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  • PANGAEA  (443)
  • American Geophysical Union  (2)
  • Elsevier BV  (1)
  • Nature Publishing Group  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Climatic controls on central African hydrology during the past 20,000 years (2005)
    [s.l.] : Nature Publishing Group
    Nature 437 (2005), S. 1003-1006 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Past hydrological changes in Africa have been linked to various climatic processes, depending on region and timescale. Long-term precipitation changes in the regions of northern and southern Africa influenced by the monsoons are thought to have been governed by precessional variations in summer ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature03945
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    Paper (German National Licenses)
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  • 2
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    Forcing of tropical Atlantic sea surface temperatures during the mid-Pleistocene transition (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 19 (2004): PA4029, doi:10.1029/2003PA000892.
    Description: We compare a new mid-Pleistocene sea surface temperature (SST) record from the eastern tropical Atlantic to changes in continental ice volume, orbital insolation, Atlantic deepwater ventilation, and Southern Ocean front positions to resolve forcing mechanisms of tropical Atlantic SST during the mid-Pleistocene transition (MPT). At the onset of the MPT, a strong tropical cooling occurred. The change from a obliquity- to a eccentricity-dominated cyclicity in the tropical SST took place at about 650 kyr BP. In orbital cycles, tropical SST changes significantly preceded continental ice-volume changes but were in phase with movements of Southern Ocean fronts. After the onset of large-amplitude 100-kyr variations, additional late glacial warming in the eastern tropical Atlantic was caused by enhanced return flow of warm waters from the western Atlantic driven by strong trade winds. Pronounced 80-kyr variations in tropical SST occurred during the MPT, in phase with and likely directly forced by transitional continental ice-volume variations. During the MPT, a prominent anomalous long-term tropical warming occurred, likely generated by extremely northward displaced Southern Ocean fronts. While the overall pattern of global climate variability during the MPT was determined by changes in mean state and frequency of continental ice volume variations, tropical Atlantic SST variations were primarily driven by early changes in Subantarctic sea-ice extent and coupled Southern Ocean frontal positions.
    Description: The Dutch scientific funding organization (NWO) is thanked for financial support (project 75019617).
    Keywords: Sea surface temperatures ; Mid-Pleistocene transition ; Tropical Atlantic
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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    PAPER (OA)
  • 3
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    Correction to “Forcing of tropical Atlantic sea surface temperatures during the mid-Pleistocene transition” (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 20 (2005): PA1019, doi:10.1029/2005PA001134.
    Keywords: Sea-surface temperatures ; Mid-Pleistocene transition ; Tropical Atlantic
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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    PAPER (OA)
  • 4
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    Wetland expansion on the continental shelf of the northern South China Sea during deglacial sea level rise (2020)
    Elsevier BV
    In:  EPIC3Quaternary Science Reviews, Elsevier BV, 231, pp. 106202-106202, ISSN: 0277-3791
    Details
    Publication Date: 2023-05-31
    Description: To identify environmental causes for past changes in vegetation in subtropical East Asia, we present carbon isotope compositions of plant-wax n-alkanes and provide estimates of the C4-plant contribution across the past four glacial terminations and interglacials, based on cores recovered from the northern South China Sea. Our results show a comparable C4-plant contribution between the Last Glacial Maximum (LGM) and the Holocene. An increase of the C4-plant contribution by 15–20% is found for Terminations IV, II and I relative to subsequent interglacial peaks, coeval with an expansion of Cyperaceae and Poaceae. In contrast, Termination V reveals a lower C4-plant contribution than Marine Isotope Stage (MIS) 11c. The data exhibit a long-term trend, with a stepwise increase of the C4-plant contribution across interglacials MIS 11c, 9e, 7e and 1. We suggest that no substantial changes in humidity levels over glacial-interglacial cycles occurred facilitating a similar C3/C4-plant ratio for the LGM and the Holocene. Instead, deglacial sea-level rises caused an extensive development of floodplains and wetlands on the exposed continental shelf, providing habitats for the spread of C4 sedges and grasses. The progressive subsidence of Chinese coastal areas and the broadening of the continental shelf over the late Quaternary explains the nearly absence of C4 plant occurrence during Termination V and a gradual increase of the C4-plant contribution across interglacial peaks. Taken together, changes in coastal environments should be considered when interpreting marine-based vegetation reconstructions from subtropical Asia.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
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    PAPER (OA)
  • 5
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    (Supplementary Table B) Data for locations employed as representatives of potential catchment areas (2012)
    PANGAEA
    Details
    Publication Date: 2023-03-03
    Keywords: Aridity index; Calculated; Center for Marine Environmental Sciences; Distance; Evapotranspiration, potential; LATITUDE; LONGITUDE; MARUM; Precipitation, annual mean; Temperature, annual mean
    Type: Dataset
    Format: text/tab-separated-values, 390 data points
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    DATA PANGAEA
  • 6
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    (Supplementary Table A ) Locations employed for calculation of continental environmental conditions with WebWIMP Modelling program and values obtained as displayed in Fig. 1 (2012)
    PANGAEA
    Details
    Publication Date: 2023-03-03
    Keywords: Aridity index; Center for Marine Environmental Sciences; Evapotranspiration, potential; LATITUDE; LONGITUDE; MARUM; Precipitation, annual mean; Temperature, annual mean
    Type: Dataset
    Format: text/tab-separated-values, 304 data points
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    DATA PANGAEA
  • 7
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    Hydrogen isotopic composition of sediment cores from a transect off western Africa (2013)
    PANGAEA
    In:  Supplement to: Collins, James A; Schefuß, Enno; Mulitza, Stefan; Prange, Matthias; Werner, Martin; Tharammal, Thejna; Paul, André; Wefer, Gerold (2013): Estimating the hydrogen isotopic composition of past precipitation using leaf-waxes from western Africa. Quaternary Science Reviews, 65, 88-101, https://doi.org/10.1016/j.quascirev.2013.01.007
    Details
    Publication Date: 2023-03-03
    Description: The hydrogen isotopic composition of plant leaf-wax n-alkanes (dDwax) is a novel proxy for estimating dD of past precipitation (dDp). However, vegetation life-form and relative humidity exert secondary effects on dDwax, preventing quantitative estimates of past dDp. Here, we present an approach for removing the effect of vegetation-type and relative humidity from dDwax and thus for directly estimating past dDp. We test this approach on modern day (late Holocene; 0-3 ka) sediments from a transect of 9 marine cores spanning 21°N-23°S off the western coast of Africa. We estimate vegetation type (C3 tree versus C4 grass) using d13C of leaf-wax n-alkanes and correct dDwax for vegetation-type with previously-derived apparent fractionation factors for each vegetation type. Late Holocene vegetation-corrected dDwax (dDvc) displays a good fit with modern-day dDp, suggesting that the effects of vegetation type and relative humidity have both been removed and thus that dDvc is a good estimate of dDp. We find that the magnitude of the effect of C3 tree - C4 grass changes on dDwax is small compared to dDp changes. We go on to estimate dDvc for the mid-Holocene (6-8 ka), the Last Glacial Maximum (LGM; 19-23 ka) and Heinrich Stadial 1 (HS1; 16-18.5 ka). In terms of past hydrological changes, our leaf-wax based estimates of dDp mostly reflect changes in wet season intensity, which is complementary to estimates of wet season length based on leaf-wax d13C.
    Keywords: Center for Marine Environmental Sciences; MARUM
    Type: Dataset
    Format: application/zip, 2 datasets
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    DATA PANGAEA
  • 8
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    Distribution and stable isotopic compositions of hydrogen and carbon of plant-wax derived n-C29 and -C31 alkanes in terrestrial, coastal and offshore surface sediments (2013)
    PANGAEA
    In:  Supplement to: Leider, Arne; Hinrichs, Kai-Uwe; Schefuß, Enno; Versteegh, Gerard J M (2013): Distribution and stable isotopes of plant wax derived n-alkanes in lacustrine, fluvial and marine surface sediments along an Eastern Italian transect and their potential to reconstruct the hydrological cycle. Geochimica et Cosmochimica Acta, 117, 16-32, https://doi.org/10.1016/j.gca.2013.04.018
    Details
    Publication Date: 2023-03-03
    Description: Reconstructing terrestrial water budgets is of prime importance for understanding past climate and environment. To shed more light on how plant-wax derived n-alkanes may be used for this purpose we investigated the distribution and stable isotopic compositions of hydrogen (dD) and carbon (d13C) of plant-wax derived n-C29 and -C31 alkanes in terrestrial, coastal and offshore surface sediments in relation to hydrology along a NW-SE transect east of the Italian Apennines from the Po River to the Eastern Gulf of Taranto. The plant wax average chain length increases southward and may relate to increasing temperature and/or aridity. The plant wax dD of the terrestrial and coastal samples also increases southward and mainly reflects changes in the dD of precipitation. The d13C of plant waxes is primarily interpreted in terms of C3 vegetation changes rather than varying contributions by C4 plants. The plant wax d13C-dD composition of the Po River and Apennine rivers differs considerably from that in southern Italy, and suggests a mainly southern source for plant waxes in marine sediments of the Gulf of Taranto. This calibration provides a basis for the reconstruction of past changes in the Italian water balance and n-alkane source areas.
    Keywords: Center for Marine Environmental Sciences; MARUM
    Type: Dataset
    Format: application/zip, 3 datasets
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    DATA PANGAEA
  • 9
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    Compound specific stable isotopes, BIT, pollen and spores of Miocene to Pliocene sediments of ODP Hole 175-1085A (2013)
    PANGAEA
    In:  Supplement to: Dupont, Lydie M; Rommerskirchen, Florian; Mollenhauer, Gesine; Schefuß, Enno (2013): Miocene to Pliocene changes in South African hydrology and vegetation in relation to the expansion of C4 plants. Earth and Planetary Science Letters, 375, 408-417, https://doi.org/10.1016/j.epsl.2013.06.005
    Details
    Publication Date: 2023-03-03
    Description: Pollen and stable carbon (d13C) and hydrogen (dD) isotope ratios of terrestrial plant wax from the South Atlantic sediment core, ODP Site 1085, is used to reconstruct Miocene to Pliocene changes of vegetation and rainfall regime of western southern Africa. Our results reveal changes in the relative amount of precipitation and indicate a shift of the main moisture source from the Atlantic to the Indian Ocean during the onset of a major aridification 8 Ma ago. We emphasise the importance of declining precipitation during the expansion of C4 and CAM (mainly succulent) vegetation in South Africa. We suggest that the C4 plant expansion resulted from an increased equator-pole temperature gradient caused by the initiation of strong Atlantic Meridional Overturning Circulation following the shoaling of the Central American Seaway during the Late Miocene.
    Keywords: Center for Marine Environmental Sciences; MARUM
    Type: Dataset
    Format: application/zip, 3 datasets
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    DATA PANGAEA
  • 10
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    Sedimentary climate indicators of sediment core MD08-3167 and GeoB1711-4, southwestern Africa (2014)
    PANGAEA
    In:  Supplement to: Collins, James A; Schefuß, Enno; Govin, Aline; Mulitza, Stefan; Tiedemann, Ralf (2014): Insolation and glacial–interglacial control on southwestern African hydroclimate over the past 140 000 years. Earth and Planetary Science Letters, 398, 1-10, https://doi.org/10.1016/j.epsl.2014.04.034
    Details
    Publication Date: 2023-03-03
    Description: The past climate evolution of southwestern Africa is poorly understood and interpretations of past hydrological changes are sometimes contradictory. Here we present a record of leaf-wax dD and View the MathML source taken from a marine sediment core at 23°S off the coast of Namibia to reconstruct the hydrology and C3 versus C4 vegetation of southwestern Africa over the last 140 000 years (140 ka). We find lower leaf-wax dD and higher View the MathML source (more C4 grasses), which we interpret to indicate wetter Southern Hemisphere (SH) summer conditions and increased seasonality, during SH insolation maxima relative to minima and during the last glacial period relative to the Holocene and the last interglacial period. Nonetheless, the dominance of C4 grasses throughout the record indicates that the wet season remained brief and that this region has remained semi-arid. Our data suggest that past precipitation increases were derived from the tropics rather than from the winter westerlies. Comparison with a record from the Congo Basin indicates that hydroclimate in southwestern Africa has evolved in antiphase with that of central Africa over the last 140 ka.
    Keywords: Center for Marine Environmental Sciences; MARUM
    Type: Dataset
    Format: application/zip, 9 datasets
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    DATA PANGAEA
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