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Sigman, Daniel M; Altabet, Mark A; Francois, Roger; McCorkle, Daniel C; Gaillard, Jean-Francois (1999): CN of diatom-bound organic matter in surface sediments [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.856899, Supplement to: Sigman, DM et al. (1999): The isotopic composition of diatom-bound nitrogen in Southern Ocean sediments. Paleoceanography, 14(2), 118-134, https://doi.org/10.1029/1998PA900018

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Abstract:
Treatment of diatom microfossils from Southern Ocean sediments with hot perchloric acid leaves a "diatom-bound" N fraction which is 0-4 per mil lower in d15N than the bulk sediment, typically 3 per mil lower in recent Antarctic diatom ooze. Results from Southern Ocean surface sediments indicate that early diagenetic changes in bulk sediment N content and d15N are not reflected in diatom-bound N, suggesting that diatom-bound N is physically protected from early diagenesis by the microfossil matrix. A meridional transect of multicores from the Indian sector of the Southern Ocean shows a northward increase in the d15N of diatom-bound N, suggesting that diatom-bound d15N, like bulk sedimentary d15N, varies with nitrate utilization in the overlying surface waters. The d15N of diatom-bound N is 3-4 per mil higher in glacial age Antarctic sediments than in Holocene sediments, supporting the hypothesis, previously based on bulk sediment d15N, that nitrate utilization in the surface Antarctic was higher during the last ice age. While there are important uncertainties, the inferred range of utilization changes could potentially explain the entire ~80 ppm amplitude of observed glacial/interglacial variations in atmospheric CO2.
Coverage:
Median Latitude: -51.098144 * Median Longitude: 74.196300 * South-bound Latitude: -63.883300 * West-bound Longitude: 56.000000 * North-bound Latitude: -46.000000 * East-bound Longitude: -169.233300
Date/Time Start: 1996-09-07T01:00:00 * Date/Time End: 1996-09-07T01:00:00
Minimum DEPTH, sediment/rock: 0.0425 m * Maximum DEPTH, sediment/rock: 0.0950 m
Event(s):
ANTARES-I_KBE3 * Latitude: -49.000000 * Longitude: 58.000000 * Location: Southern Ocean * Campaign: MD75 (ANTARES-I,35MF75_1) * Basis: Marion Dufresne (1972) * Method/Device: MultiCorer (MUC)
ANTARES-I_KTB5 * Latitude: -55.000000 * Longitude: 72.000000 * Location: Southern Ocean * Campaign: MD75 (ANTARES-I,35MF75_1) * Basis: Marion Dufresne (1972) * Method/Device: MultiCorer (MUC)
ANTARES-I_KTB6 * Latitude: -52.000000 * Longitude: 61.000000 * Location: Southern Ocean * Campaign: MD75 (ANTARES-I,35MF75_1) * Basis: Marion Dufresne (1972) * Method/Device: MultiCorer (MUC)
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1Event labelEventSigman, Daniel M
2Latitude of eventLatitudeSigman, Daniel M
3Longitude of eventLongitudeSigman, Daniel M
4DEPTH, sediment/rockDepth sedmSigman, Daniel MGeocode
5Depth, top/minDepth topmSigman, Daniel M
6Depth, bottom/maxDepth botmSigman, Daniel M
7Carbon/Nitrogen ratioC/NSigman, Daniel Mdiatom-bound organic matter (molar)
Size:
27 data points

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