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| Titel |
A synthesis of marine sediment core δ¹³C data over the last 150 000 years |
| VerfasserIn |
K. I. C. Oliver, B. A. A. Hoogakker, S. Crowhurst, G. M. Henderson, R. E. M. Rickaby, N. R. Edwards, H. Elderfield |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 6, no. 5 ; Nr. 6, no. 5 (2010-10-08), S.645-673 |
| Datensatznummer |
250003760
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| Publikation (Nr.) |
 copernicus.org/cp-6-645-2010.pdf |
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| Zusammenfassung |
The isotopic composition of carbon, δ13C, in seawater is used in reconstructions of ocean circulation, marine productivity, air-sea gas exchange, and biosphere carbon storage. Here, a synthesis of δ13C measurements taken from foraminifera in
marine sediment cores over the last 150 000 years is presented. The
dataset comprises previously published and unpublished data from benthic and planktonic records throughout the
global ocean. Data are placed on a common δ18O age scale suitable for examining orbital timescale variability but not millennial events, which are removed by a 10 ka filter. Error estimates account for
the resolution and scatter of the original data, and uncertainty in the
relationship between δ13C of calcite and of dissolved inorganic
carbon (DIC) in seawater. This will assist comparison with δ13C
of DIC output from models, which can be further improved using model
outputs such as temperature, DIC concentration, and alkalinity to
improve estimates of fractionation during calcite formation.
High global deep ocean δ13C, indicating isotopically heavy carbon, is obtained during Marine Isotope Stages (MIS) 1, 3, 5a, c and e, and low δ13C during MIS 2, 4 and 6, which are temperature minima, with larger amplitude variability in the Atlantic Ocean than the Pacific Ocean. This is
likely to result from changes in biosphere carbon storage, modulated
by changes in ocean circulation, productivity, and air-sea gas
exchange. The North Atlantic vertical δ13C gradient is greater
during temperature minima than temperature maxima, attributed to
changes in the spatial extent of Atlantic source waters. There are
insufficient data from shallower than 2500 m to obtain a coherent
pattern in other ocean basins. The data synthesis indicates that
basin-scale δ13C during the last interglacial (MIS 5e) is not
clearly distinguishable from the Holocene (MIS 1) or from MIS 5a and
5c, despite significant differences in ice volume and atmospheric
CO2 concentration during these intervals. Similarly, MIS 6 is
only distinguishable from MIS 2 or 4 due to globally lower δ13C
values both in benthic and planktonic data. This result is obtained
despite individual records showing differences between these
intervals, indicating that care must be used in interpreting large
scale signals from a small number of records. |
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