Meckler, Anna Nele; Ren, Haojia Abby; Sigman, Daniel M; Gruber, Nicolas; Plessen, Birgit; Schubert, Carsten J; Haug, Gerald H (2011): (Table 1) N-isotope record of planktonc foraminifera of sediment core MD02-2550C2 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.829514, Supplement to: Meckler, AN et al. (2011): Deglacial nitrogen isotope changes in the Gulf of Mexico: Evidence from bulk sedimentary and foraminifera-bound nitrogen in Orca Basin sediments. Paleoceanography, 26(4), PA4216, https://doi.org/10.1029/2011PA002156
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Abstract:
Constraining variations in marine N2-fixation over glacial-interglacial timescales is crucial for determining the role of the marine nitrogen cycle in modifying ocean productivity and climate, yet paleo-records from N2-fixation regions are sparse. Here we present new nitrogen isotope (d15N) records of bulk sediment and foraminifera test-bound (FB) nitrogen extending back to the last ice age from the oligotrophic Gulf of Mexico (GOM). Previous studies indicate a substantial terrestrial input during the last ice age and early deglacial, for which we attempt to correct the bulk sediment d15N using its observed relationship with the C/N ratio. Both corrected bulk and FB-d15N reveal a substantial glacial-to-Holocene decrease of d15N toward Holocene values of around 2.5 per mil, similar to observations from the Caribbean. This d15N change is most likely due to a glacial-to-Holocene increase in regional N2-fixation. A deglacial peak in the FB-d15N of thermocline dwelling foraminifera Orbulina universa probably reflects a whole ocean increase in the d15N of nitrate during deglaciation. The d15N of the surface dwelling foraminifera Globigerinoides ruber and the corrected bulk d15N show little sign of this deglacial peak, both decreasing from last glacial values much earlier than does the d15N of O. universa; this may indicate that G. ruber and bulk N reflect the euphotic zone signal of an early local increase in N2-fixation. Our results add to the evidence that, during the last ice age, the larger iron input from dust did not lead to enhanced N2-fixation in this region. Rather, the glacial-to-Holocene decrease in d15N is best explained by a response of N2-fixation within the Atlantic to the deglacial increase in global ocean denitrification.
Coverage:
Latitude: 26.946200 * Longitude: -91.345700
Date/Time Start: 2002-07-08T16:18:00 * Date/Time End: 2002-07-08T16:18:00
Minimum DEPTH, sediment/rock: 0.38 m * Maximum DEPTH, sediment/rock: 8.98 m
Event(s):
MD02-2550C2 (MD022550C2) * Latitude: 26.946200 * Longitude: -91.345700 * Date/Time: 2002-07-08T16:18:00 * Elevation: -2248.0 m * Recovery: 9.09 m * Location: Orca Basin * Campaign: MD127 (IMAGES IX - PAGE) * Basis: Marion Dufresne (1995) * Method/Device: Calypso Square Core System (CASQS)
Parameter(s):
# | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
---|---|---|---|---|---|---|
1 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
2 | AGE | Age | ka BP | Geocode | ||
3 | Globigerinoides ruber, δ15N | G. ruber δ15N | ‰ air | Meckler, Anna Nele | ||
4 | Globigerinoides ruber, δ15N, standard error | G. ruber δ15N std e | ± | Meckler, Anna Nele | ||
5 | Number of measurements | n | # | Meckler, Anna Nele | of total measurements | |
6 | Number of subsamples | Subsamples | # | Meckler, Anna Nele | subsamples prepared separately | |
7 | Orbulina universa, δ15N | O. universa δ15N | ‰ air | Meckler, Anna Nele | ||
8 | Orbulina universa, δ15N, standard error | O. universa δ15N std e | ± | Meckler, Anna Nele | ||
9 | Number of measurements | n | # | Meckler, Anna Nele | of total measurements | |
10 | Number of subsamples | Subsamples | # | Meckler, Anna Nele | subsamples prepared separately | |
11 | Foraminifera, planktic δ15N | Foram plankt δ15N | ‰ air | Meckler, Anna Nele | 125-250 µm size fraction, mixed species | |
12 | Foraminifera, planktic δ15N, standard error | Foram plankt δ15N std e | ± | Meckler, Anna Nele | 125-250 µm size fraction, mixed species | |
13 | Number of measurements | n | # | Meckler, Anna Nele | 125-250 µm size fraction, mixed species, of total measurements | |
14 | Number of subsamples | Subsamples | # | Meckler, Anna Nele | 125-250 µm size fraction, mixed species, subsamples prepared separately |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
107 data points