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| Titel |
Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania) |
| VerfasserIn |
I. Bouimetarhan, L. Dupont, H. Kuhlmann, J. Pätzold, M. Prange, E. Schefuß, K. Zonneveld |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 5 ; Nr. 11, no. 5 (2015-05-11), S.751-764 |
| Datensatznummer |
250117284
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| Publikation (Nr.) |
 copernicus.org/cp-11-751-2015.pdf |
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| Zusammenfassung |
| In tropical eastern Africa, vegetation distribution is largely controlled by
regional hydrology, which has varied over the past 20 000 years. Therefore,
accurate reconstructions of past vegetation and hydrological changes are
crucial for a better understanding of climate variability in the tropical
southeastern African region. We present high-resolution pollen records from
a marine sediment core recovered offshore of the Rufiji River delta. Our data
document significant shifts in pollen assemblages during the last
deglaciation, identifying, through changes in both upland and
lowland vegetation, specific responses of plant communities to atmospheric
(precipitation) and coastal (coastal dynamics and sea-level changes)
alterations. Specifically, arid conditions reflected by a maximum pollen
representation of dry and open vegetation occurred during the Northern
Hemisphere cold Heinrich event 1 (H1), suggesting that the expansion of drier
upland vegetation was synchronous with cold Northern Hemisphere
conditions. This arid period is followed by an interval in which forest and
humid woodlands expanded, indicating a hydrologic shift towards more humid
conditions. Droughts during H1 and the shift to humid conditions around 14.8 kyr BP in the uplands are consistent with latitudinal shifts of the
intertropical convergence zone (ITCZ) driven by high-latitude Northern
Hemisphere climatic fluctuations. Additionally, our results show that the
lowland vegetation, consisting of well-developed salt marshes and mangroves
in a successional pattern typical for vegetation occurring in intertidal
habitats, has responded mainly to local coastal dynamics related to marine
inundation frequencies and soil salinity in the Rufiji Delta as well as to the
local moisture availability. Lowland vegetation shows a substantial
expansion of mangrove trees after ~ 14.8 kyr BP, suggesting an
increased moisture availability and river runoff in the coastal area. The
results of this study highlight the decoupled climatic and environmental
processes to which the vegetation in the uplands and the Rufiji Delta has
responded during the last deglaciation. |
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