Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years

noaa-ocean-16914 Central Arctic Sedimentary 231Pa/230Th Ratios from the Past 35,000 Years Hoffmann, S.S.; McManus, J.F.; Curry, W.B.; Brown-Leger, S. Central Arctic Sedimentary 231Pa/230Th Ratios from the Past 35,000 Years 2014-07-10 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16914 Investigator S.S. Hoffmann Investigator J.F. McManus Investigator W.B. Curry Investigator S. Brown-Leger earth science paleoclimate paleoceanography 230Th,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa excess,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.5 earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.5 earth science paleoclimate paleoceanography age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th excess,sediment,null,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 232Th,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,one standard error,dimensionless,null,paleoceanography,averaged|corrected,null,N,null earth science paleoclimate paleoceanography 232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.7 earth science paleoclimate paleoceanography 230Th excess,sediment,null,gram per square meter per kiloyear,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,averaged|corrected,null,N,null earth science paleoclimate paleoceanography 231Pa,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 238U/232Th,sediment,null,dimensionless,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.7 earth science paleoclimate paleoceanography 230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa excess,sediment,null,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 231Pa,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 238U,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography 230Th excess,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 238U/232Th,sediment,two standard error,dimensionless,null,paleoceanography,null,null,N,null earth science paleoclimate paleocean radiogenic isotope geoscientificInformation 45920 cal yr BP 1590 cal yr BP Complete 78.13 88.87 -178.72 178.87 -3471 -1034 Ocean Arctic Ocean PL94-AR BC20>LATITUDE 83.18>LONGITUDE 174.09 Ocean Arctic Ocean PL94-AR BC08>LATITUDE 78.13>LONGITUDE -176.88 Ocean Arctic Ocean PL94-AR BC16>LATITUDE 80.33>LONGITUDE -178.72 Ocean Arctic Ocean PL94-AR BC26>LATITUDE 88.8>LONGITUDE 143.48 Ocean Arctic Ocean PL94-AR BC28>LATITUDE 88.87>LONGITUDE 140.18 Ocean Arctic Ocean PL94-AR BC17>LATITUDE 81.27>LONGITUDE 178.87 Ocean Arctic Ocean PL94-AR BC32>LATITUDE 85.72>LONGITUDE 37.75 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Hoffmann, S.S., J.F. McManus, W.B. Curry, and L.S. Brown-Leger 2013 Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years Nature 497 603-606 10.1038/nature12145

The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deepwater exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation. STUDY NOTES: U-series radionuclide records from seven Arctic sediment cores, with excess 231Pa/230Th ratios interpreted as indicators of 231Pa export in the water column. Age models are from calibrated radiocarbon measurements on polar foraminifer species N. pachyderma (sinistral).

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