Bulk sediment nitrogen isotopes from the northern Peru Margin over the last 25 kyr Bova, S.C.; Herbert, T.D.; Altabet, M.A. Bova, S.C. Herbert, T.D. Altabet, M.A. earth science/paleoclimate/paleoceanography (delta 15N,sediment,null,per mil,null,paleoceanography,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (sample identification,null,null,null,null,paleoceanography,null,null,C,sample identification used by 14C laboratory) earth science/paleoclimate/paleoceanography (age,benthic foraminifer,null,radiocarbon year before present,null,paleoceanography,null,accelerator mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (age,benthic foraminifer,one standard deviation,radiocarbon year,null,paleoceanography,null,accelerator mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (KNR195-5 CDH41>LATITUDE -1.265667>LONGITUDE -89.698) (KNR195-5 CDH26>LATITUDE -3.986>LONGITUDE -81.308667) (KNR195-5 GGC43>LATITUDE -1.252167>LONGITUDE -89.6845) (KNR195-5 CDH23>LATITUDE -3.749167>LONGITUDE -81.134167) Atmospheric carbon dioxide (CO2) levels rose by ~90 ppmv during the last deglaciation, but the source of this carbon remains unknown. One popular hypothesis suggests carbon accumulated in the deep Southern Ocean, becoming increasingly radiocarbon (14C)-depleted during the last glacial period, and was released into Antarctic Intermediate Water (AAIW) and, subsequently, the atmosphere during deglaciation. Detection of extremely 14C-deplete carbon in the intermediate-depth tropical oceans during periods of atmospheric CO2 rise was initially considered the "smoking gun" for the hypothesis, but attempts to reproduce the anomalies closer to the Southern Ocean source have largely failed. Here, we present new 14C records from four cores recovered at intermediate depths in the eastern equatorial Pacific (EEP). In the context of additional geochemical records, including benthic foraminiferal stable isotopes and sedimentary nitrogen isotopes, we demonstrate that the extreme 14C anomalies observed during the last deglaciation do not reflect the radiocarbon content of AAIW. We show that, although AAIW likely transported modestly 14C-deplete carbon to the EEP subsurface, the extreme 14C signatures might reflect a distinct source of aged carbon arriving from the north, suggesting the North Pacific helped transport deep ocean carbon to the atmosphere during the last deglaciation. In the EEP, additional local hydrothermal inputs of 14C-free carbon near the Galapagos Islands magnified the already low-14C signatures. Finally, regardless of arrival route (North/South Pacific or hydrothermal), 14C-deplete carbon was released from the EEP subsurface during a late deglacial pulse of renewed upwelling, likely contributing to the Younger Dryas rise in atmospheric CO2. STUDY NOTES: Provided Keywords: deglaciation, upwelling, Younger Dryas NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Bova, S.C. Investigator : Herbert, T.D. Investigator : Altabet, M.A. 2018-10-12 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/25430 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh23-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-d15n.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh41-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-ggc43-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh23-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-d15n.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh41-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-ggc43-14c.txt English https://www.ncdc.noaa.gov/paleo/study/25430 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh23-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-d15n.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh41-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-cdh26-14c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bova2018/bova2018-ggc43-14c.txt Bova, S.C., Herbert, T.D., and Altabet M.A.2018Ventilation of northern and southern sources of aged carbon in the eastern equatorial Pacific during the Younger Dryas rise in atmospheric CO2Paleoceanography and Paleoclimatologyin press START YEAR: 28238 cal yr BP * END YEAR: 1102 cal yr BP -89.698 -3.986 -81.134167 -1.252167