Large Lakes Observatory
University of Minnesota Duluth
2205 E. 5th St.,
Research Laboratory Building 204
Duluth, MN 55812
Tel. (218) 726-8128
Fax: (218) 726-6979
email: tcj at d.umn.edu
- Paleoclimatology based on the analysis of lake sediment cores, on time scales ranging from decades to millennia, focusing on tropical East Africa.
- Sedimentary processes in large lakes, including lake floor morphology, sediment erosion and redeposition by bottom currents, and pore water geochemistry.
- Acoustic remote sensing of large lake basins, using high-resolution seismic reflection profiling, side scan sonar and multi-beam sonar.
- Water sustainability and climate in the Great Lakes region of East Africa.
Scripps Institution of Oceanography, Ph.D.
University of Washington, B.S.
- The nature of tropical climate change in East Africa based on analysis of sediment cores from the large lakes of the Rift Valley.
- Developing new analytical approaches for improving our interpretation of lake sediment records in terms of past environmental conditions and refining the geochronology in lake sediment cores.
- Sedimentary processes in large lakes: turbidity plumes and the effects of surface and internal waves on sediment dynamics.
- Sustaining water quality and biodiversity in the Great Lakes of East Africa.
(* refers to graduate student or post-doc advisee)
Johnson, T. C., Werne, J. P., Brown, E. T., Abbott, A. N., Berke, M. A., Steinman, B. A., Halbur, J., Contreras Quintana, S., Grossheusch, S., Deino, A., Lyons, R. P., Scholz, C. A., Schouten, S., and Sinninghe Damsté, J. S., 2016, A progressively wetter climate in southern East Africa over the past 1.3 million years: Nature, v. 537, p. 220-224.
Lyons, R. P., Scholz, C. A., Cohen, A. S., King, J. W., Brown, E. T., Ivory, S. J., Johnson, T. C., Deino, A. L., Reinthal, P. N., McGlue, M. M. and Blome, M. W., 2015. A Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity. Proceedings of the National Academy of Sciences, v. 112, p. 15568 – 15573.
O'Beirne, M. D., Strzok, L. J., Werne, J. P., Johnson, T. C., and Hecky, R. E., 2015. Anthropogenic influences on the sedimentary geochemical record in western Lake Superior (1800 - present). Journal of Great Lakes Research, v. 41, p. 20-29.
Johnson, T. C. and Lane, C. S., 2014. Comment on "The Latest on Volcanic Eruptions and Climate", EOS, Transactions of the American Geophysical Union, Vol. 95, No. 39.
Berke*, M. A., Johnson, T. C., Werne, J. P., Livingstone, D. A., Grice, C., Shouten, S., Sinninghe Damste, J. S., 2014. Characterization of the last deglacial transition in tropical East Africa: Insights from Lake Albert. Palaeo-3, v. 409, p. 1-8.
Slate, J. E., Johnson, T. C., Moore, T. C., 2013. Potential impact of pre-Columbian agriculture, climate change, and tectonic activity inferred from a 5700-year paleolimnological record from Lake Nicaragua. Journal of Paleolimnology, v. 50, p. 139-149.
Lane, C. S., Chorn*, B. T. and Johnson, T. C., 2013. Ash from the Toba super eruption in Lake Malawi shows no volcanic winter at 75 ka, Proc. National Academy of Sciences, in press.
Berke, M. A., Johnson, T. C., Werne, J. P., Grice, K., Schouten, S., and Sinninghe Damste, J. S., 2012, Molecular records of climate variability and vegetation response since the Late Pleistocene in the Lake Victoria basin, East Africa, Quaternary Science Reviews, v. 55, p. 59-74.
Castañeda*, I., Werne, J.P., Johnson, T. C., and Oberem*, L., 2011. Organic Geochemical Records from Lake Malawi (East Africa) of the last 700 years, part II: Biomarker Evidence for Recent Changes in Primary Productivity. Palaeogeography, Palaeoclimatology, Palaeoecology. v. 303, pp. 140-154.
Johnson, T. C. and Scholz, C. A., 2010. Coping with Lake Kivu, East Africa, EOS, Transactions of the American Geophyscial Union, v. 91, pp 264.
*Breckenridge, A. and Johnson, T. C., 2009. Paleohydrology of the upper Laurentian Great Lakes from the late glacial to early Holocene. Quaternary Research, v. 71, pp 397 - 408.
Johnson, T. C. and Malala, J. O., 2009. Lake Turkana and its link to the Nile. In: Dumont, H. (ed.), The Nile, Origin, Environments, Limnology and Human Use. Springer Science, Berlin, pp 287 - 304.