Equatorial Atlantic Sediment Composition and Radionuclide Data Bradtmiller, L.I.; Anderson, R.F.; Fleisher, M.Q.; Burckle, L.H. Bradtmiller, L.I. Anderson, R.F. Fleisher, M.Q. Burckle, L.H. 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 earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (RC24-07>LATITUDE -1.33>LONGITUDE -11.92) (RC16-66>LATITUDE .75>LONGITUDE -36.62) (RC24-12>LATITUDE -3>LONGITUDE -11.42) (V22-182>LATITUDE -.53>LONGITUDE -17.27) (RC13-189>LATITUDE 1.87>LONGITUDE -30) (V30-40>LATITUDE -.2>LONGITUDE -23.15) (RC24-01>LATITUDE .55>LONGITUDE -13.65) 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. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Bradtmiller, L.I. Investigator : Anderson, R.F. Investigator : Fleisher, M.Q. Investigator : Burckle, L.H. 2007-07-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/6419 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc2412lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc16-66-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-07-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/r13189lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v30-40lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-01-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v22182lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bradtmiller2007 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc2412lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc16-66-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-07-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/r13189lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v30-40lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-01-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v22182lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bradtmiller2007 English https://www.ncdc.noaa.gov/paleo/study/6419 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc2412lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc16-66-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-07-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/r13189lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v30-40lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/rc24-01-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/v22182lb-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bradtmiller2007 Bradtmiller, L.I., R.F. Anderson, M.Q. Fleisher, and L.H. Burckle2007Opal burial in the equatorial Atlantic Ocean over the last 30 ka: Implications for glacial-interglacial changes in the ocean silicon cyclePaleoceanography10.1029/2006PA001282 START YEAR: 60750 14C yr BP * END YEAR: 868 14C yr BP -36.62 -3 -11.42 1.87