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| Titel |
Modern distribution of planktic foraminifers in the Fram Strait (Arctic Ocean) compared to sea floor species assemblages |
| VerfasserIn |
T. Pados, R. F. Spielhagen |
| 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 |
250060950
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| Zusammenfassung |
| Fossil planktic foraminifers are common tools in paleoceanography. The composition of
species assemblages in sediment cores is often used to reconstruct properties of water masses
in the past. The ratio between the abundances of different planktic foraminifer species
provides information about the hydrographic regime, e.g., distribution of water masses, water
temperatures and the position of the summer sea ice margin. However, for a correct
interpretation of the fossil data it is important to improve our understanding of the correlation
between recent oceanic variability and the distribution of living foraminifera. For this,
planktic foramifers were studied along a transect across the Fram Strait (Arctic
Ocean, 78Ë 50´N, 5Ë W-8Ë E). In the western part of this strait, the water column is
strongly stratified, with cold, low-saline Arctic outflow waters of the East Greenland
Current (EGC) in the upper 200 m and warmer, saline waters of Atlantic origin
underneath. In the east, the upper water column of the northward flowing West
Spitsbergen Current (WSC) consists of Atlantic Water, with a thin mixed layer on
top. Five depth intervals were sampled vertically between 500 m water depth and
the sea surface by using a large-diameter multinet at 10 stations. In the cold polar
water masses of the EGC the polar species Neogloboquadrina pachyderma (sin.)
contributes >70% to the total assemblage, while the warm Atlantic water of the WSC
yielded higher abundances of Turborotalita quinqueloba. Highest abundances of
individuals were obtained between 50 and 100 m water depth. However, unexpectedly,
in the depth interval of 300-500 m the number of individuals showed a second
peak at certain stations. Our multinet sampling results are compared to the planktic
foraminifer assemblages in sediment surface samples to investigate how well the
panktic species distribution at the sea floor reflects the surface-near environments. |
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