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Ganssen, Gerald M (1983): Stable isotope record of planktic foraminifera sampled by plankton haul and in surface sediments off North-West Africa [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.548486, Supplement to: Ganssen, GM (1983): Dokumentation von küstennahmen Auftrieb anhand stabiler Isotope in rezenten Foraminiferen vor Nordwest-Afrika. Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C37, 1-46

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Abstract:
Foraminifera shells from modern sediments document the hydrography of the coastal upwelling region off Northwest-Africa (12-35° N) through the stable isotopic composition of their shells.
Oxygen isotopes in planktonic foraminifers reflect sea surface temperatures (SST) during the main growing season of the differnt species: Globigerinoides ruber (pink and white) and G. sacculifer delineate the temperatures of the summer, Globorotalia inflata and Pulleniatina obliquiloculata those of the winter. Oxygen isotopes on Globigerina bulloides document temperature ranges of the upwelling seasons.
d18O values in planktonic foraminifera from plankton hauls resemble those from the surface sediment samples, if the time of the plankton collection is identical with that of the main growing season of the species.
The combined isotopic record of G. ruber (white) and G. inflata clearly reveals the latitudinal variations of the annual mean SST. The deviation of the d18O values from both species from their common mean is a scale for the seasonality, i.e. the maximum temperature range within one year. Thus in the summer upwelling region (north of 25° N) seasonality is relatively low, while it becomes high in the winter upwelling region south of 20° N. Furthermore, the winter upwelling region is characterized by relatively high d18O values - indicating low temperatures - in G. bulloides, the region of summer upwelling by relatively low d180 values compared with the constructed annual mean SST. Generally, carbon isotopes from the plankton hauls coincide with those from sediment surface samples. The enrichment of 13C isotopes in foraminifers from areas with high primary production can be caused by the removal of 12C from the total dissolved inorganic carbon during phytoplankton blooms. It is found that carbon isotopes from plankton hauls off Northwest-Africa are relatively enriched in 13C compared with samples from the western Atlantic Ocean. Also shells of G. ruber (pink and white) from upwelling regions are enriched in the heavier isotope compared with regions without upwelling. In the sediment, the enrichement of 13C due to high primary production can only be seen in G. bulloides from the high fertile upwelling region south of 20° N. North of this latitude values are relatively low. An enrichment of 12C is observed in shells of G. ruber (pink), G. inflata and P. obliquiloculata from summer-winter- and perennial upwelling regions respectively.
Northern water masses can be distinguished from their southern counterparts by relatively high oxygen and carbon values in the „living“ (=stained) benthic foraminifera Uvigerina sp. and Hoeglundina elegans. A tongue of the Mediterranean Outflow water can be identified far to the south (20° N) by 13C-enriched shells of these benthic foraminifera.
A zone of erosion (15-25° N, 300-600 m) with a subrecent sediment surface can be mapped with the help of oxygen isotopes in „dead“ benthic specimens.
Comparison of d18O values in aragonitic and calcitic benthic foraminifers does not show a differential influence of temperature on the isotopic composition in the carbonate. However, carbon isotopes reflect slightly differences under the influence of temperature.
Project(s):
Institute for Geosciences, Christian Albrechts University, Kiel (GIK/IfG)
Coverage:
Median Latitude: 32.180221 * Median Longitude: -11.127115 * South-bound Latitude: 12.525200 * West-bound Longitude: -19.930000 * North-bound Latitude: 34.991700 * East-bound Longitude: -6.581670
Date/Time Start: 1971-01-01T00:00:00 * Date/Time End: 1982-01-22T00:00:00
Event(s):
GIK12301-5 * Latitude: 27.040000 * Longitude: -15.049000 * Date/Time: 1971-10-30T00:00:00 * Elevation: -2896.0 m * Location: East Atlantic * Campaign: M25 * Basis: Meteor (1964) * Method/Device: van Veen Grab (VGRAB)
GIK12302-3 * Latitude: 26.003333 * Longitude: -14.666667 * Date/Time: 1971-10-30T00:00:00 * Elevation: -64.0 m * Location: East Atlantic * Campaign: M25 * Basis: Meteor (1964) * Method/Device: van Veen Grab (VGRAB)
GIK12303-3 * Latitude: 26.196667 * Longitude: -14.793333 * Date/Time: 1971-10-30T00:00:00 * Elevation: -151.0 m * Location: East Atlantic * Campaign: M25 * Basis: Meteor (1964) * Method/Device: van Veen Grab (VGRAB)
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
11 datasets

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Datasets listed in this publication series

  1. Ganssen, GM (1983): Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15658-2, off NW Africa (Table 1d). https://doi.org/10.1594/PANGAEA.544840
  2. Ganssen, GM (1983): Hydrography and plankton abundance of vertical plankton haul profile GIK15658-2, off NW Africa (Table 1c). https://doi.org/10.1594/PANGAEA.544650
  3. Ganssen, GM (1983): Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15666-8, off NW Africa (Table 1d). https://doi.org/10.1594/PANGAEA.544841
  4. Ganssen, GM (1983): Hydrography and plankton abundance of vertical plankton haul profile GIK15666-8, off NW Africa (Table 1c). https://doi.org/10.1594/PANGAEA.544651
  5. Ganssen, GM (1983): Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15678-3, off NW Africa (Table 1d). https://doi.org/10.1594/PANGAEA.544842
  6. Ganssen, GM (1983): Hydrography and plankton abundance of vertical plankton haul profile GIK15678-3, off NW Africa (Table 1c). https://doi.org/10.1594/PANGAEA.544652
  7. Ganssen, GM (1983): Stable isotopic measurement on planktonic foraminifera of vertical plankton haul samples GIK15679-2, off NW Africa (Table 1d). https://doi.org/10.1594/PANGAEA.544843
  8. Ganssen, GM (1983): Hydrography and plankton abundance of vertical plankton haul profile GIK15679-2, off NW Africa (Table 1c). https://doi.org/10.1594/PANGAEA.544653
  9. Ganssen, GM (1983): Stable isotopic measurements on planktonic foraminifera of plankton haul samples off Northwest Africa (Table 1d). https://doi.org/10.1594/PANGAEA.544654
  10. Ganssen, GM (1983): Hydrography and plankton abundance of horizontal plankton hauls sampled off Northwest Africa (Table 1b). https://doi.org/10.1594/PANGAEA.544649
  11. Ganssen, GM (1983): Stable isotopes on recent foraminifera from surface sediments off northwest Africa. https://doi.org/10.1594/PANGAEA.104423