Citation:

PANGAEA.867495, Supplement to: Weiser, J et al. (2016): Late Holocene paleoceanographic changes off south-western Africa as inferred from coccolithophore assemblages, Proc. 15th INA Conf., Bohol, Philippines. Journal of Nannoplankton Research, 36(2), 161-171

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Abstract:

Coccolith occurrences in sediment core GeoB 8323-2, from the Benguela Upwelling System off south-western Africa, were analysed to reconstruct the temporal changes in surface water conditions, upwelling intensity and associated productivity during the late Holocene (last 2.25ka BP). Absolute numbers of total coccolithophores are low throughout the core, reaching a maximum of 320 x 10^6 coccoliths/gram sediment around 770 years BP. Despite the low abundance of coccoliths, coherent patterns of a changing assemblage composition can be identified. These suggest a consistent paleoceanographic development of highly variable Late Holocene environmental change during the last three millennia. Phases of decreased upwelling in the Benguela Upwelling System are indicated by elevated abundances of Florisphaera profunda alongside reduced occurrence of Coccolithus pelagicus and C. braarudii from 2.25-2.00ka BP, ~ 1.00ka BP and during the last 200 years, also accompanied by a reduced species diversity. Sea surface temperatures estimated with a Gephyrocapsa-based transfer function are in the order of 18-20°C. These phases are intersected by periods of colder sea surface temperatures of 16-17°C and increased productivity, as indicated by an opposing trend for the aforementioned species. Given the climatological and oceanographical complexity of the area, deciphering a single driving mechanism for these changes proves difficult. Synchronous changes in the Antarctic sea ice extent, however, give credit to the conceptual model of latitudinal migration of the westerly wind belt and its interaction with the south-easterly trade winds as an important driver for oceanographic changes in the area.

Project(s):

Center for Marine Environmental Sciences (MARUM)

Geosciences, University of Bremen (GeoB)

Regional Archives for Integrated iNvestigations (RAiN)

Funding:

Federal Ministry of Education and Research (BMBF), grant/award no. 03G0840A : Regional Archives for Integrated iNvestigations

Coverage:

Latitude: -32.031500 * Longitude: 18.221500

Date/Time Start: 2003-01-29T16:40:00 * Date/Time End: 2003-01-29T16:40:00

Minimum DEPTH, sediment/rock: 0.01 m * Maximum DEPTH, sediment/rock: 2.27 m

Event(s):

GeoB8323-2 * Latitude: -32.031500 * Longitude: 18.221500 * Date/Time: 2003-01-29T16:40:00 * Elevation: -91.0 m * Recovery: 2.85 m * Campaign: * Basis: * Method/Device: Gravity corer (Kiel type) (SL) * Comment: See core description

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	DEPTH, sediment/rock	Depth sed	m	Weiser, Jens	Geocode
2	AGE	Age	ka BP	Weiser, Jens	Geocode
3	Coccolithus braarudii	C. braarudii	10⁶ #/g	Weiser, Jens
4	Coccolithus pelagicus	C. pelagicus	10⁶ #/g	Weiser, Jens
5	Calcidiscus leptoporus	C. leptoporus	10⁶ #/g	Weiser, Jens
6	Calcidiscus quadriperforatus	C. quadriperforatus	10⁶ #/g	Weiser, Jens
7	Emiliania huxleyi	E. huxleyi	10⁶ #/g	Weiser, Jens	<4µm
8	Emiliania huxleyi	E. huxleyi	10⁶ #/g	Weiser, Jens	>4µm
9	Gephyrocapsa muellerae	G. muellerae	10⁶ #/g	Weiser, Jens
10	Gephyrocapsa ericsonii	G. ericsonii	10⁶ #/g	Weiser, Jens
11	Gephyrocapsa oceanica	G. oceanica	10⁶ #/g	Weiser, Jens
12	Florisphaera profunda	F. profunda	10⁶ #/g	Weiser, Jens
13	Syracosphaera spp.	Syracosphaera spp.	10⁶ #/g	Weiser, Jens
14	Coccolithophoridae, other	Coccolith o	10⁶ #/g	Weiser, Jens
15	Coccolithophoridae, total	Coccolith	10⁶ #/g	Weiser, Jens

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

416 data points

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