@article{BergnerTrauth2004,
  author    = {Bergner, Andreas G. N. and Trauth, Martin H.},
  title     = {Comparison of the hydrologic and hydrochemical evolution of Lake Naivasha (Kenya) during three highstands between 175 and 60 kyr BP},
  year      = {2004},
  abstract  = {Three diatomite beds exposed in the Ol Njorowa Gorge south of Lake Naivasha, Central Kenya Rift, document three major lake-level highstands between 175 and 60 kyr BP. Diatom transfer-function estimates of hydrological and hydrochemical parameters suggest that a deep and large freshwater lake existed during the highstands at 135 and 80 kyr BP. In contrast, a shallower but more expanded freshwater lake existed at 110 kyr BP. The best analog for the most extreme highstand at 135 kyr BP is the highstand during the Early Holocene humid period from 10 to 6 kyr BP. The environmental conditions as reconstructed from diatom assemblages suggest long-lasting episodes of increased humidity during the high lake periods. This contrasts to the modern situation with a relatively shallow Lake Naivasha characterized by rapid water level fluctuations within a few decades. The most likely cause for the variable hydrological conditions since 175 kyr BP is orbitally driven insolation changes on the equator and increased lateral moisture transport from the ocean.},
  language  = {en}
}
@article{DuehnforthBergnerTrauth2008,
  author    = {D{\"u}hnforth, Miriam and Bergner, Andreas G. N. and Trauth, Martin H.},
  title     = {Early Holocene water budget of the Nakuru-Elmenteita basin, Central Kenya Rift},
  issn      = {0921-2728},
  doi       = {10.1007/s10933-006-9003-z},
  year      = {2008},
  language  = {en}
}
@article{TrauthBergnerFoersteretal.2015,
  author    = {Trauth, Martin H. and Bergner, Andreas G. N. and Foerster, Verena and Junginger, Annett and Maslin, Mark A. and Sch{\"a}bitz, Frank},
  title     = {Episodes of environmental stability versus instability in Late Cenozoic lake records of Eastern Africa},
  series = {Journal of human evolution},
  volume    = {87},
  journal   = {Journal of human evolution},
  publisher = {Elsevier},
  address   = {London},
  issn      = {0047-2484},
  doi       = {10.1016/j.jhevol.2015.03.011},
  pages     = {21 -- 31},
  year      = {2015},
  abstract  = {Episodes of environmental stability and instability may be equally important for African hominin speciation, dispersal, and cultural innovation. Three examples of a change from stable to unstable environmental conditions are presented on three different time scales: (1) the Mid Holocene (MH) wet dry transition in the Chew Bahir basin (Southern Ethiopian Rift; between 11 ka and 4 ka), (2) the MIS 5-4 transition in the Naivasha basin (Central Kenya Rift; between 160 ka and 50 ka), and (3) the Early Mid Pleistocene Transition (EMPT) in the Olorgesailie basin (Southern Kenya Rift; between 1.25 Ma and 0.4 Ma). A probabilistic age modeling technique is used to determine the timing of these transitions, taking into account possible abrupt changes in the sedimentation rate including episodes of no deposition (hiatuses). Interestingly, the stable-unstable conditions identified in the three records are always associated with an orbitally-induced decrease of insolation: the descending portion of the 800 kyr cycle during the EMPT, declining eccentricity after the 115 ka maximum at the MIS 5-4 transition, and after similar to 10 ka. This observation contributes to an evidence-based discussion of the possible mechanisms causing the switching between environmental stability and instability in Eastern Africa at three different orbital time scales (10,000 to 1,000,000 years) during the Cenozoic. This in turn may lead to great insights into the environmental changes occurring at the same time as hominin speciation, brain expansion, dispersal out of Africa, and cultural innovations and may provide key evidence to build new hypotheses regarding the causes of early human evolution. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{PhilipsWalzBergneretal.2015,
  author    = {Philips, Andrea and Walz, Ariane and Bergner, Andreas G. N. and Gr{\"a}ff, Thomas and Heistermann, Maik and Kienzler, Sarah and Korup, Oliver and Lipp, Torsten and Schwanghart, Wolfgang and Zeilinger, Gerold},
  title     = {Immersive 3D geovisualization in higher education},
  series = {Journal of geography in higher education},
  volume    = {39},
  journal   = {Journal of geography in higher education},
  number    = {3},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0309-8265},
  doi       = {10.1080/03098265.2015.1066314},
  pages     = {437 -- 449},
  year      = {2015},
  abstract  = {In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students reveal benefits, such as better orientation in the study area, higher interactivity with the data, improved discourse among students and enhanced motivation through immersive 3D geovisualization. This suggests that immersive 3D visualization can effectively be used in higher education and that 3D CAVE settings enhance interactive learning between students.},
  language  = {en}
}
@article{BergnerTrauthBookhagen2003,
  author    = {Bergner, Andreas G. N. and Trauth, Martin H. and Bookhagen, Bodo},
  title     = {Magnitude of precipitation : evaporation changes in the Naivasha Basin (Kenya) during the last 150 kyrs},
  year      = {2003},
  abstract  = {We modeled the two most extreme highstands of Lake Naivasha during the last 175 k.y. to estimate potential precipitation/ evaporation changes in this basin. In a first step, the bathymetry of the paleolakes at f135 and 9 k.y. BP was reconstructed from sediment cores and surface outcrops. Second, we modeled the paleohydrologic budget during the highstands using a simplified coupled energy mass-balance model. Our results show that the hydrologic and hence the climate conditions at f135 and 9 k.y. BP were similar, but significantly different from today. The main difference is a f15\% higher value in precipitation compared to the present. An adaptation and migration of vegetation in the cause of climate changes would result in a f30\% increase in precipitation. The most likely cause for such a wetter climate at f135 and 9 k.y. BP is a more intense intertropical convergence and increased precipitation in East Africa.},
  language  = {en}
}
@article{BergnerStreckerTrauthetal.2009,
  author    = {Bergner, Andreas G. N. and Strecker, Manfred and Trauth, Martin H. and Deino, Alan L. and Gasse, Francoise and Blisniuk, Peter Michael and Duehnforth, Miriam},
  title     = {Tectonic and climatic control on evolution of rift lakes in the Central Kenya Rift, East Africa},
  issn      = {0277-3791},
  doi       = {10.1016/j.quascirev.2009.07.008},
  year      = {2009},
  abstract  = {The long-term histories of the neighboring Nakuru-Elmenteita and Naivasha lake basins in the Central Kenya Rift illustrate the relative importance of tectonic versus climatic effects on rift-lake evolution and the formation of disparate sedimentary environments. Although modem climate conditions in the Central Kenya Rift are very similar for these basins, hydrology and hydrochemistry of present-day lakes Nakuru, Elmenteita and Naivasha contrast dramatically due to tectonically controlled differences in basin geometries, catchment size, and fluvial processes. In this study, we use eighteen C-14 and Ar-40/Ar-39 dated fluvio-lacustrine sedimentary sections to unravel the spatiotemporal evolution of the lake basins in response to tectonic and climatic influences. We reconstruct paleoclimatic and ecological trends recorded in these basins based on fossil diatom assemblages and geologic field mapping. Our study shows a tendency towards increasing alkalinity and shrinkage of water bodies in both lake basins during the last million years. Ongoing volcano-tectonic segmentation of the lake basins, as well as reorganization of upstream drainage networks have led to contrasting hydrologic regimes with adjacent alkaline and freshwater conditions. During extreme wet periods in the past, such as during the early Holocene climate optimum, lake levels were high and all basins evolved toward freshwater systems. During drier periods some of these lakes revert back to alkaline conditions, while others maintain freshwater characteristics. Our results have important implications for the use and interpretation of lake sediment as climate archives in tectonically active regions and emphasize the need to deconvolve lacustrine records with respect to tectonics versus climatic forcing mechanisms.},
  language  = {en}
}
@article{TrauthMaslinDeinoetal.2008,
  author    = {Trauth, Martin H. and Maslin, Mark A. and Deino, Alan L. and Strecker, Manfred and Bergner, Andreas G. N. and D{\"u}hnforth, Miriam},
  title     = {High- and low-latitude forcing of Plio-Pleistocene African climate and human evolution},
  doi       = {10.1016/j.jhevol.2006.12.009},
  year      = {2008},
  abstract  = {The late Cenozoic climate of East Africa is punctuated by episodes of short, alternating periods of extreme wetness and aridity, superimposed on a regime of subdued moisture availability exhibiting a long-term drying trend. These periods of extreme climate variability appear to correlate with maxima in the 400-thousand-year (kyr) component of the Earth's eccentricity cycle. Prior to 2.7 Ma the wet phases appear every 400 kyrs, whereas after 2.7 Ma, the wet phases appear every 800 kyrs, with periods of precessional-forced extreme climate variability at 2.7-2.5 Ma, 1.9-1.7 Ma, and 1.1-0.9 Ma before present. The last three major lake phases occur at the times of major global climatic transitions, such as the onset of Northern Hemisphere Glaciation (2.7-2.5 Ma), intensification of the Walker Circulation (1.9-1.7 Ma), and the Mid-Pleistocene Revolution (1.0-0.7 Ma). High-latitude forcing is required to compress the Intertropical Convergence Zone so that East Africa becomes locally sensitive to precessional forcing, resulting in rapid shifts from wet to dry conditions. These periods of extreme climate variability may have provided a catalyst for evolutionary change and driven key speciation and dispersal events amongst mammals and hominins in East Africa. (C) 2007 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{TrauthDeinoBergneretal.2003,
  author    = {Trauth, Martin H. and Deino, Alan and Bergner, Andreas G. N. and Strecker, Manfred},
  title     = {East African climate change and orbital forcing during the last 175 kyr BP},
  year      = {2003},
  abstract  = {Variations in the temporal and spatial distribution of solar radiation caused by orbital changes provide a partial explanation for the observed long-term fluctuations in African lake levels. The understanding of such relationships is essential for designing climate-prediction models for the tropics. Our assessment of the nature and timing of East African climate change is based on lake-level fluctuations of Lake Naivasha in the Central Kenya Rift (0°55'S 36°20'E), inferred from sediment characteristics, diatoms, authigenic mineral assemblages and 17 single-crystal 40Ar/39Ar age determinations. Assuming that these fluctuations reflect climate changes, the Lake Naivasha record demonstrates that periods of increased humidity in East Africa mainly followed maximum equatorial solar radiation in March or September. Interestingly, the most dramatic change in the Naivasha Basin occurred as early as 146 kyr BP and the highest lake level was recorded at about 139 to 133 kyr BP. This is consistent with other well-dated low-latitude climate records, but does not correspond to peaks in Northern Hemisphere summer insolation as the trigger for the ice- age cycles. The Naivasha record therefore provides evidence for low-latitude forcing of the ice-age climate cycles.},
  language  = {en}
}