noaa-ocean-13671
Southern Ocean ODP745 Miocene-Pleistocene d15N Data
Billups, K.; Aufdenkampe, A.; Hays, R.
Southern Ocean ODP745 Miocene-Pleistocene d15N Data
2013-01-03
NCDC-Paleoclimatology
ONLINE Files
Pending
https://www.ncdc.noaa.gov/paleo/study/13671
Investigator
K.
Billups
Investigator
A.
Aufdenkampe
Investigator
R.
Hays
earth science
paleoclimate
paleoceanography
depth,null,null,meter,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleoceanography
delta 15N,null,null,per mil,null,paleoceanography,averaged,null,N,null
earth science
paleoclimate
paleoceanography
delta 15N,null,null,per mil,null,paleoceanography,null,null,N,replicate 2
earth science
paleoclimate
paleoceanography
notes,null,null,null,null,paleoceanography,null,null,C,Core Section Interval
earth science
paleoclimate
paleoceanography
age,null,null,million years ago,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleoceanography
delta 15N,null,null,per mil,null,paleoceanography,null,null,N,replicate 1
earth science
paleoclimate
paleocean
nitrogen isotopes
geoscientificInformation
biogeochemical cycles
6490800 cal yr BP
1406000 cal yr BP
Complete
-59.5952
-59.5952
85.86
85.86
-4082
-4082
Ocean
Indian Ocean
ODP745>LATITUDE -59.5952>LONGITUDE 85.86
None
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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
325 Broadway, E/NE31
Boulder
CO
80305-3328
USA
online
ASCII
Katharina Billups, Anthony Aufdenkampe, and Rebecca Hays. 2013.
Late Miocene through early Pleistocene nutrient utilization and export production in the Antarctic Zone of the Southern Ocean.
Global and Planetary Change, Vol. 100, pp. 351-361.
DOI: 10.1016/j.gloplacha.2012.11.014
We use bulk sediment d15N values and opal and carbon mass accumulation rates (MAR) to reconstruct nutrient utilization and export productivity at Ocean Drilling Program Site 745 (Antarctic Zone of the Southern Ocean) spanning the late Miocene through early Pleistocene (~6.5-1.4 Ma). We investigate whether early Pliocene climatic warmth and subsequent cooling can be related to changes in high latitude productivity. Results indicate that d15N values increase to above late Holocene levels from the late Miocene through the late Pliocene (6.5 to 2 Ma). Opal and carbon MARs are low during the early Pliocene. Relatively high d15N together with low export production is consistent with a more southerly position of the Polar Frontal Zone (PFZ) allowing the expansion of nitrate depleted, low nutrient upper waters south toward Site 745. The interpretation is supported by a relatively small d15N gradient between Site 745 and a site in the Subantarctic Zone of the Southern Ocean (Site 1090). There are no unique changes in the Site 745 d15N values or export productivity at 2.7 Ma. During the late Pliocene to early Pleistocene climate transition (between ~2.1 and at 1.7 Ma), d15N values display large variations approaching those observed during the last glacial to interglacial transition in this latitude band. Opal and carbon MARs also show large fluctuations, but in the opposite sense with maxima corresponding to minima in the d15N record and vice versa. The pattern of high d15N values associated with low export production may reflect changes in nutrient utilization in response to changes in water column stratification once the PFZ has moved north of the location of Site 745. Our results provide a mechanism for enhancing early Pliocene CO2 concentrations via reduced uptake of CO2 due to low productivity in the Southern Ocean. Once the PFZ has moved north, the region may have become sensitive to changes in water column stratification, potentially contributing to fluctuations in CO2.
STUDY NOTES: Bulk sediment d15N values from ODP Site 745 in the Antarctic Zone of the Southern Ocean
for 6.5 - 1.4 ma, to assess potential changes in nitrate utilization and export production
from the late Miocene through early Pleistocene. The temporal resolution is about 30-75 kyr.
Approximately 1 g of sediment was freeze dried, ground with a mortar and pestle into a fine powder,
and homogenized. About 90-100 mg of the thus prepared bulk sediment was weighed out into tin cups.
Approximately 10 mg of powdered tin was added to each sample to aid with combustion given the low
organic matter concentrations. Samples were then analyzed at the Stroud Water Research Center
on a Thermo-Finnigan DeltaPlus XP Isotope Ratio Mass Spectrometer (IRMS) with Conflo III
interfaced in continuous flow mode to a Costech 4010 CHNS-O Elemental Analyzer (EA).
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/billups2013/billups2013.txt
USA/NOAA
DIF
Version 9.8.4
2018-12-11
2018-12-11