Eastern Equatorial Pacific 150KYr d15N and Corg Data Dubois, N.; Kienast, M. Dubois, N. Kienast, M. earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (delta 15N,sediment,null,per mil,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (organic carbon,sediment,null,weight percent,null,paleoceanography,null,elemental analysis,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean (ME0005A-27JC>LATITUDE -1.8533>LONGITUDE -82.7867) (ME0005A-24JC>LATITUDE .021667>LONGITUDE -86.463) (TR163-19P>LATITUDE 2.27>LONGITUDE -90.95) (TR163-31P>LATITUDE -3.62>LONGITUDE -83.97) High-resolution downcore records of bulk sediment nitrogen isotopes (d15N) and organic carbon (Corg) contents from multiple Eastern Tropical Pacific sites show remarkable uniformity during the last glacial stage, whereas during the Holocene and the last interglacial period, they diverge significantly. The close covariation of d15N records during glacial stages points toward regional changes in the background isotopic signal of the inorganic nitrate pool, likely caused by variations in the denitrification rates in the nearby suboxic zones. On the other hand, we attribute the divergence of the d15N and Corg records during interglacial periods to a spatial reorganization in the equatorial divergence. We posit a southward displacement of the zone of strongest upwelling in the South Equatorial Current to explain the reduced productivity and higher nitrate consumption recorded at the equator during warmer intervals. STUDY NOTES: The data set contains bulk sediment d15N and Corg content from 4 cores from the eastern equatorial Pacific covering the late Quaternary. The sedimentary d15N composition of all cores was analyzed at UBC, Vancouver, following standard procedures. Total carbon was determined with an elemental analyzer. Inorganic (i.e., carbonate mineral) carbon was determined in a carbon dioxide coulometer. Organic carbon was estimated by subtracting inorganic from total carbon. Results for the last 35 kyr have been published by Kienast et al. (2006, 2007). Age models for the last 25 kyr are based on radiocarbon dates and were adopted as previously published (see Dubois et al., 2011 and references therein). For ages older than 25 kyr BP, the age models of cores ME0005A-27JC, TR163-19P and TR163-31P are based on oxygen isotope stratigraphy (correlation to the global benthic stack LR04 (Lisiecki and Raymo, 2005)), and the presence of an ash layer (Los Chocoyos Ash Layer (Drexler et al., 1980)). The age model of core ME0005A-24JC is modified from Lyle et al. (2005), with additional correlation points to the opal, CaCO3 and SST records of core ME0005A-27JC (previously published by Dubois et al. (2010, 2011)). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Dubois, N. Investigator : Kienast, M. 2011-09-26 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12198 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.xls English https://www.ncdc.noaa.gov/paleo/study/12198 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/dubois2011b/dubois2011b.xls Dubois, N. and M. Kienast. 2011. Spatial reorganization in the equatorial divergence in the Eastern Tropical Pacific during the last 150 kyr, Geophys. Res. Lett., 38, L16606, doi:10.1029/2011GL048325. START YEAR: 149700 cal yr BP * END YEAR: 940 cal yr BP -90.95 -3.62 -82.7867 2.27