@article{WolffHaugTimmermannetal.2011,
  author    = {Wolff, Christian Michael and Haug, Gerald H. and Timmermann, Axel and Damste, Jaap S. Sinninghe and Brauer, Achim and Sigman, Daniel M. and Cane, Mark A. and Verschuren, Dirk},
  title     = {Reduced interannual rainfall variability in East Africa during the last Ice Age},
  series = {Science},
  volume    = {333},
  journal   = {Science},
  number    = {6043},
  publisher = {American Assoc. for the Advancement of Science},
  address   = {Washington},
  issn      = {0036-8075},
  doi       = {10.1126/science.1203724},
  pages     = {743 -- 747},
  year      = {2011},
  abstract  = {Interannual rainfall variations in equatorial East Africa are tightly linked to the El Nino Southern Oscillation (ENSO), with more rain and flooding during El Nino and droughts in La Nina years, both having severe impacts on human habitation and food security. Here we report evidence from an annually laminated lake sediment record from southeastern Kenya for interannual to centennial-scale changes in ENSO-related rainfall variability during the last three millennia and for reductions in both the mean rate and the variability of rainfall in East Africa during the Last Glacial period. Climate model simulations support forward extrapolation from these lake sediment data that future warming will intensify the interannual variability of East Africa's rainfall.},
  language  = {en}
}
@article{MartinezGarciaRosellMeleJaccardetal.2011,
  author    = {Martinez-Garcia, Alfredo and Rosell-Mele, Antoni and Jaccard, Samuel L. and Geibert, Walter and Sigman, Daniel M. and Haug, Gerald H.},
  title     = {Southern Ocean dust-climate coupling over the past four million years},
  series = {Nature : the international weekly journal of science},
  volume    = {476},
  journal   = {Nature : the international weekly journal of science},
  number    = {7360},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {0028-0836},
  doi       = {10.1038/nature10310},
  pages     = {312 -- U141},
  year      = {2011},
  abstract  = {Dust has the potential to modify global climate by influencing the radiative balance of the atmosphere and by supplying iron and other essential limiting micronutrients to the ocean(1,2). Indeed, dust supply to the Southern Ocean increases during ice ages, and 'iron fertilization' of the subantarctic zone may have contributed up to 40 parts per million by volume (p. p. m. v.) of the decrease (80-100 p. p. m. v.) in atmospheric carbon dioxide observed during late Pleistocene glacial cycles(3-7). So far, however, the magnitude of Southern Ocean dust deposition in earlier times and its role in the development and evolution of Pleistocene glacial cycles have remained unclear. Here we report a high-resolution record of dust and iron supply to the Southern Ocean over the past four million years, derived from the analysis of marine sediments from ODP Site 1090, located in the Atlantic sector of the subantarctic zone. The close correspondence of our dust and iron deposition records with Antarctic ice core reconstructions of dust flux covering the past 800,000 years (refs 8, 9) indicates that both of these archives record large-scale deposition changes that should apply to most of the Southern Ocean, validating previous interpretations of the ice core data. The extension of the record beyond the interval covered by the Antarctic ice cores reveals that, in contrast to the relatively gradual intensification of glacial cycles over the past three million years, Southern Ocean dust and iron flux rose sharply at the Mid-Pleistocene climatic transition around 1.25 million years ago. This finding complements previous observations over late Pleistocene glacial cycles(5,8,9), providing new evidence of a tight connection between high dust input to the Southern Ocean and the emergence of the deep glaciations that characterize the past one million years of Earth history.},
  language  = {en}
}
@article{HainSigmanHaug2011,
  author    = {Hain, Mathis P. and Sigman, Daniel M. and Haug, Gerald H.},
  title     = {Shortcomings of the isolated abyssal reservoir model for deglacial radiocarbon changes in the mid-depth Indo-Pacific Ocean},
  series = {Geophysical research letters},
  volume    = {38},
  journal   = {Geophysical research letters},
  number    = {6},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1029/2010GL046158},
  pages     = {6},
  year      = {2011},
  abstract  = {Severely negative Delta(14)C anomalies from the mid-depth Pacific and the Arabian Sea have been taken as support for the hypothesized deglacial release of a previously isolated, extremely (14)C-deplete deep ocean carbon reservoir. We report box model simulations that cast doubt on both the existence of the hypothesized deep reservoir and its ability to explain the mid-depth Delta(14)C anomalies. First, the degree of ice age isolation needed to substantially reduce the deep Delta(14)C of the deep reservoir causes anoxia and the trapping of alkalinity from CaCO(3) dissolution, the latter increasing atmospheric CO(2). Second, even with a completely (14)C-free deep reservoir, achieving the mid-depth Delta(14)C anomalies of observed duration requires ad hoc stifling of aspects of deep circulation to prevent rapid dissipation of the anomalous (14)C-free carbon to the rest of the ocean and the atmosphere. We suggest that the mid-depth anomalies do not record basin-scale Delta(14)C changes but are instead local phenomena.},
  language  = {en}
}