Eastern Equatorial Pacific 40KYr Nitrogen Isotope Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Eastern Equatorial Pacific 40KYr Nitrogen Isotope Data LAST UPDATE: 5/2010 (Original receipt by WDC Paleo) CONTRIBUTORS: Robinson, R.S., P. Martinez, L.D. Pena, and I. Cacho IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2010-045 WDC PALEO CONTRIBUTION SERIES CITATION: Robinson, R. S., et al. 2010. Eastern Equatorial Pacific 40KYr Nitrogen Isotope Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2010-045. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Robinson, R.S., P. Martinez, L.D. Pena, and I. Cacho. 2009. Nitrogen isotopic evidence for deglacial changes in nutrient supply in the eastern equatorial Pacific. Paleoceanography, 24, PA4213, doi:10.1029/2008PA001702. ABSTRACT: The Eastern Equatorial Pacific (EEP) is a high nutrient-low chlorophyll region of the ocean. Downcore nitrogen isotope records from the EEP have been previously interpreted as a direct reflection of changes in nutrient consumption. However, the observed changes in sedimentary d15N since the last glacial maximum have no coherent relationship with export productivity or an inferred variation in the iron-to-nitrate ratio of the surface waters. Rather, downcore N isotope records in the EEP strongly resemble changes in the extent of water column denitrification as recorded in nearby sedimentary d15N records along the western margin of the Americas. This similarity is attributed to the overprinting of the N isotopic composition of nitrate in the EEP through the advection of nitrate westward from the margins in the subsurface. A local nitrogen isotope record of changes in the degree of nutrient consumption is extracted from the bulk sedimentary record by subtracting two different sedimentary d15N records of denitrification changes from two new EEP d15N records (TR163-22 and ODP Site 1240). The denitrification records used are from 1) the Central American margin (ODP Site 1242) and 2) the South American margin (GeoB7139-2). The degree of consumption in the surface waters declines rapidly from elevated values during the last glacial maximum to a pair of minima around 15 and 11–13 ka, and finally it increases into the Holocene. The derived EEP nitrogen isotope record indicates that the regional peak in export productivity occurred when the supply of nutrients exceeded the apparently high demand. The influx of nutrients during the deglaciation is attributed to the resumption of intense overturning in the Southern Ocean and the release of sequestered CO2 and nutrient- rich, O2 poor waters from the deep ocean. This has important implications for understanding the glacial-interglacial scale variation in intermediate water suboxia and water column denitrification. GEOGRAPHIC REGION: Eastern Equatorial Pacific PERIOD OF RECORD: 41 - 2 KYrBP FUNDING SOURCES: USSSP and the University of Rhode Island, to R.S.R. DESCRIPTION: Bulk sedimentary nitrogen isotope and nitrogen content data from piston core TR163-22 and ODP Site 1240 in the eastern equatorial Pacific Ocean. All nitrogen content and isotope data were measured by EA-IRMS on bulk sediment. Core locations: ODP 1240: 0.2ºN, 86ºW, 2921m depth. TR163-22: 0º5'N, 92.3ºW, 2830m depth. DATA: 1. ODP Site 1240 Nitrogen isotopic data Column 1: Depth (mcd) Column 2: Age (ky) Column 3: Bulk d15N (per mil vs. air) Column 4: Total Nitrogen, %TN Depth Age d15N %TN 0.03 2.19 0.07 2.75 0.11 3.31 0.15 3.87 6.11 0.11 0.19 4.43 5.8 0.09 0.23 4.99 6.36 0.1 0.27 5.41 6.54 0.1 0.31 5.69 5.73 0.1 0.35 5.97 5.71 0.11 0.39 6.25 5.97 0.11 0.43 6.53 0.12 0.47 6.81 6.79 0.11 0.51 7.09 6.3 0.13 0.55 7.36 6.61 0.12 0.59 7.64 6.28 0.14 0.63 7.92 4.98 0.18 0.67 8.2 6.46 0.12 0.71 8.48 5.29 0.16 0.75 8.76 5.09 0.18 0.79 8.98 5.69 0.14 0.83 9.15 5.61 0.15 0.87 9.31 4.83 0.19 0.91 9.47 4.76 0.19 0.95 9.64 4.65 0.21 0.99 9.8 5.44 0.19 1.03 9.97 4.97 0.22 1.08 10.17 4.69 0.2 1.11 10.29 5.05 0.21 1.15 10.46 4.89 0.23 1.19 10.75 5.56 0.16 1.23 11.18 5.6 0.18 1.27 11.61 5.39 0.17 1.31 12.04 5.62 0.17 1.35 12.47 5.42 0.18 1.39 12.83 6.14 0.16 1.43 12.99 5.68 0.16 1.47 13.16 5.59 0.15 1.53 13.43 6.23 0.14 1.57 13.64 6.38 0.16 1.61 13.85 1.65 14.07 5.98 0.16 1.69 14.28 6.08 0.18 1.73 14.49 5.88 0.23 1.77 14.71 5.82 0.21 1.81 14.93 5.93 0.23 1.85 15.15 5.52 0.22 1.89 15.36 5.49 0.27 1.93 15.58 5.47 0.25 1.97 15.8 5.73 0.29 2.01 16.02 5.24 0.36 2.05 16.24 5.26 0.32 2.09 16.46 5.09 0.3 2.13 16.67 5.42 0.28 2.17 16.89 4.77 0.26 2.21 17.11 5.31 0.3 2.25 17.25 5.06 0.34 2.29 17.3 4.92 0.33 2.33 17.46 4.97 0.31 2.37 17.72 5.23 0.29 2.41 17.98 5.03 0.3 2.45 18.24 4.61 0.28 2.49 18.5 4.79 0.27 2.53 18.76 5.23 0.3 2.57 19.02 5.12 0.32 2.61 19.28 5.15 0.28 2.65 19.52 4.38 0.3 2.69 19.73 4.93 0.28 2.73 19.94 4.94 0.32 2.77 20.15 4.8 0.3 2.81 20.36 3.8 0.29 2.85 20.57 3.83 0.27 2.89 20.78 3.77 0.21 2.93 20.98 4.27 0.25 2.97 21.19 4.39 0.25 3.04 21.54 4.31 0.26 3.08 21.75 4.83 0.23 3.12 21.95 5.01 0.22 3.16 22.16 4.53 0.2 3.2 22.53 4.81 0.19 3.24 23.08 4.77 0.18 3.28 23.63 4.6 0.21 3.32 24.18 4.64 0.22 3.36 24.73 4.61 0.22 3.4 25.28 4.31 0.26 3.44 25.83 4.5 0.23 3.48 26.38 4.04 0.27 3.52 26.88 4 0.27 3.56 27.34 4.53 0.22 3.6 27.8 4.25 0.2 3.64 28.16 4.4 0.19 3.68 28.42 4.96 0.2 3.72 28.68 4.7 0.21 3.76 28.93 4.23 0.23 3.8 29.19 4.92 0.22 3.84 29.45 4.6 0.2 3.88 29.71 4.23 0.16 3.92 29.97 4.92 0.21 3.96 30.22 4.54 0.22 4 30.48 4.91 0.21 4.04 30.74 4.91 0.21 4.08 31 4.67 0.2 4.12 31.26 5.12 0.21 4.16 31.51 4.06 0.19 4.2 31.77 5.15 0.18 4.24 32.03 5.36 0.21 4.28 32.29 4.92 0.19 4.32 32.55 4.37 0.2 4.36 32.8 4.57 0.21 4.4 33.06 4.44 33.36 5.04 0.19 4.48 33.71 5.41 0.15 4.54 34.22 4.58 34.57 4.69 0.1 4.62 34.91 4.69 0.13 4.66 35.26 4.87 0.12 4.7 35.6 4.76 0.1 4.74 35.95 5.48 0.11 4.78 36.29 4.65 0.12 4.82 36.64 5.7 0.11 4.86 36.98 5.27 0.07 4.9 37.14 4.94 37.3 6.24 0.11 4.98 37.46 4.58 0.1 5.02 37.61 5.7 0.11 5.06 37.77 5.1 37.93 4.22 0.13 5.14 38.09 5.18 38.33 5.18 0.14 5.22 38.64 5.32 0.13 5.26 38.95 4.85 0.11 5.3 39.26 5.55 0.11 5.34 39.57 5.48 0.13 5.38 39.88 4.69 0.12 5.42 40.19 4.05 0.13 5.46 40.5 4.34 0.1 5.5 40.81 5.4 0.13 5.54 41.12 5.46 0.11 5.58 41.43 4.56 0.1 2. TR163-22 Nitrogen isotopic data Column 1: Depth (mcd) Column 2: Age (ky) Column 3: Bulk d15N (per mil vs. air) Column 4: Total Nitrogen, %TN Depth Age d15N %TN 15 2.98 5.9 0.06 20 3.7 4.22 0.06 25 4.38 6.17 0.05 30 5 7.42 0.06 35 5.68 5.97 0.05 40 6.3 0.04 40 6.3 0.04 45 6.98 6.24 0.04 45 6.98 0.04 50 7.6 6.78 0.05 50 7.6 0.05 55 8.18 7.38 0.05 60 8.8 6.57 0.05 60 8.8 0.06 65 9.38 6.82 70 9.9 7.82 0.06 75 10.5 5.75 0.07 75 10.5 0.06 80 11.1 6.58 0.07 85 11.6 5.83 0.07 90 12.2 5.89 0.07 90 12.2 0.07 95 12.7 6 0.06 100 13.2 5.09 0.07 105 13.8 6.23 0.07 110 14.3 6.52 0.08 115 14.5 4.96 120 15.3 4.95 0.08 120 15.3 0.08 125 15.8 5.38 0.1 130 16.3 5.5 0.13 135 16.8 6.17 0.08 140 17.3 4.84 0.1 145 17.8 5.35 0.07 150 18.2 4.47 0.08 155 18.7 5.16 0.09 160 19.2 5.27 0.09 165 19.7 4.47 0.08 170 20.1 4.81 0.08 175 20.6 4.02 0.08 180 21.1 4.13 0.09 185 21.6 3.96 0.08 190 22 5.51 0.06 195 22.5 4.53 0.08 200 23 4.67 0.07 205 23.4 5.79 0.07 210 23.9 3.98 0.06 215 24.4 3.76 0.07 220 24.8 4.34 0.08 225 25.3 4.81 0.07 230 25.8 5.29 0.06 235 26.3 5.16 0.06 240 26.8 5.5 0.07 245 27.3 0.07 245 27.3 0.07 250 27.7 5.09 0.06 250 27.7 5.34 0.06 255 28.2 4.27 0.07 260 28.7 4.44 0.06 265 29.3 4.67 0.06 270 29.8 4.3 0.07 275 30.3 4.82 0.08 275 30.3 4.52 0.08 280 30.8 5.15 0.07 285 31.3 4.69 0.08 290 31.9 4.56 0.08 295 32.4 3.8 0.07 300 33 5.01 0.07 305 33.5 4.75 0.07 310 33.8 4.97 0.06 315 34.7 5.04 0.06 315 34.7 4.73 0.06 320 35.2 4.45 0.09 330 36.2 5.36 0.06 335 37.1 5.03 0.05 340 37.7 4.97 0.06 345 38.4 4.42 0.06 350 39 5.11 0.06 350 39 5.64 0.06 360 40.35 4.54 0.06