noaa-ocean-2559 Southern Ocean Carbon and Nitrogen Isotopic Ratios Crosta, X.; Shemesh, A. Southern Ocean Carbon and Nitrogen Isotopic Ratios 2002-07-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/2559 Investigator X. Crosta Investigator A. Shemesh earth science paleoclimate paleoceanography delta 15N,organic matter,null,per mil AIR,null,paleoceanography,null,null,N,diatom-bound organic matter earth science paleoclimate paleoceanography delta 13C,organic matter,null,per mil PDB,null,paleoceanography,null,null,N,diatom-bound organic matter earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleocean carbon isotopes earth science paleoclimate paleocean nitrogen isotopes geoscientificInformation cal yr BP cal yr BP Complete -56.67 -52.33 20.78 160.23 -3912 -2740 Ocean Pacific Ocean South Pacific Ocean SO136-111>LATITUDE -56.67>LONGITUDE 160.23 Ocean Indian Ocean IO1270-10>LATITUDE -52.33>LONGITUDE 20.78 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

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Boulder CO 80305-3328 USA online ASCII Crosta, X., and A. Shemesh. 2002. Reconciling down-core anti-correlation of diatom carbon and nitrogen isotopic ratios from the Southern Ocean. Paleoceanography 17(1):1010.

Oceanic nutrient cycling in the Southern Ocean is supposed to have an important impact on glacial-interglacial atmospheric CO2 changes and global climate. In order to characterize such nutrient cycling over the last two climatic cycles, we investigated carbon and nitrogen isotopic ratios of diatom-bound organic matter (d13Cdiat and d15Ndiat respectively) in two cores retrieved form the Atlantic and Indian sectors of the Antarctic Ocean. The two cores show the same isotopic patterns. d13Cdiat values are depleted during glacial periods and enriched during interglacial periods indicating lower productivity during cold times. d15Ndiat values are enriched during glacial periods and depleted during interglacial periods arguing for greater nitrate utilization during cold times. Taken at face value, this apparent contradiction leads to opposite conclusions on the role of the Southern Ocean biological pump on the atmospheric CO2 changes. But, the two sets of data can be reconciled by a ""sea ice + mixing rate scenario"" that calls upon a balance between the effect of cutting off gas transfer at the ocean-atmosphere boundary and the effect of reducing vertical transport of nutrients through the pycnocline.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/io127010-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/so136111-tab.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/crosta2002 USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11