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| Titel |
Holocene Sea Surface and Subsurface Water Mass Variability Reconstructed from Temperature and Sea-ice Proxies in Fram Strait |
| VerfasserIn |
Kirstin Werner, Robert F. Spielhagen, Juliane Müller, Katrine Husum, Evgenia S. Kandiano, Leonid Polyak |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131556
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| Publikation (Nr.) |
 EGU/EGU2016-11981.pdf |
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| Zusammenfassung |
| In two high-resolution sediment cores from the West Spitsbergen continental margin we
investigated planktic foraminiferal, biomarker and dinocyst proxy data in order to reconstruct
surface and subsurface water mass variability during the Holocene. The two study sites are
today influenced by northward flowing warm and saline Atlantic Water. Both foraminiferal
and dinocyst (de Vernal et al., 2013) temperature reconstructions indicate a less-stratified,
ice-free, nutrient-rich summer surface ocean with strong Atlantic Water advection between
10.6 and 8.5 cal ka BP, likely related to maximum July insolation during the early Holocene.
Sea surface to subsurface water temperatures of up to 6∘C prevailed until ca 5 cal ka BP. A
weakened contribution of Atlantic Water is found when subsurface temperatures strongly
decreased with minimum values between ca 4 and 3 cal ka BP. High planktic foraminifer
shell fragmentation and increased oxygen isotope values of the subpolar planktic
foraminifer species Turborotalita quinqueloba as well as increasing concentrations
of the sea ice biomarker IP25 further indicate cool conditions. Indices associated
with IP25 as well as dinocyst data suggest a sustained cooling and consequently
sea-ice increase during the late Holocene. However, planktic foraminiferal data
indicate a slight return of stronger subsurface influx of Atlantic Water since ca 3
cal ka BP. The observed decoupling of cooling surface and warming subsurface
waters during the later Holocene might be attributed to a strong pycnocline layer
separating cold sea-ice fed surface waters from enhanced subsurface Atlantic Water
advection.
Reference:
de Vernal, A., Hillaire-Marcel, C., Rochon, A., Fréchette, B., Henry, M., Solignac, S.,
Bonnet, S., 2013. Dinocyst-based reconstructions of sea ice cover concentration during the
Holocene in the Arctic Ocean, the northern North Atlantic Ocean and its adjacent seas.
Quaternary Science Reviews 79, 111-121. |
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