Dr. Daniel R. Engstrom, Director

Adjunct Professor, Geology & Geophysics, and Water Resource Science University of Minnesota

Ph.D., University of Minnesota (Ecology), 1983
M.S., University of Minnesota (Zoology), 1975
B.A., University of Minnesota (Zoology), 1971

Phone: 651-433-5953 ext. 11
email: or

Research Interests

My research centers on the use of lake sediment records to understand long-term environmental change, particularly the effects of human activities on water quality, atmospheric chemistry, and biogeochemical processes on a global scale. I'm particularly interested in approaches that quantify the magnitude and rates of change and establish mechanistic linkages to modern-day systems.

• Atmospheric mercury deposition and cycling
  Mercury (Hg) is a highly toxic pollutant that is carried atmospherically to remote lakes and landscapes where it is biologically concentrated through the food chain to levels in game fish that are potentially harmful to humans and fish-eating wildlife. Concentrations in aquatic systems have increased greatly over the last two centuries due to human-related emissions from industrial uses and fossil fuel combustion. My research on mercury has focused on the use of lake sediments to quantify the magnitude of the problem both throughout Minnesota and in the far corners of the Globe (Arctic Alaska, New England, Antarctica, Florida). Current research projects include studies of mercury cycling in Arctic lakes (NSF funding), quantification of mercury sources across North America (USEPA funding), and experimental manipulation of precipitation chemistry to stimulate mercury methylation in boreal wetlands (USEPA and Great Lakes Commission funding).
• Nutrient inputs and sedimentation in large rivers
  Many of the world's great rivers have been highly impacted by excess nutrients, suspended sediments, and toxic pollutants from human activities in their watersheds. Understanding the magnitude of these changes, their timing, and likely causes is critical to developing sound management strategies for their remediation. Our team has developed methods for quantifying the historical flux of these contaminants in the St. Croix and upper Mississippi basins from multiple sediment cores taken from their natural impoundments at Lake St. Croix and Lake Pepin. Through radiometric dating (210Pb, 137Cs, 14C), sediment geochemistry, and fossil diatoms, we have quantified order of magnitude changes in phosphorus loading, sedimentation, and heavy metal accumulation since the onset of regional European settlement. (Funding by the MN Pollution Control Agency and the Metropolitan Council Environmental Services)
• Sediment sources in agricultural watersheds
  Agricultural land use is a major cause of high turbidity and sedimentation in the upper Mississippi River and its tributaries. Determining the relative importance of field erosion versus stream channel erosion as contributors to this problem is a major research initiative here at the Station and one that is at the center of current efforts to reduce sediment loads to these rivers. We are working on new techniques for sediment fingerprinting using atmospherically deposited radionuclides as tracers for sediment source. The approach involves using lakes, surrounding by agricultural fields with no river/stream inputs, as reference systems to record the integrated fingerprint of field erosion only. This fingerprint is then compared with the sediments in depositional sites (reservoirs, backwaters) on the various tributaries and ultimately with the sediments in Lake Pepin, which acts as the final integrator of streambank and field erosion for more than half of Minnesota. (Funding by the MN Pollution Control Agency and USEPA).
• Natural evolution of lakes and landscapes
  This research explores the biogeochemical evolution of lakes resulting from the biotic colonization of a recently deglaciated landscape at Glacier Bay, Alaska. Glacier Bay has served as a natural laboratory for classic studies of primary terrestrial succession for almost a century, but parallel work on lake systems has never before been accomplished, either here or elsewhere in the world. Catastrophic ice recession at Glacier Bay has created a chronosequence of lakes of different ages, which we use to investigate directly the environmental forces controlling the direction and rates of limnological change. Our findings challenge the long-standing ecological paradigm that lakes become nutrient enriched as they age and its familiar corollary that cultural eutrophication is simply an acceleration of the aging process. (Funding by the NSF.)

Representative Publications

Engstrom, D.R., Schottler, S.P., Leavitt, P.R., and Havens, K.E. 2006. A re-evaluation of the cultural eutrophication of Lake Okeechobee, Florida, using multiproxy sediment records. Ecological Applications 16: 1194-1206.

Engstrom, D.R. and Fritz, S.C. 2006. Coupling between primary terrestrial succession and the trophic development of lakes at Glacier Bay, Alaska. Journal of Paleolimnology 35: 873-880.

Wiener, J.G., B.C. Knights, M.B. Sandheinrich, J.D. Jeremiason, M.E Brigham, D.R. Engstrom, L.G. Woodruff, W.F. Cannon, and S.J. Balogh. 2006. Mercury in soils, lakes, an fish in Voyageurs National Park (Minnesota): importance of atmospheric deposition and ecosystem factors. Environmental Science and Technology 20: 6261-6268.

Jeremiason, J.D., D.R. Engstrom, E.B. Swain, E.A. Nater, B.M. Johnson, J.E. Almendinger, B.A. Monson, and R.K. Kolka. 2006. Sulfate addition increases methylmercury production in an experimental wetland. Environmental Science and Technology 40: 3800-3806.

Fitzgerald, W.F., D.R. Engstrom, C H. Lamborg, C.-M. Tseng, P. Balcom, and C.R. Hammerschmidt. 2005. Modern and historic atmospheric mercury fluxes in northern Alaska: global Sources and Arctic depletion. Environmental Science and Technology 39: 557-568.

Engstrom, D.R. 2005. Long-term changes in iron and phosphorus sedimentation in Vadnais Lake, Minnesota, resulting from ferric chloride addition and hypolimnetic aeration. Lake and Reservoir Management 21:96-106.

Shapley, M.D., W.C. Johnson, D.R. Engstrom, and W.R. Osterkamp. 2005. Late Holocene flooding and drought in the Northern Great Plains, reconstructed from tree rings, lake sediments and ancient shorelines. The Holocene 15: 29-41.

Tseng, C.M., C.H. Lamborg, W.F. Fitzgerald, and D.R. Engstrom. 2004. Cycling of dissolved elemental mercury in Arctic Alaskan lakes. Geochimica Cosmochimica Acta 68: 1173-1184.

Fritz, S.C., D.R. Engstrom, and S, Juggins. 2004. Testing the inference of temporal trends from a modern chronosequence: multiple pathways of early lake ontogeny at Glacier Bay, Alaska. The Holocene 14: 828-840.

Ramstack, J.M., S.C. Fritz, and D.R. Engstrom. 2004. Twentieth-century water-quality trends in Minnesota lakes compared with pre-settlement variability. Canadian Journal of Fisheries and Aquatic Sciences 61: 561-576.

Holmes, J.A. and DR Engstrom. 2003. Non-marine ostracod records of Holocene environmental change. In Global Change in the Holocene (A. MacKay, R.W. Battarbee, H.J.B.Birks and F. Oldfield, eds.). Arnold, London. pp. 310-327.

Engstrom, DR and D.I. Wright. 2002. Sedimentological effects of aeration-induced lake circulation. Lake and Reservoir Management 18: 201-214.

Kamman, N. C. and D. R. Engstrom. 2002. Historical and present fluxes of mercury to Vermont and New Hampshire lakes inferred from 210Pb dated sediment cores. Atmospheric Environment 36: 1599-1609.

Engstrom, DR, SC Fritz, J.E. Almendinger, and S. Juggins. 2000. Chemical and biological trends during lake evolution in recently deglaciated terrain. Nature 408: 161-166.

Balogh, S.J., DR Engstrom, J.E. Almendinger, J.L. Meyer, and D.K. Johnson. 1999. A history of mercury loading in the upper Mississippi River reconstructed from the sediments of Lake Pepin. Environmental Science and Technology 33: 3297-3302.

Fitzgerald, W.F., D.R. Engstrom, R.P. Mason, and E.A. Nater. 1998. The case for atmospheric mercury contamination in remote areas. Environmental Science and Technology 32: 1-7.