Studies of Regional and Global

Environmental Change

 

  
 
 
 

The history and implications of changing dust deposition in the western US

 

Dust is an important part of the climate and biogeochemical systems of our planet. Dust can be made up of many different consitutents including minerals, organic contaminants and biological material. Dust deposition varies through time in conjunction with the glacial cycles but relatively little is known about how much human activity has altered contemporary dust fluxes. This latter question is a major research focus in our lab.

 

 

Research Results

We have recently been carrying out work in the San Juan Mountains of Colorado to reconconstruct dust deposition records using lake sediments. We also are carrying out periodic sampling of dust events from snowpack and have high volume active dust collectors installed in Southern Colorado and in Canyonlands National Park. These efforts are also complimented by studies of the fate and impact of dust in high elevation ecosystems (see Corey Lawrence's Page) and collaborative efforts with the USGS to develop a dust emission monitoring systems throughout southern Utah.

 

Dust Studies

J.C. Neff, A.P. Ballantyne, G.L. Famer, N.M. Mahowald, J.L. Conroy, C.C. Landry, J.T. Overpeck, T.H. Painter, C.R. Lawrence, and R.L. Reynolds.(2008). Recent increase in eolian dust deposition related to human activity in the Western United States. Nature - Geosciences. This study uses lake sediment records from the San Juan Mountains of Colorado to document the h istory of dust deposition to this region. The results of these cores suggest that dust fall increased 4-7X following the settlement of the western US in the mid-1800s. These rates have declined somewhat to the present but remain greatly elevated relative to the historical background flux. The sediment studies also suggest changes in the chemistry of dust deposition that may reflect the use of agricultural fetilizers and air polution. Please email for pdf

T. H. Painter, A. P. Barrett, C. C. Landry, J. C. Neff, M. P. Cassidy, C. R. Lawrence, K. P. Thatcher, L. Farmer. (2007) Impact of disturbed desert soils on duration of mountain snowcover. Geophysical Research Letters. V34, 12, L12502, 10.1029/2007GL030208. This study documents the source and impact of dust deposited to snowpack in the San Juan Mountains of Colorado. The key result from this paper is an analysis of the impacts of dust loading on snowpack melt with evidence that the presence of dust can accelerate this process by up to one month; a finding that has important implications for the management water supplies in the western US. PDF.

Goldstein, H.L., Reynolds, R.L., Reheis, M.C., Yount, J.C., and Neff, J.C. (2008). Compositional trends in eolian dustalong a transect across the southwestern United States. Journal of Geophysical Research, Earth Surface.doi:10.1029/2007JF000751. This study examines the chemical and isotopic properties of 'potholes' (small depressions in bedrock exposed to atmospheric deposition) along a gradient of sites from the Mojave to Colorado Plateau. PDF.

Reynolds, R.L., M.C. Reheis, J.C. Neff, H. Goldstein, and J. Yount.  (2006). Late Quaternary eolian dust in surficial deposits of a Colorado Plateau Grassland:  Controls on distribution and ecologic effects.  Catena v66(3), 251-266. This study is one of a set of studies carried out in locations in and around Canyonlands National Park, UT. This particular study documents the presence of dust in OSL dated layers of soil and highlights periods of historical dust accumulation in this region. PDF.

Reynolds R., J.C. Neff, M. Reheis, and P. Lamothe. Atmospheric dust in modern soil on aeolian sandstone, Colorado Plateau (USA): Variation with landscape position and contribution to potential plant nutrients. Geoderma 130:108-123. This study provides an estimate of the dust fraction of surface soils in a study sity in Canyonlands National Park, UT. Using magnetic minerals as a tracer for dust, the study shows that surface soils are dominatly eolian in origin and also uses mixing models to show that most of the plant-essential elements in these surface soils are also derived from dust. PDF.