Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial-interglacial changes in the ocean silicon cycle

noaa-ocean-6419 Equatorial Atlantic Sediment Composition and Radionuclide Data Bradtmiller, L.I.; Anderson, R.F.; Fleisher, M.Q.; Burckle, L.H. Equatorial Atlantic Sediment Composition and Radionuclide Data 2007-07-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/6419 Investigator L.I. Bradtmiller Investigator R.F. Anderson Investigator M.Q. Fleisher Investigator L.H. Burckle earth science paleoclimate paleoceanography biogenic silica,sediment,null,percent,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,232nd mass flux earth science paleoclimate paleoceanography 231Pa,sediment,unspecified margin of error,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,230Th mass flux earth science paleoclimate paleoceanography 232Th,sediment,unspecified margin of error,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,236th mass flux earth science paleoclimate paleoceanography 230Th excess,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 234U,sediment,unspecified margin of error,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,unspecified margin of error,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography age,null,null,radiocarbon year before present,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,233rd mass flux earth science paleoclimate paleoceanography 231Pa,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 234U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 238U,sediment,unspecified margin of error,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography calcium carbonate,sediment,null,weight percent,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,235th mass flux earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,231st mass flux earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,234th mass flux earth science paleoclimate paleoceanography 231Pa excess,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleocean radiogenic isotope earth science paleoclimate paleocean lithology earth science paleoclimate paleocean age control geoscientificInformation 60750 14C yr BP 868 14C yr BP 60750 cal yr BP 803 cal yr BP Complete -3 1.87 -36.62 -11.42 -4424 -3233 Ocean Atlantic Ocean South Atlantic Ocean RC24-07>LATITUDE -1.33>LONGITUDE -11.92 Ocean Atlantic Ocean North Atlantic Ocean RC16-66>LATITUDE .75>LONGITUDE -36.62 Ocean Atlantic Ocean South Atlantic Ocean RC24-12>LATITUDE -3>LONGITUDE -11.42 Ocean Atlantic Ocean South Atlantic Ocean V22-182>LATITUDE -.53>LONGITUDE -17.27 Ocean Atlantic Ocean North Atlantic Ocean RC13-189>LATITUDE 1.87>LONGITUDE -30 Ocean Atlantic Ocean South Atlantic Ocean V30-40>LATITUDE -.2>LONGITUDE -23.15 Ocean Atlantic Ocean North Atlantic Ocean RC24-01>LATITUDE .55>LONGITUDE -13.65 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

325 Broadway, E/NE31

Boulder CO 80305-3328 USA online ASCII Bradtmiller, L.I., R.F. Anderson, M.Q. Fleisher, and L.H. Burckle 2007 Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial-interglacial changes in the ocean silicon cycle Paleoceanography 10.1029/2006PA001282

The Silicic Acid Leakage Hypothesis (SALH) suggests that, during glacial periods, excess silicic acid was transported from the Southern Ocean to lower latitudes, which favored diatom production over coccolithophorid production and caused a drawdown of atmospheric CO2. Downcore records of 230Th-normalized opal fluxes and 231Pa/230Th ratios from seven equatorial Atlantic cores were used to reconstruct diatom productivity over the past 30 ka (where a is years) and to test the SALH. Downcore records of 231Pa/230Th ratios and opal fluxes are highly correlated, suggesting that they constitute a production-based record of opal flux. Opal flux records support the SALH in that glacial opal burial exceeded Holocene burial by 1.8 Gt opal/ka in the area 0°-40°W and 5°N-5°S. Earlier results from the eastern equatorial Pacific Ocean showed the opposite trend, with greater Holocene than glacial opal burial, but approximately the same magnitude of difference between glacial and interglacial opal burial. We suggest four (nonexclusive) scenarios to explain the data from both basins: (1) Increased upwelling in the equatorial Atlantic and El Niņoŋlike conditions suppressing upwelling in the eastern equatorial Pacific altered the overall nutrient supply to both basins; (2) Si leaked from the Southern Ocean because of Fe fertilization, but was prevented from upwelling in the equatorial Pacific because of El Niņoŋlike conditions during the LGM; (3) Si leaked from the Southern Ocean because diatom productivity was limited by increased sea ice extent and was again prevented from upwelling in the equatorial Pacific; or (4) changes in ocean circulation related to the decreased input of Agulhas water to the glacial South Atlantic provided excess dissolved Si to the equatorial Atlantic Ocean. A deglacial opal pulse is seen in both the Atlantic and Pacific Oceans. All four scenarios and the presence of the common deglacial opal pulse suggest a common driver in the Southern Ocean.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc2412lb-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc16-66-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-07-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/r13189lb-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v30-40lb-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-01-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v22182lb-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bradtmiller2007 USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11