles into the ocean every year, but how does this material affect trace metal availability in the ocean?


Science Highlights

Microbial trace metal trafficking on marine particles

This study provides evidence for the processing of nine particulate trace metals in multiple manners by diverse microbial communities.


Science Highlights

Volcanic emissions in the Southern Ocean: an efficient and unexpected source of iron for this remote area

This study suggests that volcanic emission can represent a significant source of bioavailable Fe to open ocean anaemic ecosystems.


Science Highlights

Surprisingly heavy silicon isotopes in the surface and deep Arctic Ocean

Brzezinski and his colleagues report on a comprehensive study of the Arctic Ocean silicic acid concentrations and silicon isotopic composition…