noaa-ocean-12196
Eastern Equatorial Pacific 100KYr Opal Flux Data
Dubois, N.; Kienast, M.; Kienast, S.S.; Calvert, S.E.; François, R.; Anderson, R.F.
Eastern Equatorial Pacific 100KYr Opal Flux Data
2011-09-26
NCDC-Paleoclimatology
ONLINE Files
Pending
https://www.ncdc.noaa.gov/paleo/study/12196
Investigator
N.
Dubois
Investigator
M.
Kienast
Investigator
S.S.
Kienast
Investigator
S.E.
Calvert
Investigator
R.
François
Investigator
R.F.
Anderson
earth science
paleoclimate
paleoceanography
organic carbon,sediment,null,weight percent,null,paleoceanography,null,gas chromatography,N,null
earth science
paleoclimate
paleoceanography
231Pa,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null
earth science
paleoclimate
paleoceanography
231Pa excess,sediment,null,gram per square meter per year,null,paleoceanography,normalized,null,N,231Pa flux; 230Th-normalized
earth science
paleoclimate
paleoceanography
age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleoceanography
230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null
earth science
paleoclimate
paleoceanography
230Th excess,sediment,null,gram per square meter per year,null,paleoceanography,normalized,null,N,230Th flux; 230Th-normalized
earth science
paleoclimate
paleoceanography
mineral matter,sediment,null,weight percent,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleoceanography
calcium carbonate,sediment,null,weight percent,null,paleoceanography,null,carbon coulometry,N,null
earth science
paleoclimate
paleoceanography
brassicasterol,sediment,null,dimensionless,null,paleoceanography,null,null,N,Relative changes in Brassicasterol content
earth science
paleoclimate
paleoceanography
232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null
earth science
paleoclimate
paleoceanography
238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null
earth science
paleoclimate
paleoceanography
organic carbon,sediment,null,gram per square meter per year,null,paleoceanography,null,null,N,carbon flux
earth science
paleoclimate
paleoceanography
calcium carbonate,sediment,null,gram per square meter per year,null,paleoceanography,null,null,N,calcium carbonate flux
earth science
paleoclimate
paleoceanography
mineral matter,sediment,null,gram per square meter per year,null,paleoceanography,null,null,N,lithogenics flux
earth science
paleoclimate
paleoceanography
biogenic silica,sediment,null,weight percent,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleoceanography
biogenic silica,sediment,null,gram per square meter per year,null,paleoceanography,null,null,N,opal flux
earth science
paleoclimate
paleoceanography
231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,normalized,null,N,230Th-normalized
earth science
paleoclimate
paleoceanography
depth,null,null,centimeter,null,paleoceanography,null,null,N,null
earth science
paleoclimate
paleocean
geochemistry
geoscientificInformation
biogeochemical cycles
99850 cal yr BP
0 cal yr BP
Complete
-3.62
2.27
-92.3983
-82.7867
-3210
-2203
Ocean
Pacific Ocean
Eastern Pacific Ocean
ME0005A-27JC>LATITUDE -1.8533>LONGITUDE -82.7867
Ocean
Pacific Ocean
Eastern Pacific Ocean
ME0005A-24JC>LATITUDE .021667>LONGITUDE -86.463
Ocean
Pacific Ocean
North Pacific Ocean
TR163-19P>LATITUDE 2.27>LONGITUDE -90.95
Ocean
Pacific Ocean
Eastern Pacific Ocean
TR163-22P>LATITUDE .515>LONGITUDE -92.3983
Ocean
Pacific Ocean
South Pacific Ocean
V19-30>LATITUDE -3>LONGITUDE -83
Ocean
Pacific Ocean
Eastern Pacific Ocean
TR163-31P>LATITUDE -3.62>LONGITUDE -83.97
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
325 Broadway, E/NE31
Boulder
CO
80305-3328
USA
online
ASCII
Dubois, N., M. Kienast, S. Kienast, S.E. Calvert, R. François,
and R.F. Anderson. 2010.
Sedimentary opal records in the eastern equatorial Pacific:
It is not all about leakage.
Global Biogeochemical Cycles, v. 24, GB4020, doi:10.1029/2010GB003821.
The clear predictions of the silicic acid leakage hypothesis (SALH)
resulted in a number of studies of downcore opal records from the
tropical Pacific. The original SALH predicts that unused silicic
acid, due to Fe-driven changes in Si versus N limitation,
escaped from the glacial Southern Ocean to equatorial upwelling
regimes where it enhanced diatom productivity, thereby decreasing
coccolith growth and lowering atmospheric CO2. In contrast to SALH
predictions, however, sedimentary records from the eastern equatorial
Pacific (EEP) do not show enhanced opal burial during the Last Glacial
Maximum (LGM) but higher rates of opal burial during the deglaciation
and marine isotopic stage 3 (MIS3). The peak in opal productivity
during the deglaciation has been attributed to increased supply
of nutrient-rich waters driven by stronger upwelling of deep water
in the Southern Ocean at the end of last glacial period. The large
peak in opal burial observed in a number of EEP cores during MIS3
was interpreted as evidence for Si leakage when Southern Ocean diatom
productivity was limited by both low dust flux and extended sea ice.
On the other hand, the paradoxical LGM decline in opal accumulation
in the EEP was explained by enhanced dust input that lowered the
diatom Si:C uptake ratio. Here we use a combination of molecular
fingerprints of algal productivity and radioisotope tracers of
sedimentation to revisit opal burial in the EEP, in particular
during the MIS3 opal peak. An increase in algal productivity
is not supported by the sedimentary concentration of brassicasterol,
an organic molecule commonly found in diatoms, or by the ratio of
(231Pa/230Th)xs,0, a proxy for opal export production. We therefore
conclude that the large peak in opal burial during MIS3 reflects
enhanced preservation of diatoms. Building on mechanisms invoked
in previous studies, we hypothesize that opal burial in the EEP
is controlled both by the physiological response of diatoms to
low-latitude Fe inputs and by the high-latitude processes leading
to silicic acid leakage.
STUDY NOTES: The data set contains compositional data (opal, CaCO3,
Corg, lithogenic) and 230Th-normalized fluxes from 6 cores
from the eastern equatorial Pacific covering the late
Quaternary, in addition to relative changes in Brassicasterol
content in core ME0005A-24JC.
The age models for cores ME0005A-24JC, TR163-19P, TR163-22P,
TR163-31P and V19-30 are adopted as previously published:
ME0005A-24JC (Lyle et al., 2005; A. Mix, unpublished data, 2006);
TR163-19P (Kienast et al., 2006); TR163-22P (Lea et al., 2006);
TR163-31P (Kienast et al., 2006); V19-30 (Shackleton et al., 1983).
The age model for core ME0005A-27JC is adopted as published
(Kienast et al., 2007) for the last 35 kyr, while the oldest
part is based on benthic d18O stratigraphy
(A. Mix, unpublished data, 2006).
Biogenic opal was determined colorimetrically following
alkaline extraction of silica (Mortlock and Froelich, 1989).
Biogenic opal values in cores TR163-19P and TR163-31P are
taken from Kienast et al. (2006) and those of core V19-30
for the last 20 kyr B.P. are taken from Bradtmiller et al. (2006).
Uranium (238U), thorium (232Th, 230Th) and protactinium (231Pa)
concentrations were determined at the University of British
Columbia (UBC), LDEO and the Woods Hole Oceanographic Institution
(WHOI) by isotope dilution on an inductively coupled plasma mass
spectrometer (ICP-MS) following total acid digestion of sediment
samples equilibrated with 229Th and 236U spikes and anion resin
column chemistry to separate the Pa and U/Th fraction
(François et al., 2004). In the calculations of 230Thxs,0
and 231Paxs,0 we use a half life for 230Th of 75.69 kyr,
a half life for 231Pa of 32.50 kyr and a A238Udet/A232Thdet
ratio of 0.50. Radioisotope data for cores TR163-19P and TR163-31P
are from Kienast et al. (2006), and those of core V19-30 for
the last 20 kyr are from Bradtmiller et al. (2006).
Data for the last 35 kyr B.P. for cores ME0005A-24JC
and ME0005A-27JC are from Kienast et al. (2007).
Carbonate (CaCO3) values were obtained from the coulometric
CO2 determinations assuming no other carbonate-bearing phase
was present.
Total carbon was determined by flash combustion gas chromatography
with CHN elemental analyzers.
Organic carbon was estimated by subtracting carbonate from
total carbon.
The lithogenic fraction was estimated from the residual
non-biogenic fraction of the sediment, after subtraction of opal,
carbonate and organic matter, except for core V19-30,
where it was calculated from 232Th, assuming a detrital
source of all 232Th and an average 232Th dust content
of 10 ppm (Taylor and McLennan, 1985).
Changes in the relative concentration of brassicasterol
in core ME0005A-24JC were determined by gas chromatography
at Dalhousie University. Approximately 1 g of freeze-dried
sediment was extracted using a Dionex Accelerated Solvent
Extraction system (ASE200). These extracts were saponified
using potassium hydroxide and purified through silica column
chromatography. The purified extracts were then treated
with bis(trimethylsilyl)trifluoroacetamide (BSTFA) to derive
trimethyl silyl esters (TMS) before gas chromatographic
analysis. Relative sterol distributions were determined
by integration of the sterol peak area in the chromatogram,
normalized to sample weight. We did not use recovery
standards and thus the normalized brassicasterol
chromatographic peak areas we report were not corrected
for potential losses during the extraction process.
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DIF
Version 9.8.4
2018-12-11
2018-12-11