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| Titel |
Sub-centennial Holocene fluctuations of surface water masses in the western Barents Sea |
| VerfasserIn |
S. Berben, K. Husum, M. Hald |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071675
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| Zusammenfassung |
| The North Atlantic Current (NAC) brings warm and saline water into the Arctic, and the
inflow is balanced by the outflow of cold surface water and by the formation of deep water to
the south. This is part of the Atlantic Meridional Overturning Circulation (AMOC). Changes
of the AMOC can greatly affect the global ocean circulation and climate, especially at high
latitudes where the inflow of warm water and heat exchange is essential for environment and
society. Hence, it is crucial to establish the natural range of oceanographic fluctuations within
this area.
Here we investigate a continuous high resolution record from the Kveithola Through,
western Barents Sea in order to elucidate the past variability of the flow of Atlantic
Water during the Holocene. The results are compared to existing records north and
south of our study site in order to map regional changes of the inflow of Atlantic
Water.
The age model has been based on ten AMS C14 dates, and show sediment accumulation
rates up to 0.034 mm/yr, enabling a sub-centennial resolution.The samples have been
analyzed for their planktic foraminiferal faunal distribution. In addition analyses of stable
isotopes (d18O, d13C) and Mg/Ca ratios will also be carried out further quantifying the
surface water mass properties as SST and SSS. Finally, analyses of shell weights and
fragments will be presented in order to evaluate the degree of preservation of the current
paleoceanographic record.
Preliminary results show a planktic foraminiferal fauna consisting of two dominating
species: the polar N. pachyderma sinistral and the sub-polar T. quinqueloba. The early
Holocene records a relative distribution between 50 and 60 % of N. pachyderma sinistral,
while throughout the mid and late Holocene T. quinqueloba dominates the fauna with values
up to 75%. Further, several other species, such as N. incompta, G. glutinata, G.
bulloides and G. uvula, are found less abundantly. During the last 1000 years G.
uvula shows a remarkable increase, possibly indicating an advanced fresh water
input.
The results of this studyconfirm a south-north time transgressive onset of Holocene
warming as previously recorded in the region. However this study finds a general
higher frequency ofT. quinquelobareflecting a very close position to the Arctic Front. |
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